Risk factors of unfavorable outcomes in chronic obstructive pulmonary disease patients treated with noninvasive ventilation for acute hypercapnic respiratory failure

Background-aim: Noninvasive mechanical ventilation (NIV) failure rate is reported to be 5%-60% of intensive care unit (ICU) patients. Despite all precautions and well-known reasons, the risk factors of NIV failure are unclear for chronic obstructive pulmonary disease (COPD) with acute respiratory failure (ARF). The aim of this study was to examine risk factors for NIV failure in COPD patients with ARF, other than well defined.

Methods: The retrospective cohort study was done in ICU of a chest disease hospital. All consecutive COPD patients with hypercapnic ARF were enrolled in study. Demographics, comorbidities, arterial blood gases, reasons of ARF and length of ICU stay were recorded. NIV success was defined as discharge from ICU and NIV failure was defined as need for intubation or died during NIV. Patients were grouped into; NIV failure and success. The groups were compared and NIV failure risk factors were analyzed.

Results: About 265 NIV success and 142 NIV failure patients were enrolled into the study. Logistic regression test showed the risk factors for NIV failure; higher APACHE-II (≥ 29) (OR:11.71, CI95%4.39-31.18, P < 0.001), culture positivity (OR:7.59, CI95%3.21-17.92, P < 0.001), sepsis (OR:6.53 CI95%3.59-11.85, P < 0.001) and pneumonia (OR:3.71 CI95%0.60-2.02, P < 0.043) significantly. COPD patients using home-based NIV had less risk for NIV failure (OR: 0.49 CI95%0.28-0.87, P < 0.014).

Conclusions: APACHE II ≥ 29 score, culture positivity, sepsis and pneumonia are the risk factors for NIV failure in COPD patients with ARF. COPD patients previously on home-based NIV showed half times less risk for NIV failure.