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1.
OBJECTIVE: To determine the effects of intravenous (IV) butorphanol on the cardiopulmonary system and on the bispectral index (BIS) in isoflurane-anesthetized alpacas. STUDY DESIGN: Randomized, blinded cross-over experimental trial. ANIMALS: Eight healthy, young (3 +/- 1 SD years) adult female alpacas weighing 64 +/- 9 SD kg. METHODS: Alpacas were anesthetized with isoflurane by mask followed by tracheal intubation and maintenance of anesthesia with isoflurane in oxygen and intermittent positive pressure ventilation. Animals were assigned to two treatments, butorphanol (0.1 mg kg(-1), IV) and saline (0.01 mL kg(-1), IV) in a randomized manner allowing a 2-week interval between treatments. Cardiovascular variables included systolic, diastolic, and mean arterial blood pressure, heart rate, pulmonary arterial pressure, pulmonary arterial occlusion pressure (PAOP), central venous pressure, cardiac output, and pulmonary temperature (TEMP). Cardiac index, systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were calculated. Bispectral index was also measured. Arterial and mixed venous blood samples were collected for blood gas analysis. All variables were recorded at baseline (time 0) and at 5, 10, 15, 30, 45 and 60 minutes following injection and were analyzed by using repeated-measures ANOVA (p < 0.05). PAOP, PVR, and BIS were analyzed by paired t-tests. RESULTS: Butorphanol decreased SVR at all times when compared with the baseline, but no difference was detected between treatments. TEMP decreased with time in both treatments, but they were not different from each other. Other cardiovascular, BIS, and blood gas variables were not different between groups. CONCLUSION AND CLINICAL RELEVANCE: We conclude that butorphanol had minimal effects on the cardiovascular system of the alpacas, causing a mild decrease in SVR.  相似文献   

2.
The purpose of this study was to determine the cardiovascular, analgesic, and sedative effects of IV medetomidine (M, 20 µg kg?1), medetomidine–hydromorphone (MH, 20 µg kg?1 ? 0.1 mg kg?1), and medetomidine–butorphanol (MB, 20 µg kg?1 ? 0.2 mg kg?1) in dogs. Using a randomized cross‐over design and allowing 1 week between treatments, six healthy, mixed‐breed dogs (five males and one female) weighing 20 ± 3 kg, were induced to anesthesia by face‐mask administration of 2.9% ET sevoflurane to facilitate instrumentation prior to administration of the treatment combinations. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), mean pulmonary arterial pressure (PAP), pulmonary arterial occlusion pressure (PAOP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output via thermodilution using 5 mL of 5% dextrose, and recording the average of the three replicate measurements. Cardiac index (CI) and systemic (SVR) and pulmonary vascular resistances were calculated. After instrumentation was completed, administration of sevoflurane was discontinued, and the dogs were allowed to recover for 30 minutes prior to administration of the treatment drugs. After collection of the baseline samples for blood gas analysis and recording the baseline cardiovascular variables, the test agents were administered IV over 10 seconds and the CV variables recorded at 5, 10, 15, 30, 45, and 60 minutes post‐injection. In addition, arterial blood was sampled for blood gas analysis at 15 and 45 minutes following injection. Intensity and duration of analgesia (assessed by toe‐pinch response using a hemostat) and level of sedation were evaluated at the above time points and at 75 and 90 minutes post‐injection. Data were analyzed using anova for repeated measures with posthoc differences between means identified using Bonferroni's method (p < 0.05). Administration of M, MH, or MB was associated with increases in SAP, MAP, DAP, PAP, PAOP, CVP, SVR, and TEMP and with decreases in HR and CI. No differences in CV variables between treatment groups were identified at any time. PaO2 increased over time in all groups and was significantly higher when MH was compared with M. At 45 minutes, PaO2 tended to decrease over time and was significantly lower when MH and MB were compared with M at 15 minutes. Analgesia scores for MH and MB were significantly higher compared with M through 45 minutes, while analgesia scores for MH were significantly higher compared with M through 90 minutes. Sedation scores were higher for MH and MB compared with M throughout 90 minutes. Durations of lateral recumbency were 108 ± 10.8, 172 ± 15.5, and 145 ± 9.9 minutes for M, MH, and MB, respectively. We conclude that MH and MB are associated with improved analgesia and sedation and have similar CV effects when compared with M.  相似文献   

