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Background and objectives: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetic cardiomyopathy characterized by potentially lethal ventricular tachycardia. Here we describe a patient with ARVC and an Implantable Cardioverter Defibrillator (ICD) in whom maxillary sinus surgery was performed under general anesthesia. Case report: The patient was a 59 year-old man who was scheduled to undergo maxillary sinus surgery under general anesthesia. He had been diagnosed as having ARVC 15 years earlier and had undergone implantation of an ICD in the same year. Electrocardiography showed an epsilon wave in leads II, aVR, and V1–V3. Cardiac function was within normal range on transthoracic echocardiography. The ICD was temporarily deactivated after the patient arrived in the operating room and an intravenous line was secured. An external defibrillator was kept on hand for immediate defibrillation if any electrocardiographic abnormality was detected. Remifentanil 0.3 μg/kg/min, fentanyl 0.1 mg, propofol 154 mg, and rocuronium 46 mg were administered for induction of anesthesia. Tracheal intubation was performed orally. Anesthesia was maintained oxygen 1.0 L.min−1, air 2.0 L.min−1, propofol 5.0–7.0 mg.kg−1.h−1, and remifentanil 0.1–0.25 μg.kg−1.min−1. The surgery was completed as scheduled and the ICD was reactivated. The patient was then extubated after administration of sugammadex 200 mg. Conclusion: We report the successful management of anesthesia without lethal arrhythmia in a patient with ARVC and an ICD. An adequate amount of analgesia should be administered during general anesthesia to maintain adequate anesthetic depth and to avoid stress and pain. Resumo: Introdução e objetivo: A Cardiomiopatia Arritmogênica do Ventrículo Direito (CAVD) é uma cardiomiopatia genética caracterizada por taquicardia ventricular potencialmente letal. Descrevemos um paciente com CAVD com Cardioversor Desfibrilador Implantável (CDI) submetido a anestesia geral para cirurgia de seio maxilar. Relato do caso: Paciente masculino, 59 anos, a ser submetido a anestesia geral para cirurgia de seio maxilar. O paciente foi diagnosticado com CAVD há 15 anos, momento em que foi submetido a implante de CDI. A eletrocardiografia mostrou onda épsilon nas derivações II, aVR e V1–V3. O ecocardiograma transtorácico revelou função cardíaca normal. Após a entrada do paciente na sala de cirurgia, o CDI foi temporariamente desativado e uma via intravenosa foi instalada. Um desfibrilador externo foi mantido próximo ao paciente caso fosse detectada alguma anormalidade eletrocardiográfica que indicasse desfibrilação do paciente. Foram administrados 0,3 mg/kg/min de remifentanil, 0,1 mg de fentanil, 154 mg de propofol e 46 mg de rocurônio para indução da anestesia. A intubação traqueal foi realizada por via oral. A anestesia foi mantida com 1 L/min de oxigênio, 2 L/min de ar, 5–7 mg/kg/h de propofol e 0,1–0,25 μg/kg/min de remifentanil. O procedimento cirúrgico proposto foi concluído e o CDI foi reativado. O tubo traqueal foi retirado após administração de 200 mg de sugamadex. Conclusão: Descrevemos técnica de anestesia bem sucedida sem arritmia letal em paciente com CAVD e CDI. Analgesia adequada deve ser administrada durante a anestesia geral para manter profundidade anestésica correta e evitar estresse e dor.

Summary Priming doses of non-depolarising neuromuscular blocking drugs given before administration of anaesthetic agents have been used to hasten the onset of neuromuscular blockade In the settings of coronavirus disease 2019 (COVID-19), this could be used to reduce the apnoeic, and potentially aerosol-generating, window To our knowledge, we report the first cases of tracheal intubation with rocuronium for COVID-19 using the priming principle Both patients needed their tracheas intubated for severe hypoxia using a rapid sequence induction technique with a priming dose of rocuronium Despite adequate pre-oxygenation a sudden, unexpected fall in arterial oxygen saturations was observed in both patients after administration of a priming dose of 2 mg of rocuronium Clinicians should consider this possible risk associated with priming doses of neuromuscular blocking drugs in the management of patients with respiratory failure due to COVID-19

