Alveolar Ventilation-Targeted vs. Spontaneous/Timed Mode for Home Non-Invasive Ventilation in Amyotrophic Lateral Sclerosis

Abstract

Introduction: Home noninvasive ventilation (NIV) is increasingly used in ALS to improve symptoms and survival. Our primary objective was to compare iVAPS vs. ST modes regarding time to first change in ventilator parameters and the number of interventions over 6 months in subjects with ALS in a respiratory therapist (RT)-led program.

Methods: In this study, 30 subjects with ALS meeting criteria for NIV initiation were randomized to iVAPS or ST. NIV was initiated using standardized protocols targeting optimal tidal volume and comfort in a daytime session. “Download” data was recorded at 1 week, 1 and 6 months. Any changes in ventilator parameters were recorded.

Results: Of the 30 subjects, 56.7% had bulbar onset ALS, 8 died and 11 in each group completed the study. Median time to first parameter change was 33.5 (IQR:7.7-96) vs. 41 (IQR: 12.5-216.5) days for iVAPS vs. ST groups, respectively (P = 0.48). The average number of RT interventions was similar between groups (1.1±1.1 vs 0.9±0.9 at 1 month, P = 0.72; 2.4±2.1 vs 2.4±2.3 at 6 months, P = 0.95; for iVAPS vs ST respectively). Adherence was significantly lower with iVAPS than ST at 1 week, but not at 1 or 6 months. Download parameters were similar between groups at 1 week and 6 months, except for higher residual apnea-hypopnea index (AHI) and less spontaneously triggered breaths with iVAPS at 6 months.

Conclusions: The time to first change of parameters and the number of interventions at 6 months from NIV initiation were similar for the iVAPS and ST modes in subjects with ALS. With iVAPS, adherence was lower transiently at NIV initiation, and the residual AHI was higher at 6 months. Alveolar ventilation-targeted NIV may require a longer adaptation period and result in greater upper airway instability in predominantly bulbar ALS subjects.