Effect of Hypercapnia Treatment on Respiratory Recovery after Spinal Cord Injury

Project Summary Abstract Title: Effect of Hypercapnia Treatment on Respiratory Recovery after Spinal Cord Injury. Respiratory and cardiovascular complications are the most common causes of death in the first year post-injury. Nearly 80% of patients with SCI, including Veterans, suffer from breathing and sleep disorders after six months of injury. However, most patients with SCI do not tolerate standard mechanical treatment leading to a lack of adherence. Therefore, identifying other therapies is important for this common condition linked to poor outcomes in the general population (heart disease, stroke, hypertension, and poor cognition). In individuals with SCI, it has been reported that chemical stimulation using acute intermittent hypoxia techniques improves ventilatory and motor recovery. The effect of intermittent hypoxia is dependent on the level of alveolar Carbon Dioxide (CO2) and may pose undesirable cardiovascular effects. However, the effect of hypercapnia alone on respiratory recovery during wakefulness and sleep in patients with SCI is unknown. The purpose of this application is to identify new therapeutic interventions for respiratory and sleep disorders in Veterans with SCI. This application proposes a pilot study to enroll 30 Veterans with SCI to receive two weeks of daily acute intermittent hypercapnia (dAIHc) treatment. There will be three specific aims to address the following hypotheses: Specific Aim (1): Measure the recruitment rate and feasibility of a pilot intervention using dAIHc in individuals with SCI. Specific Aim (2): Test the hypothesis that dAIHc will increase minute ventilation and respiratory muscle forces in individuals with SCI. Specific Aim (3): Test the hypothesis that dAIHc will improve sleep parameters in individuals with SCI.