Prognostic value of efficiently correcting nocturnal desaturations after one month of non-invasive ventilation in amyotrophic lateral sclerosis: A retrospective monocentre observational cohort study

Abstract

NIV adherence (‘quantity’ of ventilation) has a prognostic impact in amyotrophic lateral sclerosis (ALS). We hypothesized that NIV effectiveness (‘quality’) could also have a similar impact. NIV effectiveness was evaluated in 82 patients within the first month (M1) and every three months (symptoms, arterial blood bases, and nocturnal pulsed oxygen saturation − SpO₂). Kaplan-Meier survival and risk factors for mortality one year after NIV initiation were evaluated. Forty patients were considered ‘correctly ventilated’ at M1 (Group 1, less than 5% of nocturnal oximetry time with an SpO₂<90% − TS90) while 42 were not (Group 2). Both groups were comparable in terms of respiratory and neurological baseline characteristics. Survival was better in Group 1 (75% survival at 12 months) than in Group 2 (43% survival at 12 months, p = 0.002). In 12 Group 2 patients corrective measures were efficient in correcting TS90 at six months. In this subgroup, one-year mortality was not different from that in Group 1. Multivariate analysis identified independent mortality risk factors expectedly including bulbar involvement (HR = 4.31 (1.73 − 10.76), p = 0.002), ‘rapid respiratory decline’ (HR = 3.55 (1.29 − 9.75), p = 0.014) and vital capacity (HR = 0.97 (0.95 − 0.99), p = 0.010), but also inadequate ventilation in the first month (HR = 2.32 (1.09 − 4.94), p = 0.029). In conclusion, in ALS patients NIV effectiveness to correct nocturnal desaturations is an independent prognostic factor.

Key words::

• Amyotrophic lateral sclerosis
• ventilation
• chronic respiratory failure
• home mechanical ventilation
• nocturnal oximetry

Acknowledgements

JGB received congress travel support from Resmed SAS in 2008 and 2011. Logistical support was provided by the Association pour le Développement et l’Organisation de la Recherche en Pneumologie et sur le Sommeil − ADOREPS, a non-profit organization devoted to the promotion of respiratory and sleep research.

Declaration of interest: The authors have no conflicts of interest. The authors alone are responsible for the content and writing of the paper.