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Hypothermia during anaesthesia is a significant concern in veterinary practice, as it can lead to various complications, making it essential to understand the factors that contribute to temperature regulation in animals undergoing surgical procedures. This retrospective study aimed to evaluate the change in body temperature over the course of anaesthesia in dogs undergoing elective ovariohysterectomy and orchiectomy, and determine the effect of gender, dose of premedication, weight, age and duration of anaesthesia of the change of body temperature over time. One-hundred and ten dogs (n=110) that underwent elective ovariohysterectomy (n=75) and orchiectomy (n=35) surgery performed by veterinary students at the University of Adelaide were enrolled in this study. Dogs' anaesthesia records were evaluated for change in body temperature over the course of anaesthesia, and correlated with gender, two premedication doses of acepromazine (mg/kg), body weight (kg), age (months) and anaesthesia times (minutes). The analyses were performed at TPm (temperature at premedication), T0 (induction), T15, T30, T60, T90, T120 and TRec (recovery) minutes. Statistical analysis was performed using the GenStat software and included repeated measures analysis and ANOVA. Significance was considered when p < 0.05. The data showed a significant time-by-gender interaction with female dogs experienced a greater degree of heat loss than male dogs at T60 (p<0.01), T90 (p<0.01) and T120 (p<0.01). At recovery, female average temperature was higher than in males (p<0.01). There was no significant difference in body temperature when other covariates were used in the analysis. The core body temperature of female dogs decreased significantly over time compared to males, with the most pronounced differenced during the intraoperative period. However, the study's retrospective nature and limited sample size may influence the generalizability of these findings., Competing Interests: Declaration of Competing Interest Our research group has no conflict of interests to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Abdominal surgery such as ovariectomy is a traumatic event that can cause oxidative stress. The aim of the present study was to evaluate the concentration of serotonin in relation to ovariectomy-induced oxidative stress in dogs undergoing general anesthesia. Thirty-two female dogs, under general anesthesia, received meloxicam before surgery (0.2 mgkg -1 SC) and after surgery (0.1 mgkg -1 OS every 24 h). The physiological, hematological, and biochemical parameters: glycemia, aspartate transaminase (AST), alanine aminotransferase (ALT), total protein, albumin and BUN were evaluated. Oxidative stress was determined by malondialdehyde (MDA) assay, catalase (CAT), superoxide dismutase (SOD), myeloperoxidase (MPO) and butyrylcholinesterase (BuChe) at baseline, 36 and 48 h after the last administration of meloxicam. Serotonin (5-HT) concentration was also evaluated at baseline, 36 and 48 h after the last administration of meloxicam. Responses to surgical stimulus were evaluated. Physiological and hematological parameters they fell within the normal ranges for anesthetized dogs. Glycemia increased, albumin levels decreased after surgery. No rescue analgesia was required. MDA and 5-HT concentrations significantly increased from the baseline at 36 and 48 h after surgery ( p  < .001). 5-HT levels could be used as an indicator for oxidative stress induced by surgery and it might be employed for objectively quantifying the well-being of the surgical patient.

Submitting late-term pregnant mares to anesthesia for non-obstetric surgery raises concerns about the survival of the mother and fetus. This study aimed to evaluate and describe transient maternal and fetal hemodynamic changes during general inhalation anesthesia in mares during the last month of gestation. Nine adult mares in the last month of gestation were subjected to general inhalation anesthesia and dorsal recumbency for 90 minutes. Trans-anesthetic vital parameters, arterial hemogasometry, cardiac output, pulmonary arterial pressure, central venous pressure, and fetal heart rates were assessed at defined intervals. During various timespans of the anesthetic procedure, the mares demonstrated an increase in heart rate, mean arterial pressure, and diastolic pressure as well as a decrease in temperature. Additionally, arterial hemogasometry indicated respiratory acidosis. No changes in cardiac output were observed; however, there was a reduction in pulmonary arterial and central venous pressures and stroke volume. Fetal heart rate was significantly decreased. General inhalation anesthesia in late term pregnancy in mares in a recumbent position implies in significant hemodynamic and metabolic changes. Up to 90 minutes those changes does not seem to affect negatively the maternal-fetus prognosis., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Brito et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Objectives: Several anaesthetic protocols for caesarean section (c-section) have been described in dogs; however, anaesthesiological studies in cats undergoing c-section are lacking. The aim of this study was to assess the viability and outcome of kittens born from queens undergoing emergency c-section and receiving propofol or alfaxalone for anaesthetic induction and isoflurane for maintenance of general anaesthesia., Methods: All cats admitted to the Veterinary Teaching Hospital of the University of Bologna between January 2014 and December 2022 for dystocia that had undergone an emergency c-section were analysed in this retrospective study. The queens received propofol 2-6 mg/kg IV (group P) or alfaxalone 1-3 mg/kg IV (group A) administered slowly; general anaesthesia was maintained with isoflurane. Survival of all the kittens was evaluated at birth and after 24 h; in addition, heart rate, respiratory rate and mucous membrane colour were evaluated in the kittens at birth., Results: Of the 14 cats included in the study, eight received alfaxalone (group A) and six received propofol (group P) for induction of the general anaesthesia. A total of 50 kittens were born by c-section: 30 kittens in group A and 20 in group P. The overall survival of the kittens was 90% at birth: 96.7% (29/30) for group A and 80% (16/20) for group P. The 24 h survival rate was 93.1% for group A and 87.5% for group P., Conclusions and Relevance: The results of the present study demonstrated that in cats undergoing c-section, both alfaxalone and propofol are feasible for the induction of general anaesthesia., Competing Interests: Conflict of interestThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Objective: To describe the use of plasma transfusion in anaesthetized dogs, specifically the triggers for use, the population administered plasma, reported adverse events and human errors associated with transfusion., Study Design: Retrospective observational study., Animals: A total of 85 client-owned dogs., Methods: A search of electronic transfusion and anaesthetic records at a university teaching hospital was performed to identify dogs administered plasma during the study period (January 2017 to June 2021). Data collected included signalment, surgical procedure, intraoperative triggers for transfusion, the type of plasma, rate of transfusion and the presence of transfusion reactions, human errors or deviation from transfusion guidelines., Results: During this period, 85 dogs were administered plasma. Sepsis was diagnosed in 49/85 (58%) dogs, with 42/85 (49%) animals undergoing surgery for septic peritonitis. Perianaesthetic hypotension contributed to the decision to administer plasma in 67/85 (79%) dogs. In 33/85 (39%) dogs, hypotension was the only reason for transfusion, while 31/85 (36%) had other influencing factors, most commonly hypoproteinaemia. Fresh frozen plasma was administered in 95% of cases. Only 31% of transfusions were started at a slower 'test dose' rate and 79% of dogs administered boluses of plasma. No definite, probable or possible transfusion reactions were identified using current veterinary guidelines., Conclusions and Clinical Relevance: Plasma transfusions were commonly administered to dogs presenting with sepsis for haemodynamic optimization. Clinicians often chose to bolus plasma instead of initiating transfusions at the recommended initial slow starting rate. No transfusion reactions were identified; however, some reactions may have been masked by the effects of general anaesthesia and/or have been difficult to recognize in this critically ill canine population., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Objective: Complications from general anesthesia, including pneumonia and decreased wound healing, are influenced by changes in immune cell function secondary to sedatives and anesthetics. It was hypothesized that immune cell function would be depressed in the early postanesthetic period. The objective was to investigate airway immune cell function before and after a general anesthetic episode in an equine in vivo model using ex vivo cell stimulations with lipopolysaccharide (LPS) for assessment of immune function., Study Design: Prospective experimental study., Animals: Six healthy, adult, institution-owned horses., Methods: Each horse underwent a bronchoalveolar lavage (BAL) 3 days before and immediately after a 2 hour general anesthetic. The BAL fluid was examined for cytology, total nucleated cell count and isolation of immune cells. Airway immune cells were treated with LPS or media (control) for 6 hours and supernatant was analyzed via a commercially available immunoassay for cytokines [tumor necrosis factor alpha (TNFα), interleukin (IL)-1β, IL-6, interferon gamma (IFNγ) and CXC motif chemokine ligand 8 (CXCL8)]. Data were compared using t-tests and Mann-Whitney tests., Results: Before anesthesia (baseline), LPS stimulation induced a significant increase in all cytokines of interest, except CXCL8, versus control samples. Unstimulated cells, after an anesthetic episode, had a significant 1.8-fold increase in IL-1β (p = 0.029), and a significant decrease in IL-6 and TNFα (p = 0.028 and 0.033, respectively) versus baseline. Following anesthesia, stimulated cells had a significant decrease in IL-6 and TNFα (p = 0.037 and 0.042, respectively) versus baseline., Conclusions and Clinical Relevance: This study supports the use of an equine in vivo model to assess airway immune cell function in relation to general anesthetic use., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Background: Cardiac troponin I, a particular biomarker, is released into the bloodstream in response to myocardial injury., Objectives: To evaluate perioperative changes in high-sensitivity cardiac troponin I (hs-cTnI) concentration during ovariohysterectomy in cats undergoing three different anaesthesia protocols., Methods:  Twenty-one female mixed-breed cats owned by clients aged (2.2 ± 0.7 years) and weight (3.2 ± 0.5 kg) were included in our study. The cats were divided into three groups: propofol-isoflurane (PI) group (n = 7), xylazine-ketamine (XK) group (n = 7) and xylazine-isoflurane (XI) group (n = 7). After pre-anaesthetic propofol (6 mg/kg IV) was administered to cats in Group PI, a mask was placed, and anaesthesia was maintained with 3.0% isoflurane in oxygen. Cats in Group XK underwent general anesthetization with xylazine hydrochloride (2 mg/kg IM) and, 10 min later, ketamine hydrochloride (10 mg/kg IM). Cats in Group XI were administered xylazine hydrochloride (2 mg/kg IM), and then anaesthesia (3.0% isoflurane and oxygen) was continued with a mask. Blood samples were collected from all cats; preoperatively and postoperatively at 0 and 12 h (Pre-, Post-0 h and Post-12 h, respectively). Serum hs-cTnI concentrations were measured with the Advia Centaur TnI-Ultra., Results: In all 21 cats, hs-cTnI concentration increased at Post-0 h and 12 h measurement points compared to Pre-. In the XK group, hs-cTnI concentrations exhibited a significant increase at the Post-0 h (51.30 ng/L) and Post-12 h (157.70 ng/L) time points compared to Pre- (6.70 ng/L) (p < 0.05)., Conclusions: The XK group increased the concentration of hs-cTnI more than other protocols. In the PI group, the increase in hs-cTnI concentrations at Post-0 and 12 h increased less than the other two groups (p < 0.05). The PI group was found to induce less myocardial damage., (© None The Author(s). Veterinary Medicine and Science published by John Wiley & Sons Ltd.)

