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Objective To determine biomarkers for impending fluid overload during intravenous fluid administration in a feline haemorrhage-resuscitation model. Study design Randomized crossover study. Animals A group of six domestic cats (mean age and weight: 21 months; 4.9 kg, respectively). Methods The cats underwent three treatments, 2 months apart. They were anaesthetized and instrumented to measure a range of physiological, blood gas, haematological and biochemical variables over time. Samples were taken during a health check, before haemorrhage, after haemorrhage and then at 30 minute intervals during fluid resuscitation and 24 hours later. The three treatments were: 1) control, sham haemorrhage and resuscitation; 2) lactated Ringer’s solution (LRS); and 3) 6% tetrastarch 130/0.4 (Vol) where the cats underwent a controlled haemorrhage then resuscitation by administering LRS and Vol at 60 and 20 mL kg–1 hour–1, respectively, for 120 minutes. Fluid overload was identified by nasal discharge and radiographic evidence. Biomarkers were variables that exceeded the reference interval for cats during treatment. Potential biomarkers were analysed using receiver operating characteristic curves (p Results Mean ± standard deviation total blood loss was 10.2 ± 2.3, 29.3 ± 9.0 and 29.1 ± 6.3 mL kg–1 for control, LRS and Vol, respectively. The total volume of LRS and Vol administered was 120 and 40 mL kg–1, respectively. Haematocrit, albumin, magnesium, chloride-to-sodium ratio and sodium-chloride difference were identified as potential biomarkers. These variables exceeded the reference intervals from 30 minutes of resuscitation onwards. A chloride-to-sodium ratio > 0.84 was the most sensitive (90%) and specific (75%) of all potential biomarkers. Conclusions and clinical relevance Changes in physiological variables, haematocrit and albumin were poor biomarkers of impending fluid overload compared with electrolytes. Finding the ideal biomarker to identify impending fluid overload of commonly used intravenous fluids should improve the safety of their administration in cats.

To compare the effect of invasive continuous positive airway pressure (CPAP), pressure-controlled ventilation (PCV) with positive end-expiratory pressure (PEEP) and spontaneous breathing (SB) on PaOProspective randomized crossover study.A group of 15 adult male dogs undergoing elective orchidectomy.Dogs were anaesthetized [buprenorphine, medetomidine, propofol and isoflurane in an air oxygen (FiOMedian PaOCPAP resulted in similar arterial oxygenation, CO

To describe acid-base status using the Henderson-Hasselbalch, Stewart and semi-quantitative methods of analysis in a feline haemorrhage-resuscitation model.Randomized crossover study.A total of six domestic cats (mean age, 21 months; weight, 4.9 kg).Venous blood samples were taken before haemorrhage, after haemorrhage at 30 minute intervals during fluid resuscitation and at 24 hours. The cats were anaesthetized and underwent following treatments: no purposeful haemorrhage and resuscitation (NoPHR), purposeful haemorrhage followed by either lactated Ringer's solution (LRS) or 6% tetrastarch 130/0.4 (Voluven) for resuscitation. LRS and Voluven were administered at 60 and 20 mL kgThe total blood loss at 120 minutes was 10.2 ± 2.3, 29.3 ± 9.0 and 29.1 ± 6.3 mL kgIn an experimental haemorrhage and resuscitation model in cats, blood pH was similar among treatments over time regardless of severe haemorrhage and resuscitation with LRS or Voluven or mild haemorrhage and no resuscitation.

Objective To compare the effects of thiopentone, propofol and alfaxalone on arytenoid cartilage motion and establish the dose rates to achieve a consistent oral laryngoscopy examination. Study design Randomised crossover study. Animals Six healthy adult Beagle dogs. Methods Each dog was randomly administered three induction agents with a 1-week washout period between treatments. Thiopentone (7.5 mg kg −1 ), propofol (3 mg kg −1 ) or alfaxalone (1.5 mg kg −1 ) was administered over 1 minute for induction of anaesthesia. If the dog was deemed inadequately anaesthetised, then supplemental boluses of 1.8, 0.75 and 0.4 mg kg −1 were administered, respectively. Continual examination of the larynx, using a laryngoscope, commenced once an adequate anaesthetic depth was reached until examination end point. The number of arytenoid motions and vital breaths were counted during three time periods and compared over time and among treatments. Data were analysed using Friedman and Mann–Whitney U tests, Spearman rho and a linear mixed model with post hoc pairwise comparison with Tukey correction. Results The median (range) induction and examination times were 2.8 (2.0–3.0), 2.7 (2.0–3.3) and 2.5 (1.7–3.3) minutes ( p = 0.727); and 14.1 (8.0–41.8), 5.4 (3.3–14.8) and 8.5 (3.8–31.6) minutes ( p = 0.016) for thiopentone, propofol and alfaxalone, respectively. The median dose rates required to achieve an adequate anaesthetic depth were 6.3 (6.0–6.6), 2.4 (2.4–2.4) and 1.2 (1.2–1.2) mg kg −1 minute −1 , respectively. There was no significant difference for the total number of arytenoid motions ( p = 0.662) or vital breaths ( p = 0.789) among induction agents. Conclusion and clinical relevance The number of arytenoid motions were similar among the induction agents. However, at the dose rates used in this study, propofol provided adequate conditions for evaluation of the larynx with a shorter examination time which may be advantageous during laryngoscopy in dogs.

