Decreased intra-anesthetic cardiovascular complications and stable cardiac troponin I in 12 dogs undergoing repeated anesthesia for radiation therapy.

Abstract

OBJECTIVE: To describe cardiovascular intra-anesthetic complications and ultrasensitive serum cardiac troponin I (cTnI) concentrations in dogs anesthetized repeatedly for radiation therapy (RT). ANIMALS: 12 client-owned dogs anesthetized once daily (Monday through Friday) for 10 to 20 sessions, totaling 218 general anesthesia (GA) episodes. CLINICAL PRESENTATION: American Society of Anesthesiologists III sevoflurane-anesthetized dogs (median age, 10 years [range, 2 to 11]; body weight, 27.5 kg [range, 6.0 to 42.3]) undergoing RT. RESULTS: Comparing the first 5 to the last 5 GA episodes, the incidence of bradycardia (heart rate [HR] < 60 beats/min) decreased from 58.3% to 43.8%, hypotension (mean arterial pressure [MAP] < 60 mm Hg) from 28.3% to 16.3%, and hypertension (MAP > 120 mm Hg) from 20.0% to 9.4%. Tachycardia (HR > 160 beats/min [10%]) and ventricular arrhythmias (2.3%) remained infrequent. Fluid bolus administration increased from 5.0% to 20.8%; anticholinergics and inotropes decreased from 35.0% to 15.0%. Median (range) cTnI concentrations were (ng/mL) 0.073 (0.007 to 0.685) at baseline and 0.083 (0.006 to 0.685), 0.073 (0.018 to 0.286), 0.062 (0.010 to 0.265), and 0.033 (0.026 to 0.121) after 5, 10, 15, and 20 GA episodes, respectively. Two dogs had transient elevations after 5 GA episodes (0.132 and 0.500 ng/mL), which normalized; 3 had elevated baseline cTnI (0.135 to 0.685 ng/mL), which decreased during RT; 1 had cardiac disease. CLINICAL RELEVANCE: With cardiovascular monitoring and timely support, intra-anesthetic complication decreased, and cTnI remained stable or declined with repeated anesthetics. These findings support owner-informed decision-making regarding repeated GA for RT in dogs.