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1.
OBJECTIVE: To determine the cardiopulmonary and sedative effects of medetomidine hydrochloride in adult horses and to compare those effects with effects of an equipotent dose of xylazine hydrochloride. ANIMALS: 10 healthy adult female horses. PROCEDURE: 5 horses were given medetomidine (4 microg/kg of body weight, i.v.), and the other 5 were given xylazine (0.4 mg/kg, i.v.). Heart rate, respiratory rate, arterial blood pressures, pulmonary arterial blood pressures, and cardiac output were recorded, and sedation and ataxia scores were assigned before and every 5 minutes after drug administration for 60 minutes. Rectal temperature and blood gas partial pressures were measured every 15 minutes after drug administration. RESULTS: Arterial blood pressure was significantly decreased throughout the study among horses given medetomidine and was significantly decreased for 40 minutes among horses given xylazine. Compared with baseline values, cardiac output was significantly decreased 10, 20, and 40 minutes after administration of medetomidine and significantly increased 40 and 60 minutes after administration of xylazine. Despite the significant decrease in respiratory rate in both groups, results of blood gas analyses were not significantly changed over time. Ataxia and sedation scores were of similar magnitude for the 2 groups, but ataxia persisted slightly longer among horses given medetomidine. Horses resumed eating hay 10 to 55 minutes after drug administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that equipotent low doses of medetomidine and xylazine induce comparable levels of ataxia and sedation and similar cardiopulmonary changes in adult horses.  相似文献   

2.
Lumbosacral CSF pressure was measured in 6 horses via a catheter inserted through the lumbosacral space. Heart rate, facial artery pressure, central venous pressure, and CSF pressure were measured before IV injection of a saline solution control, for 15 minutes after saline solution injection, and for 60 minutes after the IV injection of 1.1 mg of xylazine/kg of body weight. Arterial pH and blood gases were analyzed before saline solution injection, 15 minutes after saline solution injection, and at 15, 30, and 60 minutes after xylazine injection. Constant craniocervical posture was maintained during sedation. Lumbosacral CSF pressure was significantly decreased for 15 minutes after xylazine injection. Diastolic arterial pressure was significantly increased 4 minutes after xylazine administration and diastolic and mean arterial pressure were increased at 6 and 8 minutes after xylazine administration. Small increases in systolic arterial blood pressure and central venous pressure, and a small decrease in heart rate were observed. There were no significant differences in the arterial blood gas values. It was concluded that IV injection of xylazine causes a decrease in intracranial pressure in healthy conscious horses. The effects may be different in horses with neurologic disease or cerebral trauma.  相似文献   

3.
Objectives To evaluate the analgesic, physiologic, and behavioral effects of the epidural administration of tiletamine/zolazepam in horses. Study design Prospective, double‐blind, randomized experimental study. Animals Five adult, healthy horses aged 10–16 years and weighing (mean ± SD) 400 ± 98 kg. Methods The horses were sedated with 1.0 mg kg?1 intravenous (IV) xylazine, and an epidural catheter was placed into the first intercoccygeal intervertebral space. After a 48‐hour resting period, epidural tiletamine/zolazepam, 0.5 mg kg?1 (treatment I) or 1.0 mg kg?1 (treatment II), diluted up to 5 mL in sterile water, was administered with a 1‐week interval between the treatments. Heart rate, respiratory rate, arterial blood pressure, and sedation were evaluated. In order to evaluate the respiratory effects, blood from the carotid artery was withdrawn at time 0 (baseline), and then after 60 and 240 minutes. Analgesia was evaluated by applying a noxious stimulus with blunt‐tipped forceps on the perineal region, and graded as complete, moderate, or absent. Data were collected before tiletamine/zolazepam administration and at 15‐minute intervals for 120 minutes, and 4 hours after tiletamine/zolazepam administration. Data were analyzed with anova and Bonferroni's test with p < 0.05. Results The results showed no significant difference between treatments in cardiovascular and respiratory measurements. Sedation was observed with both doses, and it was significantly different from baseline at 60, 75, and 90 minutes in treatment II. Moderate analgesia and locomotor ataxia were observed with both the treatments. Conclusions and clinical relevance The results suggest that caudal epidural 0.5 and 1.0 mg kg?1 tiletamine/zolazepam increases the threshold to pressure stimulation in the perineal region in horses. The use of epidural tiletamine/zolazepam could be indicated for short‐term moderate epidural analgesia. There are no studies examining spinal toxicity of Telazol, and further studies are necessary before recommending clinical use of this technique.  相似文献   

