Effects of Intraoperative Ventilation Strategy on Pulmonary Functions and Postoperative Course in the Patients Undergoing Large SurgicalProcedure

Overview

During general anaesthesia there is a decrease of functional residual capacity (FRC) and changes of pulmonary gas exchange. The goal of the studywas to evaluate the influence of ventilation strategy during general anaesthesia on chosen pulmonary function parameters and postoperative coursein the patients who underwent large surgical procedure. The prospective randomized study enrolled 67 patients. The patients of control group (groupK, n=34) were ventilated during anaesthesia in VCV ventilation mode with low PEEP (3 cmH2O). In the second group of patients (group RMP, n=33)modified recruitment maneuver was performed after 15 min from the induction of anaesthesia and then patients were ventilated in VCV ventilationmode with PEEP of 6–8 cmH2O according to body size. Followed groups did not differ in the basic demographic parameters, mode of anaesthesia andintraoperative values of SaO2, EtCO2, FiO2 and N2O, halothane and isoflurane inspired concentrations. The duration of procedure was significantlylonger in RMP group (220/187.5; 320/min vs 180/140; 257/min, P=0.026). K group compared to RMP group had progressive increase of tidal volumeduring anaesthesia (562.5±141.7 vs 658.8±178.3 ml before the beginning of spontaneous breathing, P=0.018). The use of recruitment maneuver andhigher PEEP increased effective compliance in RMP group. The recruitment maneuver in 5 of 33 patients was associated with decrease of bloodpressure lower than 20% of baseline value and in 4 patients the decrease of blood pressure was bigger than 20% of baseline value. Between the groupsthere were not differences in the incidence of postoperative complications and the length of stay in hospital. The use of intraoperative ventilatory strategybased on the „open lung“ concept is associated with better lung compliance during general anaesthesia. The positive influence on the postoperativecourse of followed population was not demonstrated.

Key words:
compliance – PEEP – recruitment – anaesthesia – postoperative complications