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1.
Objective To characterize intravenous anaesthesia with detomidine, ketamine and guaiphenesin in pregnant ponies. Animals Twelve pony mares, at 260–320 days gestation undergoing abdominal surgery to implant fetal and maternal vascular catheters. Materials and methods Pre‐anaesthetic medication with intravenous (IV) acepromazine (30 µg kg?1), butorphanol (20 µg kg?1) and detomidine (10 µg kg?1) preceded induction of anaesthesia with detomidine (10 µg kg?1) and ketamine (2 mg kg?1) IV Maternal arterial blood pressure was measured directly throughout anaesthesia and arterial blood samples were taken at 20‐minute intervals for measurement of blood gases and plasma concentrations of cortisol, glucose and lactate. Anaesthesia was maintained with an IV infusion of detomidine (0.04 mg mL?1), ketamine (4 mg mL?1) and guaiphenesin (100 mg mL?1) (DKG) for 140 minutes. Oxygen was supplied by intermittent positive pressure ventilation (IPPV) adjusted to maintain PaCO2 between 5.0 and 6.0 kPa (38 and 45 mm Hg), while PaO2 was kept close to 20.0 kPa (150 mm Hg) by adding nitrous oxide. Simultaneous fetal and maternal blood samples were withdrawn at 90 minutes. Recovery quality was assessed. Results DKG was infused at 0.67 ± 0.17 mL kg?1 hour?1 for 1 hour then reduced, reaching 0.28 ± 0.14 mL kg?1 hour?1 at 140 minutes. Arterial blood gas values and pH remained within intended limits. During anaesthesia there was no change in heart rate, but arterial blood pressure decreased by 10%. Plasma glucose and lactate increased (10‐fold and 2‐fold, respectively) and cortisol decreased by 50% during anaesthesia. Fetal umbilical venous pH, PO2 and PCO2 were 7.34 ± 0.06, 5.8 ± 0.9 kPa (44 ± 7 mm Hg) and 6.7 ± 0.8 kPa (50 ± 6 mm Hg); and fetal arterial pH, PO2 and PCO2 were 7.29 ± 0.06, 4.0 ± 0.7 kPa (30 ± 5 mm Hg) and 7.8 ± 1.7 kPa (59 ± 13 mm Hg), respectively. Surgical conditions were good but four ponies required a single additional dose of ketamine. Ponies took 60 ± 28 minutes to stand and recovery was good. Conclusions and clinical relevance Anaesthesia produced with DKG was smooth while cardiovascular function in mare and fetus was well preserved. This indicates that DKG infusion is suitable for maintenance of anaesthesia in pregnant equidae.  相似文献   

2.
A four‐month‐old, entire male guinea pig was presented for surgical repair of a closed oblique femoral fracture. Analgesia was provided with 30 µg/kg buprenorphine intramuscularly (im) four times a day and 0 · 3 mg/kg meloxicam subcutaneously once a day. The following day, anaesthesia was induced and maintained with 100 µg/kg medetomidine im, 20 mg/kg ketamine im, 30 µg/kg buprenorphine im and isoflurane in oxygen. Femoral and sciatic nerve blocks were performed with bupivacaine. The fracture was reduced and aligned using an intramedullary 1 · 4 mm K‐wire and a 3 metric polydioxanone cerclage. Three weeks postoperatively remodelling and callus formation was documented, with no evidence of complications. Complete union was present 14 weeks postoperatively.  相似文献   

3.
Prolonged surgical anaesthesia in the dog was induced with propofol (6.5 ± 1.3 mg/kg) followed by alfentanil (25.5 ± 5 μg/kg) (mean ± 1 sd) and maintained with a continuous infusion of propofol (0.14 to 0.18 mg/kg/min) and alfentanil (2 to 3 μg/kg/min). Neuromuscular blockade was produced with vecuronium (0.1 mg/kg). After induction of anaesthesia with propofol, administration of alfentanil to dogs which had received no pre-anaesthetic medication produced cardiac arrest and apnoea. Administration of atropine intravenously immediately prior to alfentanil prevented these cardiac depressant effects. The cardiac depressant effect of alfentanil was not as severe in a second group of dogs in which anaesthesia was induced with thiopentone. After commencing the continuous infusion anaesthetic regime and establishment of IPPV, blood pressure and heart rate remained stable during the remaining 4 to 6 h period of anaesthesia. Recovery from anaesthesia was smooth and uneventful. The depressant effects of alfentanil on respiration and on consciousness were reversed rapidly by administration of nalbuphine (10 mg total dose). The smooth recovery and the integration of anaesthesia and post operative analgesia attained by the reversal of alfentanil with nalbuphine make this an attractive anaesthetic regime for major surgery in dogs, provided that facilities for IPPV are available.  相似文献   