3.
ObjectiveTo investigate MK-467 as part of premedication in horses anaesthetized with isoflurane.Study designExperimental, crossover study with a 14 day wash-out period.AnimalsSeven healthy horses.MethodsThe horses received either detomidine (20 μg kg−1 IV) and butorphanol (20 μg kg−1 IV) alone (DET) or with MK-467 (200 μg kg−1 IV; DET + MK) as premedication. Anaesthesia was induced with ketamine (2.2 mg kg−1) and midazolam (0.06 mg kg−1) IV and maintained with isoflurane. Heart rate (HR), mean arterial pressure (MAP), end-tidal isoflurane concentration, end-tidal carbon dioxide tension, central venous pressure, fraction of inspired oxygen (FiO2) and cardiac output were recorded. Blood samples were taken for blood gas analysis and to determine plasma drug concentrations. The cardiac index (CI), systemic vascular resistance (SVR), ratio of arterial oxygen tension to inspired oxygen (PaO2/FiO2) and tissue oxygen delivery (DO2) were calculated. Repeated measures anova was applied for HR, CI, MAP, SVR, lactate and blood gas variables. The Student's t-test was used for pairwise comparisons of drug concentrations, induction times and the amount of dobutamine administered. Significance was set at p < 0.05.ResultsThe induction time was shorter, reduction in MAP was detected, more dobutamine was given and HR and CI were higher after DET+MK, while SVR was higher with DET. Arterial oxygen tension and PaO2/FiO2 (40 minutes after induction), DO2 and venous partial pressure of oxygen (40 and 60 minutes after induction) were higher with DET+MK. Plasma detomidine concentrations were reduced in the group receiving MK-467. After DET+MK, the area under the plasma concentration time curve of butorphanol was smaller.Conclusions and clinical relevanceMK-467 enhances cardiac function and tissue oxygen delivery in horses sedated with detomidine before isoflurane anaesthesia. This finding could improve patient safety in the perioperative period. The dosage of MK-467 needs to be investigated to minimise the effect of MK-467 on MAP.  相似文献   

4.
Objective To assess the cardiovascular effects (arterial blood pressure, heart rate, and metabolic acid–base status) of three doses (MAC multiples) of isoflurane alone and combined with butorphanol in the green iguana (Iguana iguana). Study design Prospective randomized double‐blind, two‐period cross‐over trial. Animals Six mature healthy green iguanas (Iguana iguana). Methods The iguanas received each of two treatments, saline 0.1 mL kg?1 (SAL) and butorphanol 1.0 mg kg?1 (BUT) during isoflurane anesthesia. Treatments were separated by at least 1 week. The iguanas were exposed to each of the three minimum alveolar concentration (MAC) multiples (1.0, 1.5, and 2.0) in random order. Anesthesia was induced with isoflurane and maintained using controlled ventilation. Instrumentation included use of an ECG, airway gas monitor, cloacal thermometer, esophageal pulse oximeter, and the placement of a femoral arterial catheter. Body temperature was stabilized and maintained at 32 °C. The treatment was administered, and the animals were equilibrated for 20 minutes at each MAC multiple. At each concentration, the heart rate, blood pressure (systolic, mean, diastolic), end‐tidal CO2, and SpO2 were measured. At 1.0 and 2.0 MAC, simultaneous blood samples were drawn from the tail vein/artery complex and femoral catheter for blood gas analysis. Data were analyzed using a two‐way analysis of variance for repeated measures looking for differences between treatments and among MAC multiples. Results There were no significant differences in any of the cardiovascular variables between the treatments. Significant differences among isoflurane MAC multiples were observed for HR, mean, diastolic, and systolic blood pressures. Blood pressure and heart rate decreased with an increasing dose of anesthetic. There were no significant differences between treatments or MAC multiples for any of the blood gas variables. The blood pH, PCO2, HCO3?, and hemoglobin saturation differed significantly between sites. Pulse oximetry values measured from the carotid complex did not correlate with and were significantly different from the calculated hemoglobin saturation values determined using the gas analyzer. Conclusion and clinical relevance Cardiovascular depression associated with isoflurane anesthesia in the green iguana is dose dependent. The degree of cardiovascular depression was not significantly different when isoflurane was combined with butorphanol. This finding suggests that the pre‐emptive or intraoperative use of butorphanol is unlikely to be detrimental to cardiovascular function. Butorphanol may be a useful anesthetic adjunct to isoflurane anesthesia in the green iguana.  相似文献   

5.
The purpose of this study was to determine the cardiovascular effects of 2.0% end‐tidal isoflurane in dogs administered dexmedetomidine (DEX). Using a randomized crossover design and allowing at least 2 weeks between treatments 12 adult hound dogs of either sex weighing 22 ± 1.7 SD kg were anesthetized by face mask administration of either sevoflurane or isoflurane to facilitate instrumentation prior to administration of treatment drugs. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, mean pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output (CO) via thermodilution using 5 mL of 5% dextrose, and recording the average of three replicate measurements. Cardiac index (CI) and systemic (SVR) and pulmonary vascular resistances were calculated. Following completion of instrumentation, dogs were allowed to recover for 40 minutes. After collection of baseline data, dogs were administered one of four treatments at T‐10 minutes prior to injection of DEX (500? g M–2 IM): 1) saline (SAL); 2) atropine [ATR, 0.02 (n = 6) or 0.04 (n = 6) mg kg–1 IM]; 3) ISO (2.0% end tidal concentration); or 4) ISO + ATR. Cardiovascular data were collected at T‐20 and T‐5 minutes prior to administration of DEX, and at 5, 10 , 20, 30, 40, and 60 min following DEX. Data were analyzed using anova for repeated measures with post‐hoc differences between means identified using Bonferroni's method (p < 0.05). Differences in ATR dose were not found to be significant and thus results for ATR dose groups were pooled. Administration of SAL (dexmedetomidine alone) was associated with decreases in HR and CO and increases in SAP, MAP, DAP, CVP, and SVR. Administration of ATR was associated with an increase in HR and CO compared with SAL. Administration of ISO was associated with an increase in HR and a decrease in SVR, MAP and CVP compared with SAL. Administration of ISO + ATR was associated with effects similar to that of ISO or ATR alone. We conclude that administration of ISO reduces the increase in SVR associated with administration of DEX and does not adversely affect CO.  相似文献   

