Abstract
Background/ObjectivesSildenafil decreases pulmonary vascular resistance index (PVRI), in patients with pulmonary hypertension (PH). We investigated sildenafils' effects on central hemodynamics of mechanically ventilated patients with WHO group-III PH and RV failure necessitating dobutamine administration. MethodsProspective non-controlled study involving 12 (9 males, 59±4years old), patients with the above characteristics. All patients in phase-1 (days 1–2) received dobutamine (5μg/kg/min IV). During phase-2 (days 3–6), sildenafil was started via nasogastric tube (80mg/day) and dobutamine discontinuation was attempted. Patients were designated responders or non-responders based on whether dobutamine could be stopped or not. Phase-3 lasted from day 7 to day of weaning from mechanical ventilation; or if weaning failed, until day 20 following admission (end-of-study). Invasive and echocardiographic parameters were repeatedly recorded throughout the study. ResultsSignificantly changed parameters (P<0.025) from baseline to phase-1, -2 and -3 (%change of mean ratios), in responders (n=7) included among others PVRI (−40%, −51%, −42%), RV stroke work index (RVSWI: 43%, 79%, 41%) and cardiac index (49%, 54%, 48%), which also differed significantly from non-responders (N=5). In phases-1 and -3 non-responders had not significant changes, in phase-2 PVRI (27%) and RVSWI (−22%) changed significantly. In contrast to non-responders, all responders were weaned from mechanical ventilation until the end-of-study (P<0.025). ConclusionsSildenafil may improve central hemodynamics and RV function indices in ventilated patients with WHO group-III PH and RV failure requiring dobutamine infusion, when they respond favorably to the latter. Accordingly, an adequate RV systolic reserve may be mandatory for sildenafil to exert its actions.
Published Version
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