4.
Reasons for performing study: The effects of lidocaine combined with medetomidine or lidocaine alone on cardiovascular function during anaesthesia and their effects on recovery have not been thoroughly investigated in isoflurane‐anaesthetised horses. Objectives: To determine the effects of an intraoperative i.v. constant rate infusion of lidocaine combined with medetomidine (Group 1) or lidocaine (Group 2) alone on cardiovascular function and on the quality of recovery in 12 isoflurane‐anaesthetised horses undergoing arthroscopy. Hypothesis: The combination would depress cardiovascular function but improve the quality of recovery when compared to lidocaine alone in isoflurane‐anaesthetised horses. Methods: Lidocaine (2 mg/kg bwt i.v. bolus followed by 50 µg/kg bwt/min i.v.) or lidocaine (same dose) and medetomidine (5 µg/kg bwt/h i.v.) was started 30 min after induction of anaesthesia. Lidocaine administration was discontinued 30 min before the end of surgery in both groups, whereas medetomidine administration was continued until the end of surgery. Cardiovascular function and quality of recovery were assessed. Results: Horses in Group 1 had longer recoveries, which were of better quality due to better strength and overall attitude during the recovery phase than those in Group 2. Arterial blood pressure was significantly higher in Group 1 than in Group 2 and this effect was associated with medetomidine. No significant differences in cardiac output, arterial blood gases, electrolytes and acid‐base status were detected between the 2 groups. Conclusions and potential relevance: The combination of an intraoperative constant rate infusion of lidocaine and medetomidine did not adversely affect cardiovascular function in isoflurane‐anaesthetised horses and improved the quality of recovery when compared to an intraoperative infusion of lidocaine alone.  相似文献   

5.
Objective To measure the effects of dobutamine infusion on fetal oxygenation during isoflurane anaesthesia in pregnant ewes. Study design Prospective randomized experimental study. Animals Seven clinically normal adult pregnant Rambouillet‐Dorset cross ewes with fetuses of 117–122 days gestational age. Methods The ewes were anaesthetized with ketamine (2 mg kg?1) IM, and isoflurane (FE′ISO 2.0%) in oxygen. After instrumentation and stabilization, dobutamine was infused at 4 µg kg?1minute?1 for 60 minutes and 10 µg kg?1minute?1 for 60 minutes in random order, separated by a 20‐minute washout period. Catheters were placed in the maternal and fetal carotid arteries; these were used for continuous blood pressure measurement and intermittent blood sampling. Results Maternal mean systemic carotid arterial pressure was 60 mm Hg prior to dobutamine infusion. After 5 minutes of dobutamine infusion, fetal oxygen saturation increased (p < 0.05) from 0.62 (0.17–0.71, minimum–maximum) to 0.72 (0.28–0.78) at a dose of 4 µg kg?1minute?1 and to 0.70 (0.20–0.73) at a dose of 10 µg kg?1minute?1. These increases were maintained during the infusion and were not significantly different between doses. Maternal oxygen saturation remained constant at 1.0 before and during all infusions. Although maternal heart rate and blood pressure increased (p < 0.05) by 90% and 25%, respectively, with dobutamine, this stimulant effect was not evident in the corresponding fetal variables. Maternal haemoglobin concentration increased 30% (p < 0.05) with each infusion. Conclusions Dobutamine at 4 µg kg?1minute?1 increases fetal oxygenation that is not improved by a dose of 10 µg kg?1minute?1. This increase is largely due to an increase in maternal haemoglobin concentration that, in turn, increases oxygen delivery to the placenta. Clinical relevance The use of dobutamine to treat hypotension in pregnant sheep during isoflurane anaesthesia improves fetal oxygenation. This may be true in other species.  相似文献   