6.
The cardiovascular effects following epidural injection of xylazine or isotonic saline during isoflurane anesthesia were assessed in six healthy dogs. Dogs were anesthetized with isoflurane in O2 and maintained at 2.0% end-tidal concentration. Ventilation was controlled to maintain PaCO2 at 35 to 45 mm Hg. The dorsal pedal artery was cannulated for measurement of arterial blood pressure (AP)(systolic AP, mean AP, diastolic AP) and for blood sample collection. Arterial pH and blood gas tensions (PaO2 and PaCO2) were determined. Cardiac output was measured by thermodilution. The electrocardiogram (ECG), heart rate (HR), core body temperature, central venous pressure (CVP), mean pulmonary AP, and end-tidal isoflurane concentration (ETISO) and CO2 tension (ETCO2) were monitored. Systemic vascular resistance (SVR), arterial HCO2 concentration, base balance, and cardiac index (CI) were calculated. After baseline measurements were taken, either xylazine (0.2 mg/kg) in 5 mL isotonic saline or 5 mL of isotonic saline was injected into the lumbosacral epidural space. Data were then recorded at 5, 15, 30, 45, 60, 75, 90, 105, and 120 minutes after epidural injection. Data were analyzed by two-way analysis of variance (ANOVA) for repeated measures. When significant differences were encountered, mean values were compared using Bonferroni's test. The level of significance was set at P <.05. Mean values for diastolic AP decreased at 90 and 120 minutes compared with the mean value at 15 minutes after epidural injection of xylazine. No differences were detected at any time or between treatments for HR, systolic AP, mean AP, CVP, CI, SVR, mean pulmonary AP, temperature, ETCO2, ETISO, arterial pH, PaCO2, PaO2, plasma bicarbonate concentration, or base balance. Results of this study indicate that epidural injection of xylazine (0.2 mg/kg) is associated with minimal cardiovascular side effects during isoflurane anesthesia in mechanically ventilated dogs.  相似文献   

7.
ObjectiveTo determine the effect of butorphanol, administered by intravenous (IV) infusion, on the minimum alveolar concentration of isoflurane (MACISO) in cats and to examine the dosage dependence of this effect.Study designRandomized, placebo-controlled, crossover experimental study.AnimalsA group of six healthy adult male neutered cats.MethodsCats were anesthetized with isoflurane in oxygen. A venous catheter was placed for fluid and drug administration, and an arterial catheter was placed for measurement of arterial pressure and blood sampling. Four treatments were administered at random with at least 2 week interval between treatments: saline (control), butorphanol low dosage (treatment LD; 0.25 mg kg–1 IV bolus followed by 85 μg kg–1 minute–1 for 20 minutes, then 43 μg kg–1 minute–1 for 40 minutes, then 19 μg kg–1 minute–1), medium dosage (treatment MD, double the dosages in LD) and high dosage (treatment HD, quadruple the dosages in LD). MACISO was determined in duplicate using the bracketing technique and tail clamping. Pulse rate, arterial pressure, hemoglobin oxygen saturation, end-tidal partial pressure of carbon dioxide and arterial blood gas and pH were measured.ResultsButorphanol reduced MACISO in a dosage-dependent manner, by 23 ± 8%, 37 ± 12% and 68 ± 10% (mean ± standard deviation) in treatments LD, MD and HD, respectively. The main cardiopulmonary effect observed was a decrease in pulse rate, significant in treatment HD compared with control.Conclusions and clinical relevanceButorphanol caused a dosage-dependent MACISO reduction in cats. IV infusion of butorphanol may be of interest for partial IV anesthesia in cats.  相似文献   

8.
The purpose of this study was to determine the cardiovascular effects of sodium nitroprusside (SNP)‐induced after load reduction in dogs administered dexmedetomidine (DEX). Using a randomized crossover design and allowing at least 2 weeks between treatments 12 adult hound dogs of either sex weighing 22 ± 1.7 SD kg were anesthetized by face mask administration of 2.9% ET sevoflurane to facilitate instrumentation prior to administration of treatment drugs. Dogs were intubated and instrumented to enable measurement of heart rate (HR), systolic (SAP), mean (MAP) and diastolic (DAP) arterial pressures, mean pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), central venous pressure (CVP), pulmonary arterial temperature (TEMP), and cardiac output (CO). Systemic (SVR) and pulmonary vascular resistances were calculated. Following completion of instrumentation dogs were allowed to recover for 40 minutes. After collection of baseline data, dogs were administered one of four treatments at T–10 minutes prior to injection of DEX (500? g M–2 IM): 1) saline (SAL); 2) atropine (ATR, 0.02 [n = 6] or 0.04 [n = 6] mg kg–1 IM); 3) SAL + SNP (infused at 1–10 ?g kg–1 minute–1, IV as needed to maintain MAP between 90–110 mm Hg; or 4) ATR + SNP. Cardiovascular data were collected at T‐20 minutes prior to administration of DEX, T‐5 and at 5, 10, 20, 30, 40, and 60 minutes following DEX. Data were analyzed using anova for repeated measures with post hoc differences between means identified using Bonferroni's method (p < 0.05). Differences in ATR dose were not found to be significant and thus results for ATR dose groups were pooled. Administration of SAL (dexmedetomidine alone) was associated with decreases in HR and CO and increases in SAP, MAP, DAP, CVP, and SVR. Administration of ATR was associated with an increase in HR and CO compared with SAL. Administration of SNP was associated with an increase in HR and CO and a decrease in SVR, MAP and CVP compared with SAL. Administration of SNP + ATR was associated with effects similar to that of SNP or ATR alone and resulted in an additive increase in CO. We conclude that SNP‐induced afterload reduction with or without atropine is effective in mitigating DEX‐induced impairment of cardiovascular function.  相似文献   