Background: It is presently unclear whether the hemodynamic response to intubation is less marked with indirect laryngoscopy using the GlideScope (GlideScope) than with direct laryngoscopy using the Macintosh laryngoscope. Thus, the aim of this study was to determine whether using the GlideScope lowers the hemodynamic response to tracheal intubation more than using the Macintosh laryngoscope. Methods: We performed a comprehensive literature search of electronic databases for clinical trials comparing hemodynamic response to tracheal intubation. The primary aim was to determine whether the heart rate (HR) and mean blood pressure (MBP) 60 s after tracheal intubation with the GlideScope were lower than after intubation with the Macintosh laryngoscope. We expressed pooled differences in HR and MBP between the devices as the weighted mean difference with 95% confidence interval and also performed trial sequential analysis (TSA). Second, we examined whether use of the GlideScope resulted in lower post-intubation hemodynamic responses at 120, 180, and 300 s compared with use of the Macintosh laryngoscope. For sensitivity analysis, we used a multivariate random effects model that accounted for within-study correlation of the longitudinal data. Results: The literature search identified 13 articles. HR and MBP at 60 seconds post-intubation was not significantly lower with the GlideScope than with the Macintosh (HR vs MBP: weighted mean difference = 0.22 vs 2.56; 95% confidence interval −3.43 to 3.88 vs −0.82 to 5.93; P = .90 vs 0.14; I2 = 77% vs 63%: Cochran Q, 52.7 vs 27.2). Use of the GlideScope was not associated with a significantly lower HR or MBP at 120, 180, or 300 s post-intubation. TSA indicated that the total sample size was over the futility boundary for HR and MBP. Sensitivity analysis indicated no significant association between use of the GlideScope and a lower HR or MBP at any measurement point. Conclusions: Compared with the Macintosh laryngoscope, the GlideScope did not lower the hemodynamic response after tracheal intubation. Sensitivity analysis results supported this finding, and the results of TSA suggest that the total sample size exceeded the TSA monitoring boundary for HR and MBP.

Study objective The McGrath laryngoscope is a novel self-contained videolaryngoscope with a single-use blade. There are several anecdotal reports that the McGrath is superior to the Macintosh laryngoscope for tracheal intubation. However this remains controversial. Design Meta-analysis and systematic review. Setting Operating room or intensive care unit. Measurements A comprehensive literature search was conducted to identify clinical trials that met our inclusion criteria. To qualify, studies had to be prospective randomized trials comparing tracheal intubation between the McGrath and the Macintosh in an adult population. We extracted data on success rate, glottic visualization during intubation, and intubation time from the studies identified. In subgroup analysis, we assessed the influence on each of these parameters which included airway condition (normal or difficult) and operator (novice or experienced). We then conducted a trial sequential analysis (TSA). Main results Fourteen articles met our inclusion criteria. The McGrath offered better glottic visualization than the Macintosh (risk ratio, 1.34; 95% confidence interval (CI), 1.25–1.45). However, the McGrath required longer intubation time (mean difference, 10.1 s; CI, 2.74–17.5) and demonstrated similar success rate of tracheal intubation (risk ratio, 1.00; CI, 0.95–1.05) compared to the Macintosh. TSA showed that total sample size reached the required information size (RIS) in glottic visualization and success rate. However, only 15.1% of the RIS was achieved in intubation time. In the subgroup analysis for airway condition and operator experience level, there were no subgroup differences in both glottic visualization and intubation time. Conclusions Our meta-analysis suggests that the McGrath is superior to the Macintosh in terms of glottic visualization (GRADE: moderate). However, it significantly extends intubation time (GRADE: very low) and its success rate (GRADE: very low) for tracheal intubation is not excellent. TSA suggests that further studies are necessary to confirm the results of intubation time.

