Evaluation of biphasic positive airway pressure [BIPAP] versus control mode, SIMV and CPAP in post anesthetic patients receiving elective post-operative ventilation

• Author Details:   
• Prem Kumar
• Sushma Vijay Pingale
• Naheed Azhar

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Context: Prolonged mechanical ventilation and intensive care unit (ICU) stay increases morbidity and mortality.
Objective: To evaluate the effects of biphasic positive airway pressure versus continuous mandatory ventilation (CMV), synchronized intermittent mandatory ventilation (SIMV) and continuous positive airway pressure (CPAP) in patients receiving elective post operative ventilation.
Methods and Material: 40 patients of age group 20 yrs and older of American society of anesthesiologists (ASA) physical status 1 - 3 who underwent elective abdominal surgery under general anesthesia were divided into 2 groups, group B(n=20) comprised of patients who were put on BIPAP mode and group C(n=20) who were put on CMV, SIMV, CPAP mode. Outcomes measured were ratio of arterial oxygen partial pressure to fractional inspired oxygen (PaO2/FiO2), duration of mechanical ventilation, sedation requirement, and hemodynamic instability. Patients were put on ventilator and ventilated according to protocol.
Results: The duration of mechanical ventilation was significantly reduced [p – 0.005] in group B [6.8±2.8 hours] than group C [9.9±3.6 hours]. Sedation requirement with midazolam was significantly reduced [p – 0.0001] in group B (4±2.71 mg) than group C (8.05±2.45 mg). There was no difference with respect to PaO2/FiO2 ratio and hemodynamic stability between both the groups.
Conclusions: BIPAP as compared to CMV, SIMV and CPAP mode reduces the duration of mechanical ventilation and sedation requirement which in turn reduces morbidity. Pulmonary gas exchange was similar between the two groups.

Keywords: Biphasic intermittent positive airway pressure, Pulmonary ventilation, Postoperative period