Bronchodilator responses to metaproterenol sulfate among subjects with spinal cord injury

A previous study using spirometric methods demonstrated that 42% of subjects with tetraplegia experienced significant bronchodilation following inhalation of metaproterenol sulfate (MS). Comparative studies involving subjects with paraplegia were not performed and none has been performed in this population using body plethysmography, a more sensitive method used to assess airway responsiveness. Stable subjects with tetraplegia (n = 5) or paraplegia (n = 5) underwent spirometry and determination of specific airway conductance (sGaw) by body plethysmography at baseline and 30 minutes after nebulization of MS (0.3 mL of a 5% solution). Among subjects with tetraplegia, inhaled MS resulted in significant increases in spirometric indices and sGaw. Among subjects with paraplegia, only sGaw increased significantly, although this increase was considerably less than that seen in subjects with tetraplegia. Our findings indicate that subjects with tetraplegia exhibit greater bronchodilation in response to inhaled MS than do subjects with paraplegia and that sGaw measurements may confer greater sensitivity for assessing bronchodilator responsiveness in tetraplegia.