4.
OBJECTIVE: To evaluate the influence of epidural administration of xylazine hydrochloride on the minimum alveolar concentration of isoflurane (MAC(ISAO)) and cardiopulmonary system in anesthetized dogs. ANIMALS: 6 clinically normal dogs. PROCEDURE: Dogs were anesthetized with isoflurane in oxygen after randomly being assigned to receive 1 of the following 4 treatments: epidural administration of saline (0.9% NaCl) solution or xylazine at a dose of 0.1, 0.2, or 0.4 mg x kg(-1). Experiments were performed on 5 occasions with at least a 1-week interval between experiments; each dog received all 4 treatments. Following instrumentation, the concentration of isoflurane was maintained constant for 15 minutes at the MAC(ISO) that had been determined for each dog, and data on heart rate, arterial blood pressure, respiratory rate, tidal volume, minute volume, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, and arterial pH were collected. The epidural treatment was administered, and 30 minutes later, data were again collected. From this point on, determination of the MAC(ISO) following epidural treatment (ie, MAC(ISO+EPI)) was initiated. Cardiopulmonary data were collected before each electrical supramaximal stimulus during MAC(ISO+EPI) determinations. RESULTS: The mean (+/-SD) MAC(ISO) was 1.29 +/- 0.04%. The epidural administration of xylazine at doses of 0.1, 0.2, and 0.4 mg x kg(-1) decreased the MAC(ISO), respectively, by 8.4 +/- 2.4%, 21.7 +/- 4.9%, and 33.4 +/- 2.64%. Cardiopulmonary effects were limited. CONCLUSIONS AND CLINICAL RELEVANCE: Epidural administration of xylazine decreases the MAC(ISO) in a dose-dependent manner and is associated with few cardiopulmonary effects in anesthetized dogs.  相似文献   

5.
Anaesthesia was induced in 24 horses with xylazine and ketamine and maintained with halothane (12 cases) or enflurane (12 cases) in oxygen. Pulse rate, arterial blood pressure, arterial blood gas values, respiratory rate and tidal volume were measured at regular intervals during anaesthesia. Serial venous blood samples were taken for assay of glucose, urea, haemoglobin, packed cell volume, gamma glutamyl transpeptidase, aspartate aminotransferase, alanine aminotransferase and creatine kinase. Operating conditions and the horses' behaviour in the recovery period were also recorded. In the case of the group of horses receiving enflurane, difficulty was experienced maintaining anaesthesia deep enough for surgery. This group also displayed greater respiratory depression. There were no significant differences between arterial blood pressure values, or any of the haematological or biochemical parameters recorded in each group. Recovery from anaesthesia was significantly faster in horses receiving enflurane but less smooth. It was concluded that, although enflurane appeared to be safe in the horse, the respiratory depression and the unpleasant recovery did not make it a desirable alternative to halothane.  相似文献   

