Description

Obesity, defined as a Body Mass Index (BMI) >30 kg.m-2", is characterized by increased airway resistance, labored breathing and decreased respiratory system compliance. An increased rate of obese patients undergoing laparoscopic assisted surgery (LAS) is a health care concern due to anesthesia and ventilation difficulties in the obese population. Therefore, understanding the physiology and pathophysiology of lung function is an important issue during long-lasting LAS.

Carbon dioxide pneumoperitoneum with steep Trendelenburg positioning leads to a cranial displacement of the diaphragm and an increased volume of atelectasis, with a consequent decrease of total lung volume, lung compliance, and functional residual capacity. Thus, alleviation of increased airway pressure, improvement in oxygenation and CO2 elimination are the main goals during anesthetic management in laparoscopic assisted surgery.

In pressure controlled ventilation volume-guaranteed (PCV-VG) mode, the ventilator regulates the Peak Inspiratory Pressure (PIP) to achieve the optimal TV. To achieve the target volume, ventilator parameters are regularly changed without adjusting airway pressures. Hence, PCV-VG has the advantages of both Volume-Controlled Ventilation (VCV) and pressure controlled ventilation (PCV) to preserve the target minute ventilation while maintaining a low incidence of barotraumas.

PCV-VG is a type-controlled ventilation mode with a dual character as it has the criteria of both PCV and VCV. This recent ventilation mode which is one of the pressure regulated volume controlled (PRVC) that include Auto Flow ventilation, offers the ability to reduce the inspiratory pressure and as a result the incidence of barotrauma