6.
Six ponies were anaesthetised for two hours with intermittent injections of a combination of guaiphenesin (72 mg/kg/hr), ketamine (1.4 mg/kg/hr) and detomidine (0.015 mg/kg/hr) after premedication with detomidine 0.01 mg/kg and induction of anaesthesia with guaiphenesin 50 mg/kg and ketamine 2 mg/kg. Induction of anaesthesia was smooth, the ponies were easily intubated and after intubation breathed 100% oxygen spontaneously. During anaesthesia mean pulse rate ranged between 31–44 beats per minute and mean respiratory rate between 12–23 breaths per minute. Mean arterial blood pressure remained between 110–130 mm Hg, mean arterial carbon dioxide tension between 6.1–6.9 kPa and pH between 737–7.42. Arterial oxygen tension was over 23 kPa throughout anaesthesia. Plasma glucose increased to more than 25 mmol per litre during anaesthesia; there was no change in lactate or ACTH concentration and plasma cortisol concentration decreased. Recovery was rapid and smooth. A guaiphenesin, ketamine and detomidine combination appeared to offer potential as a total intravenous technique for maintenance of anaesthesia in horses.  相似文献   

7.
OBJECTIVE: To compare the induction dose requirements of thiopental using two different infusion rates for induction of anaesthesia in dogs. STUDY DESIGN: Prospective, randomized study. ANIMALS: Fifty, healthy (ASA I or II) client-owned dogs with a mean age of 4.1 years and a mean mass of 20.4 kg undergoing elective surgery. MATERIALS AND METHODS: Animals were randomly assigned to receive an infusion of 2.5% thiopental at a rate of either 0.1 ml kg(-1) minute(-1) or 0.4 ml kg(-1)minute(-1), 30-40 minutes after pre-anaesthetic medication with intramuscular acepromazine (0.025 mg kg(-1)) and pethidine (3.5 mg kg(-1)). Thiopental administration was controlled by a precision syringe driver. Statistical analyses of the results, using the outcome 'mg kg(-1) required for induction' (log-transformed) included unpaired t-tests for all categorical data (thiopental infusion rate, breed, sex, obesity, sedation quality) and univariable linear regression for continuous variables (mass, age). All variables were then considered in a multivariable linear regression model. The quality of induction with the two different infusion rates was also assessed. RESULTS: After controlling for quality of sedation, the thiopental induction dose requirement was significantly less (p < 0.001) with the slower infusion rate (median = 7.5 mg kg(-1); range 4.9-13.7) compared with the faster infusion rate (median =11.0 mg kg(-1); range 6.6-18.0). The quality of sedation also affected the dose required (p = 0.03). The slower infusion rate was associated with a significantly poorer induction quality (p = 0.03) [corrected] CONCLUSIONS: Slow thiopental infusion (0.1 ml kg(-1) minute(-1)) for anaesthesia induction after acepromazine/pethidine pre-anaesthetic medication reduced the induction dose requirement, although the quality of induction was inferior. CLINICAL RELEVANCE: The induction dose of thiopental was reduced with a slower administration rate and so slow administration is recommended in thiopental-sensitive animals.  相似文献   

