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1.
Ten dogs were studied to determine the effects of xylazine, ketamine, and xylazine combined with ketamine on the dosage of epinephrine required to produce ventricular arrhythmia. Untreated dogs required an arrhythmogenic dose (AD) of 5.88 +/- 2.85 micrograms/kg/min. The AD was 4.28 +/- 3.25 micrograms/kg/min in xylazine-treated dogs, 3.05 +/- 2.3 micrograms/kg/min in ketamine-treated dogs, and 2.96 +/- 1.95 micrograms/kg/min in xylazine/ketamine-treated dogs. The latter two dosages were significantly less than that of the controls (p less than 0.025). The duration of increased arrhythmogenicity was also examined. Four hours after drug administration, the AD for xylazine-treated dogs was decreased further to 3.87 +/- 2.52 micrograms/kg/min (p less than 0.05). Ketamine-treated dogs had returned partially to normal with an AD of 4.09 +/- 3.09 micrograms/kg/min, as had xylazine/ketamine-treated dogs, at 4.22 +/- 2.71 micrograms/kg/min.  相似文献   

2.
The cardiovascular changes associated with anesthesia induced and maintained with romifidine/ketamine versus xylazine/ ketamine were compared using 6 horses in a cross over design. Anesthesia was induced and maintained with romifidine (100 microg/kg, IV)/ketamine (2.0 mg/kg, IV) and ketamine (0.1 mg/kg/min, IV), respectively, in horses assigned to the romifidine/ ketamine group. Horses assigned to the xylazine/ketamine group had anesthesia induced and maintained with xylazine (1.0 mg/kg, IV)/ketamine (2.0 mg/kg, IV) and a combination of xylazine (0.05 mg/kg/min, IV) and ketamine (0.1 mg/kg/min, IV), respectively. Cardiopulmonary variables were measured at intervals up to 40 min after induction. All horses showed effective sedation following intravenous romifidine or xylazine and achieved recumbency after ketamine administration. There were no significant differences between groups in heart rate, arterial oxygen partial pressures, arterial carbon dioxide partial pressures, cardiac index, stroke index, oxygen delivery, oxygen utilization, systemic vascular resistance, left ventricular work, or any of the measured systemic arterial blood pressures. Cardiac index and left ventricular work fell significantly from baseline while systemic vascular resistance increased from baseline in both groups. The oxygen utilization ratio was higher in the xylazine group at 5 and 15 min after induction. In conclusion, the combination of romifidine/ketamine results in similar cardiopulmonary alterations as a xylazine/ketamine regime, and is a suitable alternative for clinical anesthesia of the horse from a cardiopulmonary viewpoint.  相似文献   

3.
The effect of xylazine on the arrhythmogenic dose of epinephrine (ADE) was studied in 9 horses. Anesthesia was induced by administration of guaifenesin (50 mg/kg of body weight, IV) followed by thiamylal (4 to 6 mg/kg, IV) and was maintained at 1 minimal alveolar concentration (MAC) of halothane (0.89%). Base apex ECG and facial artery pressure were recorded. Epinephrine was infused in a sequence of arithmetically spaced increasing rates (initial rate 0.25 micrograms/kg/min) for a maximum of 10 minutes. The ADE was defined as the lowest epinephrine infusion rate to the nearest 0.25 micrograms/kg/min at which at least 4 premature ventricular depolarizations occurred in a 15-second period. Xylazine (1.1 mg/kg, IV) was administered after the control ADE was determined. Xylazine did not significantly alter the ADE (control, 1.12 +/- 0.38 micrograms/kg/min; xylazine, 1.21 +/- 0.46 micrograms/kg/min). Blood pressure increased transiently for 8 minutes after xylazine administration. Baseline systolic and diastolic arterial pressures and heart rate were not significantly different from control baseline pressures and heart rate 15 minutes after xylazine administration. Blood pressure and heart rate increased significantly during control and xylazine ADE determinations. Significant differences in pH, PaO2, PaCO2, or base excess were not observed between baseline and ADE in the control or xylazine groups. One horse developed atrial fibrillation, and 2 horses developed ventricular fibrillation during ADE determinations.  相似文献   

