Comparative evaluation of haemodynamic, haematobiochemical and ECG responses to tiletamine-zolazepam and ketamine-dexmedetomidine as induction agents in dogs undergoing soft tissue surgeries

Abstract

The selection of appropriate anaesthetic agents is critical for minimizing physiological stress during surgery. This study compared the clinico-physiological, haematobiochemical, and electrocardiographic responses to Tiletamine–Zolazepam (T–Z) and Ketamine–Dexmedetomidine (K–D) combinations in dogs undergoing soft-tissue surgeries. Forty client-owned dogs,
classified as ASA II, were randomly allocated into two groups (n= 20). All dogs received intramuscular butorphanol (0.2 mg/kg body weight) and glycopyrrolate (0.01 mg/kg) as premedication. Anaesthesia was induced with T–Z (4 mg/kg body weight) in group I and K–D (ketamine 5 mg/kg + dexmedetomidine 7 µg/kg) in group II, and maintained with isoflurane. Heart rate, respiratory rate, rectal temperature, mean arterial pressure, SpO‚ , ETCO₂, and ECG were recorded at predefined intervals. Blood samples collected at corresponding time points were analysed for haemoglobin, total leucocyte count (TLC), packed cell volume (PCV), AST, ALT, ALP, total protein, blood urea nitrogen, and creatinine. T–Z produced a mild positive chronotropic effect, whereas K–D was associated with bradycardia and more pronounced respiratory depression. Blood pressure increased transiently in group II, while group I showed a slight early decline followed by normalization. ECG alterations were mild, with occasional minor conduction disturbances in both groups. A significant post-induction decrease in Hb and PCV occurred in both groups, persisting through recovery; TLC decreased in group I but remained stable in group II. Serum biochemical values were largely unchanged, except for an increase in creatinine in group I. Intergroup differences were insignificant except for postinduction PCV values. Both protocols were well tolerated; however, T–Z offered a more stable cardiopulmonary profile, supporting its use where minimization of cardiovascular depression is desired. Continuous monitoring remains essential to ensure anaesthetic safety.