The Effects of Different Combinations of Anesthetic Drug on Cardiopulmonary Functions and Recovery Behavior in Horses

Abstract

The objective of this study was to identify the effects of combined anesthetic drugs on heart rate variability (HRV), respiratory function and recovery behavior in horses. Eight healthy Thai native crossbred horses were enrolled in this study. Horses were premedicated and induction with 2 protocols, protocol 1; acepromazine (0.04mg/ kg)+ xylazine (1 mg/kg)+ ketamine (2.2 mg/kg) and protocol 2; detomidine (5 mcg/kg)+ketamine (2.2 mg/kg). Heart rate and heart rate variability of 8horses were measured 20 minutes before and after administered the anesthetic drugs. Doppler was used to obtained systolic, diastolic and mean blood pressures. After anesthetic drug administration, horses premedicated and induction with acepromazine, xylazine and ketamine had the lower HR values when compared with another protocols. The HRV low frequency (LF) and high frequency (HF) powers ratio increased in horses premedicated and intubation with detomidine and xylazine. The marked hypoventilation were observed after anesthetic drugs administration in both groups. There were only minimal differences in the quality of recovery. However, overall of recovery scores were higher in group of protocol 1. This study demonstrated that acepromazine + xylazine + ketamine preserved the cardiovascular function and safe to use for the surgical applicability in horses.

Effects of xylazine and adrenaline combinations: Preliminary clinical application for non-surgical protocols of nephrosplenic entrapment in horses

“…A decrease in LF power in both groups after adrenaline administration indicated vagal inhibition. This study showed that combined drugs in both protocols increased HR and affected parasympathetic activity as a previous study [15]. The higher decrease in HF power in Group 1 indicated a high parasympathetic activity, and horses in this group had high LF/HF ratio values compared with the other group.…”

“…The echocardiographic examination (Mindray, China) with 2 MHz transducers was done to rule out cardiac pathology and evaluate heart contractility functions. The left ventricular wall structure and function were calculated by measuring the images from a two-dimensional plane as in the previous study [15]. Cardiac parameters such as HR, stroke volume, cardiac output, fractional shortening, and left ventricle internal diameter were evaluated offline.…”

“…Non-invasive cardiac autonomic nervous control measurements were performed on six horses using a Holter electrocardiography (ECG) recording device (BTL Medical Technologies, Thailand). Five electrodes were placed on the thorax's shaved skin with elastic tape, as previously described, to provide the 100 min ECG recording for the baseline and after administered xylazine and adrenaline [15]. The HRV parameters were recorded and analyzed before drug administration (baseline), 30 min (T30), and 100 min (T100) after drug administration with an analyzing program (BTL Medical Technologies).…”

“…HRV analysis provides diagnostic and prognostic information to manage the horse with severe gastrointestinal disease [14]. Many studies used various anesthetic agents, but no studies have been performed to analyze the cardiac autonomic activity using HRV in response to desire the agents with minimal cardiovascular effects in horses [15].…”