4.
The objective of this study was to evaluate the plasma pharmacokinetics of ketamine and its active metabolite norketamine administered intravenously at a dose of 0.1 mg/kg together with xylazine (0.05 mg/kg) to control the pain associated with castration in calves. A two-compartment model with an additional metabolite compartment linked to the central compartment was used to simultaneously describe the time-concentration profiles of both ketamine and its major metabolite norketamine. Parameter values estimated from the time-concentration profiles observed in this study were volume of the central compartment (Vc = 132.82 ± 68.23 mL/kg), distribution clearance (CLD = 15.49 ± 2.56 mL/min/kg), volume of the peripheral compartment (VT = 257.05 ± 41.65 mL/kg), ketamine clearance by the formation of the norketamine metabolite (CL2M = 8.56 ± 7.37 mL/kg/min) and ketamine clearance by other routes (CLo = 16.41 ± 3.42 mL/kg/min). Previously published data from rats suggest that the metabolite norketamine contributes to the analgesic effect of ketamine, with a potency that is one-third of the parent drug. An understanding of the time-concentration relationships and the disposition of the parent drug and its metabolite is therefore important for a better understanding of the analgesic potential of ketamine in cattle.  相似文献   

5.
Effects of ketamine, xylazine, and a combination of ketamine and xylazine were studied in 12 male Pekin ducks (7 to 12 weeks old; mean [+/- SD] body weight, 3.1 +/- 0.3 kg). After venous and arterial catheterization and fixation of a temperature probe in the cloaca, each awake duck was confined, but not restrained, in an open box in a dimly lit room. Blood pressure and lead-II ECG were recorded. Three arterial blood samples were collected every 15 minutes over a 45-minute period (control period) and were analyzed for pHa, PaCO2 and PaO2. After the control period, each duck was assigned at random to 1 of 3 drug groups: (1) ketamine (KET; 20 mg/kg of body weight, IV), (2) xylazine (XYL; 1 mg/kg, IV), and (3) KET + XYL (KET 20 mg/kg and XYL, 1 mg/kg; IV). Measurements were made at 1, 5, 10, 15, 30, 45, 60, and 90 minutes after drug administration. All ducks survived the drug study. Cloacal temperature was significantly (P less than or equal to 0.05) increased above control cloacal temperature at 90 minutes after the administration of ketamine, and from 10 through 90 minutes after administration of ketamine plus xylazine. In ducks of the KET group, pHa, PaCO2, and PaO2, remained unchanged after administration of the drug. In ducks of the XYL group, pHa and PaO2 decreased significantly (P less than or equal to 0.05) from control values for all time points up to and including 15 minutes after drug administration.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

6.
OBJECTIVES: To evaluate the effects of halothane and isoflurane on cardiovascular function and serum total and ionized calcium concentrations in horses, and to determine whether administration of calcium gluconate would attenuate these effects. ANIMALS: 6 clinically normal adult Thoroughbreds. PROCEDURE: Catheters were inserted for measurement of arterial blood pressures, pulmonary arterial blood pressures, right ventricular pressure (for determination of myocardial contractility), right atrial pressure, and cardiac output and for collection of arterial blood samples. Anesthesia was then induced with xylazine hydrochloride and ketamine hydrochloride and maintained with halothane or isoflurane. An i.v. infusion of calcium gluconate was begun 75 minutes after anesthetic induction; dosage of calcium gluconate was 0.1 mg/kg of body weight/min for the first 15 minutes, 0.2 mg/kg/min for the next 15 minutes, and 0.4 mg/kg/min for an additional 15 minutes. Data were collected before, during, and after administration of calcium gluconate. RESULTS: Halothane and isoflurane decreased myocardial contractility, cardiac index, and mean arterial pressure, but halothane caused greater depression than isoflurane. Calcium gluconate attenuated the anesthetic-induced depression in cardiac index, stroke index, and maximal rate of increase in right ventricular pressure when horses were anesthetized with isoflurane. When horses were anesthetized with halothane, a higher dosage of calcium gluconate was required to attenuate the depression in stroke index and maximal rate of increase in right ventricular pressure; cardiac index was not changed with calcium administration. CONCLUSIONS AND CLINICAL RELEVANCE: I.v. administration of calcium gluconate may support myocardial function in horses anesthetized with isoflurane.  相似文献   

