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1.
The objectives of this trial were to determine the ability of atipamezole, 4-aminopyridine and yohimbine to reverse the anaesthetic effects of a combination of medetomidine and ketamine in cats. Forty healthy cats were anaesthetised with 80 micrograms/kg medetomidine combined with 5 mg/kg ketamine. Thirty minutes later atipamezole (200 or 500 micrograms/kg), 4-aminopyridine (500 or 1000 micrograms/kg) or yohimbine (250 or 500 micrograms/kg) were injected intramuscularly. The doses of antagonists were randomised, so that each dose was administered to five cats, and 10 cats were injected only with physiological saline. Atipamezole clearly reversed the anaesthesia and bradycardia induced by medetomidine and ketamine. The mean (+/- sd) arousal times were 28 (+/- 4.7), 5.8 (+/- 1.8) and 7 (+/- 2.1) minutes in the placebo group, and the groups receiving 200 and 500 micrograms/kg atipamezole, respectively. The heart rates of the cats receiving 200 micrograms/kg atipamezole rapidly returned to values close to the initial ones, but 15 minutes after the injection of 500 micrograms/kg atipamezole a significant tachycardia was observed. All the cats showed moderate signs of ataxia during the recovery period. A dose of 500 micrograms/kg yohimbine also clearly reversed the anaesthetic effects of medetomidine/ketamine but 250 micrograms/kg was not effective. The dose of 500 micrograms/kg allowed a smooth recovery with no particular side effects except for some signs of incomplete antagonism of the ketamine effects, ie, ataxia and muscular incoordination. With 4-aminopyridine there were no statistically significant effects on the recovery, or the heart and respiratory rates of the cats anaesthetised with medetomidine/ketamine.  相似文献   

2.
An effective anaesthesia protocol was developed for adult free-ranging gemsbok (Oryx gazella) using a combination of A3080, medetomidine and ketamine. A short induction time; good muscle relaxation, adequate oxygenation and stable heart rate and respiration rate characterised this anaesthetic regime. Equal doses of A3080 and medetomidine (22-45 microg/kg) plus 200 mg of ketamine were administered to each animal. The anaesthesia was rapidly and completely reversed by intramuscular naltrexone at a dose of X = 0.9 +/- 0.2 mg/kg and atipamezole at a dose X +/- 90 +/- 20 microg/kg. No mortality or morbidity occurred with this protocol.  相似文献   

3.
OBJECTIVE: To determine whether IV administration of a combination of medetomidine and ketamine depresses cardiopulmonary function in healthy adult gopher tortoises. DESIGN: Prospective study. ANIMALS: 3 adult male and 3 adult female nonreleasable gopher tortoises. PROCEDURE: Prior to the study, carotid and jugular catheters were surgically placed in each tortoise for blood collection, direct arterial blood pressure monitoring, and drug administration. Heart rate, direct carotid arterial blood pressure, and body temperature were measured before and every 5 minutes for 45 minutes after IV injection of medetomidine (100 microg/kg [45.5 microg/lb]) and ketamine (5 mg/kg [2.3 mg/lb]). Carotid arterial blood samples were collected before and 5, 15, 30, and 45 minutes after medetomidine-ketamine administration to determine pH, PO2, and PCO2. Atipamezole (500 mg/kg [227 microg/lb], IV) was administered 30 minutes after administration of medetomidine-ketamine. RESULTS: The medetomidine-ketamine combination caused a moderate increase in arterial blood pressure, and moderate hypercapnia and hypoxemia. There were no significant changes in heart rate or body temperature. Intravenous administration of atipamezole rapidly induced severe hypotension. CONCLUSIONS AND CLINICAL RELEVANCE: The combination of medetomidine and ketamine administered IV resulted in effective short-term immobilization adequate for minor diagnostic procedures in gopher tortoises. This combination also caused moderate hypoventilation, and it is recommended that a supplemental source of oxygen or assisted ventilation be provided. Atipamezole administration hastens recovery from chemical immobilization but induces severe hypotension. It is recommended that atipamezole not be administered IV for reversal of medetomidine in tortoises and turtles.  相似文献   