In order to develop a long-term anesthesia for flighty antelope species in field situations, two different protocols for induction and maintenance with an intravenous infusion were evaluated in wild-caught impala ( Aepyceros melampus ). Ten adult female impala were induced with two induction protocols: one consisted of 0.2 mg/kg medetomidine, 4 mg/kg ketamine, and 0.15 mg/kg butorphanol (MKB) and one consisted of 0.375 mg/kg etorphine, 0.2 mg/kg medetomidine, and 0.2 mg/kg midazolam (EMM). In both treatments, anesthesia was maintained with a continuous intravenous infusion (CII) at an initial dose rate of 1.2 μg/kg per hr medetomidine, 2.4 mg/kg per hr ketaminen and 36 μg/kg per hr midazolam. Partial reversal was achieved with naltrexone (2 : 1 mg butorphanol; 20 : 1 mg etorphine) and atipamezole (5 : 1 mg medetomidine). Evaluation of anesthesia included respiratory rate, heart rate, rectal temperature, arterial blood pressure, oxygen saturation, end tidal carbon dioxide tension, and tidal volume at 5-min intervals, palpebral reflex and response to painful stimuli at 15-min intervals, and arterial blood gases at 30-min intervals. Plasma cortisol concentration was determined after induction and before reversal. Duration and quality of induction and recovery were evaluated. EMM caused a faster induction of 9.5 ± 2.9 min compared to 11.0 ± 6.4 min in MKB. Recovery was also quicker in EMM (EMM: 6.3 ± 5.4 min; MKB: 9.8 ± 6.0 min). However, EMM also produced more cardiopulmonary side effects, including hypoxemia and hypercapnia, and calculated oxygenation indices (PaCO

Objective To determine whether physiological, haematological, biochemical or electrolyte variables can predict severe haemorrhage in cats. Study design Randomized crossover study whereby each cat underwent mild and severe haemorrhage, with a 2 month period between events. Animals A group of six domestic cats aged 21 ± 1 months and weighing 4.9 ± 1.2 kg, mean ± standard deviation. Methods Cats were anaesthetized (buprenorphine, alfaxalone, isoflurane in oxygen at a fixed end-tidal concentration of 1.7%) before the haemorrhage event. In total, 34 variables were measured twice (prehaemorrhage and posthaemorrhage). The difference and percent change for each variable were compared between haemorrhage events (paired t test). Significant variables were placed into 13 different ratios (posthaemorrhage value of one variable divided by a posthaemorrhage value of a second variable) and compared (paired t test), and Cohen’s d (d) was calculated. Receiver operating characteristic curves were plotted and cut-off values for weak, moderate and strong indicators of severe haemorrhage were obtained. Results The blood loss was 4.5 ± 1.1 mL kg–1 and 26.8 ± 5.5 mL kg–1 for mild and severe haemorrhage events, respectively. The most significant variables with large effect sizes were heart rate (HR), systolic arterial blood pressure (SAP), end-tidal carbon dioxide (P e′ CO2), serum albumin, haematocrit and actual bicarbonate ion concentration [HCO3−(act)]. The most robust ratios were: 1) shock index (d = –2.8; HR:SAP); 2) HR:P e ′CO2 (d = –2.9); 3) serum albumin: haematocrit (d = 1.5); and 4) HR:HCO3−(act) (d = –1.6). These ratios were included in the final proposed Cat Acute Bleeding Scoring System (CABSS). Conclusions and clinical relevance Cats subjected to mild and severe haemorrhage demonstrated statistically and clinically relevant changes whereby four ratios could be created to make up the CABSS. The ratios detected and quantified the presence of severe haemorrhage in anaesthetized cats.

