Comparison of isoflurane and sevoflurane for anesthesia in beaver

We compared the hemodynamic and respiratory effects, recovery time, and cost of two gas inhalants (isoflurane and sevoflurane) for anesthetic induction and maintenance of beaver (Castor canadensis) during surgery to implant radio transmitters in the peritoneal cavity. Heart rate, respiratory rate, relative hemoglobin saturation with oxygen (SpO2), and body temperature were measured every 5 min for the first 45 min, and arterial blood gas was measured once, 25 min into the anesthetic procedure. Induction for either agent was smooth and rapid. Heart rate and respiratory rate both decreased during the procedure though neither was lower than baseline values reported in the literature for beaver. Relative hemoglobin saturation with oxygen, body temperature, and blood gas variables did not differ between each anesthetic regime. Both inhalants caused slight respiratory acidosis. Recovery time from anesthesia was highly variable (1-178 min) but did not differ statistically between drugs. Sevoflurane costs ($22.30/60 min) were much higher than isoflurane costs ($3.50/60 min). We recommend isoflurane or sevoflurane for anesthetic induction and maintenance of beaver because of the lack of physiologic differences.     

Hemodynamics of anesthetized ventilated mouse models: aspects of anesthetics,fluid support,and strain

This study evaluates the effects of anesthesia and fluid support on hemodynamic parameters of the mechanically ventilated mouse of four different strains. All experiments were performed at a similar surgical level of anesthesia, as indicated by the probing of the pedal withdrawal reflex. Three anesthetic regimens [fentanyl-fluanisone-midazolam (FFM), ketamine-medetomidine-atropine (KMA), and isoflurane (ISO)], four commonly used mouse strains (Swiss, CD-1, BalbC, and C57Bl6), and three different fluid support strategies (no fluid, 0.2 ml x h(-1) x 10 g(-1) of 6% polystarch solution, and 0.5 ml x h(-1) x 10 g(-1) saline) were studied. Mean arterial pressure (MAP) or heart rate (HR) was similar among the four strains of mice except a trend toward lower HR for the BalbC mice. In terms of MAP, KMA is the preferred anesthetic for the Swiss and CD-1 mice, whereas KMA or ISO are recommended for BalbC or C57Bl6 mice. In terms of HR, ISO is the preferred anesthetic for the Swiss, CD-1, and C57Bl6 strains. No differences in HR for the three anesthetics were observed for the BalbC strain. Compared with administration of no fluid, both saline and polystarch administration similarly increased MAP by 7 +/- 2, 10 +/- 2, and 11 +/- 2 mmHg at t = 1, 2, and 3 h, respectively, whereas fluid administration was without effect on HR. Saline supplementation resulted in an increased dry-to-wet ratio of the heart and both fluid regimens decreased total hemoglobin in the blood from 12.6 +/- 0.5 to 10.4 +/- 0.5 g/100 ml. Saline administration was associated with blood acidosis (pH 7.20 +/- 0.03) compared with the Haes (pH 7.29 +/- 0.02) or no-fluid group (pH 7.34 +/- 0.03), whereas PCO(2) was approximately 30 mmHg for all groups. We conclude that at similar surgical levels of anesthesia, the preferable type of anesthesia (ISO or KMA, but never FFM) depends on the strain used and whether MAP or HR is the focus of study. Additional fluid support is beneficial in terms of raising arterial blood pressure, although this is at the cost of changes in organ water content and increased anemia.     

Effects of anesthetics on systemic hemodynamics in mice

The aim of this study was to compare the systemic hemodynamic effects of four commonly used anesthetic regimens in mice that were chronically instrumented for direct and continuous measurements of cardiac output (CO). Mice (CD-1, Swiss, and C57BL6 strains) were instrumented with a transit-time flow probe placed around the ascending aorta for CO measurement. An arterial catheter was inserted into the aorta 4 or 5 days later for blood pressure measurements. After full recovery, hemodynamic parameters including stroke volume, heart rate, CO, mean arterial pressure (MAP), and total peripheral resistance were measured with animals in the conscious state. General anesthesia was then induced in these mice using isoflurane (Iso), urethane, pentobarbital sodium, or ketamine-xylazine (K-X). The doses and routes of administration of these agents were given as required for general surgical procedures in these animals. Compared with the values obtained for animals in the conscious resting state, MAP and CO decreased during all anesthetic interventions, and hemodynamic effects were smallest for Iso (MAP, -24 +/- 3%; CO, -5 +/- 7%; n = 15 mice) and greatest for K-X (MAP, -51 +/- 6%; CO, -37 +/- 9%; n = 8 mice), respectively. The hemodynamic effects of K-X were fully antagonized by administration of the alpha(2)-receptor antagonist atipamezole (n = 8 mice). These results indicate that the anesthetic Iso has fewer systemic hemodynamic effects in mice than the nonvolatile anesthetics.     

