Assessment of Dilute Epinephrine and Mechanical Pressure for Prevention of Feline Postoperative Scrotal Hematoma: A Randomized Controlled Trial.

To determine whether two immediately postoperative preventive procedures, dilute epinephrine (1:400,000) as a scrotal wash or application of controlled mechanical pressure to the scrotum, reduce the risk or severity of scrotal hematoma following routine castration. Male cats with two descended testicles presenting to Midwestern University's Trap Neuter Return program were eligible for inclusion. Cats were assigned via block randomization to control, dilute epinephrine wash, or controlled mechanical pressure groups. For the epinephrine group, 0.2 ml (0.008 mg) of epinephrine diluted with sterile saline was instilled inside the scrotum. In the case of mechanical pressure, a broad-based clip generating less than 0.5 kg of pressure was applied for 10 minutes. Cats were evaluated for scrotal hematoma and the need for treatment by a veterinarian blinded to treatment group. Multivariable logistic regression was used to determine if the incidence of scrotal hematoma or scrotal hematoma requiring treatment was different between groups while controlling for other variables. There were 276 cats with a median age of 30 months (IQR 12,48) and a mean weight of 3.5 kg (SD 1.2). Scrotal hematomas were noted in 15 of the 92 (16%) control cats, as compared with 12 of the 92 (13%) epinephrine and nine of the 92 (10%) pressure cats. Treatment was required for 10 (67%) control, six (50%) epinephrine, and three (33%) pressure hematomas. Regression demonstrated a decreased risk of scrotal hematoma requiring treatment for cats in the pressure group (OR = 0.2, P = .044) controlling for weight (OR = 2.2, P = .006) and surgical duration (OR = 1.1, P = .026). Weight was the only significant variable for the presence of scrotal hematoma (OR = 2.2, P < .0001). Controlled mechanical pressure applied immediately after routine castration can help decrease the proportion of scrotal hematomas that require treatment.

Comparison of the effect of isopropyl alcohol and chlorhexidine solution rinses on body temperature of female cats undergoing sterilization surgery.

OBJECTIVES: Isopropyl alcohol 70% as a rinse agent for chlorhexidine scrub has been shown to decrease body temperature more quickly than chlorhexidine solution in mice prepared aseptically prior to surgery. For this reason, some high-quality, high-volume (HQHV) surgical sterilization clinics use chlorhexidine solution rather than alcohol. We sought to determine if temperature upon entry to recovery, heat loss per kg and rate of temperature decline during surgery were different between cats rinsed with chlorhexidine solution vs 70% isopropyl alcohol following surgical scrub, and if there were significant predictors of recovery temperature. METHODS: Female cats admitted for surgery to trap-neuter-return (TNR) clinics at a veterinary college were assigned chlorhexidine solution or alcohol rinse agents via block randomization. Veterinary students and veterinarians performed spay surgeries using HQHV techniques. In recovery, heat support and reversal agents were available for cats with a low body temperature or that were slow to recover. Baseline values, outcome variables and duration of each stage (preparation, surgery, recovery) were assessed using Wilcoxon rank-sum and t-tests. Recovery temperature was evaluated using random effects multiple linear regression. RESULTS: The recovery temperature, heat loss per kg, heat loss per min, need for reversal and need for heat support in recovery were not significantly different between rinse groups. Weight <2.3 kg, body condition score <4, duration of surgery and postinduction temperature were predictors of recovery temperature. The rate of heat loss in the first 30 mins of surgery was slightly lower for cats in the alcohol rinse group and the recovery duration was shorter for cats weighing less <2.3 kg in the alcohol rinse group. CONCLUSIONS AND RELEVANCE: There were no clinically meaningful differences in body temperature between chlorhexidine and alcohol rinses. Both chlorhexidine solution and isopropyl alcohol 70% are appropriate rinse agents for aseptic preparation of feline spay surgeries.