Respiratory function monitoring in amyotrophic lateral sclerosis patients: 1-year analysis

Abstract

Introduction: Amyotrophic lateral sclerosis (ALS) is characterized by progressive lung function decline. Noninvasive ventilation (NIV) is initiated based on clinical and functional criteria, improving survival and quality of life.

Aim: To analyze clinical and respiratory function outcomes of ALS patients (pts) in charge in an outpatient clinic of a tertiary university hospital.

Methods: Retrospective analysis of ALS pts followed between January-December 2020.

Results: We included 71 pts (64.8% male), median age at diagnosis of 52±27 years. 16 pts (22.5%) had bulbar-onset ALS. At baseline, median slow vital capacity (SVC) was 3.1±1.9L, peak cough flow (PCF) 400±235L/min, oxygen saturation (StO2) 98±2% and nocturnal time with StO2<90% (T90) 1.9±14.8%. Older age at diagnosis correlated with worst SVC (r=-0.344; p=0.009) and PCF (r=-0.331; p=0.0012). Bulbar-onset had worst PCF (p=0.028) and T90 (p=0.009). 26 pts (36.6%) started mechanical in/ exsuflation, after a median time of 21±31 months. NIV was initiated in 51 pts (71.8%) at 9±20 months (median) after diagnosis (7±21 months in bulbar-onset and 10±21 months in spinal-onset (p=0.484)). Better SVC at diagnosis was associated to delay time to start NIV (r=0.318; p=0.004). Percutaneous endoscopy gastrostomy (PEG) was placed under NIV in 21 pts (29.6%). Tracheostomy was performed in 8 severe bulbar pts (11.3%), 34±50 months after diagnosis. 16 pts (22.5%) died during follow-up.

Measurements and Main Results: In these cohort, older age at diagnosis associated to worst SVC and PCF, whereas bulbar-onset pts had worst PCF and T90. Lung function evaluation was important to define NIV initiation, assisted cough and PEG strategies.