9.
Objective To evaluate disposition of a single dose of butorphanol in goats after intravenous (IV) and intramuscular (IM) administration and to relate behavioral changes after butorphanol administration with plasma concentrations. Design Randomized experimental study. Animals Six healthy 3‐year‐old neutered goats (one male and five female) weighing 46.5 ± 10.5 kg (mean ± D). Methods Goats were given IV and IM butorphanol (0.1 mg kg?1) using a randomized cross‐over design with a 1‐week interval between treatments. Heparinized blood samples were collected at fixed intervals for subsequent determination of plasma butorphanol concentrations using an enzyme linked immunosorbent assay (ELISA). Pharmacokinetic values (volume of distribution at steady state [VdSS], systemic clearance [ClTB], extrapolated peak plasma concentration [C0] or estimated peak plasma concentration [CMAX], time to estimated peak plasma concentration [TMAX], distribution and elimination half‐lives [t1/2], and bioavailability) were calculated. Behavior was subjectively scored. A two‐tailed paired t‐test was used to compare the elimination half‐lives after IV and IM administration. Behavioral scores are reported as median (range). A Friedman Rank Sums test adjusted for ties was used to analyze the behavioral scores. A logit model was used to determine the effect of time and concentration on behavior. A value of p < 0.05 was considered significant. Results Volume of distribution at steady state after IV administration of butorphanol was 1.27 ± 0.73 L kg?1, and ClTB was 0.0096 ± 0.0024 L kg?1 minute?1. Extrapolated C0 of butorphanol after IV administration was 146.5 ± 49.8 ng mL?1. Estimated CMAX after IM administration of butorphanol was 54.98 ± 14.60 ng mL?1, and TMAX was 16.2 ± 5.2 minutes; bioavailability was 82 ± 41%. Elimination half‐life of butorphanol was 1.87 ± 1.49 and 2.75 ± 1.93 hours for IV and IM administration, respectively. Goats became hyperactive after butorphanol administration within the first 5 minutes after administration. Behavioral scores for goats were significantly different from baseline at 15 minutes after IV administration and at 15 and 30 minutes after IM administration. Both time and plasma butorphanol concentration were predictors of behavior. Behavioral scores of all goats had returned to baseline by 120 minutes after IV administration and by 240 minutes after IM administration. Conclusions and Clinical Relevance The dose of butorphanol (0.1 mg kg?1, IV or IM) being used clinically to treat postoperative pain in goats has an elimination half‐life of 1.87 and 2.75 hours, respectively. Nonpainful goats become transiently excited after IV and IM administration of butorphanol. Clinical trials to validate the efficacy of butorphanol as an analgesic in goats are needed.  相似文献   

10.
ObjectiveTo test if the addition of butorphanol by constant rate infusion (CRI) to medetomidine–isoflurane anaesthesia reduced isoflurane requirements, and influenced cardiopulmonary function and/or recovery characteristics.Study designProspective blinded randomised clinical trial.Animals61 horses undergoing elective surgery.MethodsHorses were sedated with intravenous (IV) medetomidine (7 μg kg?1); anaesthesia was induced with IV ketamine (2.2 mg kg?1) and diazepam (0.02 mg kg?1) and maintained with isoflurane and a CRI of medetomidine (3.5 μg kg?1 hour?1). Group MB (n = 31) received butorphanol CRI (25 μg kg?1 IV bolus then 25 μg kg?1 hour?1); Group M (n = 30) an equal volume of saline. Artificial ventilation maintained end-tidal CO2 in the normal range. Horses received lactated Ringer’s solution 5 mL kg?1 hour?1, dobutamine <1.25 μg kg?1 minute?1 and colloids if required. Inspired and exhaled gases, heart rate and mean arterial blood pressure (MAP) were monitored continuously; pH and arterial blood gases were measured every 30 minutes. Recovery was timed and scored. Data were analyzed using two way repeated measures anova, independent t-tests or Mann–Whitney Rank Sum test (p < 0.05).ResultsThere was no difference between groups with respect to anaesthesia duration, end-tidal isoflurane (MB: mean 1.06 ± SD 0.11, M: 1.05 ± 0.1%), MAP (MB: 88 ± 9, M: 87 ± 7 mmHg), heart rate (MB: 33 ± 6, M: 35 ± 8 beats minute?1), pH, PaO2 (MB: 19.2 ± 6.6, M: 18.2 ± 6.6 kPa) or PaCO2. Recovery times and quality did not differ between groups, but the time to extubation was significantly longer in group MB (26.9 ± 10.9 minutes) than in group M (20.4 ± 9.4 minutes).Conclusion and clinical relevanceButorphanol CRI at the dose used does not decrease isoflurane requirements in horses anaesthetised with medetomidine–isoflurane and has no influence on cardiopulmonary function or recovery.  相似文献   