8.
The tested anaesthesia through a permanent infusion of a xylazine, ketamine and guaifenezine (XKG) mixture was used in ten experimental dogs without clinical signs of a disease and in fifty two patients during different surgical interventions. After joint i.m. atropine (0.05 mg/kg) and xylazine (2 mg/kg) premedication, anaesthesia in dogs was induced by an i.v. administration of 1% ketamine at a dose of 2 mg/kg, and the XKG was infused instantly after the previous treatment. The mixture contained 2.0 ml of 5% ketamine and 1.25 ml of 2% xylazine added to 100 ml of 5% guaifenezine. The infusion was applied at a rate of 3.3 ml/kg for the first five minutes and then it was maintained at constant values of 2.2 ml/kg during the whole surgical intervention (Tab. I). The induction and course of anaesthesia, and waking up and recovery from anaesthesia were evaluated in all dogs, and the trias values were also followed. These additional parameters were followed in the test group: breathing volumes, ECG values and acid-base balance parameters were determined from the collected blood samples. The observation of measurable parameters (Figs. 1 to 5) and ECG analysis did not demonstrate any large departures from the starting values, and the changes in the acid-base balance (Tab. II) suggest the partly compensated respiratory acidosis. On the basis of our results, we can recommend this tested method for general anaesthesia particularly of dogs of larger breeds and for longer-lasting operations. This method is suitable to be used first of all in the veterinary establishments where inhalation anaesthesia is not practicable.  相似文献   

9.
The effects of prolonging romifidine/ketamine anaesthesia in horses with a second injection of ketamine alone or both romifidine/ketamine compared with only induction injection of romifidine and tiletamine/zolazepam were studied in 6 horses anaesthetised in lateral recumbency on 3 random occasions. All horses were sedated with romifidine 0.1 mg/kg bwt iv and, on 2 occasions, anaesthesia was induced by iv injection of ketamine 2.2 mg/kg bwt. To prolong the ketamine-induced anaesthesia, either ketamine (I.1 mg/kg bwt iv) or ketamine and romifidine (I.1 mg/kg bwt and 0.04 mg/kg bwt iv, respectively) were given 18–20 min after the start of the ketamine injection for induction. On the third occasion, anaesthesia was induced by iv injection of 1.4 mg/kg bwt Zoletil (0.7 mg/kg bwt tiletamhe + 0.7 mg/kg bwt zolazepam). No statistically significant differences in the measured cardiorespiratory function were found between the 3 groups. Heart rate was decreased significantly after sedation but increased during anaesthesia. Arterial blood pressure increased after sedation and remained high during anaesthesia. A significant decrease in arterial oxygen tension was observed in all groups during anaesthesia. The muscle relaxation induced by romifidine was, in most cases, not sufficient to abolish the catalepsy following a repeated injection of ketamine alone. Zoletil or a repeated injection of ketaminehornifidine resulted in smoother anaesthesia. When additional time is required to complete surgery during field anaesthesia, it is advisable to prolong romifidine/ketamine anaesthesia with an injection of both romifidine and ketamine in healthy horses. When a longer procedure is anticipated from the start Zoletil is an alternative for induction of anaesthesia. The mean time to response to noxious stimuli and mean time spent in lateral recumbency was 28 and 38 min for the anaesthesia prolonged with ketamine, 3.5 and 43 rnin for the anaesthesia prolonged with ketaminehornifidine and 33 and 45 min for the anaesthesia with Zoletil. All horses reached a standing position at the first attempt.  相似文献   

10.
The pharmacodynamics and pharmacokinetics of ketamine, when administered by infusion as an adjunct to halothane anaesthesia in horses, were investigated in 5 equine patients presented for routine castration. Anaesthesia was induced with detomidine, 20 μg/kg, followed by ketamine, 2.2 mg/kg bwt, the trachea intubated and the horses allowed to breathe halothane in oxygen. Five minutes later, a constant rate infusion of ketamine, 40 μg/kg min, was commenced and the halothane vaporiser concentration adjusted to maintain a light plane of anaesthesia. The mean infusion duration was 62 min (range 40–103). The ketamine was switched off approximately 15 min before the halothane. Plasma ketamine and norketamine levels, determined by high performance liquid chromatography, ranged from 0.74–2.04 μg/ml and 0.15–0.75 μg/ml, respectively, during the infusion period. The harmonic mean elimination half-life of ketamine was 46.1 min, mean volume of distribution at steady state (Vdss) was 1365 (271) ml/kg, mean body clearance (Cl) was 32.3 (9.1) ml/min.kg, and average mean residence time for the infusion (MRTinf) was 105.9 (20.4) min, respectively. Following termination of halothane, mean times to sternal recumbency and standing were 21.1 (6.9) and 41.6 (17.0) min, respectively. Surgical conditions were considered highly satisfactory, and physiological parameters were well preserved in most animals.  相似文献   

