Evaluation of mechanical ventilation modes in the laparoscopic perioperative period with electrical impedance tomography

Abstract

Purpose Uncertainty persists regarding the optimal mode of mechanical ventilation for laparoscopic perioperative periods. Electrical impedance tomography (EIT) is an effective tool for monitoring and guiding lung-protective ventilation. This study aimed to compare the effects of pressure-controlled ventilation-volume guaranteed (PCV-VG) and volume-controlled ventilation (VCV) on pulmonary ventilation during laparoscopic surgery. Method This trial was a randomized crossover study, with the laparoscopic perioperative period divided into five phases: pre-anesthesia induction (AWAKE), post-anesthesia induction (BEGIN), the first phase of surgery (MIDDLE-1), the second phase of surgery (MIDDLE-2), and pre-wakefulness (END). EIT data were recorded at each phase, and EIT parameters were calculated to quantify pulmonary ventilation performance in both spatial and temporal dimensions. Results During the surgical period, plateau pressure (Pplat) and driving pressure (ΔP) under PCV-VG were lower, while the oxygenation index (PaO2/FiO2) was higher compared to VCV. Furthermore, PCV-VG was associated with an increased center of ventilation (45.1 ± 3.7 vs. 41.7 ± 3.5, P < 0.05), a decrease in global inhomogeneity (GI) (0.85 ± 0.16 vs. 1.06 ± 0.30, P < 0.05), and a reduction in regional ventilation delay index (RVDI) (10.5 ± 4.5 vs. 15.9 ± 5.3, P < 0.05), when compared to VCV. The improvements in pulmonary ventilation were more pronounced with PCV-VG compared to VCV during the surgical period, compared to the non-surgical period. Conclusion EIT parameters reveal significant differences in ventilation between VCV and PCV-VG during the laparoscopic perioperative period. PCV-VG improves ventilation inhomogeneity and mitigates ventilation delay caused by the Trendelenburg position and pneumoperitoneum during surgery. PCV-VG is more effective than VCV in optimizing intraoperative lung ventilation. Trial registration ClinicalTrials.gov ChiCTR2400089365