Risk factors for excessive tidal volumes delivered during intraoperative mechanical ventilation, a retrospective study.

Background: Lung Protective Ventilation (LPV) refers to a combination of measures aimed at reducing ventilator-associated lung injury. This includes: delivering tidal volumes of 6-8 ml/kg of ideal body weight, use of positive end expiratory pressure and recruitment maneuvers. With Postoperative Pulmonary Complications (PPCs) contributing towards significant morbidity and mortality following surgery, evidence indicates that effective use of LPV measures intraoperatively has been associated with reduced rates of PPCs.

Methods: We conducted a post-hoc analysis using data from a recent clinical audit on departmental ventilation practices. Potential risk factors for excessive tidal volume ventilation were assessed using univariable and multivariable regression models.

Results: Obesity and gender are independently associated with risk of excessive ventilation. In contrast, the urgency and length of surgery, the choice of airway devices and the mode of ventilation were not associated with excessive ventilation.

Conclusion: There is an association between female gender, obesity and excessive tidal volume ventilation. This may be addressed through formal, protocolized intraoperative ventilation setting.