Objective: To evaluate induced hypothermia and rewarming times in Hispaniolan Amazon parrots (HAP; Amazona ventralis) anesthetized using isoflurane, sevoflurane or desflurane, and to describe selected cardiovascular and respiratory effects., Study Design: Randomized, balanced, crossover experimental study., Animals: A group of 12 adult HAP., Methods: Parrots were premedicated with intramuscular butorphanol (0.5 mg kg -1 ) and anesthetized with the three inhalants with a 7 day washout period between events. Anesthesia was induced using isoflurane at 4 vol%, sevoflurane at 6 vol% or desflurane 12 vol% carried in oxygen, delivered via face mask. After orotracheal intubation, anesthesia maintenance was with end-tidal concentrations of 1.4-2% (Fe'Iso), 2.4-3% (Fe'Sevo) and 8.5-9.2% (Fe'Des). Hypothermia was defined as an esophageal temperature (BT) below 37.8 °C. External heat support was provided when BT dropped to 37.5 °C. Time for temperature decrease from 38.9 °C to 37.5 °C (T1), time to first increase in BT above 37.5 °C (T2) and time from external heat support to achieving 38.9 °C (T3) were recorded and compared via Friedman tests with post hoc Dunn's test. Heart rate, respiratory rate and end-tidal carbon dioxide, amongst other variables, were evaluated., Results: All inhalants caused hypothermia (T1): isoflurane, 12 (2-37) minutes [median (range)]; sevoflurane, 12 (4-18) minutes; desflurane, 11.5 (6-24) minutes, with no significant differences between treatments (p > 0.05). T2 was significantly (p = 0.042) longer for sevoflurane than for desflurane but not isoflurane. Transient apnea was observed with all inhalants, including 25% of birds anesthetized with sevoflurane. Second-degree atrioventricular block and ventricular escape beats occurred with all inhalants with hypothermia potentially exacerbating cardiac arrhythmias., Conclusions and Clinical Relevance: Hypothermia rapidly developed in butorphanol-sedated HAP anesthetized using isoflurane, sevoflurane or desflurane. Sevoflurane prolonged warming time. Hypothermia may be associated with an increased likelihood of bradyarrhythmia in parrots anesthetized with inhalants., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Medetomidine/vatinoxan (Zenalpha®) is a novel anesthetic combination used as a sedative and analgesic in dogs. Vatinoxan minimizes adverse cardiopulmonary effects associated with medetomidine administration while preserving sedation and analgesia. In this study, we evaluated the clinical safety and efficacy of 3 dosage combinations of Zenalpha with ketamine and buprenorphine extended release (ER) as compared with xylazine with ketamine and buprenorphine-ER for anesthesia of C57BL/6J mice. We hypothesized that anesthesia with 0.5 mg/kg of Zenalpha would more reliably provide a surgical anesthetic plane, lower mortality, and fewer adverse physiologic effects as compared with anesthesia with 8 mg/kg of xylazine. Ten-week-old male and female C57BL/6J mice were randomly administered 1 of 4 anesthetic cocktails subcutaneously: ketamine (80 mg/kg) and buprenorphine-ER (0.5 mg/kg) with 1) xylazine (8 mg/kg; XKB); 2) Zenalpha (0.25 mg/kg; ZKB/0.25); 3) Zenalpha (0.5 mg/kg; ZKB/0.5); or 4) Zenalpha (1.0 mg/kg; ZKB/1.0). Following drug administration, we assessed the anesthesia induction time by measuring the time to loss of righting reflex and loss of paw withdrawal reflex (PWR). Upon reaching a loss of righting reflex, physiologic parameters including heart rate, respiratory rate, oxygen saturation, indirect mean arterial blood pressure, body temperature, jaw tone, and skin color were monitored every 5 min. Thirty minutes after anesthetic drug administration (TA), atipamezole (1 mg/kg SC) was administered. Recovery time was determined through time until return of PWR, righting reflex, and ambulation. Mice were monitored for 3 d postanesthesia. Results included: 1) ZKB anesthesia caused loss of PWR in a dose-dependent manner; 2) physiologic parameters were similar between XKB and ZKB mice by TA in 100% O2; 3) ZKB groups took longer to recover and had a 20% to 30% mortality rate in the mid-to-high dosage groups. We conclude that anesthesia with 0.5 mg/kg of Zenalpha more reliably produced a surgical anesthetic plane but also led to decreased mean arterial pressure and increased mortality as compared with anesthesia with 8 mg/kg of xylazine. We recommend using Zenalpha (0.25 to 1.0 mg/kg) with 80 mg/kg ketamine and 0.5 mg/kg buprenorphine-ER to provide general anesthesia in C57BL/6 mice, along with supplemental 100% oxygen and atipamezole.

Sedation and general anaesthesia of crocodilians pose unique challenges due to their aggressive nature, poikilothermic physiology, and specific anatomical and physiological characteristics, all factors that complicate crocodilian anaesthesia. This review aimed to systematically review the literature regarding sedation and general anaesthesia of crocodilians with focus on efficacy and impact on vital parameters. A systematic literature search was performed according to PRISMA guidelines on May 2, 2023 in the databases Embase, PubMed, Scopus and Web of Science. Publications were excluded based on predefined exclusion criteria, which encompassed non-standard publications and publications unrelated to crocodilians, with fewer than five animals and/or with insufficient data on sedation and general anaesthesia. Five key factors were used to evaluate the strength of evidence: number of included animals, study design, definition of recovery time, blinded assessment of recovery and conflict of interest. Ten publications were included in this systematic review. Drugs used included alpha-2-adrenoceptor agonists, dissociative anaesthetics, benzodiazepines, neuromuscular blocking agents, propofol, alfaxalone, and inhalant gasses. The studies included in total 55 Alligator mississippiensis, 110 Crocodylus porosus, 15 Crocodylus johnstoni, and 15 Crocodylus niloticus. Factors such as temperature, administration route, dose, species, and age influenced protocols for sedation and general anaesthesia of crocodilians. The studies included used five different study designs. Only one study included a control group, done on retrospectively collected data. Blinded recovery assessments and declarations of no conflict of interest were noted in some studies. The use of four distinct recovery definitions posed challenges to comparability in this systematic review. The studies reported that medetomidine provided stable and reversible sedation, although it depressed heart rate. Alfaxalone was less stable outside the optimal temperature range. Intubation and inhalation anaesthesia were effective, and adrenaline reduced the length of the recovery period. Overall, the review provides valuable insights for veterinarians, researchers, and wildlife professionals involved in sedation and general anaesthesia of the crocodilian species, however, the literature is limited, and further research is needed to improve evidence-based medical management., (© 2024. The Author(s).)

Objective: To characterize cystometry in conscious and anesthetized sheep, including bladder response to sacral root electrical stimulation, thereby providing a baseline set of values., Methods: Single-fill cystometries were repeated in adult mule ewes both conscious (n = 5) and under general anesthesia (18) using a commercial system. Parameters including bladder capacity, detrusor (bladder) pressure, urethral opening pressure, bladder compliance, number of nonvoiding detrusor contractions, and bladder pressure change in response to electrical stimulation of the sacral roots under general anesthesia are reported. Pubmed, Embase, and Web of Science databases were searched for studies relating to ovine cystometry, and a systematic review was conducted., Results: In awake sheep, mean ± SD bladder capacity was 79.6 ± 32.2 mL, urethral opening pressure was 26.0 ± 10.7 cm H2O, and compliance was 3.5 ± 1.9 mL/cm H2O. Peak detrusor pressures during micturition reached 57.7 ± 28.3 cm H2O. In anesthetized animals, mean bladder capacity (endpoint, 50 cm H2O) was 333 ± 191 mL, and mean bladder compliance was 7.7 ± 4.9 mL/cm H2O. Values for these parameters from our systematic review are presented for comparison and reference. Electrical stimulation of the second and third sacral roots caused a greater increase in detrusor pressure than stimulation of the first and fourth sacral roots., Conclusions: We present a comprehensive set of data for normal cystometry parameters in sheep, including the first report of detrusor response to sacral root stimulation in anesthetized sheep., Clinical Relevance: This report provides a valuable set of baseline values for a potential translational model of value to neurourologic research and may be a useful reference for clinicians.