Study objective To investigate whether Airtraq® attenuate the hemodynamic responses to tracheal intubation using single-lumen tubes in adults as compared with the Macintosh laryngoscope. Design Meta-analysis. Setting Operating room. Measurements The primary outcome of this meta-analysis was to determine whether laryngoscopy using the Airtraq® reduced hemodynamic responses—heart rate (HR) and mean blood pressure (MBP)—at 60 s (s) after tracheal intubation compared to laryngoscopy with the Macintosh laryngoscope. Pooled differences in these hemodynamic responses between the two devices were expressed as weighted mean difference with 95% confidence intervals. We then conducted trial sequential analysis (TSA). The secondary outcome was to investigate whether the Airtraq® reduce the hemodynamic response at 120 s, 180 s, and 300 s after tracheal intubation compared to the Macintosh laryngoscope. We also conducted sensitivity analysis of the hemodynamic responses to tracheal intubation with the laryngoscopes using a multivariate random effects model accounting for within-study correlation of the longitudinal data. Main results From electronic databases, we selected 11 randomized controlled trials for studies that enrolled subjects satisfying our inclusion criteria. Compared with the Macintosh laryngoscope, the Airtraq® significantly reduced both HR and MBP at 60 s after tracheal intubation. In secondary outcome, the Airtraq® significantly reduced both HR and MBP at all measurement points, excluding HR at 300 s after tracheal intubation. TSA showed that total sample size reached the required information size for both HR and MBP. The sensitivity analysis revealed that the Airtraq® reduced both HR and MBP at all measurement points, excluding HR at 300 s after tracheal intubation. Conclusions The Airtraq® attenuates the hemodynamic response at 60 s after tracheal intubation compared with the Macintosh laryngoscope. (GRADE: Low) These results were supported by the sensitivity analysis. TSA suggested that the total sample size was exceeded TSA monitoring boundary both HR and MBP.

Rationale: With Duchenne muscular dystrophy (DMD) being the most common and most severe type of muscular dystrophy, DMD patients are at risk for complications from general anesthesia due to impaired cardiac and respiratory functions as the pathological condition progresses. In recent years, advances in multidisciplinary treatment have improved the prognosis of DMD patients, and the number of patients requiring surgery has increased. Remimazolam is a benzodiazepine derivative similar to midazolam. Its circulatory stability and the fact that it has an antagonist make it superior to propofol. There are no reports of pediatric patients with DMD undergoing total intravenous anesthesia with remimazolam. Patient concerns: A 4-year boy was scheduled for single-incision laparoscopic percutaneous extraperitoneal closure for inguinal hernia under general anesthesia, but the surgery was postponed because his serum creatine phosphokinase level was extremely high. Diagnosis: He was diagnosed with DMD. According to the results of the genetic test, exon deletion of the DMD gene was detected using multiplex ligation-dependent probe amplification, although he had no symptoms of DMD except for elevated serum levels of creatine phosphokinase, etc. Intervention: He was admitted for the same surgical purpose. Anesthesia was induced with 3 mg of intravenously administered remimazolam. He lost the ability to respond to verbal commands. After the intravenous administration of 100 μg of fentanyl, a continuous infusion of remifentanil (1.0 μg/kg/min) and remimazolam (15 mg/h) was started, and the endotracheal tube was inserted smoothly after the administration of 10 mg of rocuronium with which the muscle twitches disappeared in train-of-four monitoring. At the end of the surgery, 15 mg of flurbiprofen was administered intravenously. After surgery, we injected 40 mg of sugammadex to confirm a train-of-four count of 100%. Outcomes: Although the dose of remimazolam was reduced to 5 mg/h 30 minutes before the end of the surgery, it took 20 minutes after the discontinuation of remimazolam for the patient to open his eyes upon verbal command. On postoperative Day 2, he was discharged from the hospital without any complications. Lessons: Remimazolam was shown to be safe to use for general anesthesia in a pediatric patient with DMD.