Effects of isoflurane concentration on basic echocardiographic parameters of the left ventricle in rats

Transthoracic echocardiography (TTE) has become an important modality for the assessment of cardiac structure and function in animal experiments. The acquisition of echocardiographic images in rats requires sedation/anesthesia to keep the rats immobile. Commonly used anesthetic regimens include intraperitoneal or inhalational application of various anesthetics. Several studies have compared the effects of anesthetic agents on echocardiographic parameters in rats; however, none of them examined the effects of different concentrations of inhalational anesthetics on echocardiographic parameters. Accordingly, the aim of this study was to examine the effects of different concentrations of isoflurane used for anesthesia during TTE examination in rats on basic echocardiographic parameters of left ventricular (LV) anatomy and systolic function. TTE examinations were performed in adult male Wistar rats (n=10) anesthetized with isoflurane at concentrations of 1.5-3 %. Standard echocardiograms were recorded for off-line analysis. An absence of changes in basic echocardiographic parameters of LV anatomy and systolic function was found under isoflurane anesthesia using concentrations between 1.5-2.5 %. An isoflurane concentration of 3 % caused a small, but statistically significant, increase in LV chamber dimensions without a concomitant change in heart rate or fractional shortening. For the purpose of TTE examination in the rat, our results suggest that isoflurane concentrations 相似文献   

Vital signs monitoring during injectable and inhalant anesthesia in mice

Selecting the appropriate anesthetic protocol for the individual animal is an essential part of laboratory animal experimentation. The present study compared the characteristics of four anesthetic protocols in mice, focusing on the vital signs. Thirty-two male ddY mice were divided into four groups and administered anesthesia as follows: pentobarbital sodium monoanaesthesia; ketamine and xylazine combined (K/X); medetomidine, midazolam, and butorphanol combined (M/M/B); and isoflurane. In each group, rectal temperature, heart rate, respiratory rate, and O₂ saturation (SPO₂) were measured, and the changes over time and instability in these signs were compared. The anesthetic depth was also evaluated in each mouse, and the percentage of mice achieving surgical anesthesia was calculated. K/X anesthesia caused remarkable bradycardia, while the respiratory rate and SPO₂ were higher than with the others, suggesting a relatively strong cardiac influence and less respiratory depression. The M/M/B group showed a relatively lower heart rate and SPO₂, but these abnormalities were rapidly reversed by atipamezole administration. The pentobarbital group showed a lower SPO₂, and 62.5% of mice did not reach a surgical anesthetic depth. The isoflurane group showed a marked decrease in respiratory rate compared with the injectable anesthetic groups. However, it had the most stable SPO₂ among the groups, suggesting a higher tidal volume. The isoflurane group also showed the highest heart rate during anesthesia. In conclusion, the present study showed the cardiorespiratory characteristics of various anesthetic protocols, providing basic information for selecting an appropriate anesthetic for individual animals during experimentation.     

The effects of barbiturates upon the hemodynamic responses to intravenous methionine-enkephalin in dogs: modulation by the GABA complex