In veterinary medicine, PET/CT scans are generally performed with the patient under general anesthesia. The aim of this prospective crossover study was to compare the musculoskeletal uptake of 18 F-FDG and radiation doses to workers during PET/CT studies of healthy dogs and cats between sedation and general anesthesia. Volume and maximal standard uptake values (SUVmax) values of abnormal 18 F-FDG uptake in the skeletal musculature, presence of misregistration artifact, and radiation doses to workers for each PET/CT study were recorded. Sedation was associated with increased volume of 18 F-FDG uptake in the musculature of the thoracic limbs (p = .01), cervical (p = .02), and thoracic (p = .03) spine. Increased volume and SUVmax of the musculature assessed altogether were associated with the lighter degree of sedation (p = .04 for both). A significant decrease in the odds of misregistration artifact was observed for anesthetized animals in comparison with sedated (OR: 0.0, 95% CI: 0.0-0.0, p = .01). Radiation doses to workers were significantly higher for sedation compared with general anesthesia (p = .01) and for the anesthesia technician compared with the nuclear medicine technologist (p = .01). Use of sedation for PET/CT studies in dogs and cats is feasible. However, it is associated with increased physiologic musculoskeletal uptake of 18 F-FDG in the thoracic limbs, cervical, and thoracic spine, with increased frequency of misregistration artifact, and with increased radiation doses to workers. These limitations can be overcome by recognition of the uptake pattern and monitoring/rotation of the involved staff at institutions where a high caseload is expected., (© 2024 American College of Veterinary Radiology.)

Background: This retrospective observational study explored the impact of preanaesthetic electrocardiogram (ECG) assessment on preoperative echocardiography requests and modifications to a standardised anaesthetic protocol in healthy dogs., Methods: A total of 228 healthy dogs with no previously diagnosed heart disease that underwent general anaesthesia at Complutense Veterinary Teaching Hospital from December 2017 to June 2018 were included. Preanaesthetic ECGs were assessed for abnormalities, and the findings were documented. The number of dogs requiring echocardiography, based on ECG findings, and the echocardiography results were recorded. All anaesthesia-related decisions were documented., Results: Overall, 72 dogs (31.6%) exhibited ECG abnormalities. Echocardiography was requested for five dogs (2.2%). The anaesthetic protocol was changed in 11 dogs (15.3% of those with ECG abnormalities). P wave disturbances, ventricular premature complexes and impulse conduction issues were abnormalities that prompted echocardiography. Bradycardia and electrical impulse conduction abnormalities influenced protocol modifications., Limitations: The limited sample size meant that it was not possible to investigate potential correlations between demographics and ECG alterations., Conclusions: Preanaesthetic ECG screening was useful for promoting echocardiography and influencing anaesthesia plans in a subset of dogs. Despite this, further assessment of the impact of routine use of non-targeted preoperative ECG on anaesthesia-related outcomes is warranted., (© 2024 The Authors. Veterinary Record published by John Wiley & Sons Ltd on behalf of British Veterinary Association.)

Determination of acid-base status contributes important information about patient health, including for patients under anesthesia. There is a paucity of information about the determinants of acid-base status of large felids managed under anesthesia, and advancement of such knowledge may contribute to patient safety. This study serially monitored the individual metabolic acid-base status of 11 large felids, including lions ( Panthera leo ), tigers ( Panthera tigris ), and cheetahs ( Acinonyx jubatus ), under general anesthesia. We analyzed the contributions of measured strong ions (sodium, chloride, potassium, lactate), weak acids and buffers (albumin, phosphate and bicarbonate), and unmeasured anions to standardized extracellular base excess (SBE). A general linear model assessed for species differences in these parameters, with time since immobilization, SBE, and mean arterial pressure as covariates. By employing a Stewart-based analytical approach, it was possible to separate chloremic and unmeasured anion contributions to metabolic acid base status. This provided a basis for identifying mixed metabolic processes, generating differentials for underlying causes. Using normal acid base parameters for domestic felids, metabolic acidosis was found to be prevalent. Frequent evidence of unmeasured anion accumulation was also found, with unmeasured anions occasionally exceeding 5mmol/L. These findings warrant further inquiry into the drivers and clinical significance of metabolic acidosis and unmeasured anion accumulations in anesthetized large felids, encouraging further anion identity studies to elucidate possible causes. Reference ranges need to be established for acid-base parameters in large felids as a foundation for interpreting more controlled, prospective research into determinants of metabolic acid-base status in these animals under anesthesia.

Objective: To examine whether increased systemic arterial blood pressure (ABP) and decreased heart rate (HR) under inhalant anesthesia were suggestive of the Cushing reflex (CR) in dogs with neurological diseases based on magnetic resonance imaging (MRI) findings., Study Design: Retrospective case-control study., Animals: A sample of 137 client-owned dogs admitted to two veterinary teaching hospitals for diagnosis and patient care owing to suspected intracranial disease from 2005 to 2020. All dogs underwent general anesthesia for MRI of the brain., Methods: Based on MRI study reports, dogs were divided into three study groups: group A, dogs with suspected brain herniation; group B, dogs with an abnormal MRI finding but without suspicion of herniation; and group C, dogs with structurally unremarkable brains (control). Initial evaluation by an anesthesiologist resulted in 58 cases selected for further review based on suspicion of having intracranial hypertension, as indicated by ABP and HR changes under anesthesia. Anesthetic records were randomized and independently reviewed by three board-certified anesthesiologists blinded to MRI diagnosis who allocated each dog into one of three groups: 1) likely to have CR; 2) unlikely to have CR; or 3) insufficient data for determination., Results: Of the 58 cases evaluated, nine were considered likely to have CR and 48 were considered unlikely to have CR. In one case, the anesthesiologists were unable to determine whether CR occurred. Of the nine dogs with likely CR, three had an MRI diagnosis of intracranial herniation. The remaining six dogs suspected of CR belonged to the normal brain group., Conclusions and Clinical Relevance: The ABP and HR changes associated with CR are not reliably associated with brain herniation in dogs undergoing general anesthesia., (Published by Elsevier Ltd.)

Background: Complications are a practical consideration for elective magnetic resonance imaging (MRI) studies performed under general anaesthesia but relatively little is known about their distribution and risk factors., Objectives: To describe the incidence of complications associated with MRI performed under general anaesthesia at a large referral facility and evaluate potential risk factors for these complications., Study Design: Retrospective case-control study., Methods: Patient information and details of the MRI procedure were collected retrospectively from medical records of all horses that had undergone an MRI under general anaesthesia at the University of Pennsylvania, New Bolton Center, between September 2005 and April 2012. Complications and categorical variables were examined by chi-squared or Fisher's exact tests as appropriate. A mixed-effects logistic regression approach was used to evaluate associations between explanatory variables and the outcome variable (complications or pyrexia). A univariable screen was used to select variables (likelihood ratio test p < 0.2) for inclusion in the multivariable analysis. Statistical significance was inferred when p ≤ 0.05., Results: Complications were noted after MRI in 51 (17.4%) of 293 events eligible for inclusion. Complications included pyrexia (n = 35), pneumonia (n = 14), colic (n = 10), facial/nerve paralysis (n = 6), diarrhoea (n = 4), and other (n = 3). The odds of developing a post-anaesthetic complication were significantly decreased in horses that received peri-anaesthetic antimicrobials (OR 0.29, 95% CI 0.14-0.63, p = 0.002). Increased age (OR 0.87, 95% CI, 0.76-0.99, p = 0.03) and peri-anaesthetic antimicrobial administration (OR 0.23, 95% CI 0.08-0.65, p = 0.005) were associated with a decreased odds of developing pyrexia., Main Limitations: Single centre retrospective design., Conclusions: Potential complications including pyrexia, pneumonia and colic should be recognised when pursuing MRI under general anaesthesia. The administration of peri-anaesthetic antimicrobials decreased the odds of a complication and warrants consideration, particularly in horses that might be classified as high risk., (© 2023 The Authors. Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.)

Objective: To describe perioperative anesthetic management in canines with a dilated cardiomyopathy (DCM) phenotype and to compare the frequency of general anesthesia-related complications with a control group of dogs without heart disease., Animals: 30 dogs with DCM phenotype (cases) and 30 dogs without heart disease (controls)., Methods: Dogs presented to a teaching hospital between 2010 and 2024 that were diagnosed with a DCM phenotype via echocardiography were included in this study. Controls were dogs that presented during the same time period and were matched with cases based on their age, breed, and type of procedure; however, no standardization of treatment between the groups was performed. Medical records were reviewed to evaluate the occurrence of anesthetic complications., Results: Of dogs with a DCM phenotype, 2 had overt DCM, 22 had occult DCM, and 6 had equivocal DCM. Dogs with DCM exhibited a lower likelihood of being premedicated with dexmedetomidine or induced with propofol. Conversely, DCM dogs were more likely to be induced with etomidate or midazolam compared to their counterparts without DCM. Dogs with DCM demonstrated an increased likelihood of experiencing cardiac arrhythmias during anesthesia, received comparatively lower volumes of IV fluids, and were more likely to be administered dobutamine during anesthesia. No significant differences were identified in terms of postanesthesia complications or survival rates to discharge., Clinical Relevance: Dogs with a DCM phenotype, primarily characterized by asymptomatic presentation, demonstrated comparable perioperative outcomes under general anesthesia when compared to matched controls, though the lack of standardization in anesthetic management limits definitive conclusions.

Laparoscopic ovariectomy under general anesthesia was planned in a 10-year-old, 146 kg, apparently healthy female African lion (Panthera leo). The lion was immobilized via intramuscular darts containing midazolam (0.033 mg/kg), medetomidine (50 µg/kg) and ketamine (2.5 mg/kg), and intubated using an endotracheal tube (16 mm internal diameter). The anesthesia was maintained using sevoflurane (0.9-2.1% end-tidal concentration), in combination with remifentanil (0.1 µg/kg/min) and ketamine (11 µg/kg/min) at a constant rate infusion (CRI), with Hartmann's solution (5 mL/kg/hr). Surgery was conducted with stable vital signs, but hypotension (mean arterial blood pressure 55 mmHg) developed, requiring dobutamine treatment. The hypotension was effectively controlled by adjusting dobutamine from 5 µg/kg/min to 0.2 to 0.3 µg/kg/min. This case suggests possibilities that dosages in this range can be clinically useful for peri-anesthetic hypotension in lions.