Study objective Videolaryngoscopy has become more common since the 2000s. Despite several anecdotal reports in the literature, it remains unclear whether videolaryngoscopy is superior to direct Macintosh laryngoscopy for tracheal intubation in adults with obesity. This systematic review and meta-analysis focused on prospective randomised trials comparing videolaryngoscopes with the Macintosh laryngoscope for tracheal intubation in adults with obesity. Design Systematic review, Meta-analysis Setting Operating room, Obesity patients Measurements Data on success rate, intubation time, and glottic visualisation during tracheal intubation were extracted from the identified studies. In a subgroup analysis, we also compared the parameters for videolaryngoscopes with a tracheal tube guide channel and those without a tracheal tube guide channel. Data from individual trials were combined, and the DerSimonian and Laird random-effect model was used to calculate either the pooled relative risk (RR) or the weighted mean difference (WMD) as well as the corresponding 95% confidence intervals (CI). Main results Eleven articles describing 13 trials met the inclusion criteria. The performance of videolaryngoscopes was superior to that of the Macintosh laryngoscope for all outcomes. (Success rate; RR=1.11, 95% CI 1.04 to 1.18, p=0.001, I 2 =63%, Intubation time; WMD=−16.1, 95% CI −31.1 to −1.10, p=0.04, I 2 =97%, Glottic visualisation; RR=1.19, 95% CI 1.09 to 1.30, p 2 =76%) In the subgroup analysis, the performance of both types of videolaryngoscopes (with and without a tracheal tube guide channel) was superior to that of the Macintosh laryngoscope, except for intubation time with the videolaryngoscopes without a tracheal tube guide channel. Conclusions Videolaryngoscopes were superior to the Macintosh laryngoscope for tracheal intubation in adults with obesity. (GRADE score: low or very low.)

Study Objective To evaluate the efficacy of intravenous nitroglycerin (TNG) in preventing intraoperative myocardial ischemia (MI) under general anesthesia. Moreover, we analyzed the hemodynamic changes in heart rate (HR), mean blood pressure (MBP), and pulmonary capillary wedge pressure (PCWP) associated with TNG administration both before and after the induction of anesthesia. Design Meta-analysis. Setting Operating room, cardiac surgery or non-cardiac surgery, all surgeries were elective measurements. We performed a computerized search of articles on PubMed, Scopus, and the Cochrane Central Register of Controlled Trials. Meta-analysis was performed using Review Manager. The data from the individual trials were combined using a random-effects model to calculate either the pooled relative risk (RR) or the weighted mean difference (WMD) with 95% confidence interval (CI). We conducted trial sequential analysis (TSA). The primary outcome was the incidence of MI and the secondary outcomes were hemodynamic changes (HR, MBP, and PCWP). Main Results Using electronic databases, we selected 10 trials with a total of 353 patients for our review. Prophylactic intravenous TNG did not significantly decrease the incidence of MI (RR=0.61; CI, 0.33 to 1.13; P=0.12; I 2 =55). TSA corrected the CI to 0.05 to 7.39 and showed that 9.5% of the required information size was achieved. In terms of hemodynamic changes, intravenous TNG significantly reduced MBP in comparison with the placebo (MBP pre-induction: WMD=−7.27; 95% CI −14.2 to −0.33; P=0.04; I 2 =97%; MBP post-induction: WMD=−5.13; 95% CI −9.17 to −1.09; P=0.01; I 2 =73%). Conclusions Our analyses showed that prophylactic intravenous TNG does not reduce the incidence of intraoperative MI. Moreover, TSA suggests that further studies are necessary to confirm the results (GRADE: very low). Prophylactic doses of intravenous TNG significantly reduced the MBP both pre and post anesthesia induction (GRADE: very low).

