Randomized Trial of Low Expiratory Pressure Non-Invasive Ventilation for ALS (P3.179)

Objective: This pilot ALS trial investigates usage of noninvasive ventilation (NIV) with inspiratory-only positive airway pressure (IPAP) compared with bi-level positive airway pressure (PAP). Background: NIV administered as bi-level PAP improves survival in ALS patients. Yet, due to intolerance, only a proportion of ALS patients can use bi-level PAP. Because the expiratory airway pressure of bi-level PAP increases the workload of breathing, IPAP may result in increased NIV use compared with bi-level PAP. Design/Methods: This is a randomized, controlled, single-blind (subject), 2-period (AB/BA) cross-over pilot trial. Patients with ALS already using bi-level PAP were randomized to a 6-week period of standard bi-level PAP and 6-week period of IPAP-only in random order. Both treatments were administered with a laptop ventilator. Objective hours of use were obtained from the ventilator hour meter for weeks 2-6 of each treatment period. Results: Of the 28 subjects randomized, 14 subjects began IPAP; 11/14 completed the first period and 10/14 completed the second period (bi-level PAP). Of the 14 subjects beginning bi-level PAP, 7/14 completed the first period and 6/14 completed the second period (IPAP). From 17 subjects with data from both periods, the median weekly use of NIV during the IPAP period was 52.8 hours (IQR: 17.2, 72.6) and for the bi-level PAP period was 42.8 hours (IQR: 11.8, 67.0). No difference was identified in weekly hours of use between IPAP and Bi-level PAP (linear repeated measure model; p=0.75). No crossover effect was identified (p=0.94). Of the 16 subjects who provided preference data at study conclusion, 12 (75[percnt]) definitely or probably preferred IPAP to bi-level PAP. Conclusion: In ALS patients using NIV, IPAP was not associated with increased use over bi-level PAP but was preferred by patients. IPAP NIV should be explored further in ALS. Study Supported by: ALS Association Disclosure: Dr. Jacobs has nothing to disclose. Dr. Brown has nothing to disclose. Dr. Berrocal has nothing to disclose. Dr. Funckes has nothing to disclose. Dr. Gruis has received personal compensation from Alnylam Pharmaceuticals.