“More than four million abdominal surgeries are performed in the US every year and in England about 250,000 abdominal operations are performed per year. Adults undergoing upper abdominal surgery are at an increased risk of postoperative pulmonary complications.
Acute respiratory failure is a relatively common complication after abdominal surgery and is associated with significant morbidity and mortality. According to Michelet 2010, the development of respiratory complication may be explained by two pathological mechanisms.
The first is linked to surgical complications, notably with the occurrence of anastomotic leakage leading to mediastinitis, septic shock, and acute respiratory distress. The second is of medical origin, with multifactorial impairment of respiratory function.”

Implications for practice
“Data from two randomized controlled trials (RCTs) showed that in adults with acute respiratory insufficiency after upper abdominal surgery, continuous positive airway pressure (CPAP) and bilevel noninvasive positive pressure ventilation (NPPV) is effective in the
reduction of intubation rates and intensive care unit (ICU) length of stay and to improve blood gases and blood pH one hour after the intervention. The intervention also reduced the risks of pneumonia, sepsis, and surgical wound infection and is apparently safe because
it does not lead to anastomotic leakages.”

Implications for research
“New RCTs should be conducted in adults who develop respiratory insufficiency after upper abdominal surgery to compare the effects of CPAP or bilevel NPPV versus oxygen therapy on hospital mortality and hospital length of stay and to detect possible adverse events such as gastric insufflation, fistulae, pneumothorax, bleeding, skin breakdown, eye irritation, sinus congestion, oronasal drying, and patient-ventilator asynchrony. We calculated that studies involving approximately 610 participants are needed to detect a significant difference in hospital mortality.”

Faria, Debora A S et al. “Noninvasive positive pressure ventilation for acute respiratory failure following upper abdominal surgery.” The Cochrane database of systematic reviews vol. 2015,10 CD009134. 5 Oct. 2015 Free Full Text