Although there have been a large number of reports on the effects of opioids on the bispectral index (BIS) during anesthesia, the effects of pentazocine on the BIS have not been reported. In this study, 60 patients scheduled for elective oral surgery [30 females, 30 males; all American Society of Anesthesiologists Physical Status (ASA PS) category 1] were enrolled in the trials. Maintaining gender parity, we randomly assigned the patients to one of three groups: pentazocine group (0.3 mg/kg; n = 20), fentanyl group (1 μg/kg; n = 20), or saline group (n = 20); these opioids were administered intravenously 15 min after the intubation. Anesthesia was induced with thiopental and vecuronium bromide and maintained with nitrous oxide (4 l/min)–oxygen (2 l/min)–sevoflurane (1%). At 15 min after the intubation, mean arterial blood pressure (MAP), heart rate (HR), and BIS index were recorded as baseline values. MAP, HR, and BIS values were measured at 2.5-min after the intubation up to 30 min. All data were expressed as the mean ± standard deviation. Differences in BIS values, MAP, and HR among the three groups throughout the experiment were analyzed using two-way repeated-measures analysis of variance (ANOVA), and demographic data among the three groups were analyzed using one-way ANOVA. Post hoc comparisons were performed using Fisher’s protected least significant difference test. A P value of

Kennedy's disease (KD), also known as spinal and bulbar muscular atrophy, is a rare, X-linked recessive, neurodegenerative disorder of the lower motor neurons characterized by progressive bulbar and appendicle muscular atrophy. Here we report a case of a 62-year-old male patient with KD, weighing 70 kg and 173 cm tall, was scheduled for frontal sinusectomy due to sinusitis. General anesthesia was induced through propofol 80 mg, remifentanil 0.25 μg/kg/min and 40 mg rocuronium. We were successfully able to use a sugammadex on a patient suffering from KD in order to reverse rocuronium-induced neuromuscular blockade.

Whether opioids administered before skin incision, under inhalational anesthesia, improve cardiovascular and plasma catecholamine responses to surgical stimulation compared with those administered after skin incision remains unclear. We compared the effects of fentanyl injected before and after skin incision on these responses.We studied 50 healthy female patients [American Society of Anesthesiologist (ASA) physical status 1] who underwent elective total abdominal hysterectomy through an infraumbilical incision (midline incision) under nitrous oxide (60%)-oxygen-isoflurane (1.2%) anesthesia. Fentanyl (2.0 or 4.0 microg.kg(-1)) was administered i.v. 5 min before (pretreatment group) or 5 min after (posttreatment group) skin incision. Control patients received a saline injection. Heart rate (HR) and mean arterial blood pressure (MAP) were recorded 1 min before incision and serially for 30 min afterward. Plasma levels of norepinephrine (Nor) and epinephrine (Epi) were determined 1 min before incision and serially up to 20 min after skin incision.The MAP response to incision had decreased after 10 min in posttreatment fentanyl (2 microg.kg(-1)) (P0.05) and after 8, 10, 15, and 20 min in posttreatment fentanyl (4 microg.kg(-1)) ( P0.05). At the same doses, fentanyl administered before skin incision attenuated MAP response to incision after 1 min with the smaller dose (P0.05) and after 1, 3, 5, 6, 8, 10, 15, and 20 min with the higher dose (P0.05). Fentanyl suppressed Epi response to surgery 8 and 20 min after skin incision (P0.05) at both doses, except for 8 min after incision in pretreatment fentanyl (2 microg.kg(-1)). Overall, the hemodynamic and sympathoadrenergic responses after skin incision were attenuated, with the exception of plasma Nor after fentanyl irrespective of time and dose.Our results indicated that fentanyl depressed cardiovascular and plasma catecholamine responses irrespective of the time of administration, and that the higher dose of fentanyl produced a greater suppression of MAP and HR responses. In addition, the depressant effects on MAP of high-dose fentanyl administered 5 min before skin incision lasted longer than when injected 5 min after incision. At both doses, the opioid attenuated the rise in plasma Epi, but not Nor.