Objective: To compare respiratory system compliance (C RS ), expressed per kilogram of bodyweight (C RS BW), calculated without end-inspiratory pause (EIP) and after three EIP times (0.2, 0.5 and 1 seconds) with that after 3 second EIP (considered the reference EIP for static C RS ) and to determine the EIP times that provided C RS BW values in acceptable agreement with static C RS BW during controlled mechanical ventilation (CMV) in anaesthetized dogs., Study Design: Prospective, randomized, nonblinded, crossover clinical study., Animals: A group of 24 client-owned dogs with healthy lungs undergoing surgery in lateral recumbency., Methods: During CMV in dogs undergoing general anaesthesia, five EIPs [0 (no EIP), 0.2, 0.5, 1 and 3 seconds] were consecutively applied in random order. Tidal volume (Vt) was set at 10 mL kg -1 and positive end-expiratory pressure (PEEP) was not applied. Respiratory rate and inspiratory time were established according to each EIP time, setting EIP between 0 and 50% of the inspiratory time. The C RS BW was calculated as [expired Vt/(plateau pressure - PEEP)]/bodyweight and recorded every 15 seconds for 2 minutes after a 5 minute equilibration period with each EIP. One-way anova for repeated measures and the Bland-Altman analysis were used to compare C RS BW and evaluate agreement between EIP times, respectively., Results: The C RS BW was significantly greater as the EIP time increased up to 1 second (p < 0.05). In the Bland-Altman analysis, none of the tested EIPs (0, 0.2, 0.5 and 1 seconds) provided 95% confidence intervals for limits of agreement within the maximum allowed difference considered for acceptable agreement with 3 second EIP., Conclusions: and clinical relevance An EIP ≤ to 1 second does not provide a C RS BW value in acceptable agreement with static C RS BW in healthy dogs. Besides, the application of an EIP ≤ to 0.5 seconds underestimates the static C RS BW to an increasing extent as the EIP time decreases., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Introduction: The brainstem auditory evoked response (BAER) is a diagnostic approach to examine the hearing system of horses objectively. The aim of this BAER examination was the diagnosis of conductive or sensorineural hearing loss or deafness in horses with external otitis, head trauma, headshaking, tinnitus or skittish horses with eye disease. Brainstem dysfunction is induced by intracranial hypotension. BAER was used in horses with colic surgery which had a low arterial blood pressure during general anesthesia. The endoscopic finding of the guttural pouch was the ipsilateral mild to severe hypertrophy of the tympanostylohyoideum in horses with external otitis or head trauma. The otoscopic examination of standing sedated horses was done before BAER. The cartilagineous and osseous part of the external ear canal in horses with external otitis were obstructed with exsudate and tympanic membranes were not visible. Horses with right sided external otitis: right moderate to severe conductive hearing loss (significantly prolonged latencies of I, III, V and interpeak latencies I-III, I-V, III-V; thresholds of hearing levels 60 to 80 dB right); horses with left sided external otitis: left severe conductive hearing loss (no correct identification of BAER peaks, latencies not measurable, 80 dB); horse with left sided head trauma: severe left sided conductive hearing loss (blood in the left external ear canal, no visible tympanic membrane, no correct identification of BAER peaks, latencies not measurable, 80 dB); horses with head shaking: mild sensorineural hearing loss on both sides (on both sides osseous parts II/III with keratin scales of the junction, visible tympanic membranes, significantly prolonged V, I-III, I-V, 40 dB); moderate to severe skittish horses with chronic eye disease (mostly left sided equine recurrent uveitis): moderate sensorineural hearing loss on both sides (normal otoscopical findings, significantly prolonged latencies and interpeak latencies left; I-V, III-V right, 60 dB, pathological involvement in the auditory pathway of the brainstem between the cochlear nucleus and colliculus caudalis); horse with a tinnitus on both sides: mild sensorineural hearing loss on both sides (normal otoscopical findings, prolonged V, I-III, I-V, III-V, 40 dB, pathology of auditory nerve, cochlear nucleus and above the level of this nucleus); American paint horses: sensorineurale deafness on both sides (normal otoscopical findings, absent BAER peaks, isoelectric lines and 80 dB on both sides). The prolonged latencies of I, III and V including interpeak latencies I-III only left and I-V and III-V on both sides in horses with laparotomy during general anesthesia were associated with low arterial blood pressure (62 mmHg, median). These findings could demonstrate a hypotension in the brainstem too. The BAER could be a technical tool during general anesthesia for normalizing the arterial blood pressure and brainstem function to prevent imbalance of body movements after general anesthesia.

Objective: To compare changes in oesophageal (T-Oeso) and rectal (T-Rec) temperature in dogs during general anaesthesia and premedicated with fentanyl, medetomidine-fentanyl or acepromazine-fentanyl., Study Design: Prospective, randomized, blind clinical study., Animals: A total of 120 healthy dogs, aged 2-10 years and weighing 5-20 kg., Methods: Dogs were randomly allocated to one of three groups. Animals of F group were premedicated with fentanyl (0.01 mg kg -1 ), MF group with medetomidine (0.005 mg kg -1 ) and fentanyl (0.01 mg kg -1 ) and AF group with acepromazine (0.01 mg kg -1 ) and fentanyl (0.01 mg kg -1 ). Anaesthesia was induced with propofol and maintained with isoflurane in oxygen-air mixture. Fentanyl was administered continuously (0.01 mg kg -1 hour -1 ). The T-Oeso, T-Rec and ambient temperatures were recorded after induction (T0) and subsequently at 10 minute intervals for 60 minutes (T10-T60). Data were analysed using anova or their non-parametric equivalents (p < 0.05)., Results: Median T-Oeso was significantly higher in MF group between T0-T20 compared with other groups. Median T-Oeso significantly decreased in F group from 38.0 °C (T0) to 37.4 °C (T30), 37.1 °C (T40), 36.9 °C (T50) and 36.6 °C (T60), in MF group from 38.3 °C (T0) to 37.7 °C (T30), 37.5 °C (T40), 37.2 °C (T50) and 37.1 °C (T60) and in AF group from 37.7 °C (T0) to 37.3 °C (T40), 37.2 °C (T50) and 37.1 °C (T60). The T-Rec significantly decreased in F group from 38.0 °C (T0) to 37.4 °C (T40), 37.2 °C (T50) and 36.9 °C (T60), in MF group from 38.3 °C (T0) to 37.5 °C (T50) and 37.4 °C (T60) and in AF group from 38.2 °C (T0) to 37.6 °C (T40), 37.5 °C (T50) and 37.4 °C (T60)., Conclusions and Clinical Relevance: Premedication with fentanyl, medetomidine-fentanyl or acepromazine-fentanyl in the doses used decreased the T-Oeso and T-Rec. The T-Oeso at the beginning of anaesthesia was higher after premedication with medetomidine-fentanyl. However, this difference was not clinically significant., (Copyright © 2024 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To collect medication error (ME) data during the perianesthetic period from small animal clinics., Sample: 6 small animal general practice veterinary clinics., Methods: Small animal general practice veterinary clinics were recruited in this prospective observational study, with staff given a presentation on medical errors and instructed on how to submit medication error reports to an online reporting system. Errors were classified according to type and timing., Results: A total of 2,728 general anesthesia or sedation procedures were performed, with 49 ME reports submitted. One duplicated report of the same error was excluded, resulting in a ME rate of 1.8%. Most reports (69% [33/48]) were near misses. The remaining 31% were MEs that reached the patient but did not cause harm. Wrong dose errors were the most common type (63% [30/48]), of which 80% (24/30) were calculation errors. Premedication/sedation and maintenance were the most reported stages, at 47% (20/43) and 23% (10/43), respectively. None of the MEs reported resulted in an adverse event, with an approximately 2:1 ratio of near-miss to no-harm MEs. The observed patterns of MEs reported, including type and timing, represent a target for further education., Clinical Relevance: These results quantify the ME rate in general practice veterinary clinics, providing an initial benchmark for MEs during the perianesthetic period.

The postoperative period is critical for the development of complications, including hypoxemia. To detect hypoxemia early and provide appropriate care, continuous monitoring of saturation is necessary: pulse oximetry is an easily accessible and simple method for this purpose. However, a SpO 2 cut-off value to detect hypoxemia in dogs recovering from general anesthesia is lacking in the veterinary literature. The objectives of this clinical study are to validate the room air SpO 2 test (SpAT), to identify a cut-off value to discriminate hypoxemia (Phase 1), and to apply the SpAT to study the incidence of transient postoperative hypoxemia (TPH) (Phase 2) in dogs with healthy lungs recovering from general anesthesia. Phase 1: 87 dogs recovering from general anesthesia with an arterial line were included. After extubation, SpAT was performed simultaneously with arterial blood sampling. A PaO 2 < 80 mmHg was considered hypoxemia. Phase 2: 654 dogs were enrolled. They underwent general anesthesia with different ventilation settings for different procedures. After extubation, dogs were classified as hypoxemic if the SpO 2 was lower than the cut-off obtained in phase 1. Phase 1 showed that the SpO 2 cut-off is < 95% (sensitivity 100%, specificity 97.4%; area under the curve, AUC = 0.996; 95% Confidence Interval = 0.944-1; P<0.0001). In Phase 2, 169 dogs were hypoxemic. Body Condition Score (BCS) > 3/5, dorsal recumbency, FiO 2 1, absence of Positive End-Expiratory Pressure (PEEP) had a significant odds ratio to induce TPH (5.8, 1.9, 3.7, 1.7, respectively). These results showed that SpO 2 < 95% indicates PaO 2 < 80 mmHg in dogs and TPH occurs in up to 28% of cases. Identification of associated risks could be useful to prevent and to increase awareness for monitoring and treatment., Competing Interests: Declaration of Competing Interest None of the authors has any financial or personal relationships that could inappropriately influence or bias the content of the paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Present an approach to the safe and efficient provision of anesthesia and birth control measures to a large group of primates., Animals: 98 hamadryas baboons (Papio hamadryas) held in a German zoological institution., Methods: A group of 12 veterinarians, 2 zookeepers, and 6 volunteers anesthetized all animals within 2 days. The baboons were orally premedicated with midazolam (0.1 to 0.5 mg/kg) and anesthetized with medetomidine (40 to 60 µg/kg, IM) and ketamine (2 to 4 mg/kg, IM); isoflurane at rates of 1.5% to 2% was used for maintaining anesthesia if necessary. All animals received a physical examination, prophylactic medication, and tuberculin testing. For population management, the animals received a contraceptive implant (adult females), orchiectomy (young males), or vasectomy (breeding males). Young males received intratesticular blocks with lidocaine. All animals received atipamezole (125 to 150 µg/kg) before recovery., Results: Premedication resulted in anxiolysis, which facilitated separating and darting. Median time from darting to access to the animal was 10 minutes. Mean anesthetic times were 25 minutes for females and 55 minutes for males. The depth of anesthesia was appropriate for the procedures. No fatalities were recorded. One animal was injured by other baboons but recovered after treatment., Clinical Relevance: Health management and birth control measures are necessary in baboon troops under human care. Anesthesia and/or contraception of individual animals often leads to intraspecific aggression. This case series describes how to provide anesthesia and contraception to an entire troop as an alternative approach that can be adopted to future similar interventions.

