Vet Anaesth Analg [journal]
- Pharmacokinetics and pharmacodynamics of intravenous romifidine and propranolol administered alone or in combination for equine sedation. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 18.
Propranolol has been suggested for anxiolysis in horses, but its sedation efficacy and side effects, both when administered alone and in combination with α2 -adrenoceptor agonists, remain undetermined. This study aimed to document the pharmacokinetics and pharmacodynamics of propranolol, romifidine and their combination.Randomized, crossover study.Six adult horses weighing 561 ± 48 kg.Propranolol (1 mg kg(-1) ; treatment P), romifidine (0.1 mg kg(-1) ; treatment R) or their combination (treatment PR) were administered intravenously with a minimum of 1 week between treatments. Alertness, behavioral responsiveness (visual and tactile) and physiologic variables were measured before and up to 960 minutes after drug administration. Blood was collected for blood gas and acid-base analyses and measurement of plasma drug concentrations. Data were analyzed using repeated-measures analysis of variance or Friedman with Holm-Sidak and Wilcoxon rank-sum tests (p < 0.05).Systemic clearance significantly decreased and the area under the concentration-time curve significantly increased for both drugs in PR compared with P and R. Both PR and R decreased behavioral responsiveness and resulted in sedation for up to 240 and 480 minutes, respectively. Sedation was deeper in PR for the first 16 minutes. Heart rate significantly decreased in all treatments for at least 60 minutes, and PR significantly increased the incidence of severe bradycardia (<20 beats minute(-1) ).Although not associated with reduced behavioral responsiveness or sedation alone, propranolol augmented romifidine sedation, probably through alterations in romifidine pharmacokinetics, in horses administered PR. The occurrence of severe bradycardia warrants caution in the co-administration of these drugs at the doses studied.
- Gastro-oesophageal reflux in large-sized, deep-chested versus small-sized, barrel-chested dogs undergoing spinal surgery in sternal recumbency. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 7.
The aim of this study was to investigate whether an increased frequency of gastro-oesophageal reflux (GOR) is more common in large-sized, deep-chested dogs undergoing spinal surgery in sternal recumbency than in small-sized, barrel-chested dogs.Prospective, cohort study.Nineteen small-sized, barrel-chested dogs (group B) and 26 large-sized, deep-chested dogs (group D).All animals were premedicated with intramuscular (IM) acepromazine (0.05 mg kg(-1) ) and pethidine (3 mg kg(-1) ) IM. Anaesthesia was induced with intravenous sodium thiopental and maintained with halothane in oxygen. Lower oesophageal pH was monitored continuously after induction of anaesthesia. Gastro-oesophageal reflux was considered to have occurred whenever pH values > 7.5 or < 4 were recorded. If GOR was detected during anaesthesia, measures were taken to avoid aspiration of gastric contents into the lungs and to prevent the development of oesophagitis/oesophageal stricture.The frequency of GOR during anaesthesia was significantly higher in group D (6/26 dogs; 23.07%) than in group B (0/19 dogs; 0%) (p = 0.032). Signs indicative of aspiration pneumonia, oesophagitis or oesophageal stricture were not reported in any of the GOR cases.In large-sized, deep-chested dogs undergoing spinal surgery in sternal recumbency, it would seem prudent to consider measures aimed at preventing GOR and its potentially devastating consequences (oesophagitis/oesophageal stricture, aspiration pneumonia).
- Evaluation of a new handheld point-of-care blood gas analyser using 100 equine blood samples. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 7.
To determine whether the Enterprise point-of-care blood analysis system (EPOC) produces results in agreement with two other blood gas analysers in regular clinical use (i-STAT and Radiometer ABL77) and to investigate the precision of the new machine when used with equine whole blood.Prospective, randomized, non-blinded, comparative laboratory analyser study.Horses admitted to a university teaching hospital requiring arterial or venous blood gas analysis as part of their routine clinical management.One hundred equine blood samples were run immediately, consecutively and in randomized order on three blood gas analysers. Results of variables common to all three analysers were tested for agreement and compared with guidelines used in human medicine. These require 80% of results from the test analyser to fall within a defined range or percentage of results from the comparator devices to achieve acceptability. Additionally, 21 samples were run twice in quick succession on the EPOC analyser to investigate precision.Agreement targets were not met for haematocrit, haemoglobin and base excess for either i-STAT or ABL77 analysers. EPOC precision targets were not met for partial pressure of carbon dioxide, ionized calcium, haematocrit and haemoglobin. Overall comparative performance of the EPOC was good to excellent for pH, oxygen tension, potassium, bicarbonate and oxygen saturation of haemoglobin, but marginal to poor for other parameters.The EPOC may be useful in performing analysis of equine whole blood, but trend analysis of carbon dioxide tension, ionized calcium, haematocrit and haemoglobin should be interpreted with caution. The EPOC should not be used interchangeably with other blood gas analysers.