In conscious animals, the intravenous administration of enkephalins increases heart rate (HR) and mean systemic arterial blood pressure (MAP); however, when given during barbiturate anesthesia, enkephalins reduce HR and MAP. We have investigated the potential role of the gamma-aminobutyric acid (GABA) complex (consisting of chloride-ion channel and binding sites for GABA, benzodiazepine, and barbiturate/picrotoxin) as the site of modulation of enkephalin responses by certain anesthetic agents in our chronically instrumented dog model. In our model, methionine-enkephalin (Met5-ENK) (35 micrograms/kg intravenously) increased HR and MAP, but following induction of general anesthesia with barbiturate (pentobarbital) or of sedation with benzodiazepine (diazepam), Met5-ENK produced vasodepressor responses despite differing levels of consciousness in the treated animals. Subsequent administration of picrotoxin restored pressor responses to Met5-ENK in the barbiturate-treated dogs, but not in those treated with benzodiazepine; picrotoxin did not alter the level of consciousness. Picrotoxin had no effect upon Met5-ENK responses in the conscious state. In contrast, alpha-chloralose, a convulsive anesthetic agent which does not appear to alter GABA complex activity, blunted but did not reverse pressor responses to Met5-ENK, despite causing a level of anesthesia similar to that produced by barbiturate. The observed pressor response to Met5-ENK during alpha-chloralose anesthesia was totally inhibited by naloxone, indicating that this response was still mediated by opiate receptors. Our data are compatible with modulation of enkephalin responses by GABA complex activity. Systemic enkephalins may generate afferent signals which may subsequently undergo GABA complex processing; the state of activation of the GABA complex may then determine whether systemic enkephalin signals are translated as vasopressor or vasodepressor responses.     

雷米芬太尼联合丙泊酚对妇科腹腔镜手术患者的血流动力学及麻醉苏醒的影响

目的:探讨雷米芬太尼联合丙泊酚对妇科腹腔镜手术患者的血流动力学及麻醉苏醒的影响。方法:将116例拟行妇科腹腔镜手术患者随机分为观察组和对照组,观察组给予雷米芬太尼联合丙泊酚全凭静脉麻醉,对照组给予芬太尼联合丙泊酚全凭静脉麻醉。比较两组术中平均动脉压(MAP)、心率(HR)、血气分析指标、患者麻醉后睁眼时间、拔管时间及答问切题时间。结果:麻醉诱导后两组平均动脉压(MAP)及心率(HR)均显著下降(P0.05);观察组插管即刻及插管后2 min MAP及HR显著低于对照组(P0.05);观察组麻醉后睁眼时间、拔管时间、答问切题时间显著早于对照组(P0.05);与气腹前相比,气腹10 min、20 min及60min的PaCO2均升高(P0.05),两组各时点其他血气分析指标比较无显著差别(P0.05)。结论:妇科腹腔镜手术给予雷米芬太尼联合丙泊酚全凭静脉麻醉,可显著减轻插管应激心血管反应,保持血流动力学稳定,效果优于芬太尼联合丙泊酚麻醉。     

Long-term anaesthesia using inhalatory isoflurane in different strains of mice-the haemodynamic effects

The aim of this study was to establish a simple and safe method of anaesthesia for intravital microcirculatory observations in small laboratory animals. The usefulness of isoflurane inhalation anaesthesia has been investigated in different strains of mice commonly used in experimental medicine. These were the hairless (hr/hr, n = 12), the BALB/c (n = 12) and the nude mouse (nu/nu, n = 3). Anaesthesia was maintained by mask inhalation of isoflurane vaporized at concentrations of up to 4% in the induction phase, at 1.5% during acute surgical procedures and at 0.8-1.3% during prolonged experimental observations. Isoflurane was vapoured in a N(2)O/O(2) mixture and saturated with 32-36% F(i)O(2). During observations the body temperature was kept constant at 37 degrees C. The tail artery was cannulated for monitoring of mean arterial blood pressure (MAP) and heart rate (HR). To maintain the body fluid balance, isotonic saline was administered at a constant rate of 0.2 ml/h. Arterial blood samples were drawn for blood-gas analysis at the end of the experiments. All animals survived the anaesthesia protocol lasting between 3 and 6.5 h. During isoflurane inhalation, no breathing complications or changes in systemic circulatory parameters were observed. Mean values of MAP and HR were 79+/- 3 mmHg and 486+/- 13 min(-1), respectively, over the entire observation period. A moderate acidosis was recorded in animals under isoflurane anaesthesia, with alterations of arterial blood pH, p(a)O(2) and pCO(2) values (7.29+/- 0.06, 130+/- 19 mmHg and 35.6+/- 4.7 mmHg, respectively). In conclusion, inhalation anaesthesia with isoflurane is useful for experimental studies in the mouse due to (1) the simplicity of administration of the anaesthetic, (2) the rapid induction of anaesthesia, (3) easy control of the depth of anaesthesia, (4) the low percentage of complications, and (5) stable MAP and HR during observations lasting several hours. The proposed technique is especially suitable for observations of the microcirculation under intravital fluorescence microscopy.     

