Effect of recumbency and body condition score on open-lung positive end-expiratory pressure and respiratory system compliance following a stepwise lung recruitment manoeuvre in healthy dogs during general anaesthesia

Abstract

The aim was to assess the effects of recumbency and body condition score (BCS) on open-lung positive end-expiratory pressure (OL-PEEP) and quasistatic respiratory system compliance (Crs) following stepwise lung recruitment manoeuvre (RM) in healthy dogs under general anaesthesia. Thirty-four dogs were anaesthetised and mechanically ventilated (tidal volume of 10 mL/kg) without PEEP for 1 min (baseline). A stepwise RM was then performed and the individual OL-PEEP was subsequently applied. The Crs was registered at baseline and every 10-min for 50 min after RM. Dogs were classified into either dorsal or lateral recumbency groups, and as normal (score 4–5/9) or high (≥6/9) BCS groups. The OL-PEEP was higher in lateral than in dorsal recumbency (P = .002), but differences were not observed between normal and high BCS (P = .865). The Crs was increased from baseline at all time points after RM in all groups. The Crs did not differ between dorsally and laterally recumbent dogs at any time point. However, the baseline Crs was significantly lower in dogs with a high BCS than in those with a normal BCS (P < .001); therefore, the absolute change from baseline was considered when comparing Crs after the RM and it was similar in both BCS groups. In conclusion, in anaesthetised healthy dogs the OL-PEEP following RM was lower when dogs were positioned in dorsal than in lateral recumbency. The Crs after RM remained unchanged regardless of the dogs' recumbency. A stepwise RM followed by OL-PEEP could compensate for the potential negative impact of moderately increased BCS on Crs.