Horses Auto-Recruit Their Lungs by Inspiratory Breath Holding Following Recovery from General Anaesthesia

Mosing, Martina, Waldmann, Andreas D, MacFarlane, Paul, Iff, Samuel, Auer, Ulrike, Bohm, Stephan H, Bettschart-Wolfensberger, Regula and Bardell, David ORCID: 0000-0003-1573-1706 (2016) Horses Auto-Recruit Their Lungs by Inspiratory Breath Holding Following Recovery from General Anaesthesia. PLOS ONE, 11 (6). e0158080-e0158080.

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Abstract

This study evaluated the breathing pattern and distribution of ventilation in horses prior to and following recovery from general anaesthesia using electrical impedance tomography (EIT). Six horses were anaesthetised for 6 hours in dorsal recumbency. Arterial blood gas and EIT measurements were performed 24 hours before (baseline) and 1, 2, 3, 4, 5 and 6 hours after horses stood following anaesthesia. At each time point 4 representative spontaneous breaths were analysed. The percentage of the total breath length during which impedance remained greater than 50% of the maximum inspiratory impedance change (breath holding), the fraction of total tidal ventilation within each of four stacked regions of interest (ROI) (distribution of ventilation) and the filling time and inflation period of seven ROI evenly distributed over the dorso-ventral height of the lungs were calculated. Mixed effects multi-linear regression and linear regression were used and significance was set at p<0.05. All horses demonstrated inspiratory breath holding until 5 hours after standing. No change from baseline was seen for the distribution of ventilation during inspiration. Filling time and inflation period were more rapid and shorter in ventral and slower and longer in most dorsal ROI compared to baseline, respectively. In a mixed effects multi-linear regression, breath holding was significantly correlated with PaCO2 in both the univariate and multivariate regression. Following recovery from anaesthesia, horses showed inspiratory breath holding during which gas redistributed from ventral into dorsal regions of the lungs. This suggests auto-recruitment of lung tissue which would have been dependent and likely atelectic during anaesthesia.

Item Type:	Article
Uncontrolled Keywords:	Lung, Animals, Horses, Carbon Dioxide, Blood Gas Analysis, Anesthesia, General, Anesthesia Recovery Period, Electric Impedance, Inhalation, Time Factors, Breath Holding
Depositing User:	Symplectic Admin
Date Deposited:	12 Mar 2019 10:07
Last Modified:	19 Jan 2023 00:57
DOI:	10.1371/journal.pone.0158080
Related URLs:	Author Publisher
URI:	https://livrepository.liverpool.ac.uk/id/eprint/3034077