11.
This clinical study analysed the anaesthetic sparing effect of a medetomidine constant rate infusion (CRI) during isoflurane anaesthesia in horses. Forty healthy horses undergoing different types of orthopaedic and soft tissue surgeries were studied in a randomized trial. Orthopaedic surgeries were primarily arthroscopies and splint bone extractions. Soft tissue surgeries were principally castrations with one ovariectomy. All horses received 0.03 mg kg?1 acepromazine IM 1 hour prior to sedation. Group A (11 orthopaedic and nine soft tissue surgeries), was sedated with 1.1 mg kg?1 xylazine IV, group B (13 orthopaedic and seven soft tissue surgeries) with 7 µg kg?1 medetomidine IV. Anaesthesia was induced in both groups with 2.2 mg kg?1 ketamine and diazepam 0.02 mg kg?1 IV. Maintenance of anaesthesia was with isoflurane (ISO) in 100% oxygen, depth of anaesthesia was always adjusted by the first author. Group B received an additional CRI of 3.5 µg kg?1 hour?1 medetomidine. Respiratory rate (RR), heart rate (HR), mean arterial blood pressure (MAP), Fe ′ISO and Fe ′CO2 were monitored with a methane insensitive monitor (Cardiocap 5, Ohmeda, Anandic, Diessenhofen) and noted every 5 minutes. Arterial blood was withdrawn for gas analysis (PaO2, PaCO2) 5 minutes after the induction of anaesthesia and every 30 minutes thereafter. Dobutamine (DOB) was given as a CRI to maintain mean arterial blood pressure above 70 mm Hg. Data were averaged over time (sum of measurements/number of measurements) and tested for differences between groups by unpaired t‐tests. There were no significant differences between the groups in terms of body mass (group A, 508 ± 73.7 kg; group B, 529.25 ± 78.4 kg) or duration of anaesthesia (group A, 125.5 ± 36 minutes; group B, 121.5 ± 48.4 minutes). The mean Fe ′ISO required to maintain a surgical plane of anaesthesia was significantly higher in group A (1.33 ± 0.13%) than in group B (1.07 ± 0.19%; p = 2.78 × 10?5). Heart rate was different between the two groups (group A, 42.2 ± 8.3; group B, 32.6 ± 3.5; p = 8.8 × 10?5). Dobutamine requirements were higher in group A (group A, 0.72 ± 0.24 μg kg?1 minute?1; group B, 0.53 ± 0.23 μg kg?1 minute?1; p = 0.023). Respiratory rate, Fe ′CO2, PaO2, PaCO2 were not different between the groups. Adjustment of anaesthetic depth subjectively was easier with the medetomidine infusion and isoflurane (group B) than with isoflurane as a sole agent (group A). In group A 12 horses and in group B five horses showed purposeful movements on 27 (A) and 12 (B) occasions. They were given thiopental (group A, 0.0114 mg kg?1 minute?1; group B, 0.0023 mg kg?1 minute?1). In group A, a further 17 horses were given ketamine to deepen anaesthesia (52 occasions, 0.00426 mg kg?1 minute?1) whereas in group B only nine horses needed ketamine (34 occasions, 0.00179 mg kg?1 minute?1). An infusion of 3.5 µg kg?1 MED during ISO anaesthesia resulted in a significantly reduced ISO requirement.  相似文献   

12.
Fentanyl is used in small animals for perioperative analgesia during anaesthesia. Severe bradycardia and asystole were observed on bolus administration of a 3 µg/kg loading dose of fentanyl in two dogs under isoflurane anaesthesia. Premedication with 10 µg/kg glycopyrrolate did not prevent asystole in the first case; and although bradycardia was treated with 5 µg/kg glycopyrrolate administered intravenously in the second case, the heart rate continuously decreased and asystole subsequently developed. Asystole in both cases was quickly corrected by intravenous administration of 0 · 04 mg/kg atropine and closed chest compressions. This case report describes asystole induced by fentanyl administration in isoflurane anaesthetised dogs. Atropine was more effective than glycopyrrolate in the treatment of fentanyl‐induced asystole.  相似文献   