7.
The purpose of this study was to determine a satisfactory combination of guaifenesin, ketamine, and xylazine (GKX) that would produce safe and satisfactory total intravenous anesthesia in donkeys for use under field conditions. Donkeys require higher amounts of ketamine in GKX to achieve satisfactory anesthetic levels without producing excessive depression with guaifenesin. Five adult standard donkeys (average weight, 264 kg) were anesthetized with 1.5 mg/mL ketamine, 0.5 mg/mL xylazine, 50 mg/mL guaifenesin (GKX-1); 2.0 mg/mL ketamine, 0.5 mg/mL xylazine, 50 mg/mL guaifenesin (GKX-2); or 2.0 mg/mL ketamine, 0.75 mg/mL xylazine, 50 mg/mL guaifenesin (GKX-3). For the first trial, two donkeys received GKX-1, two received GKX-2, and one received GKX-3. One donkey received GKX-1, one received GKX-2, and three received GKX-3 for the second trial. In the final trial, two received GKX-1, two received GKX-2, and one received GKX-3. Donkeys were sedated with xylazine (1.1 mg/kg body weight) intravenously, and anesthesia was induced using intravenous GKX-1, GKX-2, or GKX-3. Anesthesia was maintained for 45 minutes; temperature, respiration rate, heart rate, hemoglobin saturation, partial pressure of arterial oxygen (PaO2), partial pressure of carbon dioxide in arterial gas (PaCO2), and pH were measured. There was no significant difference between combinations for temperature, respiration rate, heart rate, hemoglobin saturation, PaCO2, or pH. At 30 and 45 minutes, GKX-3 produced significantly (P < .05) lower PaO2 values than GKX-1 and GKX-2. GKX-3 is not recommended for field use in donkeys because of respiratory depression (PaO2= 48.7 [±5.84] and 46.0 ± 3.11 mmHg at 30 and 45 minutes, respectively), whereas more voluntary movement was apparent with GKX-1. GKX-2 produced satisfactory anesthesia without significant respiratory depression in donkeys and should produce safe and effective anesthesia in donkeys under field conditions.  相似文献   

8.
OBJECTIVE: To investigate renal function in clinically normal dogs when awake and during anesthesia with medetomidine; xylazine, ketamine, and halothane (XKH) combination; or propofol. ANIMALS: 10 adult female Beagles. PROCEDURES: At intervals of 15 days, dogs were administered medetomidine (0.05 mg/kg, IV); XKH combination (xylazine [1 mg/kg, IV], ketamine [5 mg/kg, IV], and halothane [1% end-tidal concentration]); or propofol (6 mg/kg, IV) to induce anesthesia or no treatment. Glomerular filtration rate was assessed on the basis of renal uptake (RU; determined via renal scintigraphy) and plasma clearance (CL) of technetium 99m-labeled diethylenetriamine pentaacetic acid ((99m)Tc-DTPA). RESULTS: In awake dogs, mean +/- SEM RU was 9.7 +/- 0.4% and CL was 3.86 +/- 0.23 mL/min/ kg. Renal uptake and CL of (99m)Tc-DTPA were not significantly modified by administration of XKH (RU, 11.4 +/- 0.9%; CL, 4.6 +/- 0.32 mL/min/kg) or propofol (RU, 9.7 +/- 0.3%; CL, 3.78 +/- 0.37 mL/min/kg). Half-life elimination time of plasma (99m)Tc-DTPA decreased significantly in XKH-anesthetized dogs, compared with the value in awake dogs (14.4 minutes and 28.9 minutes, respectively). However, glomerular filtration rate was significantly decreased by administration of medetomidine (RU, 3.9 +/- 0.1%), and the time to maximum kidney activity was significantly increased (867 +/- 56 seconds vs 181 +/- 11 seconds without anesthesia). CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that anesthesia with propofol or an XKH combination did not alter renal function in healthy Beagles, but anesthesia with medetomidine decreased early RU of (99m)Tc-DTPA.  相似文献   

