Comparison of the Use of Forced Vital Capacity (FVC) and Predicted Body Weight (PBW) in Selecting Tidal Volume for Laparoscopic Cholecystectomy in Obese Patients

Correct tidal volume selection is very important in mechanically ventilated patients. In this study, we aimed to investigate whether there is a difference between the effects of PBW and FVC calculations on lung mechanics and oxygenation in determining optimal tidal volume. Seventy patients, aged 18–65 years, ASAI-III, BMI ≥ 30 kg/m2, who underwent laparoscopic cholecystectomy and preoperatively underwent pulmonary function tests were included in the study. Patients were randomly divided into two groups. Two different methods were used in tidal volume calculation. Tidal volume was calculated based on PBW in patients in Group PBW (n = 35). In patients in Group FVC (n = 35), tidal volume was calculated on the basis of FVC. Heart rate, blood pressure, SPO2, plateau pressure, minute volume, EtCO2, and driving pressure were evaluated in all patients. The demographic characteristics of the patients were similar. Tidal volume calculated according to FVC was significantly higher (p < 0.001). SPO2 values measured at 15.30 and 45. minutes were similar in both groups (p = 0.263, p = 0.562, and p = 0.999, respectively). Plateau pressure was similar in both groups at 15 min (p = 0.398). Plateau pressure was significantly higher in Group FVC at 30 and 45 min (p = 0.046, p = 0.037). The driving pressure values calculated at 15.30 and 45. minutes were similar in both groups (p = 0.077, p = 0.158, and p = 0.086, respectively). It has been observed that tidal volume application based on PBW and FVC is successful in maintaining intraoperative oxygenation in obese patients undergoing laparoscopic surgery. There was no significant difference between the two methods in terms of oxygenation and hemodynamic effects.