11.
Butorphanol tartrate (0.5 mg/kg intravenously [IV]) was administered to six ewes (group 1), 10 minutes before administration of tiletamine-zolazepam (12 mg/kg IV). In six ewes (group 2), butorphanol tartrate and tiletamine-zolazepam were administered simultaneously. Time of administration of butorphanol did not alter hemodynamics or duration of anesthesia significantly. Anesthesia was adequate for 25 to 45 minutes (mean, 31 min) in group 1. The sheep in group 2 were anesthetized effectively for 25 to 50 minutes (mean, 39 min). Neither dosing regimen caused significant changes in right atrial pressure, heart rate, pulmonary vascular resistance, or pulmonary capillary wedge pressure. Mean arterial blood pressure (MABP) decreased an average of 18% from baseline values of 113 mm Hg to a minimum of 84 mm Hg at minute 60 in group 1, and from 111 mm Hg to 92 mm Hg at minute 75 in group 2. The decrease was significant only for group 1. Cardiac output (CO) was significantly decreased 24% from 6.6 L/min at minute 45 in group 1, and 32% from 6.3 L/min at minute 15 in group 2. Systemic vascular resistance (SVR) was increased significantly at minute 15, 11% in group 1 and 37% in group 2. Mild respiratory acidosis was measured by significant decreases in arterial pO2 and pH and a significant increase in pCO2 without significant changes in HCO3-. Results of this study show that (1) tiletamine-zolazepam and butorphanol tartrate produce adequate anesthesia for 25 to 50 minutes; (2) the cardiovascular and anesthetic effects of the dosing schedules were similar; and (3) tiletamine-zolazepam and butorphanol result in decreased CO and MABP with a concomitant increase in SVR, and mild respiratory acidosis.  相似文献   

12.
ObjectiveTo compare the haemodynamic effects of three premedicant regimens during propofol-induced isoflurane anaesthesia.Study designProspective, randomized cross-over study.AnimalsEight healthy purpose-bred beagles aged 4 years and weighing mean 13.6 ± SD 1.9 kg.MethodsThe dogs were instrumented whilst under isoflurane anaesthesia prior to each experiment, then allowed to recover for 60 minutes. Each dog was treated with three different premedications given intravenously (IV): medetomidine 10 μg kg?1 (MED), medetomidine 10 μg kg?1 with MK-467 250 μg kg?1 (MMK), or acepromazine 0.01 mg kg?1 with butorphanol 0.3 mg kg?1 (AB). Anaesthesia was induced 20 minutes later with propofol and maintained with isoflurane in oxygen for 60 minutes. Heart rate (HR), cardiac output, arterial blood pressures (ABP), central venous pressure (CVP), respiratory rate, inspired oxygen fraction, rectal temperature (RT) and bispectral index (BIS) were measured and arterial and venous blood gases analyzed. Cardiac index (CI), systemic vascular resistance index (SVRI), oxygen delivery index (DO2I), systemic oxygen consumption index (VO2I) and oxygen extraction (EO2) were calculated. Times to extubation, righting, sternal recumbency and walking were recorded. The differences between treatment groups were evaluated with repeated measures analysis of covariance.ResultsHR, CI, DO2I and BIS were significantly lower with MED than with MMK. ABP, CVP, SVRI, EO2, RT and arterial lactate were significantly higher with MED than with MMK and AB. HR and ABP were significantly higher with MMK than with AB. However, CVP, CI, SVRI, DO2I, VO2I, EO2, T, BIS and blood lactate did not differ significantly between MMK and AB. The times to extubation, righting, sternal recumbency and walking were significantly shorter with MMK than with MED and AB.Conclusions and clinical relevanceMK-467 attenuates certain cardiovascular effects of medetomidine in dogs anaesthetized with isoflurane. The cardiovascular effects of MMK are very similar to those of AB.  相似文献   

