Ventilation mode effect on weaning outcome in COPD with type II respiratory failure.

OBJECTIVE

To compare adaptive support ventilation (ASV) with synchronized intermittent mandatory ventilation plus pressure support ventilation (SIMV+PSV) in patients with chronic obstructive pulmonary disease (COPD) and type II respiratory failure, and to identify predictors of weaning failure.

METHODS

This retrospective study classified patients into ASV and SIMV+PSV groups based on ventilation mode received. We collected blood gas values, respiratory mechanics (peak inspiratory pressure [Ppeak], plateau pressure [Pplat], mean airway pressure [Pmean]), pulmonary function indices, and clinical outcomes. Pulmonary function was not measured during invasive mechanical ventilation. Baseline values were obtained from stable pre-intubation records, and post-treatment values were assessed after successful extubation in awake, cooperative, and clinically stable patients. Firth-corrected logistic regression identified independent predictors of weaning failure.

RESULTS

Both groups showed similar improvements in blood gas values. ASV achieved greater reductions in Ppeak, Pplat, and Pmean, and larger improvements in forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow rate (PEFR), which were assessed after successful extubation, compared to SIMV+PSV (all P<0.001). The ASV group had lower ventilator-associated pneumonia (VAP) incidence (P=0.023), reintubation rate (P=0.042), and weaning failure rate (P=0.007); in-hospital mortality did not differ. Higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score, pre-treatment arterial carbon dioxide tension (PaCO2), pre-treatment Pplat, and SIMV+PSV mode independently increased weaning failure risk, whereas higher pre-treatment pH and FEV1 were protective (all P<0.05).

CONCLUSION

ASV reduced airway pressures, improved post-extubation pulmonary function, and was associated with fewer VAP events, reintubations, and weaning failures than SIMV+PSV in COPD patients with type II respiratory failure.