What determines immediate use of invasive ventilation in patients with COPD?

The choice between non-invasive ventilation (NIV) and invasive ventilation in patients with an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) may be irrational. The aim of this study was to examine those patient characteristics, and circumstances deemed important in the choice made between NIV and invasive ventilation in the intensive care unit (ICU).

We first examined 95 admissions of AECOPD patients on nine ICUs and identified variables associated with invasive ventilation. Thereafter, a questionnaire was sent to ICU personnel to study the relative importance of different factors with a possible influence on the decision to use invasive ventilation at once.

Univariable analysis showed that increasing age [odds ratio (OR) 1.06 per year] and increasing body mass index (BMI) (OR 1.11 per kg/m(2) ) were associated with immediate invasive ventilation, while there was no such association with arterial blood gases or breath rate. BMI was the only factor that remained associated with immediate invasive ventilation in the multivariable analysis [OR 1.12 (95% confidence interval 1.03-1.23) kg/m(2) ]. Ranking of responses to the questionnaire showed that consciousness, respiratory symptoms and blood gases were powerful factors determining invasive ventilation, whereas high BMI and age were ranked low. Non-patient-related factors were also deemed important (physician in charge, presence of guidelines, ICU workload).

Factors other than those deemed most important in guidelines appear to have an inappropriate influence on the choice between NIV and immediate intubation in AECOPD in the ICU. These factors must be identified to further increase the appropriate use of NIV.