13.
OBJECTIVE: To determine cardiovascular responses to administration of butorphanol in isoflurane-anesthetized horses. STUDY DESIGN: Retrospective evaluation of anesthetic records. ANIMALS: Seventy-six horses anesthetized for a variety of clinical surgical procedures. METHODS: Anesthetic records of clinical equine patients anesthetized between January 1999 and December 2003 were searched. The records were reviewed for horses in which anesthesia was induced with ketamine and a benzodiazepine and maintained with isoflurane, and horses that received butorphanol intraoperatively. Exclusion criteria included horses in which the rate of infusion of an inotrope or end-tidal isoflurane concentration was changed 10 minutes before or after the butorphanol bolus. The horses were separated into two groups: group 1 horses received butorphanol at intervals as part of a balanced protocol, group 2 horses had > or = 10% increase in heart rate (HR) or blood pressure within 10 minutes prior to butorphanol administration. RESULTS: Eighty-nine butorphanol administration events matched the criteria for inclusion, 49 in group 1 and 40 in group 2. There were no significant changes after butorphanol administration in systolic arterial pressure (SAP), mean arterial pressure (MAP), diastolic arterial pressure (DAP), and heart rate (HR) in group 1, or in end-tidal carbon dioxide concentration or hemoglobin oxygen saturation in either group. There were significant decreases in SAP (p < 0.0001), MAP (p < 0.0005), and DAP (p < 0.0008) after butorphanol administration in group 2. CONCLUSIONS AND CLINICAL RELEVANCE: The results presented here confirm that butorphanol can be administered to horses during isoflurane anesthesia without adverse effects on HR and arterial blood pressure. The results imply that butorphanol can deepen the plane of anesthesia and obtund sympathetic stimulation from a surgical procedure.  相似文献   

14.
ObjectiveTo evaluate the effects of butorphanol on cardiopulmonary parameters in dogs anesthetized with desflurane and breathing spontaneously.Study designProspective, randomized experimental trial.AnimalsTwenty dogs weighing 12 ± 3 kg.MethodsAnimals were distributed into two groups: a control group (CG) and butorphanol group (BG). Propofol was used for induction and anesthesia was maintained with desflurane (10%). Forty minutes after induction, the dogs in the CG received sodium chloride 0.9% (0.05 mL kg?1 IM), and dogs in the BG received butorphanol (0.4 mg kg?1 IM). The first measurements of body temperature (BT), heart rate (HR), arterial pressures (AP), cardiac output (CO), cardiac index (CI), central venous pressure (CVP), stroke volume index (SVI), pulmonary arterial occlusion pressure (PAOP), mean pulmonary arterial pressure (mPAP), left ventricular stroke work (LVSW), systemic (SVR) and pulmonary (PVR) vascular resistances, respiratory rate (fR), and arterial oxygen (PaO2) and carbon dioxide (PaCO2) partial pressures were taken immediately before the administration of butorphanol or sodium chloride solution (T0) and then at 15-minute intervals (T15–T75).ResultsIn the BG, HR, AP, mPAP and SVR decreased significantly from T15 to T75 compared to baseline. fR was lower at T30 than at T0 in the BG. AP and fR were significantly lower than in the CG from T15 to T75. PVR was lower in the BG than in the CG at T30, while PaCO2 was higher compared with T0 from T30 to T75 in the BG and significantly higher than in the CG at T30 to T75.Conclusions and clinical relevanceAt the studied dose, butorphanol caused hypotension and decreased ventilation during desflurane anesthesia in dogs. The hypotension (from 86 ± 10 to 64 ± 10 mmHg) is clinically relevant, despite the maintenance of cardiac index.  相似文献   

15.
ObjectiveTo examine the cardiopulmonary effects of two anesthetic protocols for dorsally recumbent horses undergoing carpal arthroscopy.Study designProspective, randomized, crossover study.AnimalsSix horses weighing 488.3 ± 29.1 kg.MethodsHorses were sedated with intravenous (IV) xylazine and pulmonary artery balloon and right atrial catheters inserted. More xylazine was administered prior to anesthetic induction with ketamine and propofol IV. Anesthesia was maintained for 60 minutes (or until surgery was complete) using either propofol IV infusion or isoflurane to effect. All horses were administered dexmedetomidine and ketamine infusions IV, and IV butorphanol. The endotracheal tube was attached to a large animal circle system and the lungs were ventilated with oxygen to maintain end-tidal CO2 40 ± 5 mmHg. Measurements of cardiac output, heart rate, pulmonary arterial and right atrial pressures, and body temperature were made under xylazine sedation. These, arterial and venous blood gas analyses were repeated 10, 30 and 60 minutes after induction. Systemic arterial blood pressures, expired and inspired gas concentrations were measured at 10, 20, 30, 40, 50 and 60 minutes after induction. Horses were recovered from anesthesia with IV romifidine. Times to extubation, sternal recumbency and standing were recorded. Data were analyzed using one and two-way anovas for repeated measures and paired t-tests. Significance was taken at p=0.05.ResultsPulmonary arterial and right atrial pressures, and body temperature decreased from pre-induction values in both groups. PaO2 and arterial pH were lower in propofol-anesthetized horses compared to isoflurane-anesthetized horses. The lowest PaO2 values (70–80 mmHg) occurred 10 minutes after induction in two propofol-anesthetized horses. Cardiac output decreased in isoflurane-anesthetized horses 10 minutes after induction. End-tidal isoflurane concentration ranged 0.5%–1.3%.Conclusion and clinical relevanceBoth anesthetic protocols were suitable for arthroscopy. Administration of oxygen and ability to ventilate lungs is necessary for propofol-based anesthesia.  相似文献   