Objective: To analyze risk factors for complicated perioperative recovery of dogs undergoing either staphylectomy or folded flap palatoplasty., Study Design: Retrospective study., Animals: Seventy-six client-owned dogs., Methods: Medical records of dogs that underwent either staphylectomy or folded flap palatoplasty were reviewed for signalment, brachycephalic risk (BRisk) score, history of gastrointestinal signs, laryngeal collapse grade, presence of preoperative aspiration pneumonia, intraoperative respiratory and cardiovascular complications, length of general anesthesia, number of corrected brachycephalic obstructive airway syndrome (BOAS) components, and gastrointestinal and respiratory postoperative complications. Complicated recovery was defined as requirement for prolonged oxygen treatment and/or tracheostomy or perioperative death. Penalized logistic regression was used to identify risk factors., Results: Seventy-six dogs were enrolled in the study. Multivariate penalized logistic regression identified four risk factors for complicated recovery. These include surgery type (p = .0002), age (p = .0113), laryngeal collapse grade >2 (p < .0001) and length of general anesthesia (p = .0051)., Conclusions: In this population, dogs that had staphylectomy, increasing age, laryngeal collapse grade >2 and increasing length of general anesthesia were at increased risk for perioperative complicated recovery., Clinical Significance: The results of this study identified risk factors for perioperative complicated recovery in dogs undergoing elongated soft palate correction and may assist in surgical planning and early prediction of complications., (© 2024 The Authors. Veterinary Surgery published by Wiley Periodicals LLC on behalf of American College of Veterinary Surgeons.)

Case History: Medical records from 2009 to 2021 from a private equine referral hospital in Rochester, NH, USA were analysed for cases that underwent general anaesthesia for low-field MRI of the distal limb. These were used to determine peri-anaesthetic morbidity and mortality., Clinical Findings and Outcome: Two hundred and forty-three anaesthetic episodes were recorded in horses undergoing low-field MRI. The peri-anaesthetic complication rate prior to discharge was 6.2% (15/243). No patients experienced a fatal complication. Ninety two of the 243 patients had multiple sites imaged, 90/243 received pre-anaesthetic dantrolene, 134/243 received intra-anaesthetic dobutamine, and 15/243 were positioned in dorsal recumbency. Complications included: abdominal discomfort ("colic"; 9/243), myopathy (4/243), hyphaema (1/243) and carpal fracture (1/243). At the time of discharge, 14/15 complications had resolved. Of 135 horses for which data were available 55 became hypotensive during the procedure (lowest mean arterial pressure < 65 mmHg). Median body weight was 553 (min 363, max 771) kg. Horses were anaesthetised for a median of 150 (min 45, max 210) minutes. There was no evidence of an association between higher body weight (p = 0.051) or longer duration of anaesthesia (p = 0.421) and development of an anaesthetic complication. For categorical variables (dantrolene administration pre-anaesthesia, dobutamine administration during anaesthesia, hypotension (mean < 65 mmHg) during anaesthesia, dorsal vs. lateral recumbency, and imaging of single vs. multiple sites) , the 95% CI for the OR included 1, indicating a lack of effect of the variable on the odds of complication., Clinical Relevance: The cases included in this series suggest that low-field MRI under general anaesthesia is a viable option for diagnostic imaging in otherwise healthy horses. Complications occur, but most resolve before discharge.

Objective: To investigate the incidence of and identify risk factors associated with poor quality of recovery in dogs recovering from general anaesthesia., Study Design: Case controlled study., Methods: All dogs undergoing general anaesthesia at the University of Liverpool Small Animal Teaching Hospital between January 2020 and January 2021 were eligible for recruitment. Signalment, anaesthetic case management and a recovery score were recorded. Univariable and multivariable logistic and ordinal logistic regression analysis were used to identify factors which impact incidence of poor quality of recovery., Results: A total of 247 dogs undergoing general anaesthesia were included. Overall, 72 [29.1%; 95% confidence interval (CI) 23.8%-35.1%] dogs experienced a poor quality recovery. Of these, 40 (55.5%) required sedation to manage behaviours associated with poor recovery. Multivariable logistic regression revealed American Society of Anesthesiologists (ASA) physical status classification of III or higher was associated with a decreased incidence of poor quality recovery [odds ratio (OR) = 0.34, 95% CI 0.12-0.93, p = 0.037] and the use of multiple inhalational anaesthetics during one procedure was associated with an increased incidence of poor quality of recovery (OR = 42.5, 95% CI 3.0-598.3, p = 0.005)., Conclusions and Clinical Relevance: Poor quality recovery is common in dogs recovering from general anaesthesia and sedation is often required for resolution. It is more likely to occur in healthy veterinary patients (ASA I and II). The use of multiple inhalational anaesthetic agents during one procedure should be discouraged as this may increase the likelihood of poor quality of recovery., (Copyright © 2023 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Hypotension is a common and potentially life-threatening complication of general anaesthesia in dogs. Due to the combination of cardiovascular side effects of many anaesthetic, sedative and analgesic drugs used peri-operatively hypotension is frequently reported even in healthy dogs undergoing elective procedures. Several treatment options for hypotension have been advocated. Potential treatments include rapid administration of either crystalloid or colloid fluids; pharmacological treatments to increase cardiac output and/or systemic vascular resistance; or reduction in the delivery of the volatile anaesthetic agents. This critical appraisal considers the current evidence for which treatment is the best option for treating hypotension in healthy euvolemic dogs undergoing general anaesthesia maintained with isoflurane. Fourteen relevant studies were appraised, including 12 laboratory studies and two small clinical trials. One study demonstrated that reduction in the delivery of isoflurane may correct hypotension, but this treatment may not always be feasible. In general, rapid administration of fluids did not increase blood pressure and failed to correct hypotension. Synthetic colloids demonstrated some efficacy, but results were inconsistent between studies and large volumes may be required. Infusion of dopamine appears to be the most reliable pharmacological option consistently increasing blood pressure, cardiac output and correcting hypotension., (© 2024 The Authors. Australian Veterinary Journal published by John Wiley & Sons Australia, Ltd on behalf of Australian Veterinary Association.)

Background: Post-anaesthetic fever is a known complication of general anaesthesia, however, its incidence in horses undergoing elective magnetic resonance imaging (MRI) is unknown., Objective: To determine the incidence of post-anaesthetic fever in horses undergoing elective orthopaedic MRI and determine whether prophylactic antimicrobial therapy would be associated with a reduction in the incidence of post-anaesthetic fever. We hypothesised that prophylactic antimicrobials would be associated with a reduction in the incidence of post-anaesthetic fever., Study Design: Retrospective cross-sectional study., Methods: This retrospective study included 791 elective orthopaedic MRIs in systemically healthy horses between June 2006 and March 2020 that recovered from general anaesthesia and did not undergo surgery or intensive medical therapy soon after recovery. Potential factors associated with post-anaesthetic fever were evaluated using multivariable logistic regression. Case signalment, travel time, preanaesthetic haematology and fibrinogen abnormalities, use of prophylactic antimicrobials, peri-anaesthetic nonsteroidal anti-inflammatories, anaesthesia time and recovery time were all evaluated for association with post-anaesthetic fever., Results: Of 791 MRI cases, 44 (5.6%) developed a post-anaesthetic fever. Horses that received prophylactic antimicrobials were [odds ratio (OR) 3.8, 95% confidence interval (CI) 1.98-7.46; p ≤ 0.001] more likely to develop a post-anaesthetic fever than those that did not receive antimicrobials. Young horses (1-4 years of age) were (OR 2.8, 95% CI 1.26-6.17; p = 0.01) more likely to develop fever compared with adult horses (≥5 years of age)., Main Limitations: Limitations of this study pertain to retrospective analysis including nonrandomised case selection and incomplete data records., Conclusions: While fever may indicate infection, the majority of early post-anaesthetic fevers resolved before discharge from the hospital with no identified cause. The use of prophylactic antimicrobials to reduce the risk of post-anaesthetic fever for elective MRI is not supported by this study., (© 2023 EVJ Ltd.)