There is a growing necessity to perform long-term anesthesia in wildlife, especially antelope. The costs and logistics of transporting wildlife to veterinary practices make surgical intervention a high-stakes operation. Thus there is a need for a field-ready total intravenous anesthesia (TIVA) infusion to maintain anesthesia in antelope. This study explored the feasibility of an etorphine-ketamine-medetomidine TIVA for field anesthesia. Ten wild-caught, adult impala ( Aepyceros melampus ) were enrolled in the study. Impala were immobilized with a standardized combination of etorphine (2 mg) and medetomidine (2.2 mg), which equated to a median (interquartile range [IQR]) etorphine and medetomidine dose of 50.1 (46.2-50.3) and 55.1 (50.8-55.4) μg/kg, respectively. Recumbency was attained in a median (IQR) time of 13.9 (12.0-16.5) min. Respiratory gas tensions, spirometry, and arterial blood gas were analyzed over a 120-min infusion. Once instrumented, the TIVA was infused as follows: etorphine at a variable rate initiated at 40 μg/kg per hour (adjusted according to intermittent deep-pain testing); ketamine and medetomidine at a fixed rate of 1.5 mg/kg per hour and 5 μg/kg per hour, respectively. The etorphine had an erratic titration to clinical effect in four impala. Arterial blood pressure and respiratory and heart rates were all within normal physiological ranges. However, arterial blood gas analysis revealed severe hypoxemia, hypercapnia, and acidosis. Oxygenation and ventilation indices were calculated and highlighted possible co-etiologies to the suspected etorphine-induced respiratory depression as the cause of the blood gas derangements. Impala recovered in the boma post atipamezole (13 mg) and naltrexone (42 mg) antagonism of medetomidine and etorphine, respectively. The etorphine-ketamine-medetomidine TIVA protocol for impala may be sufficient for field procedures of up to 120-min duration. However, hypoxemia and hypercapnia are of paramount concern and thus oxygen supplementation should be considered mandatory. Other TIVA combinations may be superior and warrant further investigation.

A 4-month-old female blue wildebeest (Connochaetes taurinus) was presented for bilateral pelvic limb fracture repair. Clinical examination under anaesthesia revealed a water-hammer pulse and a haematocrit of 0.13. A xenotransfusion was performed using bovine (Bos taurus) erythrocytes because of inability to acquire a wildebeest donor. Clinical parameters improved following transfusion and the post-operative haematocrit value was 0.31. The wildebeest remained physiologically stable with a gradually declining haematocrit for the next three days. On the third post-operative day, the wildebeest refractured its femur and was humanely euthanised because of the poor prognosis for further fracture repair. Xenotransfusion using blood from domestic ruminants represents a life-saving short-term emergency treatment of anaemic hypoxia in wild ungulates. Domestic goats could be used as blood donors for rare ungulates where allodonors are not available.

Objective To compare the cardiopulmonary effects of propofol total intravenous anaesthesia (TIVA) with isoflurane in cheetahs (Acinonyx jubatus) to evaluate feasibility for field use. Study design Prospective clinical study. Animals A group of 24 adult cheetahs, 12 per group. Methods Cheetahs were immobilized with zolazepam/tiletamine (1.2 mg kg−1) and medetomidine [40 μg kg−1, both intramuscular (IM)] by darting. A maintenance protocol of propofol TIVA (group P) or isoflurane inhalation (group I) was assigned randomly to each cheetah. Anaesthesia was maintained for at least 60 minutes. Cheetahs breathed spontaneously throughout; oxygen was supplemented at 3 L minute−1. Cardiopulmonary parameters were recorded at 5 minute intervals and three arterial blood gas samples were analysed. Following maintenance, atipamezole was administered IM (200 μg kg−1) and recovery was observed. Data are reported as mean ± standard deviation; variables over time were compared using a linear mixed model (fixed: time, treatment; random: cheetah). Results Lack of response to manipulations was maintained in all cases (end-tidal isoflurane percentage 1.1 ± 0.1%, propofol rate maintained at 0.1 mg kg−1 minute−1). The heart and respiratory rates were acceptable throughout maintenance. The end-tidal carbon dioxide tension increased slowly [44.0 ± 5.0 mmHg (5.87 ± 0.67 kPa)] with no differences between groups. All cheetahs were initially markedly hypertensive [mean arterial blood pressure (MAP): (163 ± 17 mmHg)]. The MAP normalized for group I (125 ± 30 mmHg) but remained high for group P (161 ± 17 mmHg) (p Conclusions and clinical relevance Both protocols provided acceptable cardiopulmonary values. Propofol may be an alternative to isoflurane for field use, but the prolonged recovery may make it less suitable for long-term anaesthesia.

