Level 1: Likely reliable evidence
Noninvasive ventilation reduces the need for intubation compared to standard medical care in adults with acute exacerbation of chronic obstructive pulmonary disease (COPD) (Lancet. 2000;355:1931-1935; Chin Med J [Engl]. 2005;118:2034-2040). There is also evidence that noninvasive ventilation may reduce mortality in these patients (Crit Care Med. 2002;30:555-562).
Alternatives to intubation are especially important in older patients who may have “do not intubate” (DNI) orders. A recent randomized trial evaluated the effects of noninvasive ventilation on mortality and need for intubation in elderly patients with hypercapnic respiratory failure (80% with COPD) (Age Ageing. 2011;40:444-450).
Eighty-two patients (mean age 81 years) were randomly assigned to noninvasive ventilation vs. standard medical therapy. Inclusion criteria included pH <7.35, respiratory rate >20 breaths/minute, and severe dyspnea. Need for intubation was defined as the presence of one major factor or two minor factors after one hour postrandomization. Major factors included no improvement or worsening of pH, deteriorating neurological status, loss of consciousness and hemodynamic instability with loss of alertness. Minor factors included continued dyspnea, respiratory rate >35 breaths/minute, and weak cough reflex with accumulation of secretions.
Noninvasive ventilation significantly reduced the need for intubation (7.3% vs. 63.4%; P<0.001, NNT 2), in-hospital mortality (2.4% vs. 14.6%; P=0.04; NNT 9), and total mortality at 12 months (39% vs. 61%; P= 0.014; NNT 5). The mean improvement in dyspnea score at one hour was 1.0 point in the ventilation group vs. 0.4 points in the standard-care group (on 0-10 scale, P= 0.05).
Additional analysis of these data suggests that noninvasive ventilation may reduce mortality compared to intubation in patients meeting intubation criteria. Only six patients who met the criteria (two from the ventilation group and four from the standard-care group) actually received intubation.
Due to DNI orders, a total of 22 patients (21 from the standard-care group) who met intubation criteria had noninvasive ventilation only as rescue therapy. In observational analysis based on treatment received, the highest mortality at 12 months was in the intubation group (83%). Mortality was 56% in patients who received only standard medical care and 43% in patients receiving ventilation (p <0.05 comparing ventilation vs. intubation).
Alan Ehrlich, MD, is a deputy editor for DynaMed, a database that provides evidence-based information on more than 3,000 clinical topics and is updated daily through systematic surveillance covering more than 500 journals. He is also an assistant clinical professor in Family Medicine at the University of Massachusetts Medical School in Worcester.