A comparison of maximal inspiratory pressure and forced vital capacity as potential criteria for initiating non‐invasive ventilation in amyotrophic lateral sclerosis

Abstract

Using a retrospective analysis of 161 patients with amyotrophic lateral sclerosis (ALS) from the Western ALS study group (WALS) database, the sensitivity of maximal inspiratory pressure (MIP)<−60 cm H₂O and forced vital capacity (FVC)<50% as US Medicare thresholds for initiating non‐invasive ventilation (NIV) were compared. Sixty‐five per cent of patients at enrollment met the MIP criterion, compared with only 8% of patients who met the FVC criterion. There were no cases in which FVC<50% antedated MIP<−60 cm H₂O. The longitudinal data showed that patients reached the MIP criterion 4 to 6.5 months earlier than the FVC criterion. For patients with clinical signs and symptoms needing treatment with NIV, a MIP<−60 cm H₂O allows US clinicians to obtain non‐invasive ventilatory support for patients earlier than if using the FVC criterion alone.

• Maximal inspiratory pressure
• forced vital capacity
• negative inspiratory force
• amyotrophic lateral sclerosis
• non‐invasive ventilation