Endothelin-a receptor blockade does not debilitate the cardiovascular and hormonal adaptation to xenon or isoflurane anesthesia in dogs

The objective of this study was to investigate whether circulatory and hormonal changes during xenon plus remifentanil or isoflurane plus remifentanil anesthesia are altered by endothelin-A (ET(A)) receptor blockade. Eight beagle dogs were studied in four protocols (n = 7 each). After a 30-min awake period, anesthesia was induced with 8 mg/kg propofol, administered intravenously (iv), and maintained with either 0.8% +/- 0.01% (vol/vol) isoflurane plus 0.5 microg/kg/min remifentanil (Protocol 1) or 63% +/- 1% (vol/vol) xenon plus 0.5 microg/kg/min remifentanil (Protocol 2) for 1 hr. Protocols 3 and 4 were preceded by ET(A) blockade with ABT-627 (Atrasentan; iv bolus of 1 mg/kg, then 100 microg/kg/h continuously). Irrespective of Atrasentan administration, the mean arterial blood pressure (MAP) ranged between 92 and 96 mm Hg in the awake state and fell to 67 +/- 3 mm Hg in controls (mean +/- SEM) and to 64 +/- 2 mm Hg in the Atrasentan group during isoflurane plus remifentanil anesthesia, whereas MAP remained constant during xenon plus remifentanil anesthesia. A decrease in heart rate was observed during either kind of anesthesia, but bradycardia was most prominent during xenon plus remifentanil anesthesia. In the control groups, and in the Atrasentan-treated dogs, a decrease in cardiac output and an increase in systemic vascular resistance were more prominent during xenon plus remifentanil than during isoflurane plus remifentanil anesthesia. Hormonal alterations during anesthesia remained unaffected by ET(A) receptor blockade. Angiotensin II and vasopressin increased in all protocols, and adrenaline and noradrenaline concentrations rose only during xenon plus remifentanil anesthesia. We conclude that the hemodynamic and hormonal adaptation after xenon plus remifentanil and isoflurane plus remifentanil anesthesia does not depend on the endothelin system, because it is unaffected by ET(A) receptor inhibition. Therefore, the use of Atrasentan does not impair cardiovascular stability during xenon- or isoflurane-based anesthesia in our dog model. However, the way anesthesia is performed is of crucial importance for hemodynamic and hormonal reactions observed during research in animals because the release of vasopressin and catecholamines may be intensified by xenon plus remifentanil anesthesia.     

不同麻醉方法对腹腔镜子宫切除术患者血清皮质醇及儿茶酚胺的影响

目的：观察不同麻醉方法对腹腔镜子宫切除术患者血清皮质醇及儿茶酚胺的影响。方法：选择行腹腔镜子宫切除术患者42例,随机分为3组：硬膜外麻醉组（A组）、全麻组（B组）、全麻复合硬膜外阻滞组（C组）各14例,于麻醉前10min（T0）、气腹后10min（T1）、气腹后40min（T2）和术后10min（T3）四个时间点,采集静脉血测定皮质醇（COR）和儿茶酚胺（CA）浓度,并观察P旷c02、SP02及血流动力学变化。结果：与T0相比,A组T1时MAP、HR显著下降（P〈0．05）,B组T1、T2时MAP、HR、COR和CA明显升高（P〈0．05）,C组各时点MAP、HR、COR和CA差异无统计学意义;组间相比,C组各时点MAP、HR、COR和CA显著低于B组（P〈0．05）。结论：全麻复合硬膜外阻滞可以有效地调控腹腔镜子宫切除术患者的应激反应。     

