Use of noninvasive positive pressure ventilation (NIPPV) to treat acute exacerbations of chronic obstructive pulmonary disease (COPD) is on the rise, and the use of invasive mechanical ventilation is falling, according to researchers querying a large national database of hospital admissions. Coinciding with the shift in practice: a steady reduction in the overall mortality from COPD exacerbations since 1998. The data corroborates nicely what’s known from randomized trials: NIPPV prevents the need for invasive mechanical ventilation during COPD exacerbations.
Concerningly, however: also on the rise is the number of patients failing NIPPV and requiring invasive mechanical ventilation — and these patients died at an alarming rate (29%).
In this interesting look at real-world clinical practice and outcomes, Lewis Satterwhite, Fernando Holguin, Divay Chandra et al used the National Inpatient Sample to identify 612,650 admissions for COPD exacerbations between 1998-2008 that necessitated ventilatory support.
Over that time period, use of NIPPV increased 462% (rising from 1% to 4.5% of all admissions for COPD exacerbations). Invasive mechanical ventilation fell by 42% (from 6% to 3.5%).
Only about 1 in 20 patients (5%) treated with NIPPV failed and required transition to invasive mechanical ventilation, according to their data. However, those who did had an alarming 29% mortality rate. Because the absolute number of people treated with NIPPV has risen dramatically, this cohort has also steadily increased in size, to about 1,500 people (and about 500 deaths) per year.
Like the favorable mortality data, this latter finding also follows from previous clinical trials: people who are failing NIPPV may die unnecessarily if their respiratory failure goes unrecognized and they are not quickly intubated. Although authors emphasize they can’t conclusively say why those failing NIPPV died more often, it’s a possible explanation.
The authors also dare to propose the theory that this observed failure of NIPPV leading to death on IMV may not be due to poor recognition or management by physicians, but rather the inevitability of death in some people with severe COPD. This cohort could represent a group of selected patients with end-stage, severe COPD who were expected not to survive invasive mechanical ventilation and were initially placed on NIPPV in the hopes of avoiding their death on a ventilator. As the patients deteriorated and end-of-life discussions were inconclusive, they were intubated and died later, often after prolonged ICU stays on the ventilator. Their data supports the theory: this group had the longest hospitalizations, and the highest mortality of all patients. A prospective cohort study could help explain this phenomenon more definitively (but just don’t call it a death panel).
Chandra D et al. Outcomes of Noninvasive Ventilation for Acute Exacerbations of Chronic Obstructive Pulmonary Disease in the United States, 1998–2008. Am J Respir Crit Care Med 2012;185:152-159.