Impact of Cardiopulmonary Bypass Time on Postoperative Duration of Mechanical Ventilation in Patients Undergoing Cardiovascular Surgeries: A Systemic Review and Regression of Metadata

The objective of this study was to detect if cardiopulmonary bypass time duration has any impact on the duration of postoperative mechanical ventilation (MV). The study design was a systematic review and regression analysis of pooled data from previously published studies. All available data are from prospective, retrospective, cross-sectional, and observational studies. Participants included only patient/human studies. There were no interventions. PubMed and Cochrane libraries were searched by utilizing different combinations of keywords: cardiopulmonary bypass and mechanical ventilation. Inclusion criteria were: (1) English articles, (2) studies with an adult population that underwent cardiac surgeries using cardiopulmonary bypass (CPB), (3) studies where the duration of CPB is provided as well as the duration of mechanical ventilation. A regression analysis was performed on the metadata. For the hours of MV, eight studies with 13 data sets (as some studies provide data in subgroups) were included for a total number of 989 subjects. The duration of CPB ranged from 55 to 173.5 minutes for these operations. Postoperative MV hours ranged from nine to 408 hours. Stepwise multiple regression analysis found that cardiopulmonary bypass time (CPBT), age, diabetes, male gender, and ejection fraction correlated with prolonged mechanical ventilation; CPBT was the most strongly correlated variable. Cardiopulmonary bypass time appears to affect clinical outcomes adversely and is associated with prolonged MV. Avoiding CPB or limiting it to a minimum may decrease the days of MV required.