6.
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   

7.
Cardiovascular effects of xylazine and detomidine in horses   总被引：6，自引：0，他引：6  
The cardiovascular effects of xylazine and detomidine in horses were studied. Six horses were given each of the following 5 treatments, at 1-week intervals: xylazine, 1.1 mg/kg, IV; xylazine, 2.2 mg/kg, IM; detomidine, 0.01 mg/kg, IV; detomidine, 0.02 mg/kg, IV; and detomidine, 0.04 mg/kg, IM. All treatments resulted in significantly decreased heart rate, increased incidence of atrioventricular block, and decreased cardiac output and cardiac index; cardiac output and cardiac index were lowest following IV administration of 0.02 mg of detomidine/kg. Mean arterial pressure was significantly reduced for various periods with all treatments; however, IV administration of 0.02 mg of detomidine/kg caused hypertension initially. Systemic vascular resistance was increased by all treatments. Indices of ventricular contractility and relaxation, +dP/dt and -dP/dt, were significantly depressed by all treatments. Significant changes were not detected in stroke volume or ejection fraction. The PCV was significantly reduced by all treatments. Respiratory rate was significantly decreased with all treatments, but arterial carbon dioxide tension did not change. Arterial oxygen tension was significantly decreased briefly with the 3 IV treatments only.  相似文献   

8.
OBJECTIVE: To determine if a commonly used analgesic dose of xylazine has detrimental cardiovascular or haemodynamic effects in sheep. DESIGN: A physiological study following intramuscular administration of xylazine. PROCEDURE: Xylazine (50 micrograms/kg) was injected intramuscularly into six healthy Merino ewes. For 60 min heart rate, mean arterial blood pressure and cardiac output were recorded; arterial blood samples for the measurement of blood gas tensions were also collected. RESULTS: There were no significant changes in heart rate, mean arterial blood pressure, cardiac output or arterial carbon dioxide tension. A slight degree of arterial hypoxaemia was noted with a 10% reduction in arterial oxygen tension values at 30 min. CONCLUSION: The minimal changes to cardiovascular and respiratory values in this study verify the safety of previously suggested analgesic dosing regimens for sheep. Previously reported hypoxaemic effects in sheep as a result of intravenous xylazine administration appear to be reduced as a result of intramuscular administration.  相似文献   

9.
A chronic model with an ultrasonic transit time blood flow probe and strain gauge force transducers implanted on the cecum was used to evaluate cecal mechanical activity and cecal arterial blood flow in 4 conscious adult horses. Intravenous administration of xylazine (1.1 mg/kg of body weight) significantly decreased heart rate and cardiac output, but significantly increased diastolic pulmonary arterial pressure, mean pulmonary arterial pressure, carotid arterial pressure, and central venous pressure. Lateral cecal arterial blood flow after xylazine administration was decreased substantially more than was cardiac output, suggesting that xylazine caused constriction of the cecal vasculature. This effect of xylazine may have resulted from either a direct effect of xylazine on the cecal vasculature or from reflex vasoconstriction attributable to reduced cardiac output. Intravenous administration of butorphanol tartrate (0.1 mg/kg) did not significantly alter the hemodynamic responses to xylazine. Cecal mechanical activity, as measured by the motility index, was decreased for 120 minutes after administration of xylazine and for 150 minutes after administration of xylazine/butorphanol.  相似文献   

10.
Facial artery pressure, central venous pressure, heart rate, and lateral ventricle cerebrospinal fluid (CSF) pressure (LV-CSFP) were measured in 10 pentobarbital-anesthetized horses at arterial partial pressure of carbon dioxide (PaCO2) values of 40,60, and 80 mm Hg, produced by varying the inspired carbon dioxide concentration. Variables were recorded at 5-minute intervals for 15 minutes at each level of PaCO2. Arterial blood gas analysis was performed at the end of the 15-minute time period for each level of PaCO2. Lateral ventricle CSF pressure was significantly increased (p < .05) at a PaCO2 of 80 mm Hg. Cardiovascular variables were not significantly changed by changing PaCO2. The PaCO2 was returned to 40 mm Hg; 1.1 mg xylazine/kg body weight was injected intravenously in eight horses, and data were collected for 60 minutes. No significant changes were observed. No changes were observed in two control horses not receiving xylazine. Subsequently, placement of a lumbosacral subarachnoid catheter allowed simultaneous measurement of LV-CSFP and lumbosacral CSF pressure (LS-CSFP) at PaCO2 values of 40,60, and 80 mm Hg. The Pearson Correlation Coefficient between LV-CSFP and LS-CSFP was 0.94 (p < .0001) It was concluded that changes in CSF pressure could be detected at the lateral ventricle and the lumbosacral space; increasing PaCO2 to 80 mm Hg resulted in significant increases in LV-CSFP; xylazine does not increase LV-CSFP in pentobarbital-anesthetized, normocapnic horses; and under the conditions of this experiment, LV-CSFP and LS-CSFP were closely correlated.  相似文献   

