Background: Different modes of mechanical ventilation such as volume controlled ventilation (VCV) and Pressure Controlled Ventilation (PCV) are deployed to balance respiratory mechanics, gas exchange and hemodynamics in patients undergoing lumbar spine surgeries in prone position.

Methods: This prospective study included 72 patients undergoing lumbar spine surgeries in prone position. They were randomized to two Groups – Group V (who received volume controlled ventilation) and Group P (who received pressure controlled ventilation). The ventilation and hemodynamic parameters were statistically analyzed at 5 min after intubation in supine (S5), 60 min after prone (P60) and 180 min after prone (P180) position. Oxygenation parameters were assessed from ABG in supine (baseline) and at the end of surgery in prone position. Chisquare, independent t-test and ANOVA were used to compare the data between the two groups.

Results: Demographics, oxygenation and hemodynamics were comparable between the two groups. P peak and P mean increased from supine to prone position in both the groups. The P peak in VCV was higher than PCV in prone position and the difference was significant at first hour [p = 0.008] . The dynamic compliance (Cdyn) decreased in both PCV and VCV from supine to prone position. There was significant increase in Cdyn in PCV at the end of first hour in prone position (p = 0.005). Vte, MV, PEEP, RR, EtCO2, and VD/VT did not show any significant difference between the groups (p > 0.05).

Conclusion: Both VCV and PCV can be safely used to ventilate patients in prone position undergoing lumbar spine surgeries.