Comparing methods for detecting gastro-oesophageal reflux in dogs
Christiaan Blignaut and others, University of Pretoria, South Africa
Gastro-oesophageal reflux (GOR) is a common complication of general anaesthesia in dogs. The appearance of gastric fluid in the oesophagus may be transient and can pass unnoticed but the erosive effects of the acid will often cause post-operative oesophagitis and significant discomfort. The authors investigated the sensitivity and specificity of two methods for detecting the presence of gastric fluid, by pH with multichannel intraluminal impedance (pH-MII) and pH-metry, both alone and in combination. They also compared their findings with direct observation of GOR by endoscopy in anaesthetised dogs. In a group of 35 dogs, reflux was detected by endoscopy in 20 cases and by pH-MII in 19 dogs, while 13 animals were detected to have reflux by pH-metry. The authors state that endoscopy is a reliable method for detecting GOR and can also subjectively estimate the volume of fluid involved. Meanwhile, pH-MII is a promising tool for use in future studies.
Veterinary Anaesthesia and Analgesia, 51, 629-640
Safety and efficacy of trazodone and gabapentin for feline sedation
Ellen Siepmann and others, Federal University of Parana, Brazil
Anxiolytic drugs such as gabapentin and trazodone are being considered as possible alternatives to injectable sedative drugs in controlling signs of stress in cats during veterinary examinations. The authors examined the sedative effects of those two agents in combination, along with their impact on haemodynamic and echocardiographic parameters in cats. The two drugs were administered to healthy cats at a dose of 50mg trazodone and/or 100mg gabapentin. Alone and in combination, trazodone significantly reduced respiratory rate and systolic blood pressure compared with baseline and placebo. However, giving the two drugs together produced higher and more consistent sedation scores than the individual agents, with only mild effects on heart rate, respiratory rate, blood pressure and isovolumetric relaxation time.
Topics in Companion Animal Medicine, 64, 100945
Accuracy of a glucose monitoring system in healthy anaesthetised dogs
Elizabeth Pollack and others, University of Wisconsin, Madison
Monitoring and controlling blood glucose levels is important when particular groups of animals are under general anaesthesia. This includes neonates and those with diabetes, sepsis or liver disease. However, physiological changes during anaesthesia can limit the usefulness of standard point-of-care glucose monitors. The authors investigated the accuracy of an implanted sensor-based interstitial glucose monitoring system (Freestyle Libra 2; Abbott) in healthy Beagles during isoflurane anaesthesia. They report that in a crossover study comparing the results using this device with those from standard tests using whole blood samples, this method did not fully meet the ISO requirements for the accuracy of human assays. However, for canine patients at risk of perioperative hyper- or hypoglycaemia, the technology may provide a convenient and less invasive method for monitoring glucose levels.
American Journal of Veterinary Research, 86
Method for estimating pulmonary dead space in ventilated Beagles
Xiaoxiao Li and others, Sichuan University, Chengdu, China
Measurements of drug concentrations in exhaled air are valuable for monitoring patients undergoing intravenous anaesthesia. However, exhaled air contains both alveolar air and dead space air. The former participates in gas exchange and provides crucial drug concentration data while the latter interferes with monitoring accuracy. The authors investigated the application of a method for estimating pulmonary dead space based on results obtained from analysers that measure propofol concentrations in exhaled air from Beagles receiving a continuous infusion of the anaesthetic drug. Their findings suggest that the physiological dead space to tidal volume ratio in exhaled air can be accurately measured using the existing time-volume and time-CO2 curves from the anaesthetic machine, allowing adjustments to the propofol dose.
Fentanyl and lidocaine in rabbits undergoing ovariohysterectomy
Taise Fuchs and others, Pontifical Catholic University of Paraná, Brazil
Although there have been significant improvements over recent years in our understanding of rabbit analgesia, there is still no consensus on the most appropriate strategies for this species. The authors investigated the safety and efficacy of an intravenous bolus and continuous rate infusions of lidocaine and fentanyl, alone and in combination. Their findings suggest that either drug, alone or in combination, can help to provide adequate analgesia in rabbits. However, due to safety concerns, lidocaine should only be used as part of a multimodal analgesia protocol. Clinicians should also be aware that when fentanyl is given even for short periods, it has significant effects on intestinal motility that the addition of lidocaine does nothing to prevent.
Journal of Exotic Pet Medicine, 52, 62-70
Effects of general anaesthesia on body temperature in dogs during neutering
Nikki Wenham and Luiz Santos, University of Adelaide, South Australia
Around 40 percent of dogs undergoing general anaesthesia may experience episodes of reduced body temperature. Perioperative hypothermia may lead to a range of complications, including prolonged recovery times, respiratory depression and cardiac arrhythmias. The authors investigated changes in body temperature in dogs during castration and spaying procedures with the aim of identifying associated factors. The study followed 110 dogs (75 female, 35 male) from an animal shelter operated on by veterinary students. The female dogs had more significant incidents of hypothermia at 30, 60 and 90 minutes after induction; however, during recovery their core temperature was higher than that of the males. These findings suggest that additional warming strategies should be employed with female patients both pre- and intraoperatively.
The Veterinary Journal, 308, 106252
Hyperkalaemia during prolonged anaesthesia in a Greyhound
Amber O’Neill, Moorong Veterinary Clinic, Wagga Wagga, New South Wales
Potassium ions are normally present in far lower concentrations in the extracellular fluid than within cells. Unusually high extracellular levels of the ion can result in a life-threatening emergency, culminating in cardiac arrest. The authors describe a case of hyperkalaemia in a Greyhound undergoing general anaesthesia for a dental procedure. The three-year-old bitch had severe halitosis but was otherwise healthy. A severe, acute bradycardia was apparent 140 minutes after induction. A venous blood analysis revealed marked hyperkalaemia with a potassium concentration of 9.5mmol/l and normal sodium and chloride levels. The patient was treated with intravenous calcium gluconate, glucose and atropine and its serum potassium levels were restored to within the normal range inside 60 minutes.
Case Reports in Veterinary Medicine
Sedation and general anaesthesia in crocodilians
Asbjørn Onsberg Kruuse and others, University of Copenhagen, Denmark
Wildlife veterinarians face particular challenges when sedating or performing general anaesthesia on members of the crocodile family. These animals are poikilothermic, are potentially aggressive and have many distinctive physiological and anatomical features, such as the ability to shunt blood from the left to the right aortic arch. The authors review the published literature on the safety and efficacy of different techniques in these species. They note that the available evidence is limited and rather unsatisfactory, but it does show that medetomidine provides stable and reversible sedation, albeit while depressing the patient’s heart rate. Alfaxalone anaesthesia was less stable outside the optimal temperature range for these animals. Intubation and inhalation anaesthesia were effective while adrenaline reduced the length of the recovery period.