16.
Studies evaluating the effects of dobutamine in horses do not consistently report increases in cardiac output despite increases in arterial blood pressure. The concurrent administration of the α2 agonist clonidine, in people, inhibited the chronotropic effects of dobutamine and increased left ventricular stroke work ( Zimpfer et al. 1982 ). Our study was performed to determine if pre‐medication with an α2 agonist affects the response to dobutamine in anaesthetized horses. Eleven horses were anaesthetized on four separate occasions for one of four randomly assigned treatments; (I) no xylazine, no dobutamine (II) xylazine, no dobutamine (III) no xylazine, dobutamine, and (IV) xylazine, dobutamine. Horses received 0.02 mg kg?1 of butorphanol IV 10 minutes prior to anesthetic induction. Two minutes prior to induction, groups II and IV received 0.5 mg kg?1 of IV xylazine. Anaesthesia was induced with 6–7 mg kg?1 of thiopental and maintained with halothane. End‐tidal halothane concentrations were maintained between 1.1 and 1.2% in groups I and III, and 0.9–1.0% for groups II and IV. Heart rate, cardiac output, right atrial pressure, and systolic (SAP), diastolic (DAP) and mean (MAP) arterial pressure were recorded 30 minutes after beginning halothane anaesthesia (T10). Cardiac output was estimated using Lithium dilution ( Linton et al. 2000 ). Baseline measurements were repeated twice, at 5‐minute intervals (T5 and T0). At time 0 (T0), an IV infusion of either saline (100 mL hour?1) or dobutamine (0.001 mg kg?1 minute?1) was started and data recorded at 5‐minute intervals for 30 minutes (T5 – T30). Stroke volume and systemic vascular resistance (SVR) were calculated. Data were analysed using repeated measures anova (p < 0.01 significant) and Newman–Keuls for multiple comparisons. Cardiac output and stroke volume increased over time in groups III and IV. Cardiac index was higher in groups III and IV than in groups I and II from T10 until completion of the study. Estimates of cardiac index at T30 for groups I–IV were 45 ± 9, 46 ± 11, 71 ± 11, and 78 ± 19 mL kg?1 minute?1, respectively (mean ± SD). Stroke index was higher in groups III and IV than in groups I and II from T15 to T30. Values for stroke index at T30 for groups I–IV were 0.98 ± 0.19, 1.11 ± 0.18, 1.46 ± 0.21, 1.74 ± 0.33 mL kg?1. Heart rate decreased from T10–T30 in groups I and II. Heart rate was greater in groups I and III than in groups II and IV at T5 and T0. Values for heart rate at T0 for groups I–IV were 48 ± 5, 42 ± 5, 50 ± 4, 43 ± 4 beats minute?1. Systolic arterial pressure, DAP and MAP were higher in groups III and IV than in groups I and II from T5 to T30. There were no differences in SVR between groups. Dobutamine at 0.001 mg kg?1 minute?1 increased cardiac output, blood pressure, and stroke volume. Premedication with xylazine at 0.5 mg kg?1 did not appear to affect the response to dobutamine.  相似文献   

17.
ObjectiveTo evaluate the pharmacokinetics and selected pharmacodynamic effects of a commercially available l-methadone/fenpipramide combination administered to isoflurane anaesthetized ponies.Study designProspective single-group interventional study.AnimalsA group of six healthy adult research ponies (four mares, two geldings).MethodsPonies were sedated with intravenous (IV) detomidine (0.02 mg kg–1) and butorphanol (0.01 mg kg–1) for an unrelated study. Additional IV detomidine (0.004 mg kg–1) was administered 85 minutes later, followed by induction of anaesthesia using IV diazepam (0.05 mg kg–1) and ketamine (2.2 mg kg–1). Anaesthesia was maintained with isoflurane in oxygen. Baseline readings were taken after 15 minutes of stable isoflurane anaesthesia. l-Methadone (0.25 mg kg–1) with fenpipramide (0.0125 mg kg–1) was then administered IV. Selected cardiorespiratory variables were recorded every 10 minutes and compared to baseline using the Wilcoxon signed-rank test. Adverse events were recorded. Arterial plasma samples for analysis of plasma concentrations and pharmacokinetics of l-methadone were collected throughout anaesthesia at predetermined time points. Data are shown as mean ± standard deviation or median and interquartile range (p < 0.05).ResultsPlasma concentrations of l-methadone showed a rapid initial distribution phase followed by a slower elimination phase which is best described with a two-compartment model. The terminal half-life was 44.3 ± 18.0 minutes, volume of distribution 0.43 ± 0.12 L kg–1 and plasma clearance 7.77 ± 1.98 mL minute–1 kg–1. Mean arterial blood pressure increased from 85 (±16) at baseline to 100 (±26) 10 minutes after l-methadone/fenpipramide administration (p = 0.031). Heart rate remained constant. In two ponies fasciculations occurred at different time points after l-methadone administration.Conclusions and clinical relevanceAdministration of a l-methadone/fenpipramide combination to isoflurane anaesthetized ponies led to a transient increase in blood pressure without concurrent increases in heart rate. Pharmacokinetics of l-methadone were similar to those reported for conscious horses administered racemic methadone.  相似文献   