Reversible cerebral vasoconstriction syndrome (RCVS) is a group of disorders characterized by prolonged reversible cerebral vasoconstriction, associated with acute-onset, severe, episodic “thunderclap” headaches with or without other neurologic clinical features. We describe the first reported case, to our knowledge, of a patient with RCVS who was managed under general anesthesia in the field of oral and maxillofacial surgery. A 67-year-old woman with a diagnosis of RCVS made 2 months earlier was scheduled to undergo surgical extraction of the mandibular right third molar. Standard monitoring included noninvasive blood pressure measurement, pulse oximetry, and electrocardiography; a bispectral index (BIS) monitor sensor was placed on her forehead. General anesthesia was induced by target-controlled infusion of propofol to an effect site concentration of 5.0 μg · mL −1 , with remifentanil, 0.50 μg · kg −1 per minute, and rocuronium, 40 mg. After tracheal intubation, anesthesia was maintained uneventfully with remifentanil, 0.15 to 0.2 μg · kg −1 per minute, and propofol, 2.0 to 3.0 μg · mL −1 , in oxygen and air. The end-tidal carbon dioxide concentration was maintained at 38 to 42 mm Hg. The BIS reading was 40 to 60. Fentanyl, 0.1 mg, and acetaminophen, 750 mg, were administered before the end of surgery for postoperative analgesia. The postoperative course was uneventful, with no headaches or hypertensive complications. We successfully achieved anesthetic management with no appreciable clinical signs of cerebral ischemia or recurrence in a patient with RCVS. We used propofol as the anesthetic agent with BIS monitoring to detect cerebral ischemia. However, there is no definitive evidence of the utility of these measures for the prevention or diagnosis of RCVS, and further study is needed.

Background Three types of opioid receptors, mu, delta, and kappa, are present in the periphery and in the central nervous system. In contrast to the effects in the central nervous system, the antinociceptive action of opioids in the periphery is not as well characterized. The effects of intraarticular, spinal, and intramuscular injections of mu, delta, and kappa opioid agonists on the autonomic response evoked by compression of an inflamed knee joint were evaluated. Methods In halothane-anesthetized rats, arthritis was induced by injecting kaolin and carrageenan into the right knee joint. Standardized compression of the knee joint by inflation of a pediatric blood pressure cuff to 200 mmHg for 2 min produced a reliable stimulus-dependent hypertension (delta = 13 mmHg). Drugs were delivered intramuscularly, intrathecally through a chronic catheter, or intraarticularly into the right knee joint. The drug injection was performed 4 hr after induction of the inflammation. Results The intrathecal administration of mu, delta, and kappa agonists resulted in a dose-dependent blockade of the cuff-evoked increase in blood pressure. The order of intrathecal drug activity on the compression-evoked blood pressure responses with median effective dose (ED50) was sufentanil (0.02 nmol; mu) > PD117302 (0.5 nmol; kappa); spiradoline (1.5 nmol; kappa) morphine (2.4 nmol; mu) > DADL (15 nmol; delta); DPDPE (18 nmol; delta) > U-50,488H (620 nmol; kappa) > naloxone = 0. The intraarticular administration of mu and kappa, but not delta agonists, produced a dose-dependent blockade of a compression-evoked increase in blood pressure, with the order of drug activity (ED40) as follows: sufentanil (0.04 mumol) > PD117302 (0.3 mumol); spiradoline (0.8 mumol), morphine (0.9 mumol) > U-50,488H (0.9 mumol) > DPDPE (> 5 mumol); DADL (> 18 mumol) > naloxone = 0. Intramuscular injection of these agonists caused suppression, with the order of drug activity (ED50) as follows: sufentanil (0.2 mumol) > PD117302 (2 mumol); spiradoline (11 mumol) morphine (9 mumol) > DPDPE (> 5 mumol); DADL (18 mumol) > U-50,488H (22 mumol) > naloxone = 0. All intraarticular effects were reversible by injecting naloxone intramuscularly, with the ordering of naloxone potency against equiactive doses of morphine > U50,488H. Conclusions The activity of the respective agonists and the intraarticular > intramuscular ordering of systemic potency in this model indicate that opioids, by an action at mu and kappa, can exert a direct antihyperalgesic action at the terminals of primary afferents projecting to a region of inflammation. These observations offer strong support for a peripheral action of opioids in certain states in inflammation-induced hyperalgesia.