Objective: To compare the quality of recovery in horses emerging from general anesthesia with or without the assistance of a novel device (recovery-enhancing device [RED]) designed to minimize high-energy falls., Animals: 20 mixed-breed horses, between July 1, 2023, and January 24, 2024., Methods: A computer-controlled belay system designed to slow the acceleration of a horse during a fall was evaluated in this study. Horses were randomly assigned to 1 of 2 treatment groups: RED (belay, assisted) or FREE (unassisted). An inertia-measuring unit was fitted to all horses and data were live streamed and recorded onto a computer for further analysis. Recoveries were scored using the composite grading scale (CGS; 0 to 100) by 3 independent observers. Two additional unitless recovery scores (RS and RS'), based on accelerometry values (high accelerations, less desirable), were calculated for each recovery. All the recovery scores were compared between the 2 treatment groups., Results: Composite grading scale scores were 26 ± 10 and 46 ± 13 in the RED and FREE groups, respectively (P = .001). The RS was 120 ± 79 and 198 ± 34 for the RED and FREE treatment groups, respectively (P = .015). The RS' was 32 (7 to 50) and 46 (28 to 44) for the RED and FREE treatment groups, respectively (P = .038)., Clinical Relevance: The RED improves the recovery scores compared with unassisted recoveries. This device may lead to a potential reduction in the number and severity of injuries in horses and personnel involved during the recovery period.

Objective: To investigate the effect of hypoxaemia, hypotension and hypercapnia, among others, on quality of recovery from general anaesthesia in horses., Study Design: Retrospective, single-centre study., Animals: A sample of 1226 horses that underwent general anaesthesia between June 2017 and June 2021., Methods: Horses and ponies weighing > 200 kg, aged > 6 months, anaesthetized using a xylazine- or medetomidine-isoflurane balanced anaesthesia protocol and presenting a complete anaesthetic record were included. Data were extracted from the clinic record system and from the original anaesthesia records. Recoveries were divided into 'good' and 'bad' based on the available recovery scores. Influence of hypoxaemia [PaO 2 < 60 mmHg (7.99 kPa)], hypotension (mean arterial pressure < 70 mmHg for at least 15 minutes) and hypercapnia [PaCO 2 > 60 mmHg (7.99 kPa)], anaesthesia protocol, body weight, age, breed, sex, American Society of Anesthesiologists status, type of procedure, emergency or nonemergency, duration of anaesthesia, positioning, times spent in lateral and sternal recumbency during recovery, time until standing and nonassisted or assisted recovery on the assigned recovery score (good/bad) were investigated using generalized linear regression analysis (p < 0.05)., Results: Hypoxaemia and prolonged duration of anaesthesia were significantly associated with a bad recovery score. No other factors had a significant influence on recovery quality., Conclusion and Clinical Relevance: Hypoxaemia and prolonged anaesthesia duration have a negative effect on quality of anaesthetic recovery in horses. Clinically, this highlights the importance of keeping anaesthetic time as short as possible and to monitor oxygenation and treat hypoxaemia as soon as possible., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To test whether labetalol improved cardiovascular function in anaesthetized dogs injected with dexmedetomidine., Study Design: Prospective, randomized, blinded, clinical trial., Animals: A group of 20 healthy client-owned dogs undergoing ovariohysterectomy., Methods: Each dog received dexmedetomidine (5 μg kg -1 ) and methadone (0.2 mg kg -1 ) intramuscularly. General anaesthesia was induced with propofol and maintained with isoflurane in oxygen. All dogs were mechanically ventilated, and epidural anaesthesia with lidocaine was performed. Standard anaesthetic monitoring, invasive blood pressure, oesophageal Doppler and near-infrared tissue perfusion/oxygenation were applied. Peak velocity (PV), mean acceleration and stroke distance (SD) from the oesophageal Doppler were recorded. Arterial elastance (Ea) was calculated. Tissue oxygenation (rStO 2 ) was also recorded. Prior to surgery, animals received either 0.1 mg kg -1 of labetalol intravenously (IV) over 60 seconds or the equivalent volume of saline. Data were recorded for 20 minutes. Age, weight and propofol dose were compared with a Wilcoxon rank-sum test. The effects of time, treatment and their interaction with haemodynamic and perfusion variables were analysed with mixed-effect models and Tukey's post hoc tests., Results: Significant effects of the interaction between treatment and time were observed whereby heart rate (HR) was higher in dogs given labetalol (p = 0.01), whereas arterial blood pressure and Ea were lower (p < 0.01). Similarly, PV, SD and rStO 2 were higher in the labetalol group, and significant effects were detected for the interaction between treatment and time (p < 0.01)., Conclusions and Clinical Relevance: Labetalol at a dose of 0.1 mg kg -1 IV in dogs under general anaesthesia and administered a pre-anaesthetic medication of dexmedetomidine produced mild vasodilation (reduction of Ea), resulting in an increase in HR and left ventricular outflow. Although labetalol could be an effective option to achieve haemodynamic optimization after dexmedetomidine-induced vasoconstriction, future studies are needed to assess long-term effects., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

General anesthesia induces a reversible loss of consciousness (LOC), a state that is characterized by the inability to feel pain. Identifying LOC in animals poses unique challenges, because the method most commonly used in humans, responding to questions, cannot be used in animals. For over a century, loss of righting reflex (LORR) has been used to assess LOC in animals. This is the only animal method that correlates directly with LOC in humans and has become the standard proxy measure used in research. However, the reporting of how LORR is assessed varies extensively. This systematic literature review examined the consistency and completeness of LORR methods used in rats and mice. The terms 'righting reflex,' 'anesthesia,' 'conscious,' 'rats,' 'mice,' and their derivatives were used to search 5 electronic databases. The abstracts of the 985 articles identified were screened for indications that the study assessed LORR in mice or rats. Full texts of selected articles were reviewed for LORR methodological completeness, with reported methods categorized by 1) animal placement method, 2) behavioral presence of righting reflex, 3) duration of LORR testing, 4) behavioral LORR, and 5) animal position for testing LORR. Only 22 papers reported on all 5 methodological categories. Of the 22 papers, 21 used unique LORR methodologies, with descriptions of LORR methods differing in at least one category as compared with all other studies. This variability indicates that even papers that included all 5 categories still had substantial differences in their methodological descriptions. These findings reveal substantial inconsistencies in LORR methodology and reporting in the biomedical literature likely compromising study replicability and data interpretation.

Objective: To investigate the effect of isoflurane anesthesia on thermoregulation and peripheral heat loss in dorsally recumbent horses., Study Design: Prospective, clinical study., Animals: Seven adult horses (2.6 ± 1.5 years old, 455 ± 70.2 kg)., Methods: Horses underwent elective surgical procedures in dorsal recumbency under general anesthesia (GA) maintained with isoflurane in oxygen. Rectal (T R ), intranasal (T N ) and fetlock surface temperatures (T F ) were measured every 10 minutes for the first 80 minutes following induction of GA. Room temperature (T RO ) was monitored during the study. Statistical analysis to determine differences between temperature measurement sites and techniques (T R , T N and T F ), and differences over time were completed using a mixed-effects model with Tukey's multiple comparison or Dunnett's multiple comparison testing where appropriate. Significance was set at p < 0.05., Results: Following induction of anesthesia, T F was significantly increased compared with baseline (0 minutes) from 40 to 80 minutes (p < 0.01). No significant differences were detected in T R and T N at any time point compared with baseline (p > 0.05). T F was significantly lower than T N (p < 0.02) at all time points and T R from times 0 to 70 minutes (p < 0.04). There were no significant differences between T R and T N at any time (p > 0.05)., Conclusions: In horses undergoing isoflurane GA, T F increased, indicating peripheral heat loss likely because of vasodilation, whereas T R showed a clinically relevant decrease over time. These findings are suggestive of body heat redistribution during GA in horses in dorsal recumbency. Thermographic imaging of the peripheral limbs in combination with T R and T N monitoring allowed for recognition of peripheral heat redistribution in anesthetized horses., Clinical Relevance: Anesthetized horses experience peripheral heat loss through their extremities as a result of vasodilation. Mitigating peripheral heat loss may improve thermoregulation and reduce hypothermic complications in anesthetized horses., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate the effect of a single intravenous injection of branched chain amino acids (BCAAs) on body temperature in cats undergoing general anesthesia., Study Design: Prospective, blinded, randomized, crossover, experimental study., Animals: A total of 10 healthy adult cats (five female and five male)., Methods: Cats were anesthetized three times with three different treatments in a random order: 3 mL kg -1 lactated Ringer's solution (LRS), 100 mg kg -1 BCAAs (B100) or 200 mg kg -1 BCAAs (B200) solution immediately before induction of anesthesia. After induction, rectal temperature was measured every 5 minutes. Blood samples were collected for the measurement of blood glucose (BG) just before induction, at the end of the 90 minute period of anesthesia, and 24 hours after anesthesia induction. The differences between baseline and each subsequent rectal temperature, and BG measurements were analyzed. Areas under the curve (AUCs) for temperature differences were calculated for each animal for the anesthetic period (AUC T0-90 ). Parametric or nonparametric data were analyzed by one-way repeated measures anova or Friedman test. A value of p < 0.05 was considered significant., Results: There were no significant differences in AUC T0-90 between groups: 41.6 ± 7.7 for LRS, 43.4 ± 6.9 for B100 and 42.9 ± 7.5 for B200 (p = 0.368). No significant differences were observed in BG between groups at 90 minutes and 24 hours after anesthesia induction (p = 0.283 and p = 0.089, respectively). The incidence of hypoglycemia [BG ≤ 3.17 mmol L -1 (57 mg dL -1 )] after anesthesia tended to be higher in both B100 (4/10 cats) and B200 groups (3/10 cats) than in LRS group (1/10 cats)., Conclusions and Clinical Relevance: A single, preanesthetic intravenous injection of BCAAs did not attenuate heat loss during anesthesia. More cats were hypoglycemic in the BCAA groups than in the LRS group., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objective: To evaluate the relationship between oxygen reserve index (ORI) and arterial partial pressure of oxygen (PaO 2 ) in anesthetized dogs., Study Design: Prospective experimental study., Animals: A total of eight healthy adult Beagle dogs with a median age of 38 (range 20-87) months and a median body mass of 8.6 (range 7.0-13.8) kg., Methods: After induction of general anesthesia with propofol, dogs were mechanically ventilated and anesthesia maintained with isoflurane carried in oxygen. Arterial blood samples were collected from a catheter placed in the femoral artery. ORI was measured by placing a CO-oximeter sensor on the tongue. Inspired oxygen fraction (FiO 2 ) was increased from 21% to > 95% in increments of 5%. PaO 2 and ORI were recorded and compared at different times. The relationship between ORI and PaO 2 was investigated using a nonlinear function, the Hill equation, and a linear regression analysis was performed, as appropriate., Results: A total of 128 pairs of values were compared for all dogs. Applying the Hill equation to the relationship between ORI and PaO 2 resulted in R 2  = 0.80 (p < 0.001) with a Hill coefficient of 3.7. It was predicted that ORI ranged 0.1-0.9 as PaO 2 ranged 127.0-417.9 mmHg and that in the more linear portion of the range, PaO 2 of 127.0-289.9 mmHg ORI ranged 0.1-0.7. Linear regression analysis in the more linear portion showed a weak correlation (R 2  = 0.29, p = 0.006)., Conclusions and Clinical Relevance: In the present study, the Hill equation predicted the relationship between PaO 2 and ORI for PaO 2 ranging 127.0-417.9 mmHg in anesthetized dogs. However, in the linear portion of the PaO 2 , the coefficient of determination was low, indicating that ORI is not a surrogate for PaO 2 ., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Background: The inclusion of dexmedetomidine (DEX) within a balanced general anaesthesia protocol is effective in improving the clinical outcome and recovery quality of anaesthesia in horses. This study aimed to determine the pharmacokinetic profile of DEX following repeated subcutaneous (SC) administration at 2 µg/kg every 60 min till the end of the procedure in comparison to intravenous constant rate infusion (CRI) at 1 µg/kg/h in anaesthetized horses undergoing diagnostic procedures up to the end of the diagnostic procedure., Results: In the CRI and SC groups DEX maximum concentrations (C max ) were 0.83 ± 0.27 ng/mL and 1.14 ± 0.71 ng/mL, respectively, reached at a time (T max ) of 57.0 ± 13.4 min and 105.5 ± 29.9 min. Mean residence time to the last measurable concentration (MRT last ) was 11.7 ± 6.2 and 55.8 ± 19.7 min for the CRI group and SC groups, respectively. The apparent elimination half-life was 18.0 ± 10.0 min in the CRI group and 94.8 ± 69.8 min for the SC group, whereas the area under the curve (AUC 0-last ) resulted 67.7 ± 29.3 and 83.2 ± 60.5 min*ng/mL for CRI and SC group, respectively. Clearance was 16.26 ± 8.07 mL/min/kg for the CRI group. No signs of adverse effects were recorded in both groups., Conclusions: The pharmacokinetic profile of DEX following repeated SC administration in anaesthetized horses was comparable to intravenous CRI administration during the intranaesthetic period and beneficial during the recovery phase from general anaesthesia. The SC route could be considered as an alternative to CRI for improving the recovery quality of equine patients undergoing general anaesthesia., (© 2023. The Author(s).)

