Introduction: General anesthesia in prone position is related with increased airway pressure, decreased
pulmonary, and thoracic compliance.
Aim: To compare pressure-controlled (PCV) and volume-controlled (VC) ventilation in patients
undergoing lumbar spine surgery in prone position.
Methodology/Description: After ethics committee approval and written informed consent, a comparative randomized
interventional study was conducted from March to June 2017. Patients were randomized
in two groups of 30 each using sealed envelope method with 80% power and 97.5% confidence
interval of the study. Patients of either sex, ASA grade I and II, age 20 to 65 years
were included, while those with severe pulmonary disease and BMI > 30 kg/m2 were excluded. Mean and standard deviation were calculated for quantitative data
while proportions for qualitative data. For significance of difference, chi-squared
test was used for proportions and unpaired t-test for mean. A p-value of < 0.05 was considered to be significant. Peak airway pressure (P-peak),
PaO2 levels, PaCO2 levels, mean airway pressure, dynamic compliance, heart rate, systolic blood pressure,
diastolic blood pressure, and mean arterial pressure were measured.
Results: Demographic parameters and perioperative hemodynamic values were comparable with
no significant statistical difference. The P-peak levels were significantly higher
in Group VC as compared with Group PC (p < 0.05). Dynamic compliance levels during prone position were higher in Group PC
when compared with Group VC. Postoperative PaO2 level was significantly higher in Group PC compared with Group VC.
Conclusion: According to our study, PCV mode is associated with lower P-peak levels during prone
position and better oxygenation postoperatively. We concluded that PCV mode might
be more appropriate in prone position during anesthesia.