4.
OBJECTIVE: To determine anesthetic effects of ketamine and medetomidine in bonitos and mackerels and whether anesthesia could be reversed with atipamezole. DESIGN: Clinical trial. ANIMALS: 43 bonitos (Sarda chiliensis) and 47 Pacific mackerels (Scomber japonica). PROCEDURE: 28 bonitos were given doses of ketamine ranging from 1 to 8 mg/kg (0.5 to 3.6 mg/lb), i.m., and doses of medetomidine ranging from 0.2 to 1.6 mg/kg (0.1 to 0.7 mg/lb), i.m. (ratio of ketamine to medetomidine, 2.5:1 to 20:1). Doses of atipamezole equal to 1 or 5 times the dose of medetomidine were used. The remaining 15 bonitos were used to determine the anesthetic effects of ketamine at a dose of 4 mg/kg (1.8 mg/lb) and medetomidine at a dose of 0.4 mg/kg (0.2 mg/lb). The mackerels were given ketamine at doses ranging from 11 to 533 mg/kg (5 to 242 mg/lb) and medetomidine at doses ranging from 0.3 to 9.1 mg/kg (0.1 to 4.1 mg/lb; ratio of ketamine to medetomidine, 3:1 to 800:1). Doses of atipamezole equal to 5 times the dose of medetomidine were used. RESULTS: I.m. administration of ketamine at a dose of 4 mg/kg and medetomidine at a dose of 0.4 mg/kg in bonitos and ketamine at a dose of 53 to 228 mg/kg (24 to 104 mg/lb) and medetomidine at a dose of 0.6 to 4.2 mg/kg (0.3 to 1.9 mg/lb) in mackerels was safe and effective. For both species, administration of atipamezole at a dose 5 times the dose of medetomidine reversed the anesthetic effects. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a combination of ketamine and medetomidine can safely be used for anesthesia of bonitos and mackerels and that anesthetic effects can be reversed with atipamezole.  相似文献   

5.
OBJECTIVE: To determine safety and efficacy of an anesthetic protocol incorporating medetomidine, ketamine, and sevoflurane for anesthesia of injured loggerhead sea turtles. DESIGN: Retrospective study. ANIMALS: 13 loggerhead sea turtles. PROCEDURE: Anesthesia was induced with medetomidine (50 microg/kg [22.7 microg/lb], IV) and ketamine (5 mg/kg (2.3 mg/lb], IV) and maintained with sevoflurane (0.5 to 2.5%) in oxygen. Sevoflurane was delivered with a pressure-limited intermittent-flow ventilator. Heart rate and rhythm, end-tidal partial pressure of CO2, and cloacal temperature were monitored continuously; venous blood gas analyses were performed intermittently. Administration of sevoflurane was discontinued 30 to 60 minutes prior to the end of the surgical procedure. Atipamezole (0.25 mg/kg [0.11 mg/lb], IV) was administered at the end of surgery. RESULTS: Median induction time was 11 minutes (range, 2 to 40 minutes; n = 11). Median delivered sevoflurane concentrations 15, 30, 60, and 120 minutes after intubation were 2.5 (n = 12), 1.5 (12), 1.25 (12), and 0.5% (8), respectively. Heart rate decreased during surgery to a median value of 15 beats/min (n = 11). End-tidal partial pressure of CO2 ranged from 2 to 16 mm Hg (n = 8); median blood gas values were within reference limits. Median time from atipamezole administration to extubation was 14 minutes (range, 2 to 84 minutes; n = 7). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that a combination of medetomidine and ketamine for induction and sevoflurane for maintenance provides safe, effective, controllable anesthesia in injured loggerhead sea turtles.  相似文献   