13.
ObjectiveTo assess the cardiorespiratory and hypnotic-sparing effects of ketamine co-induction with target-controlled infusion of propofol in dogs.Study designProspective, randomized, blinded clinical study.AnimalsNinety healthy dogs (ASA grades I/II). Mean body mass 30.5 ± SD 8.6 kg and mean age 4.2 ± 2.6 years.MethodsAll dogs received pre-anaesthetic medication with acepromazine (0.03 mg kg?1) and morphine (0.2 mg kg?1) administered intramuscularly 30 minutes prior to induction of anaesthesia. Heart rate and respiratory rate were recorded prior to pre-medication. Animals were allocated into three different groups: Group 1 (control) received 0.9% NaCl, group 2, 0.25 mg kg?1 ketamine and group 3, 0.5 mg kg?1 ketamine, intravenously 1 minute prior to induction of anaesthesia, which was accomplished using a propofol target-controlled infusion system. The target propofol concentration was gradually increased until endotracheal intubation was possible and the target concentration at intubation was recorded. Heart rate, respiratory rate and noninvasive blood pressure were recorded immediately prior to induction, at successful intubation and at 3 and 5 minutes post-intubation. The quality of induction was graded according to the amount of muscle twitching and paddling observed. Data were analysed using a combination of chi-squared tests, Fisher's exact tests, Kruskal–Wallis, and anova with significance assumed at p< 0.05.ResultsThere were no significant differences between groups in the blood propofol targets required to achieve endotracheal intubation, nor with respect to heart rate, noninvasive blood pressure or quality of induction. Compared with the other groups, the incidence of post-induction apnoea was significantly higher in group 3, but despite this dogs in this group had higher respiratory rates overall.Conclusions and clinical relevanceUnder the conditions of this study, ketamine does not seem to be a useful agent for co-induction of anaesthesia with propofol in dogs.  相似文献   

14.
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   

15.
Objective To compare the anaesthetic and cardiopulmonary effects of a diazepam–ketamine combination with thiopentone for induction of anaesthesia in dogs. Animal population Twenty healthy dogs of various breeds weighing between 3.8 and 42.6 kg undergoing major orthopaedic or soft tissue surgery. Materials and methods Pre‐anaesthetic medication in all cases was intramuscular acepromazine and methadone given 30 minutes before induction of anaesthesia. Each animal was then randomly assigned to receive either thiopentone or diazepam and ketamine. Quality of conditions for, and time to tracheal intubation were recorded. Anaesthesia was maintained with halothane in oxygen and nitrous oxide. Heart rate, respiratory rate, systolic blood pressure, end tidal carbon dioxide tensions and oxygen saturation were recorded at 10 minute intervals throughout surgery. The quality of recovery from anaesthesia was assessed. Results The quality of induction in both groups was satisfactory. The total mean time (± SD) to tracheal intubation (162 ± 84 seconds) was significantly longer in dogs receiving diazepam and ketamine compared to dogs receiving thiopentone (62 ± 28 seconds). Heart rate, systolic blood pressure and end tidal carbon dioxide concentration were not significantly different between groups. Respiratory rate was significantly higher in the diazepam–ketamine group between 0 and 30 minutes. The quality of recovery was similar in each group. Conclusions There appear to be fewer differences between the induction agents examined in this study than was previously believed. No pressor, or other cardiovascular stimulating effects were detected in the dogs that received diazepam and ketamine. Clinical relevance The absence of obvious differences between groups suggests that pre‐anaesthetic medication, inhaled anaesthetics and the physiological effects of surgery itself probably had a greater effect on the variables studied than the induction agent used. Further studies are required to determine whether diazepam and ketamine offers significant advantages over other induction agents in the unhealthy dog.  相似文献   

