The reversal of the cardiovascular effects of the α2-adrenoceptor agonist detomidine by the α2-antagonist atipamezole was studied. Nine horses were given detomidine 20 μg/kg iv. On a separate occasion they were given atipamezole 100 μg/kg iv 15 mins after the detomidine injection. Blood gas tensions were measured and clinical signs of sedation were also observed.
The analgesic activity of fentanyl was measured in sheep using both thermal and mechanical test systems. Fentanyl at a dose rate of 5 μg/kg given intravenously (iv) produced significant analgesia to thermal pain for some 30 mins but no detectable mechanical antinociceptive activity. However, at a dose rate of 10 μg/kg the drug produced both thermal (for 60 mins) and mechanical (40 mins) antinociceptive effects.
A commercial human pulse oximeter was used in several species to measure heart rate and arterial oxygen saturation (SaO2), and the results compared with those from an ECG and bench oximeter. The heart rates were always the same, but differences in the SaO2 ranged between 4.2 per cent to 10.3 per cent. Correlation coefficients between the two SaO2 measurement techniques ranged from 0.81 to 0.94, depending on the species investigated.
The analgesic actions of buprenorphine, butorphanol, nalbuphine and pentazocine were assessed in the rabbit by analgesiometry using a thermal stimulus. All four compounds produced effective analgesia without causing serious respiratory depression. Increased dose rates of buprenorphine, butorphanol and nalbuphine produced only a minor increase in the maximum degree of analgesia attained. At the highest dose rates of nalbuphine and butorphanol which were assessed there appeared to be a reduction in the degree of analgesia and its duration of action whereas increased dose rates of buprenorphine produced progressively longer periods of analgesia (0.0075mg/kg - 150min; 0.03mg/kg -660min; 0.3mg/kg - >780 min).
A device capable of testing the nociceptive threshold to mechanical stimuli has been developed for use in horses. It was operated by compressed gas and was designed so that the part attached to the horse was semi disposable. The stimulus was applied via a 2mm diameter blunt ended pin and had a number of safety features incorporated in the design to ensure that the maximum force applied was 27 newtons. The device has been used to assess the response to detomidine in a group of thoroughbreds and has proved reliable and robust in use.
Value-added data have become an increasingly common evaluation tool for schools and teachers. Many school districts have begun to adopt these methods and have released results publicly. In this paper, we use the unique public release of value-added data in Los Angeles to identify how this measure of school quality is capitalized into housing prices. Via difference-in-differences, we find no evidence of a response to either school or teacher value-added rank, even though school-zone boundary fixed-effects estimates indicate that test score levels are capitalized into home prices. Given ample evidence that this information was new to residents, widely dispersed, and easily available, our results suggest that people did not significantly value it on the margin. This has implications for the effectiveness of providing value-added information as a tool to help parents choose schools.
Medetomidine (25 μg/kg) and ketamine (1mg/kg) were administered intramuscularly to anaesthetise 13 sheep for experimental oral surgery. Anaesthesia was characterised by good muscle relaxation and tachypnoea. Heart rates were not significantly different from those recorded before administration of the anaesthetic agents. Spontaneous recovery from anaesthesia was allowed in five sheep. In eight sheep atipamezole, at a total dose of 125 μg/kg, divided and administered both intravenously and intramuscularly, hastened return to full awareness.
The cephalic venous pressure and triceps compartmental pressure were measured in the right forelimb of anaesthetised, normotensive ponies with the limb in various positions. Compartmental pressure was only significantly higher than the control position when the leg was pushed hard forward. Venous pressure was significantly higher than the control position in three limb positions.
The effect of combinations of nalbuphine (0.3 mg/kg) with either detomidine (10 μg/kg) or acepromazine (50 μg/kg) was investigated in ponies. Nalbuphine enhanced the degree of sedation produced by both sedatives; sedation with detomidine and nalbuphine was profound. Cardiovascular and respiratory effects were mild and could usually be attributed to the effect of the sedative itself. Side effects were minimal and gave no cause for concern. It was concluded that nalbuphine, in combination with acepromazine or detomidine, is a safe and effective sedative for use in ponies.
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.
