THE EFFECT OF OXYGEN ON PULMONARY MUSCLE FUNCTION IN PATIENTS WITH SPINAL CORD INJURY

Abstract

S421 INTRODUCTION: Pulmonary muscle dysfunction is common in Spinal Cord injury (SCI) patients [1] Depending on the level and degree of SCI, respiration may be impaired by paralysis of intercostal, accessory and abdominal muscles. Oxygen therapy has been shown to improve pulmonary function in normal volunteers [2]. The purpose of this study was to see if oxygen therapy might improve the pulmonary function of SCI patients. METHODS: This study was approved by Human Subjects Committee. SCI patients were eligible for study entry. Three groups of patients were studied. Group I - included quadriplegic patients with level of injury C1-C7, Group II - included paraplegic patients with level of injury T1-T7 and Group III - included paraplegic patients with level of injury T8-T12. We measured tidal volume (TV), respiratory rate (RR), labored breathing index (LBI) and oxygen saturation (SaO2) before and after oxygen administration (4L/min) in each patient. Tidal volume was measured using a spirometric flowmeter (Ohmeda 5410). Labored breathing index (LBI), an index of rib cage and abdominal respiratory muscle synchrony, was measured with a Respitrace (non-invasive monitoring system; NIMS; Miami Beach, Fl). The Respitrace uses a respiratory impedance plethysmographic method with two elastic bands, one band is placed around the rib cage (at the nipple line) and the other band is around the abdomen (at the umbilicus). Oxygen saturation was measured with a pulse oximeter (Ohmeda 3700). We evaluated the effect of oxygen on pulmonary function using 2-way ANOVA with post - hoc testing as appropriate. A p < 0.05 was considered statistically significant. RESULTS: Five patients were studied in each group Table 1Table 1A normal LBI is 1.0.; an LBI > 1.3 indicates dys-coordination between abdominal and rib cage respiratory muscles. DISCUSSION: Oxygen therapy significantly improved LBI. Cervical SCI patients had significantly higher LBI than thoracic SCI as measured by LBI and TV. The degree of pulmonary muscle dysfunction in SCI patients varies with the level of injury; the higher the level of injury, the greater the dysfunction. Cervical SCI patients had the worst breathing pattern and smallest TV.