High frequency oscillatory ventilation (HFOV) provides no mortality benefit over conventional ventilation in early respiratory distress

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1. Early initiation of high frequency oscillatory ventilation (HFOV) showed no mortality benefit over a conventional low-tidal-volume, high-PEEP ventilation strategy in acute respiratory distress syndrome (ARDS).

2. Early HFOV was associated with higher use of pressors and sedatives; and higher mortality — but the mortality effect might be an overestimate as the trial was terminated early strategy (47% vs 35%).

The Oscillation for ARDS Treated Early (OSCILLATE) trial, published this week in NEJM, showed that early initiation of HFOV did not reduce (and might have increased) the mortality of ARDS patients compared to conventional low-tidal-volume, high-PEEP ventilation. As patients on HFOV also required more vasoactive medications than the control group, one plausible mechanism for these results is hemodynamic instability.

In theory, high frequency, very-low volume ventilation might limit lung injury in comparison to the higher ventilatory pressure and volume generated by conventional ventilation.  This thought had not been formally tested in adults aside from smaller trials demonstrating the safety of HFOV (1). The findings of the present trial and the OSCAR trial published in the same issue (2) weaken the promise of HFOV as a clinical breakthrough in this syndrome.

The findings of this multi-country multicenter trial are likely to be generalizable. Of note, the effect on mortality might be an overestimate as is known to occur when trials are terminated early. Including an analysis of causes of death in future studies might further explain the mortality effect seen here.

Click to read the study in NEJM

Click to read an accompanying editorial in NEJM

This [multicenter randomized controlled trial] assigned comparable patients with new ARDS to HFOV or a conventional low-tidal-volume, high-PEEP ventilation strategy (with HFOV reserved for refractory hypoxemia). The trial was ended early as HFOV was associated with a higher in-hospital mortality than the conventional strategy (47% vs 35%, RR 1.33, 95% CI 1.09-1.64). The HFOV group also received more vasopressors, neuromuscular blockers and sedatives than the control group.

Further reading:

1. A prior trial demonstrating safety of HFOV

2. The OSCAR trial demonstrating similar results in the same issue

By [MP] and [MS]

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