6.
The combination of medetomidine-zolazepam-tiletamine with subsequent antagonism by atipamezole was evaluated for reversible anaesthesia of free-ranging lions (Panthera leo). Twenty-one anaesthetic events of 17 free-ranging lions (5 males and 12 females, body weight 105-211 kg) were studied in Zimbabwe. Medetomidine at 0.027-0.055 mg/kg (total dose 4-11 mg) and zolazepam-tiletamine at 0.38-1.32 mg/kg (total dose 50-275 mg) were administered i.m. by dart injection. The doses were gradually decreased to improve recovery. Respiratory and heart rates, rectal temperature and relative haemoglobin oxygen saturation (SpO2) were recorded every 15 min. Arterial blood samples were collected from 5 lions for analysis of blood gases and acid-base status. For anaesthetic reversal, atipamezole was administered i.m. at 2.5 or 5 times the medetomidine dose. Induction was smooth and all lions were anaesthetised with good muscle relaxation within 3.4-9.5 min after darting. The predictable working time was a minimum of 1 h and no additional drug doses were needed. Respiratory and heart rates and SpO2 were stable throughout anaesthesia, whereas rectal temperature changed significantly over time. Atipamezole at 2.5 times the medetomidine dose was sufficient for reversal and recoveries were smooth and calm in all lions independent of the atipamezole dose. First sign of recovery was observed 3-27 min after reversal. The animals were up walking 8-26 min after reversal when zolazepam-tiletamine doses < 1 mg/kg were used. In practice, a total dose of 6 mg medetomidine and 80 mg zolazepam-tiletamine and reversal with 15 mg atipamezole can be used for either sex of an adult or subadult lion. The drugs and doses used in this study provided a reliable, safe and reversible anaesthesia protocol for free-ranging lions.  相似文献   

7.
A combination of medetomidine hydrochloride (medetomidine) and ketamine hydrochloride (ketamine) was evaluated in 16 boma-confined and 19 free-ranging impalas (Aepyceros melampus) to develop a non-opiate immobilisation protocol. In free-ranging impala a dose of 220 +/- 34 microg/kg medetomidine and 4.4 +/- 0.7 mg/kg ketamine combined with 7500 IU of hyaluronidase induced recumbency within 4.5 +/- 1.5 min, with good muscle relaxation, a stable heart rate and blood pH. PaCO2 was maintained within acceptable ranges. The animals were hypoxic with reduced oxygen saturation and low PaO2 in the presence of an elevated respiration rate, therefore methods for respiratory support are indicated. The depth of sedation was adequate for minor manipulations but additional anaesthesia is indicated for painful manipulations. Immobilisation was reversed by 467 +/- 108 microg/kg atipamezole hydrochloride (atipamezole) intramuscularly, but re-sedation was observed several hours later, possibly due to a low atipamezole:medetomidine ratio of 2:1. Therefore, this immobilisation and reversal protocol would subject impalas to possible predation or conspecific aggression following reversal if they were released into the wild. If the protocol is used on free-ranging impala, an atipamezole:medetomidine ratio of 5:1 should probably be used to prevent re-sedation.  相似文献   

8.
The cardiorespiratory parameters, the depth of anaesthesia and the quality of recovery were evaluated in six spontaneously breathing dogs that had been premedicated with medetomidine (40 microg/kg, supplemented with 20 microg/kg an hour later), administered with either propofol (1 mg/kg followed by 0.15 mg/kg/minute, intravenously), or with ketamine (1 mg/kg followed by 2 mg/kg/hour, intravenously) and propofol (0.5 mg/kg followed by 0.075 mg/kg/minute, intravenously). The dogs' heart rate and mean arterial blood pressure were higher and their minute volume of respiration and temperature were lower when they were anaesthetised with propofol plus ketamine, and a progressive hypercapnia leading to respiratory acidosis was more pronounced. When the dogs were anaesthetised with propofol/ketamine they recovered more quickly, but suffered some unwanted side effects. When the dogs were anaesthetised with propofol alone they recovered more slowly but uneventfully.  相似文献   

9.
A controlled trial was conducted to assess suitability of combinations of medetomidine and ketamine for the ovariectomy of cats, to investigate the possible side effects, and to compare medetomidine/ketamine with a combination of xylazine and ketamine. Three hundred and thirty-seven cats were submitted to surgery; 100 were anaesthetised with 80 micrograms/kg medetomidine and 5 mg/kg ketamine, 137 with 80 micrograms/kg medetomidine and 7.5 mg/kg ketamine, and 100 were anaesthetised with 1 mg/kg xylazine and 10 mg/kg ketamine. The combinations were injected intramuscularly in the same syringe. The anaesthesia provided by the medetomidine/ketamine combinations was characterised by good muscle relaxation, good analgesia and minimal side effects. The only difference between the two doses of ketamine was the length of the period of anaesthesia. The advantages of the medetomidine/ketamine combination in comparison with xylazine/ketamine were the need for a lower dose of ketamine, a longer duration of action and better analgesia. Similar side effects were observed with both medetomidine/ketamine and xylazine/ketamine combinations.  相似文献   