The influence of surgery and anesthesia on aspects of malignant tumor has received considerable attention in recent years. It is suggested that in vitro studies, clinically available anesthetics, such as intravenous anesthetics, local anesthetics and opioids have, more or less, possible antitumor potential against human malignant tumor cells. Although natural killer (NK) cells play an important role in tumor and metastasis surveillance, the reported effects of the anesthetics on the NK cell activity in human are controversial. Animal studies indicate that the neuroendocrine stress response to the surgery suppresses the immune function, particularly NK cell cytotoxicity, and increases the metastatic burden under inhalational anesthesia alone. Moreover, animal studies indicate that the addition of spinal block and optimum postoperative analgesia independently reduce the metastatic burden by blocking the stress response under inhalational anesthesia alone. Considering inconclusive results, especially in human, about evaluating the influence of anesthetics on malignant tumor, further studies in basic and clinical settings are required to study the effects of anesthetics on malignant tumor.

The effects of intrathecally administered adrenergic agonists (alpha-1-methoxamine, alpha-2-dexmedetomidine, clonidine, and ST-91, beta-isoproterenol) on nociceptive (tail-flick reflex) and cardiovascular changes (blood pressure and heart rate) evoked by immersing the tail in 53 degrees C water were examined in rats anesthetized with halothane (0.75%) and in which intrathecal catheters had been chronically implanted. Administration of intrathecal alpha-2, but not alpha-1 or beta agonists, produced a dose-dependent block of the tail-flick and evoked cardiovascular responses with the order of activity being as follows: dexmedetomidine greater than clonidine greater than ST-91 much greater than methoxamine greater than or equal to isoproterenol. These effects were readily reversed by the alpha-2 antagonist idazoxan. Intravenously administered dexmedetomidine at a dose that is active when given intrathecally (0.33 micrograms) was without effect on either the tail-flick or the evoked cardiovascular responses. Without drugs, the halothane MAC was 1.23 +/- 0.07%. In the presence of intrathecally administered dexmedetomidine (0.33 micrograms), the MAC was significantly reduced to 0.9 +/- 0.09%. The intrathecal administration of alpha-2 agonists resulted in a rapid decrease in resting blood pressure and heart rate with the magnitude of hypotension being as follows: dexmedetomidine greater than clonidine greater than ST-91. These data suggest a potent spinal alpha-2-receptor-mediated modulation of somatomotor and autonomic responses to pain.

The effects of enflurane (0.5%, 1.5% and 2.5%) on the excitation and inhibition of dorsal horn wide dynamic range (WDR) neuronal activity induced by bradykinin (BK) injection was studied in spinal cats. Extracellular activity was recorded in the dorsal horn from single WDR neurons responding to noxious and non-noxious stimuli applied to the cutaneous receptive fields on the left hind paw foot pads of decerebrate, spinal cord transected (L(1-2)) cats. When 10 microg of BK was injected into the femoral artery ipsilateral to the recording site as the noxious test stimulus, 24 of 26 WDR neurons (92%) gave excitatory responses and 2 (8%) gave inhibitory responses. On the other hand, when the injection of 10 microg of BK into the femoral artery contralateral to the recording site was used as the noxious test stimulus, 7 of 12 WDR neurons (58%) gave inhibitory responses, 3 (25%) gave excitatory responses, and 2 (17%) showed no response. The excitatory neuronal activity in WDR neurons was not depressed by 0.5% or 1.5% enflurane but was depressed significantly by 2.5%. However, the inhibitory neuronal activity in WDR neurons was significantly depressed by 0.5%, 1.5% and 2.5% enflurane. We have found that enflurane reduces the excitation as well as the inhibition of dorsal horn WDR neuronal activity induced by BK injection. These results suggest that the reduction of excitatory and inhibitory responses produced by noxious stimulation is likely to be the fundamental basis of the enflurane-induced anesthetic state in terms of WDR neurons.