- Cardiovascular effects of dexmedetomidine, with or without MK-467, following intravenous administration in cats. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 5.
To characterize the cardiovascular effects of dexmedetomidine, with or without MK-467, following intravenous (IV) administration in cats.Prospective Latin square experimental study.Six healthy adult purpose-bred cats.Cats were anesthetized with desflurane in oxygen for instrumentation with a carotid artery catheter and a thermodilution catheter in the pulmonary artery. One hour after discontinuation of desflurane, cats were administered dexmedetomidine (25 μg kg(-1) ), MK-467 (600 μg kg(-1) ), or dexmedetomidine (25 μg kg(-1) ) and MK-467 (600 μg kg(-1) ). All treatments were administered IV as a bolus. Cardiovascular variables were measured prior to drug administration and for 8 hours thereafter. Only data from the dexmedetomidine and dexmedetomidine-MK-467 treatments were analyzed.Dexmedetomidine produced significant decreases in heart rate, cardiac index and right ventricular stroke work index, and significant increases in arterial blood pressure, central venous pressure, pulmonary artery pressure and systemic vascular resistance index. Dexmedetomidine combined with MK-467 resulted in significant but transient decrease in blood pressure and right ventricular stroke work index.Following IV co-administration, MK-467 effectively attenuated dexmedetomidine-induced cardiovascular effects in cats. The drug combination resulted in transient reduction in arterial blood pressure, without causing hypotension.
- Professor Emeritus E. Wynn Jones MRCVS, FRCVS, PhD. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 4.
- Clinical evaluation of intranasal medetomidine-ketamine and medetomidine-S(+)-ketamine for induction of anaesthesia in rabbits in two centres with two different administration techniques. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 4.
The aim was to compare efficacy and side effects of induction with medetomidine-ketamine or medetomidine-S(+)-ketamine by intranasal (IN) instillation in rabbits and to evaluate both protocols during subsequent isoflurane anaesthesia.Prospective, blinded, randomized experimental study in two centres.Eighty-three healthy New Zealand White rabbits undergoing tibial or ulnar osteotomy.Medetomidine (0.2 mg kg(-1) ) with 10 mg kg(-1) ketamine (MK) or 5 mg kg(-1) S(+)-ketamine (MS) was administered IN to each rabbit in a randomized fashion. In Centre 1 (n = 42) rabbits were held in sternal recumbency, and in Centre 2 (n = 41) in dorsal recumbency, during drug instillation. Adverse reactions were recorded. If a rabbit swallowed during endotracheal intubation, half of the initial IN dose was repeated and intubation was re-attempted after 5 minutes. Anaesthesia was maintained with isoflurane. Heart rate, blood pressure, end-tidal carbon dioxide concentration and blood gases were recorded. Data were analysed using Student's t-test, Mann-Whitney test and Fisher's exact test.In all, 39 animals were assigned to the MK group and 44 to the MS group. Two rabbits in the MS group held in dorsal recumbency died after instillation of the drug. Eight (MK) and 11 rabbits (MS) were insufficiently anaesthetized and received a second IN dose. One rabbit in MK and three in MS required an isoflurane mask induction after the second IN dose. There were no significant differences between treatments for induction, intraoperative data, blood gas values and recovery data.This study indicated that medetomidine-ketamine and medetomidine-S(+)-ketamine were effective shortly after IN delivery, but in dorsal recumbency IN administration of S(+)-ketamine led to two fatalities. Nasal haemorrhage was noted in both cases; however, the factors leading to death have not been fully elucidated.
- Ultrasound-guided vessel catheterization in adult Yorkshire cross-bred pigs. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jul 4.
To describe an ultrasound-guided approach for venous and arterial vascular access and catheterization in anesthetized adult Yorkshire cross-bred pigs.Prospective experimental study.Ten adult female Yorkshire cross-bred pigs, weighing 78.4 ± 5.6 kg (mean ± standard deviation).Using ultrasound guidance and the Seldinger technique, a 7 Fr, 20 cm triple-lumen central venous catheter was placed in the external jugular vein and an 18 gauge, 16 cm catheter was placed in the femoral artery. The success rate of catheterization and the incidence of catheter patency over 24 hours of general anesthesia were recorded.Catheterization of the external jugular vein was successful in 10 out of 10 pigs and catheterization of the femoral artery was successful in eight out of 10 pigs. A surgical dissection technique on the femoral artery was performed in two pigs. Venous and arterial catheter patency was maintained in all pigs over the 24 hour study period.Ultrasound guidance resulted in success rates of 100% for catheterization of the external jugular vein and 80% for catheterization of the femoral artery in anesthetized adult Yorkshire cross-bred pigs. This technique is a noninvasive, easily performed alternative to surgical exposure of the vessels in large pigs undergoing surgical instrumentation for biomedical device testing.