9.
Objective  The study was undertaken to evaluate the use of ketamine, xylazine, and diazepam along with a local retrobulbar nerve block for routine phacoemulsification in the dog.
Animals  Ten clinically healthy mixed-breed dogs of either sex, weighing between 10 and 15 kg.
Procedures  Ten mixed-breed dogs were selected for unilateral cataract removal by phacoemulsification. Standard preoperative preparations for cataract surgery were followed. Pre-anesthetic medication consisted of atropine sulfate (0.02 mg/kg, SC). Anesthesia was induced by xylazine HCl (1.0 mg/kg, IM) followed by ketamine (5.0 mg/kg, IM). Anesthesia was maintained subsequently with IV ketamine and diazepam to effect and depth of anesthesia was assessed clinically by pedal reflex and jaw reflex. After induction of anesthesia, a retrobulbar nerve block was performed using 2 mL of 2% lignocaine. Eye position was graded after retrobulbar block and IOP was examined preoperative, post-anesthetic, 6 h postoperative and 24 h after surgery. Phacoemulsification was performed using the phaco-chop technique and an intraocular lens was placed. Anesthetic recovery and postoperative recovery following surgery was recorded.
Result  The exposure of the globe in all the dogs was adequate; the desired central fixation of the eye was obtained and surgery could be performed uneventfully. The mean IOP recorded after induction of anesthesia was 15.75 ± 0.82, which was not significantly ( P  > 0.01) different from pre-anesthetic values (14.85 ± 0.85).
Conclusion  Phacoemulsification was successfully performed with this anesthetic regimen without encountering major intraoperative or anesthetic complications.  相似文献   

10.
Ventricular arryhythmias including ventricular fibrillation were produced with epinephrine in dogs induced to an anesthetic state with thiamylal and maintained with halothane. In dogs given (premedicated) xylazine 20 minutes prior to anesthesia, ventricular arrhythmias, including ventricular fibrillation, were induced with much smaller doses of epinephrine than in nonpremedicated dogs. Dogs premedicated with acetylpromazine 20 minutes prior to anesthesia with thiamylal and halothane displayed protection from epinephrine-induced arrhythmias. Caution is advised from using xylazine in the presence of halothane if epinephrine is to be administered.  相似文献   

11.
To determine the effects of yohimbine and tolazoline on the cardiovascular, respiratory and sedative effects of xylazine, four horses were sedated with xylazine and treated with either yohimbine, tolazoline or saline. Xylazine was administered as an intravenous (i.v.) bolus (1.0 nig/kg) followed by a continuous infusion at the rate of 12 μg/kg/min. Heart rate, respiratory rate, mean arterial pressure, arterial blood gases, and the chin-to-floor distance were recorded throughout the experiment. After 60 min, either yohimbine or tolazoline was administered i.v. in incremental doses until reversal of sedation (defined as the return of the chin-to-floor distance to baseline values) was achieved. A control group in which a saline bolus was administered instead of an antagonist drug was included for comparison.
The average dose of yohimbine administered was 0.12 ± 0.02 (SEM) mg/kg. While the average dose of tolazoline was 7.5 ± 1.1 mg/kg. Both tolazoline and yohimbine antagonized the ventricular bradycardia and A-V conduction disturbances observed with xylazine administration. No change in mean arterial pressure was observed with xylazine or yohimbine administration, but tolazoline caused persistent mild systemic hypertension. There were no clinically significant changes in respiratory rate or arterial blood gas values with administration of either xylazine, yohimbine or tolazoline. The chin-to-floor distance decreased significantly with xylazine administration and increased significantly with administration of either yohimbine or tolazoline. In conclusion, both yohimbine and tolazoline successfully antagonized the cardiovascular and CNS depression associated with xylazine administration.  相似文献   

12.
Reversal of hemodynamic alterations induced by midazolam maleate (1.0 mg/kg of body weight), xylazine hydrochloride (0.44 mg/kg), and butorphanol tartrate (0.1 mg/kg) with yohimbine (0.1 mg/kg) and flumazenil (0.25 mg/kg) was evaluated in 5 dogs. The dogs were anesthetized with isoflurane for instrumentation. With return to consciousness, baseline values were recorded, and the midazolam/xylazine/butorphanol mixture with glycopyrrolate was administered IV. Hemodynamic data were recorded for 60 minutes, and then a reversal mixture of yohimbine and flumazenil was administered IV. All variables were measured 1 minute from beginning of the reversal injection. Mean arterial pressure, pulmonary arterial pressure, systemic vascular resistance, and right ventricular stroke work index increased significantly (P < 0.05) above baseline at 60 minutes. Cardiac index and central venous pressure significantly decreased below baseline at 60 minutes. After reversal, mean arterial pressure and central venous pressure significantly decreased from baseline, whereas cardiac index, pulmonary arterial pressure, and right ventricular stroke work index increased significantly above baseline. Heart rate, cardiac index, and right ventricular stroke work index increased significantly above the 60-minute value after reversal. Mean arterial pressure and systemic vascular resistance decreased significantly (P < 0.05) below the 60-minute value after reversal. The hemodynamic alterations accompanying midazolam/xylazine/butorphanol sedation-anesthesia may be rapidly reversed with a combination of yohimbine and flumazenil.  相似文献   

