Agreement between invasive and oscillometric arterial blood pressure measurement using a high-definition oscillometric device in normotensive New Zealand White rabbits using two different anaesthetic protocols

Abstract

OBJECTIVE: To use American College of Veterinary Internal Medicine (ACVIM) criteria to evaluate a high-definition oscillometric (HDO) blood pressure monitoring device versus invasive blood pressure (IBP) measurement in normotensive rabbits anaesthetized with two different anaesthetic protocols. STUDY DESIGN: Prospective experimental study. ANIMALS: A group of 20 healthy adult New Zealand White rabbits weighing 4.36 ± 0.37 kg (mean ± standard deviation). MATERIALS AND METHODS: Rabbits were premedicated with butorphanol 0.5 mg kg-1 and midazolam 0.5 mg kg-1 subcutaneously (SC, group BMA) or ketamine 25 mg kg-1 and medetomidine 0.4 mg kg-1 SC (group KM). Anaesthesia was induced with alfaxalone administered intravenously (group BMA) or isoflurane by face mask (group KM) and maintained with isoflurane in oxygen. IBP was measured from the central auricular artery. The cuff for the HDO monitor was placed distal to the left elbow and distal to the left tarsus. Agreement between invasive and HDO measurements was evaluated using Bland-Altman method. RESULTS: In group KM there was better agreement between the HDO device and IBP when the cuff was placed on the thoracic limb, with 100% and 91% of the readings for mean (MAP) and diastolic arterial pressure (DAP), respectively, within 10 mmHg of the IBP measurements. The agreement, although worse, also met the ACVIM criteria for systolic arterial pressure (SAP; 53% of the readings within 10 mmHg). In group BMA, the device met the criteria with the cuff on the thoracic limb only, and only for MAP and DAP (73% and 75% of the measurements within 10 mmHg of the IBP, respectively) but not for SAP (12%). CONCLUSION AND CLINICAL RELEVANCE: The HDO device met most of the ACVIM criteria for noninvasive blood pressure measurement in anaesthetized rabbits, specifically when the cuff was placed distal to the elbow and the anaesthetic protocol included ketamine and medetomidine.