Intraoperative Protective Ventilation and Postoperative Pulmonary Complications

Inclusion Criteria: * Adults ( 18 years) scheduled for elective surgery expected to last 2 h, * elective intraperitoneal abdominal or pelvic surgery including: gastric; biliary; pancreatic; hepatic; major bowel, ovarian, renal tract, bladder, and prostatic; radical hysterectomy; and pelvic exenteration; * at least intermediate risk of PPCs defined by a risk score 26 Exclusion Criteria: * Inability or refusal to provide consent * Refusal of clinicians caring for patient to follow the protocol * Participation in interventional investigation within 30 days of the time of the study * Pregnancy * Emergency surgery * Severe obesity (above Class I, BMI 35) * Significant lung disease: any diagnosed or treated respiratory condition that (a) requires home oxygen therapy or non-invasive ventilation, (b) severely limits exercise tolerance to \<4 METs (e.g. patients unable to do light housework, walk flat at 4 miles/h or climb one flight of stairs), or (c) required previous lung surgery80 * Significant heart disease: cardiac conditions that limit exercise tolerance to \<4 METs * Renal failure: peritoneal or hemodialysis requirement or preoperative creatinine 2 mg/dL; * Neuromuscular disease that impairs ability to ventilate without assistance * Severe chronic liver disease (Child-Pugh Score of 10 -15) * Sepsis * Malignancy or other irreversible condition for which 6-month mortality is estimated 50% * Bone marrow transplant.