Objective To characterize a propofol–medetomidine-ketamine total intravenous anaesthetic in impala ( Aepyceros melampus). Study design Prospective clinical study. Animals Ten adult female impala. Materials and methods Impala were immobilized at 1253 m above sea level with 2.0 mg thiafentanil and 2.2 mg medetomidine via projectile darts. Propofol was given to effect (0.5 mg kg −1 boluses) to allow endotracheal intubation, following which oxygen was supplemented at 2 L minute −1 . Anaesthesia was maintained with a constant-rate infusion of medetomidine and ketamine at 5 μg kg −1 hour −1 and 1.5 mg kg −1 hour −1 , respectively, and propofol to effect (initially 0.2 mg kg −1 minute −1 ) for 120 minutes. The propofol infusion was titrated according to reaction to nociceptive stimuli every 15 minutes. Cardiopulmonary parameters were monitored continuously and arterial blood gas samples were analysed intermittently. After 120 minutes' maintenance, the thiafentanil and medetomidine were antagonized using naltrexone (10:1 thiafentanil) and atipamezole (5:1 medetomidine), respectively. Results All impala were successfully immobilized. The median dose [interquartile range (IQR)] of propofol required for intubation was 2.7 (1.9–3.3) mg kg −1 . The propofol–medetomidine–ketamine combination abolished voluntary movement and ensured anaesthesia for the 120 minute period. Propofol titration showed a generally downward trend. Median (IQR) heart rate [57 (53–61) beats minute −1 ], respiratory rate [10 (9–12) breaths minute −1 ] and mean arterial blood pressure [101 (98–106) mmHg] were well maintained. Arterial blood gas analysis indicated hypoxaemia, hyper- capnia and acidaemia. Butorphanol (0.12 mg kg −1 ) was an essential rescue drug to counteract thiafentanil-induced respiratory depression. All impala regurgitated frequently during the maintenance period. Recovery was calm and rapid in all animals. Median (IQR) time to standing from antagonist administration was 4.4 (3.2–5.6) minutes. Conclusions and clinical relevance A propofol–medetomidine–ketamine combination could provide adequate anaesthesia for invasive procedures in impala. The propofol infusion should begin at 0.2 mg kg −1 minute −1 and be titrated to clinical effect. Oxygen supplementation and airway protection with a cuffed endotracheal tube are essential.

Induction of anaesthesia occasionally has been associated with undesirable behaviour in dogs. High quality of induction of anaesthesia with propofol has been well described while in contrast variable induction and recovery quality has been associated with diazepam-ketamine. In this study, anaesthetic induction and recovery characteristics of diazepam-ketamine combination with propofol alone were compared in dogs undergoing elective orchidectomy. Thirty-six healthy adult male dogs were used. After habitus scoring (simple descriptive scale [SDS]), the dogs were sedated with morphine and acepromazine. Forty minutes later a premedication score (SDS) was allocated and general anaesthesia was induced using a combination of diazepam-ketamine (Group D/K) or propofol (Group P) and maintained with isoflurane. Scores for the quality of induction, intubation and degree of myoclonus were allocated (SDS). Orchidectomy was performed after which recovery from anaesthesia was scored (SDS) and times to extubation and standing were recorded. Data were analysed using descriptive statistics and Kappa Reliability and Kendall Tau B tests. Both groups were associated with acceptable quality of induction and recovery from anaesthesia. Group P, however, was associated with a poorer quality of induction (p = 0.014), prolonged induction period (p = 0.0018) and more pronounced myoclonus (p = 0.003), but had better quality of recovery (p = 0.000002) and shorter recovery times (p = 0.035) compared with Group D/K. Diazepam-ketamine and propofol are associated with acceptable induction and recovery from anaesthesia. Propofol had inferior anaesthetic induction characteristics, but superior and quicker recovery from anaesthesia compared with diazepam-ketamine.

Radiological examination and surgical biopsy were required of a swelling in the cervical region in a healthy 200 kg, six-month-old hand-reared female giraffe ( Giraffa camelopardalis ). Induction was with intramuscular administration of medetomidine, butorphanol and ketamine and maintained with 1.5 per cent isoflurane-in-oxygen on a circle anaesthetic machine. Induction and maintenance were uneventful but recovery delayed and characterised by hindlimb weakness, opistotonus and torticollis of the head and neck. Atipamezole and naltrexone were administered to facilitate recovery but with minimal clinical improvement. Venous blood gas analysis indicated moderate metabolic acidosis, hypochloraemia, increased anion gap and marked hypocalcaemia (0.64 mmol/l). Intravenous administration of 60 ml calcium borogluconate resulted in a rapid improvement in muscle tone and the ability to stand. Hypocalcaemia was diagnosed in a juvenile giraffe after anaesthesia characterised by delayed recovery. Intravenous administration of calcium borogluconate resulted in rapid recovery of muscle strength and ambulance.