13.
This study was carried out to determine whether yohimbine antagonizes the retrograde flow of spermatozoa into the urinary bladder of dogs caused by xylazine. Adult dogs were assigned to one of four groups of six dogs each and treated as follows: saline control, xylazine (2.2 mg/kg, i.m.), yohimbine (0.2 mg/kg, im.), yohimbine/xylazine (yohimbine, 0.2 mg/kg, i.m., followed 10 min later by xylazine. 2.2 mg/kg, i.m.). Pre- and post-treatment urine were collected by cystocentesis from all dogs. The mean (± SD) adjusted total number of spermatozoa in the post-treatment urine of xylazine-treated dogs (141.02 ± 136.75 × 106) was 15 times higher ( P < 0.05) than the number in the post-treatment urine of control dogs (9.16 ± 20.26 × 106), 1763 times higher ( P < 0.05) than the number in the urine of yohimbine-treated dogs (0.08 ± 0.20 × 106), and 56 times higher ( P < 0.05) than the total number in the post-treatment urine of yohimbine/xylazine-treated dogs (2.54 ± 4.54 × 106). These results confirm that xylazine induces a significant ( P = 0.007) displacement of spermatozoa into the urinary bladder of dogs and demonstrate that pre-treatment with yohimbine prevents this effect.  相似文献   

14.
The arrhythmogenic dose of epinephrine (ADE) was determined in six dogs during halothane (1.35%) anesthesia before and after xylazine administration (1.1 mg/kg, i.v. bolus; 1.1 mg/kg/hr, i.v. infusion). The arrhythmogenic dose was determined by constant infusion of freshly mixed epinephrine (100 microgram/ml). The ADE was defined as the total dose of epinephrine which produced four or more intermittent or continuous premature ventricular contractions within a 15-sec period. Total dose was calculated as a function of infusion rate and time to arrhythmia. Following xylazine administration, ADE significantly decreased from 6.28 +/- 0.522 to 4.17 +/- 0.679 micrograms/kg. At the end of i.v. xylazine bolus administration, heart rate significantly decreased (115 +/- 4 to 99 +/- 4.9 b.p.m.), and mean arterial pressure significantly increased (83 +/- 4.0 to 122 +/- 3.4 mm Hg). Heart rate measured immediately prior to epinephrine-induced arrhythmia formation was significantly increased following xylazine administration (177 +/- 8 vs 78 +/- 3 b.p.m.). Mean arterial blood pressure was unchanged. Apparently, xylazine, a mixed alpha agonist, potentiated halothane-induced myocardial sensitization to ventricular arrhythmogenesis and was associated with a significant increase in heart rate, but not blood pressure, during subsequent epinephrine infusions.  相似文献   

15.
The influence of atropine on anesthesia induced by xylazine-pentobarbital administration was studied in 5 dogs. The combination of xylazine (2.2 mg/kg of body weight, IM) and pentobarbital (14.0 mg/kg, IV) caused anesthesia with the duration of absence of the pedal reflex, duration of anesthesia, and the time from return of consciousness to ambulation to be 107.4, 123.4, and 59.2 minutes, respectively. Bradycardia and short-term respiratory depression were observed. An IM injection of atropine sulfate (0.045 mg/kg) did not significantly change the durations of absence of the pedal reflex and of anesthesia, the time from return of consciousness to ambulation, or the pattern of respiration in the anesthetized dogs. The PaO2 increased gradually in both groups; however, atropine caused a marked tachycardia and increased the PaCO2. Fifteen minutes after pentobarbital injection, administration of atropine sulfate caused a slight but significant (P less than 0.01) decrease in arterial pH. Although atropine sulfate antagonized xylazine bradycardia, the data indicated that it may have caused increased respiratory depression in dogs anesthetized with xylazine and pentobarbital.  相似文献   

