CTRI

INTRODUCTION: Postoperative pulmonary complications often occur in patients after major surgery incidence (2 â€“ 6%) and result in attributable morbidity and mortality. The mechanical power of ventilation is a recently introduced ventilation parameter that summarizes the amount of energy per unit of time transferred from the ventilator to the respiratory system, and part of this energy acts directly on lung tissue where it can cause iatrogenic harm. The effects of the intraoperative mechanical power on the occurrence of postoperative pulmonary complications in PCV mode have not yet been investigated thoroughly. In theory, limiting the intraoperative mechanical power could reduce the risk for postoperative pulmonary complications and as such improve postoperative outcomes. Mechanical power in VCV MP (J/min) = 0.098Ã—RRÃ— TVÃ— (Ppeak - PEEP). In that of PCV mode is MP(J/min) = 0.098Ã—RRÃ—TV(PEEP + Î”Pinsp) [Î”Pinsp = Pressure above PEEP (cm of H2O)].

METHODOLOGY: Patients scheduled will have invasive arterial pressure monitoring as a part of their routine care. Patients will receive either Volume controlled Ventilation (VCV) or Pressure controlled Ventilation (PCV) mode of ventilation after a baseline ABG. Patients will be assigned to receive lung ventilation with either VCV mode with low tidal volume (VT) (6 ml/kg predicted body weight, PBW) or PCV mode to generate a volume equal to 6 ml per kg predicted body weight. The VT, FiO2 and PEEP will be fixed and maintained for the duration of the surgical procedure. All other aspects of intra-operative care, including the inspired fraction of oxygen (FiO2), respiratory rate, anaesthesia technique (including type of sedative used), fluid management, use of vasoactive drugs, analgesia plan, use of prophylactic antibiotics and antiemetics agents, will be administered at the discretion of the treating anaesthesiologist. Neuromuscular blocking agents will be used in all patients according to local protocol. On the day of surgery, baseline preoperative lung ultrasound will be done before surgery. Postoperative lung ultrasound is done after 24 hours and patient is monitored for 72 hours. Mechanical power is calculated to compare the efficacy between two modes of ventilation.

STATISTICS: All analyses were performed using R version 4.0.2 (R Foundation for Statistical Computing), and a two-sided P less than 0.05 was considered significant. Continuous variables will be reported as median with their interquartile ranges and categorical variables as total number & percentage (%). Proportions will be compared with Fisher exact tests and continuous variables will be compared using t test or Wilcoxon rank sum test, as appropriate. The following variables will be considered for adjustment : age, sex, baseline SpO2, baseline bicarbonate, randomisation group and the Assess Respiratory Risk in Surgical Patients in Catalonia (ARISCAT) score.

HYPOTHESIS: Pressure controlled ventilation is non â€“ inferior to volume controlled ventilation in terms of mechanical power.

EXPECTED OUTCOME : Equal or lower incidence of post operative pulmonary complications in pressure controlled ventilation compared to volume controlled ventilation.

BENEFITS : Least postoperative pulmonary complications, so early mobilisation, lesser hospital days & early discharge.

NOVELTY OF STUDY: There are no studies based on mechanical power using pressure controlled ventilation in perioperative period.