10.
Twenty five captive chimpanzees were anaesthetised with intramuscular medetomidine at approximately 50 pg/kg plus ketamine at approximately 5mg/kg or 2mg/kg. Anaesthesia produced by both doses was characterised by rapid induction, prolonged and stable immobilisation, excellent relaxation and calm recovery. No qualitative differences were noted between the two dose rates when assessed 15 minutes after injection. Medetomidine was antagonized in 8 animals with intramuscular atipamezole, producing a mean recovery time of 16 minutes. Medetomidine was antagonized in 9 animals with intravenous and intramuscular atipamezole, giving a mean recovery time of 5.7 minutes. It is concluded that medetomidine-ketamine anaesthesia offers a number of advantages over other single-injection anaesthetic techniques in chimpanzees.  相似文献   

11.
A dose range was determined for anaesthesia of 20 recently boma-captured roan antelope (Hippotragus equinus) with the synthetic opiate A3080 combined with medetomidine and ketamine. A dose of 10-30 micro/kg A3080 (x = 20+/-8 microg/kg) combined with 5-21 microg/kg medetomidine (x = 13+/-7 microg/kg) plus 0.29-1.11 mg/kg ketamine (x = 0.71+/-0.24 mg/kg) was found to be safe and effective for the field conditions in this study. The anaesthesia produced by this drug combination was predictable and characterised by a short induction time, good muscle relaxation, and acceptable physiological parameters for anaesthesia periods ranging from 49-103 min (x = 64+/-19 min). The wide range (3-4-fold) of doses with acceptable results is also an indication that this drug combination has a wide margin of safety in roan antelope, making it desirable for field use. When 2 dose levels (2-3-fold dif ference) were retrospectively evaluated, no statistical difference was found in induction times, and no observable clinical differences in the anaesthetic episodes were seen. Based on this study, the recommended dose range in roan antelope for this combination is 10-13 microg/kg A3080, 5-6 microg/kg medetomidine and 0.3-0.6 mg/kg ketamine. The anaesthesia produced by this combination was rapidly and completely reversed by i.m. or i.v. injections of naltrexone at 30 times the A3080 dose (x = 0.60+/-0.25 mg/kg) and atipamezole at 3 times the medetomidine dose (x = 38+/-20 microg/kg). No residual effects from ketamine were noted following reversal of A3080 and medetomidine. No mortality was associated with this protocol.  相似文献   

12.
Twenty-six adult semi-free-ranging Bennett's wallabies were anesthetized. Animals in group MA received medetomidine 0.1 mg/kg and alfaxalone 4 mg/kg i.m. in a 5-ml dart, whereas those in group MK received medetomidine 0.1 mg/kg and ketamine 5 mg/kg i.m. in a 3-ml dart. Dosages were based on estimated body weights. The wallabies were allowed to recover spontaneously or, if still nonresponsive at the end of the procedure, were given atipamezole 0.5 mg/kg (half the dose via i.m. and the other half via i.v.). Heart rate and respiratory rate were monitored at 5-min intervals, temperature at 10-min intervals, and two arterial blood samples were taken for blood gas analysis. Statistical analysis was performed by using analysis of variance (P < 0.05). The use of 5-ml darts in group MA compared with 3-ml darts in group MK could potentially increase the risk of iatrogenic trauma and should be considered. Induction and maintenance of anesthesia were satisfactory in both groups. There were no significant differences between the groups in mean time to first effect, recumbency, and approach, or to time to sternal recumbency and standing after reversal with atipamezole. Although bradycardia was present in both groups, no statistical differences were calculated for respiratory rate and heart rate, whereas the mean cloacal temperature was significantly lower in group MA (P = 0.01). Mixed acid-base disturbances occurred in both groups. All but one animal in group MK needed atipamezole at the end of the procedure. No adverse effects were observed after recovery.  相似文献   

