Chelonian Sedation and Anesthesia.

Anesthetic management of chelonians represents a unique challenge; the order Chelonia includes numerous species that display diverse anatomic features, habitats, body sizes, temperaments, and metabolic rates. Owing to their peculiar characteristics, safe and effective sedation and anesthesia may be more complicated than in other animals. For example, gas inductions are not indicated, and intravenous catheterization requires practice. The pharmacology of anesthetic drugs is severely impacted by body/environmental temperature, site of administration, and organ function. This review will summarize the current knowledge in terms of anatomy, physiology, and drug metabolism in chelonians, before discussing practical aspects of anesthesia.

A Suspected Anaphylactoid Reaction to Propofol in a Dog.

Anaphylactoid reactions to anaesthetic drugs are rarely reported in veterinary medicine. The aim of this report is to describe a suspected anaphylactic reaction to propofol in a 14 years old Shih-Tzu undergoing general anaesthesia for ovariohysterectomy due to a pyometra. The anesthetic protocol included intramuscular methadone for premedication and fentanyl, midazolam and propofol intravenously for co-induction. At endotracheal intubation, the glottis appeared subjectively thickened. Shortly after induction and endotracheal intubation, desaturation, hypercapnia and bradycardia occurred; chest compliance at manual ventilation was poor and peripheral pulses were weak. The procedure was aborted. Pulmonary oedema was diagnosed at thoracic radiography and a cardiogenic origin was excluded via echocardiography. Fluid therapy and glucocorticoids were administered, and mechanical ventilation was started in the intensive care unit. Two hours later, the owner opted for euthanasia due to financial constraints.

Corneal abrasion and microbial contamination in horses following general anaesthesia for non-ocular surgery.

OBJECTIVE: To evaluate the incidence of corneal abrasions/ulceration and microbial contamination in horses undergoing general anaesthesia. STUDY DESIGN: Prospective, observational, clinical study. ANIMALS: A total of 40 client-owned healthy horses scheduled for elective non-ophthalmic procedures. METHODS: Conjunctival sac swabs were taken, fluorescein dye applied and digital images recorded from both eyes of the horses after preanaesthetic medication and 24 hours after recovery from general anaesthesia. A paraffin-based bland ophthalmic ointment was applied on the ocular surface intraoperatively following collection of a sample into a sterile container. All samples underwent aerobic, anaerobic and fungal culture. Subject demographics, chronology of ophthalmic ointment use, anaesthesia duration, recumbency after induction, during surgery and recovery, fluorescein uptake and culture results were recorded. Descriptive statistics were performed. RESULTS: Complete data were collected from 34 horses; six (17.6%) developed mild unilateral generalized fluorescein uptake consistent with corneal abrasions. Recumbency on the operating table was the only risk factor significantly associated with corneal abrasions. A total of 11 bacterial species were identified; Staphylococcus spp. (15 eyes) and Micrococcus spp. (eight eyes) were the most frequently isolated bacteria. Two fungal species were isolated postoperatively (Aspergillus spp., Saccharomyces spp.) in two eyes. Ointment contamination was recorded in two cases (5%) but cross-contamination was not recognized. CONCLUSIONSAND CLINICAL RELEVANCE: Incidence of corneal abrasion/ulceration in horses undergoing general anaesthesia and contamination rate of ophthalmic solutions are similar to those previously reported in dogs.

Adverse reactions following administration of contrast media for diagnostic imaging in anaesthetized dogs and cats: a retrospective study.

OBJECTIVE: To evaluate incidences of adverse reaction after the administration of contrast media. STUDY DESIGN: Retrospective observational study. ANIMALS: Animals included 356 dogs and 58 cats receiving non-ionic iodinated contrast agents, and 425 dogs and 49 cats receiving gadolinium-based contrast agents. METHODS: Anaesthesia records of dogs and cats receiving intravenous (IV) gadobutrol for magnetic resonance imaging (MRI) or IV iohexol for computed tomography (CT) were reviewed. Changes in pulse rate, respiratory rate and mean arterial pressure at 5 minutes after administration of the contrast medium were evaluated. Changes of 10-20% were considered mild, those of >20% moderate, and reactions that required immediate treatment were considered severe. Associations of sex, age and weight with contrast reaction were investigated using logistic regression. Differences in the incidences of reactions to CT and MRI contrast media were examined with chi-squared tests. A p-value of <0.05 was considered to indicate statistical significance. RESULTS: Of cats receiving iohexol, eight (13.8%) had mild and 10 (17.2%) had moderate reactions. Of cats receiving gadobutrol, six (12.2%) had mild and six (12.2%) had moderate reactions. No cats had severe reactions and the risk for reaction was not associated with type of medium, age, weight or sex (p > 0.2). Of dogs receiving iohexol, 64 (18.0%) had mild, 65 (18.3%) had moderate and three (0.8%) had severe reactions. Of dogs receiving gadobutrol, 42 (9.9%) had mild, 87 (20.5%) had moderate and one (0.2%) had a severe reaction. When dogs receiving iohexol were compared with those receiving gadobutrol, the odds ratio of a moderate reaction was 2.0 (95% confidence interval 1.34-3.10; p = 0.001). These estimates did not change substantially after adjustment for age, weight and sex. CONCLUSIONS AND CLINICAL RELEVANCE: Severe reactions to iohexol and gadobutrol are rare in dogs and cats; moderate reactions are more likely with iohexol than with gadobutrol.