16.
Objective To characterize responses to different doses of propofol in horses pre‐medicated with xylazine. Animals Six adult horses (five females and one male). Methods Each horse was anaesthetized four times with either ketamine or propofol in random order at 1‐week intervals. Horses were pre‐medicated with xylazine (1.1 mg kg?1 IV over a minute), and 5 minutes later anaesthesia was induced with either ketamine (2.2 mg kg?1 IV) or propofol (1, 2 and 4 mg kg?1 IV; low, medium and high doses, respectively). Data were collected continuously (electrocardiogram) or after xylazine administration and at 5, 10 and 15 minutes after anaesthetic induction (arterial pressure, respiratory rate, pH, PaO2, PaCO2 and O2 saturation). Anaesthetic induction and recovery were qualitatively and quantitatively assessed. Results Differences in the quality of anaesthesia were observed; the low dose of propofol resulted in a poorer anaesthetic induction that was insufficient to allow intubation, whereas the high dose produced an excellent quality of induction, free of excitement. Recorded anaesthesia times were similar between propofol at 2 mg kg?1 and ketamine with prolonged and shorter recovery times after the high and low dose of propofol, respectively (p < 0.05; ketamine, 38 ± 7 minutes; propofol 1 mg kg?1, 29 ± 4 minutes; propofol 2 mg kg?1, 37 ± 5 minutes; propofol 4 mg kg?1, 50 ± 7 minutes). Times to regain sternal and standing position were longest with the highest dose of propofol (32 ± 5 and 39 ± 7 minutes, respectively). Both ketamine and propofol reversed bradycardia, sinoatrial, and atrioventricular blocks produced by xylazine. There were no significant alterations in blood pressure but respiratory rate, and PaO2 and O2 saturation were significantly decreased in all groups (p < 0.05). Conclusion The anaesthetic quality produced by the three propofol doses varied; the most desirable effects, which were comparable to those of ketamine, were produced by 2 mg kg?1 propofol.  相似文献   

17.
Abstract: Protocols for utilizing intravenous infusions of sufentanil were developed for experimental cardiac surgery in swine and dogs. After initial experiences with fentanyl, sufentanil was selected for these procedures due to its increased potency and shorter half life thus requiring a smaller volume for infusion and more control. In dogs with experimental mitral valve regurgitation, an initial bolus of sufentanil 3 γg/kg IV was followed by a continuous IV infusion at a rate of 9–13 γg/kg/hr. Swine used in experiments involving cardiac conduction system ablation received ketamine 33 mg/kg IM and acepromazine 1.1 mg/kg IM as a preanesthetic combination. Following the preanesthetic, an initial infusion of sufentanil 15 γg/kg/hr was started and a loading dose of sufentanil 7 γg/kg IV was administered as a bolus for induction. They were then maintained by a continuous IV infusion at a rate of 15–30 γg/kg/hr. Dogs but not pigs required periodic supplementation of anaesthesia with isoflurane and/or nitrous oxide during portions of the experimental protocol. No anaesthetic related deaths have occurred in either species using these anaesthetic protocols for cardiac procedures.  相似文献   

18.
REASONS FOR PERFORMING STUDY: To search for long-term total i.v. anaesthesia techniques as a potential alternative to inhalation anaesthesia. OBJECTIVES: To determine cardiopulmonary effects and anaesthesia quality of medetomidine-ketamine anaesthesia induction followed by 4 h of medetomidine-propofol anaesthesia in 6 ponies. METHODS: Sedation consisted of 7 microg/kg bwt medetomidine i.v. followed after 10 min by 2 mg/kg bwt i.v. ketamine. Anaesthesia was maintained for 4 h with 3.5 microg/kg bwt/h medetomidine and propofol at minimum infusion dose rates determined by application of supramaximal electrical pain stimuli. Ventilation was spontaneous (F(I)O2 > 0.9). Cardiopulmonary measurements were always taken before electrical stimulation, 15 mins after anaesthesia induction and at 25 min intervals. RESULTS: Anaesthesia induction was excellent and movements after pain stimuli were subsequently gentle. Mean propofol infusion rates were 0.89-0.1 mg/kg bwt/min. No changes in cardiopulmonary variables occured over time. Range of mean values recorded was: respiratory rate 13.0-15.8 breaths/min; PaO2 29.1-37.9 kPa; PaCO2 6.2-6.9 kPa; heart rate 31.2-40.8 beats/min; mean arterial pressure 90.0-120.8 mmHg; cardiac index 44.1-59.8 ml/kg bwt/min; mean pulmonary arterial pressure 11.8-16.4 mmHg. Recovery to standing was an average of 31.1 mins and ponies stood within one or 2 attempts. CONCLUSIONS: In this paper, ketamine anaesthesia induction avoided the problems encountered previously with propofol. Cardiovascular function was remarkably stable. Hypoxaemia did not occur but, despite F(I)O2 of > 0.9, minimal PaO2 in one pony after 4 h anaesthesia was 8.5 kPa. POTENTIAL RELEVANCE: The described regime might offer a good, practicable alternative to inhalation anaesthesia and has potential for reducing the fatality rate in horses.  相似文献   