Objective: To describe the acquisition and pitfalls of a 3-view transesophageal echocardiography (TEE) protocol in anesthetized, dorsally recumbent dogs., Animals: 8 beagles, 1 to 2 years old, 7.4 to 11.2 kg., Methods: Dogs were anesthetized, mechanically ventilated, and placed in dorsal recumbency. A TEE probe was advanced, and 3 views were performed: midesophageal 4-chamber and long axis (ME 4C and ME LAX) and caudal esophageal short axis (CE SAX) at the level of the papillary muscles. Probe insertion depth, flexion, omniplane angle, and image acquisition time were recorded. Two observers assessed 24 video clips each and identified anatomical structures., Results: The ME 4C and ME LAX were obtained at 35 (30 to 40) cm insertion depth, omniplane at 0° and 103° (90 to 116), respectively. Views were obtained in ≤30 seconds once the TEE was in the cervical esophagus. Left-sided structures were identified in all cases, whereas right-sided structures were not always simultaneously obtained in the ME 4C, requiring further probe manipulation. All structures were identified on ME LAX. CE SAX was obtained at 40 (35 to 45) cm, omniplane at 0°, and in 15 (10 to 90) seconds. A true SAX view (circular left ventricle at the level of papillary muscles) could not be obtained in all dogs., Clinical Relevance: A 3-view TEE protocol using core views as those described in humans may be applicable to dogs under general anesthesia and in dorsal recumbency. The CE SAX view at the level of the papillary muscles appears more difficult to obtain with consistency than midesophageal views.

Surgical correction is the typical treatment for an entropion. However, considerable anesthetic risk exists for a subset of patients, particularly rabbits and guinea pigs. In a high number of these cases, this represents the main reason for reluctance to treat an entropion. The following report describes the case of a 9-year-old rabbit with a superficial cornea defect and a mild entropion of the upper eyelid. Eversion of the eyelid from a mild entropion to a normal position was attained by the subdermal injection of a hyaluronic acid filler (Alayna SG 24 Distinct ® , BSC Medical Devices GmbH, Munich, Germany) without necessitating general anesthesia or sedation. Following a period of 273 days, a relapse occurred which was subsequently successfully treated with a repeat injection. An entropion of the contralateral eye became evident during the follow-up period and was also effectively managed by a single subdermal filler injection. In the reported case, treatment with subdermal hyaluronic acid injection proved to be well tolerated and efficacious., Competing Interests: Die Autorin gibt an, dass kein Interessenkonflikt besteht., (Thieme. All rights reserved.)

Objective: To compare the effects of intramuscular premedication with a novel nonanalgesic [alfaxalone-midazolam-acepromazine (AMA)] and an analgesic [ketamine-midazolam-detomidine (KMD)] protocol on sedation end points and propofol requirements for induction of anesthesia in swine., Study Design: Prospective experimental study., Animals: A total of 27 Yorkshire cross gilts weighing approximately 30 kg., Methods: Two sedation protocols, AMA and KMD, were compared. Time from intramuscular injection to ataxia, recumbency and nonresponsiveness to tactile stimulation was recorded. The propofol dose requirement for induction of general anesthesia and tracheal intubation, and any adverse events (paddling, twitching), were recorded. Data were tested for normality using a Shapiro-Wilk test. Propofol requirements were compared using a Student's t test. Times from injection to sedation end points were compared using a Mood's test, and significance was confirmed using a Kaplan-Meier curve with Wilcoxon test survival analysis., Results: Sedation end points were reached significantly faster with KMD than with AMA. Nonresponsiveness occurred in 5 (0-16) and 9.5 (5-36) minutes for KMD and AMA, respectively (p = 0.011). No significant difference (p = 0.437) was found between propofol doses used in either group (KMD; 64.38 ± 5.98 mg, AMA; 72.00 ± 7.57 mg). More adverse events were noted with AMA (11/16 pigs) than with KMD (1/11 pigs)., Conclusions and Clinical Relevance: In pigs, AMA can be used as a reliable sedation protocol. Frequency of adverse events and time to reach sedation end points between AMA and KMD differed, but the dose of propofol needed to induce general anesthesia was not significantly different., (Copyright © 2023 Association of Veterinary Anaesthetists and American College of Veterinary Anesthesia and Analgesia. Published by Elsevier Ltd. All rights reserved.)

Objectives: To investigate the association between body mass and hypotension during general anaesthesia in dogs undergoing surgical and diagnostic procedures within a referral hospital., Materials and Methods: Retrospective evaluation of the anaesthetic records of 1789 dogs was performed. Data on signalment, anaesthetic protocol and physiological variables, including mean arterial pressure, were collected. A multivariable generalised linear model was used to identify associations between explanatory variables, including body mass, and hypotension., Results: In the population studied, increasing body mass (per 10 kg) was significantly associated with decreasing odds of hypotension (odds ratio 0.68; 95% confidence interval: 0.60 to 0.77). Additional variables associated with a decreased odds of hypotension were pre-anaesthetic medication with alpha-2 agonists (odds ratio 0.63; 95% confidence interval 0.48 to 0.82) and increased body temperature (per 1°C) during general anaesthesia (odds ratio 0.77; 95% confidence interval 0.67 to 0.88). Brachycephaly (odds ratio 1.72; 95% confidence interval 1.25 to 2.38), ASA physical status classification >3 (odds ratio 2.03; 95% confidence interval 1.16 to 3.56), undergoing a surgical procedure (versus diagnostic) (odds ratio 1.57; 95% confidence interval 1.10 to 2.23) and bradycardia (odds ratio 1.37; 95% confidence interval 1.05 to 1.80) were independently associated with increased odds of hypotension., Clinical Significance: Dogs of lower body mass and brachycephalic breeds may be at higher risk of hypotension during general anaesthesia or alternatively represent subpopulations in which accurate blood pressure measurement presents a greater challenge. Monitoring blood pressure accurately in these groups requires particular attention and provisions for treating hypotension should be readily accessible., (© 2023 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.)

