RELEVANT FACTORS OF NON-INVASIVE POSITIVE PRESSURE VENTILATION FAILURE IN THE COPD PATIENTS WITH SEVERE RESPIRATORY FAILURE

Objective To study the failure-related factors in the treatment of severe respiratory failure due to chronic obstructive pulmonary disease (COPD) using non-invasive positive pressure ventilation (NIPPV), and to find the time that NIPPV be replaced by invasive ventilation when NIPPV failure occurs. Methods Sixty-seven patients with severe respiratory failure due to COPD were investigated and divided into NIPPV failure group and NIPPV success group. Physiological and clinical parameters were studied comparatively between two groups. Factors associated with failure of NIPPV were analyzed. Results Failure rate of NIPPV was 37.31% (25/67). PaCO_2 were higher ,and PaO_2 and pH were lower significantly in patients in NIPPV failure group, compared with NIPPV success group (t=4.13-6.87,P0.05). Logistic regression analysis showed that the NIPPV failure was significantly associated with PaO_26.0 kPa, PaCO_210.0 kPa and pH7.10. In NIPPV success group, there was obvious improvement of PaO_2, PaCO_2 and pH at two and six hours after NIPPV therapy compared with baseline (t=3.49-6.35,P(0.05)). In NIPPV failure group, there was not statistical difference in arterial blood gas between after and before NIPPV therapy. (Conclusion NIPPV) failure in patients with severe respiratory failure due to COPD is influenced by markedly abnormal PaO_2, PaCO_2 and pH. Improvement of arterial blood gas within 6 hours after NIPPV is an index for predicting the success of the treatment.