Non-invasive Ventilation in Amyotrophic Lateral Sclerosis (ALS) Using the iVAPS Mode

Overview

Home non-invasive ventilation (NIV) is the standard-of-care as initial therapy for patients with ALS with worsening symptoms or deteriorating respiratory function, and has been recommended by the American Academy of Neurology (AAN) practice parameter for ALS. This study will compare the current standard BiST mode of ventilation with the new iVAPS mode. The main study hypothesis is that the iVAPS mode, initiated in a single daytime trial, will result in a reduction of the number of respiratory therapist interventions and changes in ventilator settings as compared with the standard BiST mode. This will be assessed over a period of one year. In addition this study will test whether the iVAPS mode is superior to BiST mode with respect to: comfort and ease of use; improvement in nighttime and daytime symptoms of hypoventilation; compliance (hours used per day); physiologic parameters (daytime and overnight oxygen saturation and transcutaneous CO2 level).

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder that is incurable, progressive, manifested by muscle weakness and wasting, and caused by degeneration of motor neurones. The limited data available suggest the incidence of ALS in Canada to be approximately 2 per 100,000 persons. The disease is characterized by progressive weakness of respiratory muscles, leading to respiratory insufficiency which is often the cause of death in patients with ALS. Home non-invasive ventilation (NIV) is the standard-of-care as initial therapy for patients with ALS with worsening symptoms or deteriorating respiratory function, and has been recommended by the American Academy of Neurology (AAN) practice parameter for ALS. The symptomatic and survival benefits offered by NIV to patients with ALS make the optimization of ventilation a priority in terms of physiological variables but also symptoms to improve comfort, and consequently, compliance. The Intelligent Volume-Assured Pressure Support (iVAPS) is a ventilator mode on the Stellar 150 ventilator (Resmed) that uses an algorithm to target alveolar ventilation. It has a learning mode to determine the initial optimal settings to commence ventilation, and is an adaptive mode, which constantly monitors the patient's spontaneous ventilation and adjusts the level of pressure support to maintain target alveolar ventilation. The aim of the study is to determine the feasibility of long-term non-invasive home ventilation in ALS patients using the Stellar 150 IVAPS mode, initiated during a single daytime trial, and to assess the number of respiratory therapist interventions subsequently required as well as several patient-centered outcomes. The study will be conducted among patients with ALS referred to the National Program of Home Ventilatory Assistance (NPHVA) at the Montreal Chest Institute. The province-wide program provides home ventilation services to patients with a variety of neuromuscular and other disorders. Referred patients will be randomized to receive traditional Bilevel ventilation in ST mode (BiST) or iVAPS and will be followed over a period of one year. Respiratory therapist interventions (beyond scheduled visits) and changes in ventilator settings will be based on patient complaints and aimed at optimizing patient comfort and ventilator use. In addition, symptoms questionnaires will be administered regularly, overnight oxymetry and transcutaneous capnography (at 6 and 12 months) will be performed. Compliance data will be assessed regularly from ventilator memory downloads at each of the scheduled respiratory therapist home visits (1 week, 1, 6 and 12 months).