Comparison of pressure and volume controlled ventilation in terms of mechanical power in upper abdominal surgery

Objective: The mechanical power created by mechanical ventilation, as a new concept, can enable to evaluate the effect of different components in the lung. It is also associated with lung damage in intensive care and anesthesia. The aim of this study is to compare the mechanical power of volume-controlled ventilation (VCV) and pressure-controlled ventilation (PCV), which are two different ventilation modes that we frequently use in anesthesia practice. Materials and methods: Following ethics committee approval, 66 patients with ASA classification 1,2 were included in the prospective randomized study. 6 patients were excluded from the study for different reasons. One patient was excluded from the study due to having a saturation value of 95% during preoperative monitoring. The patients in the 1st group were started to be ventilated in VCV mode with 6-8 ml/ibw, respiratory rate of 12, 5 PEEP (positive end expiratory pressure). After 3 measurements were taken at 10-minute intervals, mechanical ventilation mode was switched to PCV to form the same tidal volume, with a respiratory rate of 12 per minute and a PEEP of 5. After allowing 10 minutes of "washout", 3 measurements were taken at 10-minute intervals and these mechanical ventilation changes and measurements were continued throughout the case. For the patients in group 2, mechanical ventilation was started at PCV mode by adjusting the pressure value to form a tidal volume of 6-8 ml/ibw, respiratory rate of 12 and 5 PEEP. After 3 measurements were taken at 10-minute intervals, the same tidal volume, respiratory rate and PEEP values were set at VCV. After allowing 10 minutes of "washout", 3 measurements were taken at 10-minute intervals and measurements were continued throughout the case with ventilation changes. Results: The study was completed with 59 patients. Mechanical power values calculated in VCV mode were found to be significantly lower than PCV mode (8.48+2.59 vs 11.99+3.5 J/dk ) (p<0.001). There was no significant difference between the calculated mechanical power values in the same mechanical ventilation modes in the two groups. There was no significant difference in mechanical power between the same mechanical ventilation modes in the same group. No postoperative pulmonary complications were encountered, and the length of stay in G1 and G2 was similar. MP Group 1 (VCV->PCV) Group 2 (PCV->VCV) VCV1 8,4±2,3 8,3±2,9 0,932 a PCV1 12±3,1 11±3,1 0,282 a VCV2 8,8±2,6 8,2±2,4 0,340 a PCV2 12,9±3,5 11,6±3,5 0,167 a VCV3 9±2,7 8,2±2,8 0,255 a PCV3 13,1±4 11,2±3,6 0,062 a VCV: Volume controlled ventilation, PCV: Pressure controlled ventilation, MP: Mechanical Power a.Student-t test Conculusion: For the first time in the literature, we compared the mechanical power of VCV and PCV in healthy lung. VCV leads to a significantly lower mechanical power. The flow curves between the two modes play a role in this difference; therefore, we think that the resistive component is effective in PCV. The initial ventilation mode had no effect on MP in our patients with the crossover model. Larger studies are needed to elucidate the effect of different components of mechanical power.