- Behavioral and cardiopulmonary effects of dexmedetomidine-midazolam and dexmedetomidine-midazolam-butorphanol in the silver fox (Vulpes vulpes). [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jun 28.
To evaluate the behavior and some cardiopulmonary variables of dexmedetomidine-midazolam or dexmedetomidine-midazolam-butorphanol in the silver fox (Vulpes vulpes).Blinded, randomized design.Sixteen adult silver foxes, aged 7-9 months, weighing 6.0-9.2 kg.Animals were randomly assigned to dexmedetomidine (50 μg kg(-1) ) and midazolam (0.45 mg kg(-1) ) (group DM) or to dexmedetomidine (30 μg kg(-1) ), midazolam (0.45 mg kg(-1) ) and butorphanol (0.25 mg kg(-1) ) (group DMB), administered intramuscularly. Pulse rate (PR), respiratory rate (fR ), noninvasive arterial pressures, oxygen saturation (SpO2 ), rectal temperature (T) and behavioral scores (posture, sedation, antinociception, jaw relaxation and auditory response) were measured at 5, 10, 20, 30, 40, 50 and 60 minutes after injection. Time from drug injection to recumbency with no response to stimuli (IT) and time from administration of atipamezole (0.2 mg kg(-1) ) to standing with coordination (RT) were recorded. The occurrences of adverse events were recorded. Data were analyzed by two-tailed unpaired t-tests and Bonferroni post hoc tests. Significant differences were accepted at p<0.05.There were no statistically significant differences between the groups for IT or RT. Arterial pressures were higher in DMB at each time point except at 5 minutes. PR was lower in DM at each time point except at 10 and 60 minutes. No significant difference was found between the groups for fR , SpO2 and T. The behavioral scores were significantly lower (lower quality immobilization) in DMB at 5, 10 and 60 minutes.IT and RT were not different between the groups. Both protocols provided immobilization for 30-40 minutes with excellent muscle relaxation and analgesia adequate for clinical examinations and some simple surgical procedures.
- Effects of dexmedetomidine combined with ropivacaine on sciatic and femoral nerve blockade in dogs. [JOURNAL ARTICLE]
- Vet Anaesth Analg 2016 Jun 28.
To evaluate motor and sensory blockade of combining dexmedetomidine with ropivacaine, administered perineurally or systemically, for femoral and sciatic nerve blocks in conscious dogs.Randomized, controlled, experimental study.Seven healthy Beagle dogs, aged 3.3 ± 0.1 years and weighing 11.0 ± 2.4 kg.Dogs were anesthetized with isoflurane on three separate occasions for unilateral femoral and sciatic nerve blocks and were administered the following treatments in random order: perineural ropivacaine 0.75% (0.1 mL kg(-1) ) on each nerve and intramuscular (IM) saline (0.2 mL kg(-1) ) (GCON ); perineural dexmedetomidine (1 μg mL(-1) ) and ropivacaine 0.75% (0.1 mL kg(-1) ) on each nerve and IM saline (0.2 mL kg(-1) ) (GDPN ); and perineural ropivacaine 0.75% (0.1 mL kg(-1) ) on each nerve and IM dexmedetomidine (1 μg mL(-1) , 0.2 mL kg(-1) ) (GDIM ). Nerve blocks were guided by ultrasound and electrical stimulation and dogs were allowed to recover from general anesthesia. Sensory blockade was evaluated by response to clamp pressure on the skin innervated by the saphenous/femoral, common fibular and tibial nerves. Motor blockade was evaluated by observing the ability to walk and proprioception. Sensory and motor blockade were evaluated until their full recovery.No significant differences in onset time to motor and sensory blockade were observed among treatments. Duration of motor blockade was not significantly different among treatments; however, duration of tibial sensory blockade was longer in the GDPN than in the GDIM treatment.Although a longer duration of sensory blockade was observed with perineural dexmedetomidine, a significant increase compared with the control group was not established. Other concentrations should be investigated to verify if dexmedetomidine is a useful adjuvant to local anesthetics in peripheral nerve blocks in dogs.
- Symbols in Veterinary Anaesthesia and Analgesia: a Tower of Babel? [EDITORIAL]
- Vet Anaesth Analg 2016 Jun 23.