16.
Reasons for performing study: No studies have been reported on the effects of enoximone in anaesthetised colic horses. Objective: To examine whether enoximone improves cardiovascular function and reduces dobutamine requirement in anaesthetised colic horses. Methods: Forty‐eight mature colic horses were enrolled in this prospective, randomised clinical trial. After sedation (xylazine 0.7 mg/kg bwt) and induction (midazolam 0.06 mg/kg bwt, ketamine 2.2 mg/kg bwt), anaesthesia was maintained with isoflurane in oxygen and a lidocaine constant rate infusion (1.5 mg/kg bwt, 2 mg/kg/h). Horses were ventilated (PaCO2<8.00 kPa). If hypotension occurred, dobutamine and/or colloids were administered. Ten minutes after skin incision, horses randomly received an i.v. bolus of enoximone (0.5 mg/kg bwt) or saline. Monitoring included respiratory and arterial blood gases, heart rate (HR), arterial pressure and cardiac index (CI). Systemic vascular resistance (SVR), stroke index (SI) and oxygen delivery index (DO2I) were calculated. For each variable, changes between baseline and T10 within each treatment group and/or colic type (small intestines, large intestines or mixed) were analysed and compared between treatments in a fixed effects model. Differences between treatments until T30 were investigated using a mixed model (α= 0.05). Results: Ten minutes after enoximone treatment, CI (P = 0.0010), HR (P = 0.0033) and DO2I (P = 0.0007) were higher and SVR lower (P = 0.0043) than at baseline. The changes in CI, HR and SVR were significantly different from those after saline treatment. During the first 30 min after enoximone treatment, DO2I (P = 0.0224) and HR (P = 0.0003) were higher than after saline administration. Because the difference in HR between treatments was much clearer in large intestine colic cases, an interaction was detected between treatment and colic type in both analyses (P = 0.0076 and 0.0038, respectively). Conclusions: Enoximone produced significant, but short lasting, cardiovascular effects in colic horses. Potential relevance: Enoximone's cardiovascular effects in colic horses were of shorter duration than in healthy ponies.  相似文献   

17.
Objective- This study evaluates the clinical usefulness and anesthetic effect of propofol, and compares these effects with those of xylazine-ketamine-halothane anesthesia in sheep.
Study Design- Prospective, randomized, clinical trial. Animals or Sample Population- Fourteen healthy adult male sheep.
Methods- Sheep were randomly assigned to two different drug regimens: (1) Bolus injection of propofol (3 mg/kg, intravenously [IV]) followed by continuous intravenous infusion and (2) xylazine (0.11 mg/kg, IV) and ketamine (2.2 mg/kg, IV) for induction followed by halothane anesthesia. Heart rate, respiratory rate, and arterial blood pressures were monitored during anesthesia. Venous blood samples were collected for blood gas analysis. Quality of induction and recovery were also recorded.
Results- The average dose of propofol used to induce and maintain anesthesia was 6.63 ±2.06 mg/kg and 29.3 ±11.7 mg/kg/hr (0.49 ±0.20 mg/kg/min), respectively. The duration of propofol anesthesia was 45.3 ±13.2 minutes and recovery to standing occurred in 14.7 ±5.7 minutes. Sheep receiving xylazine-ketamine-halothane were anesthetized for 35.9 ±4.0 minutes and recovery to standing occurred within 28.5 ±7.5 minutes. Sheep anesthetized with propofol had a significantly higher heart rate, diastolic blood pressure and Pvo2, and a lower Pvco2 at 30 minutes and lower BE at 15 and 30 minutes than sheep anesthetized with xylazine-ketamine-halothane.
Conclusions- Propofol anesthesia was characterized by a smooth induction, effective surgical anesthesia and rapid recovery which was comparable to anesthesia with xylazine-ketamine-halothane.
Clinical Relevance- Propofol may be indicated in situations when it is desirable to maintain anesthesia with an intravenous infusion followed by a rapid recovery in healthy sheep.  相似文献   

