Impact of oxygen supplementation method on the anaesthetic recovery of horses undergoing Colic Surgery

Abstract

Hypoxemia is one of the most common complications in the peri anaesthesia period, which results in evident consequences in recovery. This study aims to assess the effects of intranasal or endotracheal O2 supplementation (15 L/min) during anaesthetic recovery of horses undergoing colic surgery. Twenty-four animals will be given 10 - 15 µg/kg detomidine, and afterwards, given a combination of 2 mg/kg ketamine and 0.1 mg/kg diazepam and maintained under general anaesthesia with isoflurane and controlled ventilation to adjust the expired carbon dioxide concentration between 35 - 45 mmHg. Changes in the anaesthetic protocol and perianaesthetic continuous infusions may occur if needed. At recovery time, the animals will be randomly distributed into one of three experimental groups (n = 8): animals without oxygen supplementation (Control), with nasal oxygen supplementation (O2-Nasal) or with tracheal oxygen supplementation (O2-Tracheal). Arterial blood samples will be taken right away after the animal is placed in the recovery room (Rec-0), and at 30 (Rec-30) and 60 (Rec-60) minutes after the start of recovery. The potential of hydrogen (pH), partial pressure of oxygen (PaO2), partial pressure of carbon dioxide (PaCO2), arterial oxygen saturation (SaO2), base excess (BE-), bicarbonate concentration (HCO3-), electrolytes (Na+, K+ and Ca2+) glucose (Glu), hematocrit (Hct) and haemoglobin (Hb) will be determined. The quality of recovery will be assessed by a specific recovery quality score. It will be expected that at least one of the O2 supplementation methods will be effective to increase PaO2 values at adequate levels to avoid hypoxemia in the animals during recovery from inhalant anaesthesia due to colic syndrome.(AU)