Comparative Analysis of Pressure Controlled and Volume Controlled Ventilation on Respiratory Mechanics, Haemodynamics and Systemic Stress Response in Patients Undergoing Surgery in Prone Position.

BACKGROUND: General Anaesthesia in prone position is related with increased airway pressure, decreased pulmonary and thoracic compliance. AIM: Comparision of pressure controlled and volume controlled ventilation in patients undergoing lumbar spine surgery in prone position.METHODS: After ethics committee approval & written informed consent, a comparative randomized interventional study was conducted from July-December 2017. Randomization was done using random number tables. Patients of either sex, ASA grade I&II, age 25-55 yrs were included while those with severe pulmonary ,cardiovascular, endocrine disease & BMI> 30kg/m2 were excluded. Patients were randomly assigned to VCV group (n = 30), or PCV group (n = 30). Haemodynamic (HR,SBP,DBP,MAP), Respiratory (P-Peak,P-mean,C-dyn) variables,blood glucose,S.cortisol were measured and ABG analysis was done 10 minutes after intubation (T1), 30 minutes after prone positioning(T2) and 60 minuts after extubation(T3). RESULTS: Demographic parameters , perioperative hemodynamic values were comparable with no significant statistical difference.The P-Peak levels were lower and dynamic compliance was higher in PCV group during both T1 and T2 with p value of less than 0.05 Postoperative PaO2 level was significantly higher in Group PCV compared with Group VCV.The difference between post operative and preoperative serum cortisol and blood glucose levels was significantly less in patients ventilated with PCV mode.CONCLUSION: According to our study,PCV mode is associated with lower P-peak levels during prone position, better oxygenation postoperatively and lesser systemic stress response.We concluded that PCV mode might be more appropriate in prone position surgeries.