19.
Reasons for performing study: Dexmedetomidine has been administered in the equine as a constant‐rate infusion (CRI) during inhalation anaesthesia, preserving optimal cardiopulmonary function with calm and coordinated recoveries. Inhalant anaesthetic sparing effects have been demonstrated in other species, but not in horses. Objectives: To determine the effects of a CRI of dexmedetomidine on the minimal alveolar concentration (MAC) of sevoflurane in ponies. Methods: Six healthy adult ponies were involved in this prospective, randomised, crossover, blinded, experimental study. Each pony was anaesthetised twice (3 weeks washout period). After induction with sevoflurane in oxygen (via nasotracheal tube), the ponies were positioned on a surgical table (T0), and anaesthesia was maintained with sevoflurane (expired sevoflurane fraction 2.5%) in 55% oxygen. The ponies were randomly allocated to treatment D (dexmedetomidine 3.5 µg/kg bwt i.v. [T10–T15] followed by a CRI of dexmedetomidine at 1.75 µg/kg bwt/h) or treatment S (bolus and CRI of saline at the same volume and rate as treatment D). After T60, MAC determination, using a classic bracketing technique, was initiated. Stimuli consisted of constant‐current electrical stimuli at the skin of the lateral pastern region. Triplicate MAC estimations were obtained and averaged in each pony. Monitoring included pulse oximetry, electrocardiography, anaesthetic gas monitoring, arterial blood pressure measurement and arterial blood gases. Normocapnia was maintained by mechanical ventilation. Analysis of variance (treatment and period as fixed factors) was used to detect differences between treatments (α= 0.05). Results: An intravenous (i.v.) dexmedetomidine CRI decreased mean ± s.d. sevoflurane MAC from 2.42 ± 0.55 to 1.07 ± 0.21% (mean MAC reduction 53 ± 15%). Conclusions and potential relevance: A dexmedetomidine CRI at the reported dose significantly reduces the MAC of sevoflurane.  相似文献   

20.
This study examined the pharmacokinetics of propofol by infusion in ponies using an analyser for the rapid measurement of propofol concentrations. The analyser (Pelorus 1000; Sphere Medical Ltd., Cambridge, UK) has a measurement cycle of approximately five minutes. Ten Welsh‐cross ponies (weighing 135–300 kg) undergoing minor procedures were studied after premedication with acepromazine 0.03 mg/kg and detomidine 0.015 mg/kg. Anaesthesia was induced with ketamine 2 mg/kg and diazepam 0.03 mg/kg, and maintained with an infusion of propofol at an initial rate of 0.16 mg/kg/min for the first thirty minutes, after a bolus of 0.3 mg/kg; and ketamine by infusion (20–40 μg/kg/min). Blood samples (<2 mL) were collected prior to, during and after the infusion, and on assuming standing position. Anaesthesia was uneventful; with the duration of infusion 31–89 min. Blood propofol concentrations during the infusion ranged between 1.52 and 7.65 μg/mL; pseudo‐steady state concentrations 3.64–6.78 μg/mL, and concentrations on assuming standing position 0.75–1.40 μg/mL. Propofol clearance and volume of distribution were 31.4 (SD 6.1) mL/min/kg and 220.7 (132.0) mL/kg, respectively. The propofol analyser allows titration of propofol to a given concentration; and may be useful for anaesthesia in animals where kinetics are unknown; in disease states; and where intercurrent therapies affect propofol disposition.  相似文献   

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