LEFT-VENTRICULAR FUNCTION DURING WEANING OF PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Objective: Determine the evolution of left ventricular ejection fraction during weaning. Design: Prospective study. Setting. Intensive care unit of a university teaching hospital. Patients and participants: 12 consecutive mechanically ventilated patients, without documented coronary artery disease, suffering from acute exacerbation of chronic obstructive pulmonary disease and able to be weaned. Measurements and results. Left ventricular ejection fraction was determined during mechanical ventilation, inspiratory pressure support (10 cmH2O) and spontaneous ventilation with constant inspiratory oxygen fraction using technetium-99m radionuclide angiography. Spontaneous ventilation induced a significant decrease in left ventricular ejection fraction from 54.5+/-12.4 to 47.0+/-13% (p<0.01). Inspiratory pressure support induced a slight but non-significant decrease in left ventricular ejection fraction from 55.0+/-12.1 to 50.3+/-12.4%. Left ventricular ejection fraction was homogeneously reduced by spontaneous ventilation without patent regional wall motion abnormalities of the left ventricle. Myocardial a thallium-201 imaging performed 15 min after weaning showed a normal perfusion in the left ventricle anterior and posterior free wall. Conclusion: Weaning of patients suffering from chronic obstructive pulmonary disease without coronary artery disease induced a significant reduction in left ventricular ejection fraction. The non significant decrease in left ventricular ejection fraction observed with inspiratory pressure support suggested that our results might be explained by a weaning induced increase in afterload.