Influence of the end inspiratory pause on ventilatory efficiency and respiratory mechanics in patients undergoing robotic surgery under a tailored open lung approach: a prospective-paired study.

Abstract

Introduction: The effect of modifying the end inspiratory pause (EIP) on the variations in the physiological dead space (VDphys) in patients undergoing robotic surgery ventilated under a tailored open lung approach has not been addressed before.

Material and methods: This prospective-paired study was carried out in a tertiary hospital. Following an alveolar recruitment manoeuvre (ARM) and the application of a tailored open-lung positive end-expiratory pressure (PEEPOL), participants consecutively received three EIP levels (30%, 40%, and 10%). The sequence was repeated after pneumoperitoneum and the Trendelenburg position and following a second ARM for patients with suspected lung collapse based on an Air test.

Results: Eighteen adult subjects were included. The use of an EIP of 10% was asso-ciated with a higher VDphys, both before pneumoperitoneum: 210 mL (IQR 200-237) vs. 197 mL (IQR 173-217) and 196.8 (IQR 185-218) with EIP 30% and 40%, respectively (P < 0.001 and P = 0.006) and after pneumoperitoneum: 212 mL (IQR 198-228) vs. 202 mL (IQR 181-213), P = 0.001. The application of ARMs and PEEPOL led to a significant reduction in driving pressure [5 cmH₂O (IQR 5-6) vs. 7 cmH₂O (IQR 6-10), P < 0.001], despite concurrent increases in PEEP [12 cmH₂O (IQR 10-13) vs. 5 cmH₂O, P < 0.001] and plateau pressure [17 cmH₂O (IQR 16-19) vs. 12 cmH₂O (IQR 12-15)].

Conclusions: The use of an EIP of 30-40% compared to 10% in patients undergoing robotic surgery optimises lung mechanics and minimises ventilation inefficiencies both before and during the establishment of pneumoperitoneum and Trendelenburg positioning.