Weaning from mechanical ventilation in COPD patients: interest to measure, in post-extubation, the airway occlusion pressure (P0.1), in order to indicate non-invasive pressure support ventilation (NIPSV) to prevent relapse

Aims of the study

Methods of NIPSV are being proposed more and more for acute exacerbations of COPD (Brochard: N Engl J Med 1995, 333:817-822) and also for respiratory insufficiency observed after extubation (Meduri: Chest 1996, 109:179-193). Objective of our prospective study: to compare parameters measured just before extubation, then in post-extubation, between COPD patients who have benefitted from NIPSV (group I) to those who did not necessitate NIPSV (group II) after weaning with pressure support (PS) ventilation.

Patients and methods

Twenty-eight COPD patients completed the study. In group I (n = 10), patients had suspected ventilatory muscle fatigue after weaning from mechanical ventilation. They presented, in 72 h post-extubation, a markup of PaCO₂ of at least 20% as compared to the value measured post-extubation, and a respiratory rate > 25/min. Eighteen patients entered in group II.

We measured (Ventilator = EVITA 2 - Dräger°) P0.1, respiratory rate (RR), RR/V_T, PaO₂, PaCO₂, (i) before extubation, with PS = 6 crnH₂O, then (ii) in postextubation, during a session of facial mask ventilation of 30 min, with PS = 4 cmH₂O. We compared the two groups of patients using Mann-Whitney U test for quantitative variables.

Results

See table.

Conclusion

P0.1 measured in postextubation seems to be a valuable index to indicate promptly NIPSV in order to prevent relapse after weaning from mechanical ventilation, in COPD patients.

Table