Effect of noninvasive positive-pressure ventilation on survival in amyotrophic lateral sclerosis

Background: Noninvasive positive-pressure ventilation may benefit patients with amyotrophic lateral sclerosis and respiratory insufficiency. Objective: To determine 1) whether patients tolerant of noninvasive positive-pressure ventilation have better survival than intolerant patients and 2) whether bulbar symptoms account for intolerance of noninvasive positive-pressure ventilation. Design: Observational cohort study. Setting: Tertiary care referral center. Patients: 39 patients with amyotrophic lateral sclerosis who were treated with noninvasive positive-pressure ventilation. Intervention: Noninvasive positive-pressure ventilation was started for patients with new orthopnea, new hypercapnia, or both. Patients were divided into two groups: those tolerant of and those intolerant of noninvasive positive-pressure ventilation. Results: The risk for death from onset of respiratory insufficiency was higher for intolerant patients than for tolerant patients. (relative risk, 3.1 [95% CI, 1.8 to 9.6]). Moderate or severe bulbar symptoms were more prevalent among intolerant patients than among tolerant patients (67% compared with 33%; P = 0.04). Conclusions: Among patients with amyotrophic lateral sclerosis, those who are tolerant of noninvasive positive-pressure ventilation have better survival than do those who are intolerant. Bulbar symptoms partially account for intolerance of noninvasive positive-pressure ventilation.