11.
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   

12.
OBJECTIVE: To investigate the effects of buprenorphine on cardiopulmonary variables and on abdominal auscultation scores in horses. ANIMALS: 6 healthy adult horses. PROCEDURES: Horses were restrained in stocks and allocated to 2 treatments in a randomized crossover design, with 1-week intervals between each treatment. Saline (0.9% NaCl) solution was administered IV as a control, whereas buprenorphine (10 mug/kg, IV) was administered to the experimental group. Cardiopulmonary data were collected for 120 minutes after buprenorphine or saline solution administration. Abdominal auscultation scores were monitored for 2 and 12 hours after drug administration in the control and experimental groups, respectively. RESULTS: Following control treatment, horses remained calm while restrained in the stocks and no significant changes in cardiopulmonary variables were observed throughout the study. Buprenorphine administration caused excitatory phenomena (restlessness and head shaking). Heart rate, cardiac index, and arterial blood pressure were significantly increased after buprenorphine administration until the end of the observational period (120 minutes). Minimal changes were found in arterial blood gas tensions. Abdominal auscultation scores decreased significantly from baseline for 4 hours after buprenorphine administration. CONCLUSIONS AND CLINICAL RELEVANCE: Buprenorphine induced excitement and hemodynamic stimulation with minimal changes in arterial blood gas tensions. These effects may impact the clinical use of buprenorphine in horses. Further studies are indicated to investigate the effects of buprenorphine on gastrointestinal motility and fecal output.  相似文献   

13.
Caudal epidural analgesia was achieved in 6 adult horses on 3 successive occasions at weekly intervals by injection of lidocaine, xylazine, and a combination of lidocaine/xylazine through indwelling epidural catheters. Analgesia was defined as a lack of response to pinprick and hemostat pressure in the skin of the perineal area. A significant (P < 0.05) difference was not found for time of onset of analgesia between lidocaine (4.3 +/- 0.8 minutes, mean +/- SEM) and the lidocaine/xylazine combination (5.3 +/- 1.3 minutes). Time to onset of analgesia after administration of xylazine was significantly (P < 0.05) longer (32.0 +/- 3.4 minutes) than that for either of the other 2 treatments. Duration of analgesia was significantly (P < 0.05) longer for the combination (329.8 +/- 6.2 minutes) than for either drug used alone (lidocaine, 87.2 +/- 7.5 minutes; xylazine, 204.2 +/- 12.9 minutes). Pulse and respiratory rates were not significantly altered by any of the drugs. Neurologic sequelae were not clinically apparent after administration of the drugs or after chronic epidural catheterization.  相似文献   