Background It is now well established that wide dynamic range neurons (WDR) can possess widespread cutaneous inhibitory receptive fields, as well as excitatory receptive fields, in specific regions of the body. The ability of ketamine to depress the excitatory responses of spinal WDR neurons indicates that the analgesia produced by this agent may be a result, in part, of this spinal action. The primary purpose of this study was to investigate the effects of ketamine on the WDR propriospinal inhibitory mechanism that is induced by a bradykinin (BK) injection as a noxious test stimuli. Methods In decerebrate, spinal cord-transected cats (L1-L2), the effects of a low (0.5 mg.kg-1, intravenous) and a high (10 mg.kg-1, intravenous) dose of ketamine on the neuronal activity of spinal dorsal horn WDR neurons evoked by femoral artery injection of BK (10 micrograms) was examined. Extracellular activity was recorded from single WDR neurons that responded to noxious and innocuous stimuli applied to the cutaneous receptive fields on the foot pads of the left hind paw. Results After ipsilateral BK administration, the activity of the WDR neurons was found to be increased (excited) in all ten neurons that were examined. In contrast, the activity of these neurons was found to be decreased (inhibited) in five of these ten neurons after BK administration into the contralateral femoral artery. The 10 mg.kg-1 dose of ketamine significantly suppressed the excitatory activity observed in all 15 of the WDR neurons examined. A comparison of the effects produced by the 0.5-mg.kg-1 and the 10-mg.kg-1 intravenous doses reveals that the amount of suppression was dose-related. In addition, the inhibitory WDR neuronal activity induced by contralateral BK injection was also significantly reduced by both the 0.5- and the 10-mg.kg-1 doses of ketamine. Conclusions These results indicate that this reduction of excitatory and inhibitory responses of WDR neurons after noxious stimulation is likely to be the fundamental basis for the spinal cord component of ketamine-induced analgesia.

Hepatic oxygen delivery and consumption were assessed in mongrel dogs receiving 2MAC of halothane combined with graded hypoxic hypoxemia (21-8% oxygen). Hepatic blood flow was measured using electromagnetic flowmetry; hepatic oxygen delivery and consumption were calculated from measured hepatic blood flow and oxygen content in hepatic arterial, portal venous and hepatic venous blood. In hypoxia-halothane group, total hepatic blood flow decreased at mild hypoxia (15% O2) from control value, but recovered to control level at moderate hypoxia (10% O2), then again decreased at 8% O2. Oxygen supply to the liver was decreased with the augmentation of hypoxia in hypoxia-halothane and hypoxia-alone groups, and it was significantly lower in the hypoxia-halothane group at 15 and 12% O2. Hepatic oxygen consumption also decreased from air control values with the increment of hypoxia, but there was no significant difference between the groups. Arterial ketone body ratio, which indicates mitochondrial energy charge level, decreased with the development of hypoxia but there was no significant difference in this ratio between the groups. These results show that halothane aggravated oxygen supply to the liver at mild to moderate hypoxia (15-12% O2), but did not worsen it specifically at more serious hypoxia (10-8% O2) compared with hypoxia alone. Hepatic hypoxia itself could not thus be a main cause of halothane hepatotoxicity.

人工股関節全置換術 (THR) における全身麻酔と硬膜外麻酔を併用した群との比較を特に出血量と輸血量について行なった. 術中出血量は、全身麻酔群では1090.2±496ml(mean±SD), 硬膜外麻酔併用群では869.2±368.8ml, 術後出血量は, 全身麻酔群では460±188.5ml, 硬膜外麻酔併用群では436±253.6mlで術中と術後の輸血量を加えた全輸血量は, 全身麻酔群で1156.1±507ml, 硬膜外麻酔併用群で915±416.4mlで, 術中出血量, 全輸血量ともに, 硬膜外麻酔併用群で, 有意に少なかった. 術前術後のHb値は, 両群とも有意差がなかった. THRの麻酔では, 硬膜外麻酔を併用すると, 術中出血量, 輸血量を減少させ, 出血および輸血による合併症を軽減できる点で有利であると考えられた.