Anaesthetic records of horses with colic anaesthetised between June 1987 and May 1989 were reviewed. pH and blood gas analyses were performed during 157 operations from which the horses were allowed to recover. A PaO2 of 8.0 kPa or less was measured during anaesthesia in seven of these horses. The horses were of different breeds, ages and sexes. Anaesthesia was induced with xylazine, guaifenesin and ketamine in four horses and with xylazine, guaifenesin and thiobarbiturate in three horses. Anaesthesia was maintained with inhalation anaesthetic agent and oxygen: isoflurane in five horses, halothane in one horse, and initially halothane but later isoflurane in one horse. Systolic arterial pressures during anaesthesia ranged from 80 to 150 mmHg, diastolic arterial pressures were between 60 and 128 mmHg, and heart rates were between 28 and 44 beats /min. Controlled ventilation was initiated at the start of anaesthesia. PaCO2 exceeded 6.7 kPa in three horses but was subsequently decreased by adjustment of the ventilator. PaO2 of 8.0 kPa or less was measured during early anaesthesia, with one exception, and persisted for the duration of anaesthesia. The horses' inspired air was supplemented with oxygen during recovery from anaesthesia, at which time measurement of blood gases in three horses revealed no increase in PaO2. Recovery from anaesthesia was uneventful. The surgical problems involved primarily the large intestine in five horses and the small intestine in two horses. Six horses were discharged from the hospital alive; one horse was reanaesthetised later the same day and destroyed without regaining consciousness. We concluded that none of the objective values recorded during the pre-anaesthetic evaluation could have been used to predict the complication of intraoperative hypoxaemia. We observed that once hypoxaemia developed it persisted for the duration of anaesthesia and even into the recovery period when the horses were in lateral recumbency and regaining consciousness. We assume that the altered metabolism from anaesthetic agents and hypothermia combined with adequate peripheral perfusion contributed to the lack of adverse consequences in six of the horses. The contribution of hypoxaemia to the deteriorating condition of the seventh horse is speculative.
Over 150 veterinary surgeons from 53 small animal practices collaborated in a prospective survey of anaesthetic accidents and emergencies by recording all anaesthetics administered and detailing the problems they encountered. From these records it is estimated that 1 in 679 of the healthy dogs and cats died primarily as a result of anaesthesia; many of these deaths apparently occurred at a time when the animal was not under close observation. Anaesthetics involving the use of xylazine seemed to result in an exceptionally high mortality rate. Complications following endotracheal intubation appeared to be associated with several deaths in cats. The death rate in cats and dogs with pathological but not immediately life-threatening conditions was estimated to be 1 in 31. There was no evidence to suggest that some breeds (with the possible exception of the Pekingese) were more likely than others to die under anaesthesia.
Equine field practice commonly requires short- to medium-term anesthesia being induced in horses for either minor surgical or diagnostic procedures or for urgent medical care in emergency situations. Performing a general anesthetic in the field further increases the risk associated with equine anesthesia which already is high when compared with small animal or human anesthesia, even under best of hospital conditions. For this reason, cases for field anesthesia should be carefully selected and appropriate anesthesia protocols chosen by taking into account the peculiar setting of the location, the physical condition of the patient, and the specific circumstances of the surgical, diagnostic, or other procedures planned. This review provides an overview of the anesthetic techniques suitable for field anesthesia. First, the approach to the equine patient under field as compared with hospital conditions is addressed, followed by a detailed discussion of common field anesthetic protocols reported for use in adult horses and in foals. Finally, anesthetic protocols suitable for horses suffering injuries during or immediately after maximum exercise are addressed.
Micro agglutination testing was used to detect specific antibodies against five pathogenic Leptospiraserovars (icterohaemorrhagiae, pomona, canicola, wolfii and ballum) in 793 alpaca and 195 vicuña serum samples collected in the Huancavelica and Ayacucho Departments of Peru. The study revealed that 89.6% of the alpacas and 77.4% of the vicuñas were positive to one or more serovars. In alpacas, the titers varied from 1:100 to 1:1600 for reactions to icterohaemorrhagiae (43.4%) and pomona (37.8%), whereas among vicuñas titers varied from 1:100 to 1:400 for reactions to the same serovarsicterohaemorrhagiae (69.2%) and pomona (8.2%). The alpacas also had antibodies to canicola (7.8%) and wolfii (0.6%). These results show that these animals had previous exposure to 4 of the 5 serovars tested, and the elevated titers to icterohaemorrhagiae and pomona in alpacas suggest a recent infection event.
To devise a method for assessing evoked muscle strength on nerve stimulation [mechanomyography (MMG)] in the anaesthetized minipig.Prospective observational.Sixty male Göttingen minipigs weighing 10.5–26.0 kg.After cadaveric studies, a limb fixation device was constructed which allowed the twitch responses of the pelvic limb digital extensor muscles to be measured by force-displacement transduction in response to supramaximal train-of-four (TOF) stimulation of the common peroneal nerve. The device was tested in 60 minipigs weighing 10.5–26.0 kg positioned in dorsal recumbency.The technique recorded the MMG of the common peroneal–pelvic limb digital extensor nerve-muscle unit for up to 12 hours during which twitch height remained constant in 18 animals in which single twitch duration was <300–500 ms. In 42, in which twitch duration was >300–500 ms, 2 Hz nerve stimulation caused progressive baseline elevation (reverse fade) necessitating a modified signal capture method for TOF ratio (TOFR) computation. However, T1 was unaffected. The mean (range) of the TOFR in pigs with reverse fade was 1.2 (1.1–1.3).The technique allowed MMG recording in unparalysed pigs in response to TOF nerve stimulation and revealed a hitherto unreported complication of MMG monitoring using TOF in animals: reverse fade. This complicated TOFR calculation.