14.
The cardiovascular effects of medetomidine, detomidine, and xylazine in horses were studied. Fifteen horses, whose right carotid arteries had previously been surgically raised to a subcutaneous position during general anesthesia were used. Five horses each were given the following 8 treatments: an intravenous injection of 4 doses of medetomidine (3, 5, 7.5, and 10 microg/kg), 3 doses of detomidine (10, 20, and 40 microg/kg), and one dose of xylazine (1 mg/kg). Heart rate decreased, but not statistically significant. Atrio-ventricular block was observed following all treatments and prolonged with detomidine. Cardiac index (CI) and stroke volume (SV) were decreased with all treatments. The CI decreased to about 50% of baseline values for 5 min after 7.5 and 10 microg/kg medetomidine and 1 mg/kg xylazine, for 20 min after 20 microg/kg detomidine, and for 50 min after 40 microg/kg detomidine. All treatments produced an initial hypertension within 2 min of drug administration followed by a significant decrease in arterial blood pressure (ABP) in horses administered 3 to 7.5 microg/kg medetomidine and 1 mg/kg xylazine. Hypertension was significantly prolonged in 20 and 40 microg/kg detomidine. The hypotensive phase was not observed in 10 microg/kg medetomidine or detomidine. The changes in ABP were associated with an increase in peripheral vascular resistance. Respiratory rate was decreased for 40 to 120 min in 5, 7.5, and 10 microg/kg medetomidine and detomidine. The partial pressure of arterial oxygen decreased significantly in 10 microg/kg medetomidine and detomidine, while the partial pressure of arterial carbon dioxide did not change significantly. Medetomidine induced dose-dependent cardiovascular depression similar to detomidine. The cardiovascular effects of medetomidine and xylazine were not as prolonged as that of detomidine. KEY WORDS: cardiovascular effect, detomidine, equine, medetomidine, xylazine.  相似文献   

15.
OBJECTIVE: To evaluate cardiopulmonary effects of glycopyrrolate in horses anesthetized with halothane and xylazine. ANIMALS: 6 horses. PROCEDURE: Horses were allocated to 2 treatment groups in a randomized complete block design. Anesthesia was maintained in mechanically ventilated horses by administration of halothane (1% end-tidal concentration) combined with a constant-rate infusion of xylazine hydrochloride (1 mg/kg/h, i.v.). Hemodynamic variables were monitored after induction of anesthesia and for 120 minutes after administration of glycopyrrolate or saline (0.9% NaCl) solution. Glycopyrrolate (2.5 microg/kg, i.v.) was administered at 10-minute intervals until heart rate (HR) increased at least 30% above baseline or a maximum cumulative dose of 7.5 microg/kg had been injected. Recovery characteristics and intestinal auscultation scores were evaluated for 24 hours after the end of anesthesia. RESULTS: Cumulative dose of glycopyrrolate administered to 5 horses was 5 microg/kg, whereas 1 horse received 7.5 microg/kg. The positive chronotropic effects of glycopyrrolate were accompanied by an increase in cardiac output, arterial blood pressure, and tissue oxygen delivery. Whereas HR increased by 53% above baseline values at 20 minutes after the last glycopyrrolate injection, cardiac output and mean arterial pressure increased by 38% and 31%, respectively. Glycopyrrolate administration was associated with impaction of the large colon in 1 horse and low intestinal auscultation scores lasting 24 hours in 3 horses. CONCLUSIONS AND CLINICAL RELEVANCE: The positive chronotropic effects of glycopyrrolate resulted in improvement of hemodynamic function in horses anesthetized with halothane and xylazine. However, prolonged intestinal stasis and colic may limit its use during anesthesia.  相似文献   

16.
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   

17.
To test the hypothesis that epidural administration of lidocaine, xylazine or xylazine plus hyaluronidase provides reduced pain and stress during electroejaculation in bulls, eight 30-month-old Nellore bulls received saline solution (control), 2% lidocaine, 2% xylazine or 2% xylazine plus hyaluronidase injected into the first intercoccygeal (Co1–Co2) epidural space in randomized order. Heart rate, respiratory rate, mean arterial pressure, analgesia, animal behavior and motor blockade were evaluated before treatment and at predetermined intervals during and after treatment. Pain and stress were scored subjectively, and semen quality was evaluated. The onset of anesthetic action was significantly faster with lidocaine (3.0 ± 1.2 min) than with xylazine or xylazine plus hyaluronidase (8.9 ± 1.5 and 5.5 ± 2.6 min, P=0.021 and P=0.012, respectively), and the onset of anesthesia with xylazine plus hyaluronidase was significantly faster than that with xylazine alone (P=0.032). Treatment with xylazine or xylazine plus hyaluronidase resulted in less discomfort than treatment with lidocaine, as indicated by animal behavior. Changes in heart rate, respiratory rate and arterial pressure were within acceptable limits. Penile protrusion and semen emission occurred in all animals during all four treatments. Our results suggest that xylazine plus hyaluronidase reduced discomfort during electroejaculation more effectively than xylazine or lidocaine alone. Further experiments are necessary to determine whether electroejaculation with xylazine plus hyaluronidase is feasible for obtaining semen from Nellore bulls unaccustomed to being handled or restrained.  相似文献   

