Acute Left Ventricular Dysfunction during Unsuccessful Weaning from Mechanical Ventilation

Abstract

The authors studied the hemodynamic effects of rapidly weaning from mechanical ventilation (MV) 15 patients with severe chronic obstructive pulmonary disease (COPD) and cardiovascular disease who were recovering from acute cardiopulmonary decompensation. In each patients, 10 min of spontaneous ventilation (SV) with supplemental oxygen resulted in reducing the mean esophageal pressure (.hivin.X .+-. SD, + 5 .+-. 3 to - 2 2.5 mm Hg, P < .01) and increasing cardiac index (CI) (3.2 .+-. 0.09 to 4.3 .+-. 1.31/min/M2, P < .001), systemic blood pressure (BP 77 .+-. 12 to 90 .+-. 11 mmHg, P < .001), heart rate (HR 97 .+-. 12 to 112 .+-. 16 beats/min, P < .001), and, most importantly, transmural pulmonary artery occlusion pressure markedly increased (PAOPtm 8 .+-. 5 to 25 .+-. 13 mmHg, P < .001), mandating a reinstitution of MV. In four patients with left ventricular (LV) catheters, the PAOP correlated with the LV end-diastolic pressure during both MV and SV. Gated blood pool imaging showed SV increased the VL end-diastolic volume index (65 .+-. 24 to 83 .+-. 32/M2, P < .002) with LV ejection fraction unchanged. Patients were treated for a mean of 10 days with diuretics, resulting in a reduction of blood volume (4.55 .+-. 0.91 to 3.56 .+-. 0.55 l) and body weight (-5 kg, P < .001). Subsequently, nine of the 15 patients were weaned successfully from mechanical ventilation with unchanged PAOP.