Mechanical ventilation in patients with hypoxemia due to refractory heart failure.

OBJECTIVE

The goal of this study was to evaluate the safety and efficacy of mechanical ventilation (MV), including noninvasive positive pressure ventilation (NPPV) and endotracheal intubation (ETI) in patients with very severe hypoxemia due to refractory heart failure (RHF).

METHODS

In addition to conventional treatment, eighteen patients with hypoxemia due to RHF were assigned to receive NPPV (n=10) or ETI (n=8) based on the severity of their clinical status. Arterial blood gas, PaO(2)/FiO(2), vital signs including respiratory rate (RR), heart rate (HR) and systolic blood pressure (SBP), left ventricular ejection fraction (LVEF) and left ventricular end-diastolic volume (LVEDV) were recorded before and after MV in each group.

RESULTS

The patients in the ETI group showed more severe hypoxemia and respiratory acidosis in comparison with the patients in the NPPV group. Both the NPPV and ETI significantly increased PaO(2), PaO(2)/FiO(2) and arterial oxygen saturation (SaO(2)) (p <0.01) and reduced RR and HR (p <0.01) after MV in comparison to that before MV. Both the NPPV and ETI significantly increased LVEF (p <0.05) and decreased LVEDV (p <0.01) at the time of weaning from MV in comparison to that before MV. Moreover, PaO(2) correlated with LVEF (r=0.882, p=0.01 and r=0.736, p=0.037) while it also inversely correlated with LVEDV (r=-0.645, p=0.044 and r=-0.756, p=0.030) at the time of weaning from MV in the NPPV and ETI groups, respectively. There were two failed cases in the NPPV group. They were transferred immediately to be treated with ETI and were equivalent to the others in the ETI group.

CONCLUSIONS

Both NPPV and ETI are safe and effective modalities for improving hypoxemia and left heart function in patients with RHF. These results suggest that invasive MV should be applied to very severe patients with RHF as quickly as possible when an expected clinical improvement cannot be obtained by NPPV.