A randomised controlled study to evaluate and compare the efficacy of High Frequency Nasal Oxygenation with conventional oxygen therapy for postoperative oxygenation in patients undergoing exploratory laparotomies

Postoperative pulmonarycomplication (PPC) is a common complication after surgery resulting inincreased morbidity, mortality and prolonged hospital stay. Post operativehypoxaemia has been reported in 10-50% of patients after surgery and inabdominal surgeries it has been reported as high as 40%. To prevent this,oxygen therapy has been a norm after surgery. Recently, high-flow nasal cannula(HFNC) has been evaluated for this indication and found to be superior toconventional oxygen therapy (COT) in cardiac and thoracic surgeries, obese patients,critically ill patients and in neonates. However, its use in specific patientsubpopulation still needs to be investigated.This study is undertaken toevaluate and compare the efficacy of High Frequency Nasal Oxygenation withconventional oxygen therapy for postoperative oxygenation in patientsundergoing exploratory laparotomies for prevention of postoperative pulmonarycomplications.

Thepresent RCT includes patients aged 18-65 years, scheduled for exploratoryabdominal surgeries under GA with ARISCAT score ≥26 i.e., moderate to highrisk.  Patients with chronic obstructivepulmonary disease or asthma causing limitations in everyday activities,  heartfailure with clinical symptoms equivalent to NYHA functional classification> 2,  restrictivelung disease with > 20% reduction in total lung capacity,  BMI>40kg/m2 or inabilityto comprehend oral or written information will be excluded

 After adequate reversal of neuromuscular blockade and removal ofendotracheal tube, patients in both the group will be shifted to postoperativeroom and depending on the group allocation, they will receive either COT orHFNC. Patients in High flow nasaloxygenation (HFNO) group will receive a flow rate of 35 to 60 L/min and FiO2will be titrated (from 45% to 100%) by the treating clinician to maintain aperipheral oxygen saturation (SpO2) of 95% or more. The COT group will receiveoxygen via simple facemask with oxygen flow titrated (from 45% to 100%) by thebedside clinician to maintain a SpO2 of 95% or more. In COT group, eachadditional litre/min of oxygen adds an FiO2 of 0.4 for the first 3liters andFiO2 of 0.3 for every litre thereafter. Arterial blood samples will becollected after extubation at various designated time points i.e. after 2nd hr, 6th hr, 12th and 24th hr.Non-invasive blood pressure (NIBP), Heart rate (HR) will be recorded for 2 hrs.

The primary outcome is to determinePaO2/FiO2 at the end of 24th hr between thetwo groups and secondary outcomes are PaO2, SaO2/FiO2, PaCO2, patientsatisfaction, chest X ray proven PPCs, proportion of PPCs and acute hypoxemicrespiratory failure, proportion of reintubation or non-invasive ventilation(NIV) use and complications.