常用麻醉剂对麻醉小鼠超声心功能的影响

目的:比较常见的多种麻醉剂对小鼠心脏超声结果的影响。方法:C57BL/6小鼠25只,随机分5组,每组5只。首先在清醒状态下,借助小动物高频超声系统(Vevo2100)评价小鼠心功能,然后分别用戊巴比妥钠、水合氯醛、三溴乙醇、氯胺酮/地西泮及异氟烷麻醉,再次对心功能进行评价。比较6种不同处理情况下,超声反映的小鼠心功能的差异。结果:与清醒状态相比,5种麻醉方式下,小鼠的心率及心功能均有不同程度降低。其中,戊巴比妥钠、水合氯醛、三溴乙醇及异氟烷麻醉组的左心收缩功能显著降低(P0.01),而氯胺酮/地西泮麻醉的小鼠与清醒组相比,收缩功能无明显差异(P0.05),但其余参数也有显著差异(P0.01)。结论:不论何种麻醉方式,都会对小鼠心率及心功能造成一定影响,但其同组内仍具有可比性;因此应根据现实条件及实验需要选择麻醉剂,并贯彻始终,保持试验中麻醉条件的一致性。     

The clinical use of desflurane.

Desflurane, a newly introduced potent, inhaled anesthetic, differs from its predecessors in having a lower solubility in blood and tissues. The lower solubility imparts a greater control to the maintenance of anesthesia and a more rapid elimination and recovery from anesthesia. In other respects, the pharmacological properties of desflurane resemble those of its sister anesthetic, isoflurane, currently the most widely-used potent anesthetic in this and other countries. The qualitative exceptions to this resemblence are that desflurane is more pungent and produces a greater increase in heart rate, particularly at deeper levels of anesthesia.     

Continuous measurement of gas uptake and elimination in anesthetized patients using an extractable marker gas.

Measurement of pulmonary gas uptake and elimination is often performed, using nitrogen as marker gas to measure gas flow, by applying the Haldane transformation. Because of the inability to measure nitrogen with conventional equipment, measurement is difficult during inhalational anesthesia. A new method is described, which is compatible with any inspired gas mixture, in which fresh gas and exhaust gas flows are measured using carbon dioxide as an extractable marker gas. A system was tested in eight patients undergoing colonic surgery for automated measurement of uptake of oxygen, nitrous oxide, isoflurane, and elimination of carbon dioxide with this method. Its accuracy and precision were compared with simultaneous measurements made with the Haldane transformation and corrected for predicted nitrogen excretion by the lungs. Good agreement was obtained for measurement of uptake or elimination of all gases studied. Mean bias was -0.003 l/min for both oxygen and nitrous oxide uptake, -0.0002 l/min for isoflurane uptake, and 0.003 l/min for carbon dioxide elimination. Limits of agreement lay within 30% of the mean uptake rate for nitrous oxide, within 15% for oxygen, within 10% for isoflurane, and within 5% for carbon dioxide. The extractable marker gas method allows accurate and continuous measurement of gas uptake and elimination in an anesthetic breathing system with any inspired gas mixture.     

Mass-spectrometry analysis of disflurane,propofol, and fentanyl in plasma and cerebrospinal fluid

Concentrations of anesthetic agents were measured in blood plasma and cerebrospinal fluid using mass spectrometry with a membrane interface. Sampling of biological fluids was performed during balanced inhalational (disflurane and fentanyl) anesthesia and total intravenous (propofol and fentanyl) anesthesia. A rapid test method for the concentration measurement of organic molecules in biological fluids is described. This method does not require long-term sample processing before injecting the sample into the mass spectrometer interface. The pervaporation properties (uptake, diffusion, and evaporation) of anesthetic agents from biological fluids in a silicone membrane were used in the mass spectrometry interface. We report on the possibility of using a mass spectrometer with a membrane interface for the measurement of the absolute concentration of anesthetic agents in blood plasma for study of the properties of the blood–brain barrier.     

