[Non-invasive intermittent mechanical ventilation: usefulness in treatment of chronic severe heart failure]

The higher respiratory work and less inspiratory muscle strength of patients with cardiac failure may contribute to decrease their functional capacity.

To assess the effects of non invasive intermittent mechanical ventilation on clinical parameters, peripheral perfusion, cardiac and inspiratory muscle function.

Patients with chronic cardiac failure, functional capacity III-IV were subjected to 6 sessions of nasal non invasive intermittent ventilation during 4 hours or to simulated ventilation (controls).

Fifteen ventilated patients and six controls completed the protocol. Ventilated patients improved the Mahler transition score for dyspnea by 4 +/- 1.6 points. They also improved their aerobic capacity, increasing the exercise duration from 10.9 +/- 4 to 12.7 +/- 5 min and their maximal oxygen consumption from 14.6 +/- 4 to 16.4 +/- 5.7 ml/kg/min. These patients also decreased their O2 and CO2 ventilatory equivalents. Maximal inspiratory pressure increased from 67.9 +/- 23.6 to 80.19 +/- 21.4 cm H2O, sustained maximal inspiratory pressure increased from 101.4 +/- 48 to 133 +/- 53 cm H2O and maximal endurance increased from 132 +/- 52 to 162 +/- 58 g in ventilated patients. None of these variables was modified in control patients. No changes were observed in renal function, blood volume, arterial gases, spirometry or plasma catecholamine levels in any group.

Intermittent nasal ventilation or other measures to improve inspiratory muscle function may be beneficial for patients with severe cardiac failure.