Can Non-invasive Ventilation Settings Predicts Functional and Survival Outcome in ALS Patients?

Introduction: The lack of more specific tools, with low costs, that may be associated with the ALSFRS-R (Amyotrophic Lateral Sclerosis Functional Scale-Revised) score to assist in analyzing the prognosis, is a constraint factor in the follow-up of ALS ventilated patients. Objective: we analyzed the potential predictors of ALSFRS-R functional decline related to Non-Invasive ventilation (NIV) settings, Nocturnal Pulse Oximetry (NPO), and Pulmonary Function Test (PFT). Methods: Prospective, comparative trial of 60 consecutive ALS patients, compliant to NIV, during 5 years of follow-up. Subjects were assigned to Group 1 (not-survivors) or Group 2 (survivors) at end of study. Data from ALSFRS-R, NPO, PFT and NIV settings were collected once each three months. Results: No clinical or laboratory differences were observed between groups for any variable at admission. Disease duration from onset as well as Total use of NIV presented non-significant differences at end of study. However, these 2 variables were correlated positively with Expiratory Positive Airways Pressure (EPAP), Inspiratory Positive Airways Pressure (IPAP) and backup breath rate (all parameters of NIV), maximal inspiratory pressure (MIP-PFT), and SpO2mean (NPO). Multivariate Cox regression analysis showed that data from NIV settings and PFT were predictors of functional decline. Conclusions: For the first time, determinants of functional decline are significantly related to NIV equipment settings as well as to compliance data.