The Impact of Protective Ventilation Strategy, Applied in Patients During Prolonged Gynecological Surgery, on Postoperative Oxygenation

Abstract

Atelectasis occurs in nearly 90% of patients operated under general anaesthesia and persists for about 24 hours after laparoscopic surgery and 3 days after open surgery. According to some randomized studies, intraoperative application of mechanical protective ventilation with a low tidal volume (VT), positive end-expiratory pressure (PEEP) and recruitment maneuvers (RMs) decreases left to right shunting and improves postoperative oxygenation. During these trials statistically significantly higher values of oxygen partial pressure (PaO2) in arterial blood gas analysis and PaO2/FiO2 ratio (FiO2 – fraction of inspired oxygen; FiO2 = 0.21) were observed in patients ventilated with PEEP and RMs.

Our purpose is to prove that the application of PEEP in patients during prolonged gynecological surgery can improve postoperative oxygenation and decrease the incidence of postoperative atelectasis.

In this observational cohort study we included women, who underwent conventional gynecological surgery with a duration of more than 2 hours. Pa- tients were divided into 2 groups – control group A (35 patients) and exposed group B (35 patients). The ones in the control group were ventilated with a tidal volume (VT) of 8–10 ml/kg, without PEEP and RMs, whereas those in group B were ventilated with VT = 6−8 ml/kg (based on ideal body weight), PEEP = 6 cm H2O and RMs performed after intubation, at every disconnection from the ventilator and at extubation.

We proved that the patients in group B had statistically significantly higher values of PaO2 and PaO2/FiO2 on the first postoperative day, therefore intraoperative protective mechanical ventilation improves postoperative oxygenation. We also observed a significantly reduced incidence of newly developed postoperative atelectasis in this patient group. Patients in group A had a significantly longer stay in intensive care unit (ICU) than those in group B. The use of protective ventilation strategy (low VT, PEEP and RMs) in patients during prolonged gynecological surgery can decrease the incidence of postoperative atelectasis and improves oxygenation on the first postoperative day.