Aim: The current research aimed to evaluate the potential effect of adding platelet-rich fibrin (PRF) to the decellularized bovine pericardium (DBP) on the distal limb of donkeys' full-thickness cutaneous wounds healing (Equus asinus)., Materials and Methods: Healthy male donkeys (n = 12) were used in this study. Under general anesthesia, 6 cm2 full-thickness incisions were made on the middle dorsolateral surface of both forelimbs' metacarpi. The left forelimbs were control wounds, while the right wounds were treated with PRF/DBP. Control wounds were bandaged with a standard dressing after saline irrigation and were evaluated at days 4, 7, 10, 13, 16, 19, 22, 25, and 28 post-wounding. PRF/DBP-treated wounds were dressed with a combination of PRF/DBP at the first, second, and third weeks post-wounding. Clinical and histopathological examinations of the wounds were performed to assess the healing process. Additionally, the immunohistochemical evaluation and gene expression profiles of myofibroblastic and angiogenic genes (transforming growth factor-β1, vascular endothelial growth factor-A, fibroblast growth factor 7 (FGF-7), and collagen type 3α1) were analyzed., Results: PRF/DBP wounds had a significantly faster healing process (61.3 ± 2.6 days) than control wounds (90.3 ± 1.4 days) (p < 0.05). The immunohistochemical examination and gene expression profile revealed significant enrichment in PRF/DBP wounds compared to control wounds., Conclusion: PRF/DBP dressing can be considered a natural and cost-effective biomaterial for enhancing the recovery of donkeys' distal limb injuries., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: Hypothermia during the perianaesthetic period may lead to an increased risk of morbidity in veterinary patients. However, the timeline of the decrease in body temperature during general anaesthesia has been minimally investigated., Methods: Anaesthetic records of 1097 client-owned dogs were examined. Change in body temperature (ΔBT = baseline temperature - time point temperature) was plotted over time for all dogs. The slope of ΔBT was calculated for each 15-minute interval, and the magnitude of the largest ΔBT and the time point at which the largest ΔBT occurred were determined for each record., Results: A rapid decline in ΔBT occurred from 0 to 15 minutes, a slower decline occurred from 15 to 60 minutes and a plateau occurred from 60 to 240 minutes. The largest ΔBT occurred at 75 (15-240) minutes from baseline, with a maximum ΔBT of -2.06°C (-0.06°C to -8.72°C)., Limitations: This is a retrospective study. As such, there were missing data points and potential confounding factors could not be controlled for., Conclusions: Anaesthetised dogs exhibited a distinct pattern of decrease in body temperature, with the most rapid reduction occurring within the first 15 minutes. The effects of procedures and anaesthetic agents on the timeline and pattern of heat loss warrant further investigation., (© 2023 British Veterinary Association.)

Cardiovascular disease is a frequent cause of death in the critically endangered Vancouver Island marmots ( Marmota vancouverensis ). This warrants the use of anesthetic protocols with minimal cardiovascular adverse effects. In this study, 12 adult male woodchucks ( Marmota monax ) were used as models for Vancouver Island marmots. The objective was to compare the physiological effects of two premedication protocols during induction and maintenance of anesthesia with sevoflurane. The two premedications were ketamine 10 mg/kg and midazolam 0.5 mg/kg (KM) or ketamine 10 mg/kg, midazolam 0.5 mg/kg, and butorphanol 1.0 mg/kg (KMB), administered intramuscularly prior to mask induction. Each marmot underwent three anesthetic events and protocols were assigned using a blinded randomized crossover design. Heart rate, respiratory rate, oxygen saturation, and body temperature were recorded throughout, and blood gases were assessed following induction. Resistance to induction was scored and time to induction was recorded. Although mask induction with sevoflurane was successful in all events (mean induction time of 2.1 min), KMB premedication resulted in a faster induction (mean induction time reduced by 1.2 ± 0.3 min) and lower resistance scores. Both protocols resulted in significant cardiovascular and respiratory depression; however, animals that received KMB were more hypercapnic than KM by 8.8 ± 2.8 mm Hg ( P = 0.03) (mean venous partial pressure of carbon dioxide [PvCO2] for all: 79.9 mm Hg). In conclusion, if shorter induction times are desired, KMB premedication is preferred. However, cardiorespiratory variables including blood pressure should be monitored, and endotracheal intubation is recommended to allow for ETCO2 monitoring and provision of intermittent positive pressure ventilation.

The primary purpose of perioperative IV fluid administration is to preserve tissue perfusion by maintaining or restoring the effective circulating intravascular volume. Fluids are drugs that produce beneficial or harmful effects dependent upon their composition, osmotic potential, kinetics, and dose. Appropriate dosing requires an understanding of body fluid compartments, fluid balance, and the administered fluids' behavior in the body. Anesthetic drugs and general anesthesia produce CNS, neuroendocrine, and macro-/microvascular hemodynamic effects. These effects modulate the response to IV fluid administration and promote interstitial fluid accumulation, third-space fluid loss, and fluid overload. This narrative review discusses current knowledge regarding anesthesia-associated physiologic and IV fluid kinetic changes that influence the efficacy of IV fluid administration during the intraoperative period. A rationale for intraoperative fluid dosing that addresses intraoperative hypotension, blood loss, and practices that promote fluid overload is provided. Intraoperative IV fluid administration should be individualized and monitored by dynamic goal-directed methods that evaluate fluid responsiveness.

Systemic anesthesia in penguins is often achieved using inhalation anesthetic agents alone, and information on injectable drugs for systemic anesthesia is limited. General anesthesia with a minimal effect on circulatory dynamics is necessary to perform noninvasive examinations and treatments in animals, including penguins. In this study, alfaxalone (ALFX), an injectable anesthetic agent, was examined to establish the optimal anesthetic method for gentoo penguins ( Pygoscelis papua ). Alfaxalone was administered intravenously through the metatarsal vein, and anesthesia was maintained by a constant rate infusion (CRI). A biological monitor was used to record numerous clinical indices, and the anesthetic depth was evaluated every 5 minutes during anesthesia; the CRI was adjusted until the optimal anesthetic depth was obtained. Anesthesia depth was assessed, and the CRI rate was adjusted. The CRI was stopped, and the time until recovery was recorded. Blood samples were collected to analyze plasma concentrations of ALFX. The mean total dose of ALFX required for anesthetic induction was 9 ± 1.9 mg/kg, the intubation time was 126 ± 21 seconds, and the maintenance infusion rate of ALFX was 0.3 ± 0.08 mg/kg/min. The time from discontinuation of anesthesia to extubation was 42 ± 23 minutes, and the time to recovery was 90 ± 33 minutes. Significant changes in the heart rate and blood pressure were not observed during the anesthetic events. The plasma concentration of ALFX under stable anesthesia was 6734 ± 4386 ng/mL (range, 3315-14 326 ng/mL). Although anesthesia using ALFX tended to result in a prolonged time to recovery in gentoo penguins, rapid induction of anesthesia and stable hemodynamics during anesthetic maintenance were achieved. Therefore, ALFX may be considered a suitable anesthetic method for noninvasive examinations and treatments in penguins.

Objective: To evaluate the effects of rocuronium and sugammadex on the patient state index (PSI) in dogs anesthetized with propofol., Animals: 6 intact healthy male Beagles., Procedures: Anesthesia was induced with and maintained on a propofol infusion. The estimated plasma propofol concentration (ePC) was recorded. Baseline PSI and train-of-four ratio (TOFR) readings were collected for 2 minutes in stable general anesthesia. Neuromuscular blockade (NMB) was induced with 0.6 mg/kg, IV, rocuronium, and full NMB was confirmed with a TOFR of 0. After 5 minutes, the neuromuscular function was restored with 4 mg/kg sugammadex, IV (reversal), and monitored for 5 minutes. Throughout the data collection, ePC, PSI, and TOFR were recorded every 15 seconds and compared with mixed-effect ANOVA., Results: Baseline ePC, PSI, and TOFR were 3.63 ± 0.38, 41 ± 6, and 0.97 ± 0.08 µg/mL, respectively. There was no difference between the baseline of ePC and PSI from NMB or reversal. Compared to the baseline, the TOFR decreased to 0 with NMB (P < .001) and returned to 0.96 ± 0.08 (P = .721) on reversal. After 5 minutes, sugammadex fully reversed 5 out of 6 dogs to TOFR > 0.90 and partially reversed 1 animal to TOFR = 0.80., Clinical Relevance: There was no evidence that NMB with rocuronium and sugammadex-induced reversal interfered with PSI readings under steady-state total intravenous anesthesia with propofol. Further evaluation of PSI is warranted to assess its utility in a clinical population to detect changes in levels of consciousness during NMB.

Objective:  The aim of this article was to describe the technique and outcomes of standing surgical management of splint bone fractures and to compare outcome variables and hospitalization cost to a group with similar fractures treated under general anaesthesia., Study Design:  It is a single-institution retrospective study. Surgical technique, surgical time, hospitalization cost and complications were retrieved from the medical records of horses treated surgically for splint bone fractures (2008-2020). Owner telephone follow-up provided data about athletic outcome, client satisfaction and cosmetic appearance., Results:  Forty-nine horses (13 standing, 36 under general anaesthesia) with 57 fractures (18 contaminated and 39 non-contaminated) were included. Seven fractures were in the proximal third (4 standing, 3 under general anaesthesia), 18 in the middle third (5 standing, 13 under general anaesthesia) and 30 were distal (4 standing, 26 under general anaesthesia). No significant difference between groups in surgical time was found (p= 0.8). Average total cost was 522 CAN$ lower for the standing group for non-contaminated fractures (p= 0.02). Three horses of the general anaesthesia group demonstrated postoperative colic signs and one case of the standing group was re-operated due to sequestration. Based on follow-up information (range: 3.8-151.2 months), no significant differences in cosmetic and athletic outcomes were found between groups., Conclusion:  Surgical management of splint bone fractures in the standing horse is a valuable alternative for horses selected based on behaviour. When compared to general anaesthesia, standing management of splint bone fractures did not alter the surgical time or outcome variables and avoided general anaesthesia-associated risks., Competing Interests: None declared., (Thieme. All rights reserved.)