18.
Objective To investigate the cardiopulmonary effects of a xylazine–guaiphenesin–ketamine infusion combined with inter‐coccygeal extradural (lidocaine) anaesthesia in calves. Study design Prospective study. Animals Five Holstein Friesian calves (one steer, four heifers) aged 6 weeks weighing 65.2 ± 2.7 kg. Materials and methods Calves were anaesthetized with isoflurane in oxygen for instrumentation. At least 12 hours later, xylazine (0.2 mg kg?1 IM) was given. After 15 minutes, an infusion of xylazine hydrochloride (0.1 mg mL?1), guaiphenesin (50 mg mL?1) and ketamine (1 mg mL?1) (X–G–K) was infused at a rate of 1.1 mL kg?1 hour?1 IV. Oxygen (4 L minute?1) was delivered by nasotracheal tube 30 minutes later. Inter‐coccygeal (Co1–Co2) extradural anaesthesia (lidocaine 2%, 0.18 mL kg?1) was administered 30 minutes later. Cardiopulmonary variables were obtained in the unsedated standing calves 10 minutes after xylazine, 15 and 30 minutes after X–G–K without O2, 15 and 30 minutes after X–G–K with O2 and 5, 15, 30, 45 and 60 minutes after extradural anaesthesia. Data were analysed using a repeated measurement analysis of variance including an autoregressive covariance structure of order 1 (correlations at different time intervals). Results Xylazine caused significant (p < 0.05) decreases in heart rate (HR), cardiac output (Qt) and index (CI), stroke volume and stroke index, mean, systolic and diastolic arterial blood pressure (MAP, SAP, DAP), left (LVWSI) and right ventricular stroke work index (RVWSI), mean, systolic and diastolic pulmonary arterial pressure (MPAP, SPAP, DPAP), arterial pH, arterial oxygen tension (PaO2), arterial base excess, arterial HCO3? concentration, arterial saturation, packed cell volume, arterial and venous oxygen content (CaO2, CvO2), O2 consumption and O2 delivery (V?O2, ?O2). Increases in systemic vascular resistance (SVR) and pulmonary vascular resistance (PVR) were observed. During X–G–K infusion without O2, HR, Qt and CI increased gradually while SVR, PVR and MAP decreased. Left ventricular stroke work index and PaO2 remained constant, while O2 supplementation improved PaO2. Coccygeal extradural anaesthesia had little effect on cardiopulmonary variables. Respiratory rate (f) and PaCO2 significantly increased over the experiment. Conclusions and clinical relevance Xylazine caused adverse cardiopulmonary effects in calves. Improvement occurred during xylazine–guiaphenesin–ketamine infusion. Cardiac index and arterial blood pressure remained below baseline values while sustained increases in respiration rate and PaCO2 were observed. Inter‐coccygeal extradural anaesthesia had only minor effects. Oxygen supplementation proved advantageous during guiaphenesin, ketamine and xylazine infusion in healthy calves in combination with coccygeal extradural anaesthesia induced persistent cardiopulmonary depression.  相似文献   

19.
ObjectiveTo evaluate the cardiovascular, respiratory, electrolyte and acid–base effects of a continuous infusion of dexmedetomidine during propofol–isoflurane anesthesia following premedication with dexmedetomidine.Study designProspective experimental study.AnimalsFive adult male Walker Hound dogs 1–2 years of age averaging 25.4 ± 3.6 kg.MethodsDogs were sedated with dexmedetomidine 10 μg kg?1 IM, 78 ± 2.3 minutes (mean ± SD) before general anesthesia. Anesthesia was induced with propofol (2.5 ± 0.5 mg kg?1) IV and maintained with 1.5% isoflurane. Thirty minutes later dexmedetomidine 0.5 μg kg?1 IV was administered over 5 minutes followed by an infusion of 0.5 μg kg?1 hour?1. Cardiac output (CO), heart rate (HR), ECG, direct blood pressure, body temperature, respiratory parameters, acid–base and arterial blood gases and electrolytes were measured 30 and 60 minutes after the infusion started. Data were analyzed via multiple linear regression modeling of individual variables over time, compared to anesthetized baseline values. Data are presented as mean ± SD.ResultsNo statistical difference from baseline for any parameter was measured at any time point. Baseline CO, HR and mean arterial blood pressure (MAP) before infusion were 3.11 ± 0.9 L minute?1, 78 ± 18 beats minute?1 and 96 ± 10 mmHg, respectively. During infusion CO, HR and MAP were 3.20 ± 0.83 L minute?1, 78 ± 14 beats minute?1 and 89 ± 16 mmHg, respectively. No differences were found in respiratory rates, PaO2, PaCO2, pH, base excess, bicarbonate, sodium, potassium, chloride, calcium or lactate measurements before or during infusion.Conclusions and clinical relevanceDexmedetomidine infusion using a loading dose of 0.5 μg kg?1 IV followed by a constant rate infusion of 0.5 μg kg?1 hour?1 does not cause any significant changes beyond those associated with an IM premedication dose of 10 μg kg?1, in propofol–isoflurane anesthetized dogs. IM dexmedetomidine given 108 ± 2 minutes before onset of infusion showed typical significant effects on cardiovascular parameters.  相似文献   

20.
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   

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