EXTRAVASCULAR LUNG WATER AND VENTILATORY MANAGEMENT IN CHILDREN AFTER OPEN HEART SURGERY

The accumulation of extravascular lung water (EVLW) after cardiac surgery of congenital heart disease may predicted from the preoperative level of pulmonary blood flow. This accumulation of EVLW may adversely affect ventilatory parameters. Lung compliance (LC), cardiac index (CI), blood arterial oxygen tension (PaO), left atrial pressure (LAP)and EVLW were measured serially immediately postoperative in two groups of children after complete repair of congenital heart disease contrasted by their level of pulmonary blood flow: Tetralogy of Fallot (TOF, n=10, 4.6±1.9 years) and ventrvcular septal defect with pulmonary arterial hypertension (VSD+PAH, n=10, 5.4±2.0 years).Using a double indicator-dilution technique (DIDT) the EVLW peaked at the 16th hour postoperation in TOF group and at the 8 th hour postoperation inthe VSD with PAH group. During the first 24 hours after surgery the EVLW was consistently higher in the VSD with PAH group (P<0.01). There was a negative correlation between the EVLW and LC, CI and PaOand no correlation between the EVLW and LAP. In three hypoxemic patients of the VSD with PAH group the LC deteriorated while the EVLW was elevated. After treatment with positive end expiratory pressure (PEEP) the hypoxemia corrected as the LC increased and the EVLW decreased, with no change in the CI. Thus, measurement of EVLW provides a sensitive method for explaining changes in LC, that may lead to a more rational adjustment of mechanical ventilator parameters.