18.
Objective —The purpose of this study was to determine the hemodynamic effects of epidural ketamine administered during isoflurane anesthesia in dogs. Study Design —Prospective, single-dose trial. Animals —Six healthy dogs (five males, one female) weighing 25.3 ± 3.88 kg. Methods —Once anesthesia was induced, dogs were maintained at 1.5 times the predetermined, individual minimum alveolar concentration (MAC) of isoflurane. Dogs were instrumented and allowed to stabilize for 30 minutes before baseline measurements were recorded. Injection of 2 mg/kg of ketamine in 1 mL saline/4.5 kg body weight was then performed at the lumbosacral epidural space. Hemodynamic data were recorded at 5, 10, 15, 20, 30, 45, 60, and 75 minutes after epidural ketamine injection. Statistical analysis included an analysis of variance (ANOVA) for repeated measures over time. All data were compared with baseline values. A P < .05 was considered significant. Results —Baseline values ±standard error of the mean (X ± SEM) for heart rate, mean arterial pressure, mean pulmonary artery pressure, central venous pressure, pulmonary capillary wedge pressure, cardiac index, stroke index, systemic vascular resistance, pulmonary vascular resistance, and rate-pressure product were 108 ± 6 beats/min, 85 ± 10 mm Hg, 10 ± 2 mm Hg, 3 ± 1 mm Hg, 5 ± 2 mm Hg, 2.3 ± 0.3 L/min/m2, 21.4 ± 1.9 mL/beat/m2, 3386 ± 350 dynes/sec/cm5, 240 ± 37 dynes/sec/cm5, and 12376 ± 1988 beats/min±mm Hg. No significant differences were detected from baseline values at any time after ketamine injection. Conclusions —The epidural injection of 2 mg/kg of ketamine is associated with minimal hemodynamic effects during isoflurane anesthesia. Clinical Relevance —These results suggest that if epidural ketamine is used for analgesia in dogs, it will induce minimal changes in cardiovascular function.  相似文献   

19.
Effect of yohimbine on xylazine-ketamine anesthesia in cats   总被引：3，自引：0，他引：3  
Xylazine and ketamine are an anesthetic combination used in feline practice for routine surgical procedures. In a controlled study, we evaluated the effects of yohimbine, an antagonist of xylazine, on the anesthesia induced by this anesthetic combination in cats. Two intramuscular doses of xylazine and ketamine (2.2 mg of xylazine/kg plus 6.6 mg of ketamine/kg and 4.4 mg of xylazine/kg plus 6.6 mg of ketamine/kg) caused approximately 60 and 100 minutes of anesthesia, respectively, in control cats. When yohimbine (0.1 mg/kg) was given intravenously 45 minutes after ketamine administration, the cats regained consciousness within 3 minutes. They were ambulatory 1 to 2 minutes after regaining consciousness. Yohimbine also reversed the bradycardia and respiratory depression elicited by xylazine-ketamine. The results indicated that yohimbine may be useful for controlling the duration of xylazine-ketamine anesthesia in cats.  相似文献   

20.
OBJECTIVE: To determine the effects of ketamine hydrochloride, xylazine hydrochloride, and lidocaine hydrochloride after subarachnoid administration in goats. ANIMALS: 6 healthy goats. PROCEDURE: In each goat, ketamine (3 mg/kg), xylazine (0.1 mg/kg), lidocaine (2.5 mg/kg), and saline (0.9% NaCI) solution were injected into the subarachnoid space between the last lumbar vertebra and first sacral vertebra (time 0). Analgesic, ataxic, sedative, cardiovascular, and respiratory effects and rectal temperature were evaluated before (baseline) and 2, 5, 10, 15, and 30 minutes after administration and at 30-minute intervals thereafter as needed. RESULTS: Administration of anesthetics induced varying degrees of analgesia. Onset of the analgesic effect was more delayed for xylazine (mean +/- SD, 9.5 +/- 2.6 minutes) than for ketamine (6.7 +/- 2.6 minutes) or lidocaine (3.5 +/- 1.2 minutes). Duration of analgesia induced by xylazine (88.3 +/- 15 minutes) was twice as long as the duration of analgesia induced by ketamine (48.8 +/- 13.5 minutes) but similar to that induced by lidocaine (66.5 +/- 31 minutes). Xylazine induced bradycardia, whereas ketamine caused a nonsignificant increase in heart rate. Xylazine induced a reduction in arterial pressure, whereas ketamine or lidocaine did not affect arterial pressure. CONCLUSIONS AND CLINICAL RELEVANCE: Subarachnoid administration of xylazine in goats resulted in longer duration of analgesia of the tail, perineum, hind limbs, flanks, and caudodorsal rib areas than administration of ketamine or lidocaine. However, xylazine caused bradycardia and respiratory depression. Additional studies are needed to determine whether the analgesia would be sufficient to allow clinicians to perform surgical procedures.  相似文献   

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