Effects of open lung concept on respiratory function after cardiopulmonary bypass
Objective:To explore the effects of open lung concept(OLC) on pulmonary function in patients who underwent cardio-pulmonary bypass(CPB).Methods: 24 patients underwent cardiac surgery with CPB were divided randomly into conventional mechanical ventilation group(CMV),OLC started directly after intubation(early open lung group,EOL) and OLC started 30min after arrival in the intensive care unit(late open lung group,LOL).FiO2,peak airway pressure,tidal volume,and positive end-expiratory pressure(PEEP) were measured.Arterial blood was taken for gas analysis at the same time and static pulmonary compliance(Cst),oxygen index(OI) were calculated before operation,after CPB and 120 min,240 min,and 360 min after arrival in ICU.Results: Compared with these before operation and from the end of CPB to 240 min after arrival in ICU,Cdyn was significantly lower in CMV group(P0.01) and OI was lower till 360 min after arrival in ICU(P0.01).No reducing of Cdyn was found in EOL group after CPB.In LOL group,Cdyn and OI began to increase after OLC was applied but Cdyn was lower than that of EOL group till 120 min after arrival in ICU(P0.05) and the PEEP needed to keep the lung open was higher,which was 12±0.71 cmH2O vs 10±0 cmH2O(P0.01).Conclusions: OLC ventilation leads to an attenuated lung injury after cardiac surgery.Early application of the OLC has a more pronounced effect compared with late application of this ventilation strategy.