Comparative study of two different modes of noninvasive home mechanical ventilation in chronic respiratory failure

Summary

Study objective

Two modes of noninvasive home mechanical ventilation (NIHMV) with volumetric ventilators were compared in patients with chronic respiratory failure.

Design

Retrospective, parallel-group, comparative study.

Setting

Third-level teaching Hospital in Barcelona (Spain).

Patients and methods

We studied 110 patients with chronic hypercapnic respiratory failure secondary to neuromuscular disease, kyphoscoliosis or post-tuberculosis sequelae, starting NIHMV with volumetric ventilators. The assist/control (A/C) ventilation mode was used in 45 patients and the control (C) mode in 65 patients. Clinical characteristics, pulmonary function results and arterial blood gas findings were assessed in each patient before establishing ventilation and at 6 and 12 months after. The patient's satisfaction with ventilation, the time required for adaptation, and compliance with the prescription were also assessed.

Measurements and results

Significant improvements in PaO₂ and PaCO₂ ($P<0.001$) were found at 6 and 12 months with both modes of mechanical ventilation. There were no significant differences between the two modes for pulmonary function or blood gas parameters with the exception of maximum inspiratory pressure (MIP) in patients receiving the C mode, which was significantly different as compared to the baseline value after 12 months of use (mean±sd: 36.6±14.8 and 44.7±24.2 cmH₂O, respectively; $P=0.010$). No significant differences were found in adaptation, compliance with ventilation or patient satisfaction between the two modes studied.

Conclusions

According to several factors analysed, results with the A/C or C mode used with volumetric ventilators appear to be comparable in patients with chronic respiratory disease receiving NIHMV. Choice of mode will depend on the acquired experience of the prescribing physicians in each centre.