18.
Five horses were anaesthetised twice with thiopentone sodium, guaifenesin and halothane. The second anaesthesia was 16 days after the first and two days following oral administration of trichlorfon. Heart rate, carotid arterial, pulmonary arterial and right atrial pressures, cardiac output and blood temperature were measured every 15 minutes for 120 minutes. Heart rate, carotid arterial pressure and cardiac output were similar on both occasions. Pulmonary arterial and right atrial pressures were highest during anaesthesia after treatment with trichlorfon when compared with values obtained before treatment. Pulmonary vascular resistance was significantly decreased at four measurement times during anaesthesia after treatment with trichlorfon. All cardiovascular measurements were within ranges accepted as normal for halothane anaesthesia in horses. In a second experiment, four ponies were anaesthetised with xylazine and ketamine on two occasions one week apart. Two ponies received trichlorfon two days before the second anaesthesia. Heart rate, arterial pressure and respiratory rate recorded during anaesthesia were not different in ponies after organophosphate treatment. The time to standing after the second anaesthesia was significantly increased in all ponies.  相似文献   

19.
Xylazine, midazolam and a midazolam/ketamine combination were administered to 6 goats in a randomised 3-way block design. All goats received all treatments with at least a 7-day interval between treatments. Statistically significant (P < 0.05) changes were observed in some of the measured cardiopulmonary variables for xylazine and midazolam/ ketamine. Xylazine administration resulted in statistically significant decreases in minute volume, arterial partial pressure of oxygen, heart rate and mean arterial blood pressure. The increase in arterial partial pressure of carbon dioxide was not statistically significant. For the midazolam/ketamine combination, the decrease in tidal volume was statistically significant, but not the decrease in minute volume and increase in arterial partial pressure of carbon dioxide. The decrease in the arterial partial pressure of oxygen was also statistically significant. The mean arterial blood pressure for the combination was statistically significantly higher compared to xylazine. The changes in cardiopulmonary variables after midazolam administration were not statistically significant, such as tidal and minute volume, arterial partial pressure of oxygen and carbon dioxide. However, clinically significant effects such as hypoventilation and hypoxia were observed after its administration. The change in mean arterial blood pressure was minimal.  相似文献   

20.
The purpose of this study was to compare and evaluate sedation with intravenous xylazine (1.1 mg/kg bodyweight [BW]) versus intravenous romifidine (100 micrograms/kg BW) followed by induction of anesthesia with intravenous diazepam (0.04 mg/kg BW) and ketamine (2.2 mg/kg BW). Twelve healthy horses were used in a blinded, randomized, cross-over design. Heart rate, presence of 2nd degree atrioventricular heart blocks (2 degrees AVB), respiratory rate, arterial blood pressures, blood gases, packed cell volume, total serum proteins, and duration of anesthesia and recumbency were recorded. Induction and recovery quality was evaluated using a 0 to 4 score. Response to stimulation with noise, pressure, and cutaneous electrical stimulation was assessed at 5 minute intervals during recumbency to evaluate the depth of anesthesia. Heart rate was lower and 2 degrees AVB more frequent in the romifidine group, while blood pressure was lower in the xylazine group. Duration of anesthesia was longer in the romifidine group (mean 20.8, s mean 2.3 min) versus the xylazine group (mean 15.8, s mean 1.6 min), while induction and recovery were excellent in both groups. Respiratory rates, blood gas values, packed cell volumes, and total protein levels did not differ between groups. The results indicate that romifidine premedication followed by diazepam and ketamine is a very satisfactory regime for short duration intravenous anesthesia in horses.  相似文献   

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