13.
This investigation evaluated the cardiopulmonary effects of medetomidine, ketamine, and butorphanol anesthesia in captive juvenile Thomson's gazelles (Gazella thomsoni). Butorphanol was incorporated to reduce the dose of medetomidine necessary for immobilization and minimize medetomidine-induced adverse cardiovascular side effects. Medetomidine 40.1 +/- 3.6 microg/kg, ketamine 4.9 +/- 0.6 mg/kg, and butorphanol 0.40 +/- 0.04 mg/kg were administered intramuscularly by hand injection to nine gazelles. Times to initial effect and recumbency were within 8 min postinjection. Cardiopulmonary status was monitored every 5 min by measuring heart rate, respiratory rate, indirect blood pressure, end-tidal CO2, and indirect oxygen-hemoglobin saturation by pulse oximetry. Venous blood gases were collected every 15 min postinjection. Oxygen saturations less than 90% in three gazelles suggested hypoxemia. Subsequent immobilized gazelles were supplemented with intranasal oxygen throughout the anesthetic period. Sustained bradycardia (<60 beats per minute, as compared with anesthetized domestic calves, sheep, and goats) was noted in eight of nine gazelles. Heart and respiratory rates and rectal temperatures decreased slightly, whereas systolic, mean, and diastolic blood pressure values were consistent over the anesthetic period. Mild elevations in end tidal CO2 and PCO2 suggested hypoventilation. Local lidocaine blocks were necessary to perform castrations in all seven of the gazelles undergoing the procedure. Return to sternal recumbency occurred within 7 min and return to standing occurred within 12 min after reversal with atipamezole (0.2 +/- 0.03 mg/kg) and naloxone (0.02 +/- 0.001 mg/kg). Medetomidine, ketamine, and butorphanol can be used to safely anesthetize Thomson's gazelles for routine, noninvasive procedures. More invasive procedures, such as castration, can be readily performed with the additional use of local anesthetics.  相似文献   

14.
The sedative and immobilizing effects of the alpha 2-adrenoceptor agonist medetomidine alone or combined with the dissociative anesthetic ketamine, were studied in blue foxes. Medetomidine at doses of 25 and 50 micrograms/kg induced moderate to deep sedation, but only with the highest medetomidine dose tested, 100 micrograms/kg, was the immobilization complete. Medetomidine 50 micrograms/kg combined with ketamine 2.5 mg/kg rapidly induced complete immobilization, characterized by good myorelaxation, and no clinically significant alterations in serially determined hematologic and serum chemistry parameters. The alpha 2-adrenoceptor antagonist atipamezole effectively reversed the medetomidine- or medetomidine-ketamine-induced immobilizations. A transient increase in heart rates was noted after each atipamezole injection.  相似文献   

15.
Medetomidine, either 5, 10 or 20 (μg/kg, was administered together with pethidine, 2 mg/kg, by either the intramuscular or subcutaneous route to 88 dogs from a clinical population. Administration of all the drug combinations consistently produced profound sedation in the dogs, accompanied by dramatic reductions in heart rate. The degree of sedation was similar to that seen after 40 μg/kg medetomidine is administered on its own to dogs. Intramuscular administration produced more reliable sedation, but was associated with more pain than subcutaneous administration. In a number of dogs, sedation permitted the completion of various diagnostic or therapeutic procedures. Several dogs were anaesthetised with thiopentone and the induction doses required were characteristically low (mean doses between 2 to 3·3 mg/kg depending on the dose of medetomidine and the route of administration). Administration of atipamezole at the termination of sedation or anaesthesia, produced a rapid and full recovery (mean time to standing between seven and 11 minutes).  相似文献   

16.
The optimal dose of medetomidine-ketamine-buprenorphine was determined in 25 Cape ground squirrels (Xerus inauris) undergoing surgical implantation of a temperature logger into the abdominal cavity. At the end of anaesthesia, the squirrels were given atipamezole intramuscularly to reverse the effects of medetomidine. The mean dose of medetomidine was 67.6 +/- 9.2microg/kg, ketamine 13.6 +/- 1.9 mg/kg and buprenorphine 0.5 +/- 0.06 microg/kg. Induction time was 3.1 +/- 1.4 min. This produced surgical anaesthesia for 21 +/- 4.2 min. Atipamezole 232 +/- 92 microg/kg produced a rapid recovery. Squirrels were sternally recumbent in 3.5 +/- 2.2 min.  相似文献   

