Is the success of positive pressure ventilation dependent on the level of care?

Objective

To report our experience with positive pressure ventilation (PPV), pressure support ventilation or assisted-controlled pressure mechanical ventilation mode, delivered by face mask (nine patients) or tracheostomy (one patient) in acute hypercapnic respiratory failure (AHRF).

Design

An observational study.

Setting

A respiratory care unit.

Patients and intervention

Ten patients with AHRF, related to bronchial superinfection or pneumonia, were treated with PPV. The mean (± standard deviation) PaCO₂ and pH at entrance were, respectively, 95.96 ± 12.86 mmHg and 7.29 ± 0.05.

Results

PPV resulted in a significant improvement in PaCO₂ (from 95.96 ± 12.86 mmHg to 73.72 ± 10.95 mmHg) and pH (from 7.29 ± 0.05 to 7.39 ± 0.05) within 2 hours. However, NIMV was discontinued in three patients (33%) after more than 5 days and endotracheal intubation was required because of inability to wean (one patient) or to manage bronchial secretions (two patients).

In the other patients NIMV was effective in improving PaCO₂ (from 95.96 ± 12.86 mmHg to 51.16 ± 11.75 mmHg) and pH (from 7.29 ± 0.05 to 7.40 ± 0.06). Five patients continued mechanical ventilation at home.

Conclusion

Application of PPV is feasible outside the ICU, also when baseline pH should indicate admission to the ICU (pH < 7.25 in three patients) or the respiratory intermediate care unit (pH < 7.3 in one patient). Since all these patients but one avoided endotracheal intubation, whereas two patients with pH > 7.3 were intubated, arterial blood pH at entrance probably does not predict success or failure and it is not suitable to decide the level of care.