Effects of inhalational anesthesia on blood gases and pH in California sea lions

Despite the widespread use of inhalational anesthesia with spontaneous ventilation in many studies of otariid pinnipeds, the effects and risks of anesthetic‐induced respiratory depression on blood gas and pH regulation are unknown in these animals. During such anesthesia in California sea lions (Zalophus californianus), blood gas and pH analyses of opportunistic blood samples revealed routine hypercarbia (highest P_CO2 = 128 mm Hg [17.1 kPa]), but adequate arterial oxygenation (P_O2 > 100 mm Hg [13.3 kPa] on 100% inspiratory oxygen). Respiratory acidosis (lowest pH = 7.05) was limited by the increased buffering capacity of sea lion blood. A markedly widened alveolar‐to‐arterial P_O2 difference was indicative of atelectasis and ventilation‐perfusion mismatch in the lung secondary to hypoventilation during anesthesia. Despite the generally safe track record of this anesthetic regimen in the past, these findings demonstrate the value of high inspiratory O₂ concentrations and the necessity of constant vigilance and caution. In order to avoid hypoxemia, we emphasize the importance of late extubation or at least maintenance of mask ventilation on O₂ until anesthetic‐induced respiratory depression is resolved. In this regard, whether for planned or emergency application, we also describe a simple, easily employed intubation technique with the Casper “zalophoscope” for sea lions.     

Diurnal Blood Pressure Variations Are Associated with Changes in Distal–Proximal Skin Temperature Gradient

It is generally assumed that skin vascular resistance contributes only to a small extent to total peripheral resistance and hence to blood pressure (BP). However, little is known about the impact of skin blood flow (SBF) changes on the diurnal variations of BP under ambulatory conditions. The main aim of the study was to determine whether diurnal patterns of distal SBF are related to mean arterial BP (MAP). Twenty-four-hour ambulatory measurements of BP, heart rate (HR) and distal (mean of hands and feet) as well as proximal (mean of sternum and infraclavicular region) skin temperatures were carried out in 51 patients (men/women?=?18/33) during a 2-d eye hospital investigation. The standardized ambulatory protocol allowed measurements with minimal interference from uncontrolled parameters and, hence, some conclusive interpretations. The distal minus proximal skin temperature gradient (DPG) provided a measure for distal SBF. Individual cross-correlation analyses revealed that the diurnal pattern of MAP was nearly a mirror image of DPG and hence of distal SBF. Scheduled lunch and dinner induced an increase in DPG and a decline in MAP, while HR increased. Low daytime DPG (i.e. low distal SBF) levels significantly predicted sleep-induced BP dipping (r?=??.436, p?=?.0014). Preliminary path analysis suggested that outdoor air temperature and atmospheric pressure may act on MAP via changed distal SBF. Changes in distal SBF may contribute to diurnal variation in MAP, including sleep-induced BP dipping and changes related to food intake. This finding might have an impact on individual cardiovascular risk prediction with respect to diurnal, seasonal and weather variations; however, the underlying mechanisms remain to be discovered.     

Field use of isoflurane as an inhalant anesthetic in the American marten (Martes americana)

We evaluated the effectiveness and practicality of using isoflurane as an inhalation anesthetic with oxygen as a gas carrier for American martens (Martes americana) in a field setting. Sixty-eight martens were trapped in the Waswanipi Cree Model Forest (Québec, Canada) from October to November 2005 and anesthetized with isoflurane in 100% oxygen (1 l/min) using a face mask. Induction setting of isoflurane was 3% for all animals. Mean (+/-SD) length of induction was 1.8+/-1.2 min. Maintenance isoflurane settings ranged from 1% to 4%. Procedures lasted an average of 16.4+/-7.1 min and were uneventful. Length of recovery, defined as the interval between the end of the procedure and animal release, was short (6.3+/-2.8 min), and well below reported lengths of recovery using injectable anesthetics (>/=70 min). As compared to open drop administration of isoflurane described in previous studies, the use of an anesthesia machine prevents the risk of potential fatal anesthetic overdose. We conclude that among anesthesia techniques currently available, isoflurane with oxygen as a gas carrier is a safe and useful field anesthetic in martens, when issues with equipment portability can be overcome.     