17.
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18.
The quality and duration of anaesthesia, cardiorespiratory effects and recovery characteristics of a morphine, medetomidine, ketamine (MMK) drug combination were determined in cats. Six healthy, adult female cats were administered 0.2 mg/kg morphine sulphate, 60 microg/kg medetomidine hydrochloride, and 5 mg/kg ketamine hydrochloride intramuscularly. Atipamezole was administered intramuscularly at 120 min after MMK administration. Time to lateral recumbency, intubation, extubation and sternal recumbency were recorded. Cardiorespiratory variables and response to a noxious stimulus were recorded before and at 3 min and 10 min increments after drug administration until sternal recumbency. The time to lateral recumbency and intubation were 1.9+/-1.2 and 4.3+/-1.2 min, respectively. Body temperature and haemoglobin saturation with oxygen remained unchanged compared to baseline values throughout anaesthesia. Respiratory rate, tidal volume, minute volume, heart rate, and blood pressure were significantly decreased during anaesthesia compared to baseline values. One cat met criteria for hypotension (systolic blood pressure <90 mmHg). End tidal carbon dioxide increased during anaesthesia compared to baseline values. All but one cat remained non-responsive to noxious stimuli from 3 to 120 min. Time to extubation and sternal recumbency following atipamezole were 2.9+/-1.1 and 4.7+/-1.0 min, respectively. MMK drug combination produced excellent short-term anaesthesia and analgesia with minimal cardiopulmonary depression. Anaesthesia lasted for at least 120 min in all but one cat and was effectively reversed by atipamezole.  相似文献   

19.
Medetomidine/ketamine sedation in calves and its reversal with atipamezole   总被引：1，自引：0，他引：1  
Atipamezole was used to reverse the sedation induced in calves by medetomidine/ketamine. Thirteen claves subjected to umbilical surgery received medetomidine 20 μg/kg bodyweight (bwt) and ketamine 0.5 mg/kg bwt intravenously (iv) from a mixture of the drugs in one syringe. Atipamezole was given at doses of 20 to 60 μg/kg iv and intramuscularly (im) to the calves at the end of the operation. Following the administration of medetomidine and ketamine, PaCO2 increased whereas pH, PaO2 and heart rate decreased. Reversing the effects of medetomidine with atipamezole did not cause undesirable effects; recovery was rapid and smooth, most of the animals reached a standing position within 1 to 3 mins after the atipamezole injection.  相似文献   

20.
OBJECTIVE: To determine the minimal infusion rate of propofol in combination with medetomidine for long-term anesthesia in ponies and the effects of atipamezole on recovery. ANIMALS: 12 ponies. PROCEDURE: Ponies were sedated with medetomidine (7 microg/kg of body weight, IV). Ten minutes later, anesthesia was induced with propofol (2 mg/kg, IV). Anesthesia was maintained for 4 hours, using an infusion of medetomidine (3.5 microg/kg per hour, IV) and propofol at a rate sufficient to prevent ponies from moving after electrical stimulation. Arterial blood pressures and blood gas analysis, heart rates, and respiratory rates were monitored. For recovery, 6 ponies were given atipamezole (60 microg/kg, IV). Induction and recovery were scored. RESULTS: Minimal propofol infusion rates ranged from 0.06 to 0.1 mg/kg per min. Mean arterial blood pressure was stable (range, 74 to 86 mm Hg), and heart rate (34 to 51 beats/min) had minimal variations. Variable breathing patterns were observed. Mean PaO2 (range, 116 to 146 mm Hg) and mean PaCO2 (range, 48 to 51 mm Hg) did not change significantly with time, but hypoxemia was evident in some ponies (minimal PaO2, 47 mm Hg). Recovery was fast and uneventful with and without atipamezole (completed in 20.2 and 20.9 minutes, respectively). CONCLUSIONS AND CLINICAL RELEVANCE: Infusion of a combination of medetomidine and propofol was suitable for prolonged anesthesia in ponies. Recovery was rapid and uneventful. A combination of propofol and medetomidine may prove suitable for long-term anesthesia in horses. Monitoring of blood gases is essential because of potential hypoxemia.  相似文献   

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