Nevertheless, the median hospital stay was shorter in the protective-ventilation group than in the nonprotective-ventilation group . Discussion In this trial, intraoperative lung-protective mechanical ventilation, in comparison with nonprotective ventilation, led to improved clinical outcomes and reduced healthcare utilization after abdominal surgery. The observed price of postoperative complications in our study was slightly higher than predicted.25 This is due, partly, to the exclusion of patients with a minimal risk of complications, as well as the huge proportion of patients who underwent major abdominal procedures, which are associated with increased morbidity rates.We considered a two-sided P value of less than 0.05 to indicate statistical significance. Results Characteristics of the analysis Population January 1 From, 2000, to December 31, 2011, a total of 22,248 extremely premature infants were born alive at one of the 25 study centers and met criteria for inclusion in the study. Among these infants, 6075 died during the birth hospitalization; 6045 of the infants who died had a coded cause of death listed in the registry. Gestational age, birth weight, and sex were related across the three birth-year periods for both live births and deaths . Extremely premature infants who died were 14 days younger in gestational age than surviving infants .