Hemodynamic response to anesthesia in pregnant and nonpregnant ICR mice

Mean arterial blood pressure (BP) and heart rate (HR) during and after recovery from anesthesia in pregnant and nonpregnant ICR mice were evaluated. Mice were evaluated during mechanical ventilation, from 15 to 60 min after induction of anesthesia. The anesthetic protocols were pentobarbital (80 mg/kg, given intraperitoneally [i.p.]); two low doses of ketamine and xylazine (90 mg/kg, 7.5 mg/kg, respectively, i.p., with a second dose given 20 min after the initial dose); and a single high dose of ketamine and xylazine (150 mg/kg, 12.5 mg/kg, respectively, i.p.). The BP was measured in the right carotid artery, using a fluid-filled catheter connected to a chamber containing a solid-state pressure transducer. Mechanical ventilation was performed via tracheotomy, using a normalized minute ventilation of 3.5 ml*min-1*g-1 for nonpregnant mice and 3.0 ml*min-1*g-1 for pregnant mice. Mean BP was lower and HR was higher in pregnant than in nonpregnant mice for each anesthetic protocol. Pentobarbital induced significantly greater tachycardia and hypotension than did the other protocols. The average BP and HR were similar between two low doses and a single high dose of ketamine and xylazine. During spontaneous breathing from 30 to 180 min after recovery from anesthesia by use of a single low dose, ketamine and xylazine induced similar HR profiles, but mean BP in pregnant mice recovered earlier than did that in nonpregnant mice. These results suggest that ketamine and xylazine induced adequate anesthesia for superficial surgical procedures in pregnant and nonpregnant mice while inducing small changes in HR and BP, and pregnancy resulted in a different hemodynamic reaction in response to ketamine and xylazine. These data will be useful for the design and interpretation of physiologic protocols using pregnant and nonpregnant genetically targeted mice.     

Isoflurane activates intestinal sphingosine kinase to protect against bilateral nephrectomy-induced liver and intestine dysfunction

Acute kidney injury (AKI) frequently leads to systemic inflammation and extrarenal organ dysfunction. Volatile anesthetics are potent anti-inflammatory agents and protect against renal ischemia-reperfusion injury. Here, we sought to determine whether isoflurane, a commonly used volatile anesthetic, protects against AKI-induced liver and intestinal injury, the mechanisms involved in this protection, and whether this protection was independent of the degree of renal injury. Bilateral nephrectomy-induced AKI under pentobarbital sodium anesthesia led to severe hepatic and intestinal injury with periportal hepatocyte vacuolization, small intestinal necrosis, apoptosis, and proinflammatory mRNA upregulation. In contrast, isoflurane anesthesia reduced hepatic and intestinal injury after bilateral nephrectomy. Mechanistically, isoflurane anesthesia upregulated and induced small intestinal crypt sphingosine kinase-1 (SK1) as SK1 mRNA, protein, and enzyme activity increased with isoflurane treatment. Furthermore, isoflurane failed to protect mice treated with a selective SK inhibitor (SKI-II) or mice deficient in the SK1 enzyme against hepatic and intestinal dysfunction after bilateral nephrectomy, demonstrating the key role of SK1. Therefore, in addition to its potent anesthetic properties, isoflurane protects against AKI-induced liver and intestine injury via activation of small intestinal SK1 independently of the effects on the kidney. These findings may help to elucidate the cellular signaling pathways underlying volatile anesthetic-mediated hepatic and intestinal protection and result in novel clinical applications of volatile anesthetics to attenuate perioperative complications arising from AKI.     

Cardiopulmonary,hematological, serum biochemical and behavioral effects of sevoflurane compared with isoflurane or halothane in spontaneously ventilating goats

This study compares cardiopulmonary, hematological, serum biochemical and behavioral effects of sevoflurane, isoflurane or halothane anesthesia in spontaneously breathing, conventionally medicated goats. Six male adult goats were anesthetized repeatedly at 2-week intervals with three anesthetics. Goats were administered atropine (0.1 mg/kg) intramuscularly, and 10 min later, induced to anesthesia by an intravenous infusion of thiopental (mean 14.3 mg/kg). After intubation, goats were anesthetized with halothane, isoflurane or sevoflurane in oxygen and maintained at surgical depth of anesthesia for 3 h. Recovery from anesthesia with sevoflurane was more rapid than that with isoflurane or halothane. Time-related hypercapnia and acidosis were observed during halothane anesthesia, but not observed during sevoflurane or isoflurane anesthesia. Both hypercapnia and acidosis during sevoflurane anesthesia did not differ from isoflurane anesthesia, but were less during halothane anesthesia, especially at prolonged maintenance period. There were no significant differences between anesthetics in respiration and heart rates, arterial pressures, hematological and serum biochemical values. It was concluded that sevoflurane is an effective inhalant for use in goats showing the most rapid recovery from anesthesia, and that cardiopulmonary effects of sevoflurane are similar to isoflurane than halothane.