THE EFFECT OF CONTINUOUS POSITIVE AIRWAY PRESSURES ON LUNG-VOLUMES INTETRAPLEGIC PATIENTS

Continuous positive airway pressure (CPAP) is widely advocated for the treatment of respiratory complications. However the effects of CPAP o n the respiratory function of tetraplegic patients have not yet been i nvestigated. The purpose of this study was to examine the effects of b reathing with different levels of CPAP on the relationship between clo sing volume (CV) and functional residual capacity (FRC) in ten recentl y injured, but otherwise healthy tetraplegic patients with lesions bet ween the fourth and eighth cervical segments. Lung volumes were measur ed before, during and after 32 min of zero end-expiratory pressure and 5 and 10 cm H2O of CPAP. FRC was measured by the open-circuit nitroge n washout method and CV was measured by the single breath nitrogen was hout method. FRC was unaffected by zero end-expiratory pressure, but b oth 5 cm H2O and 10 cm H2O of CPAP caused significant increases in FRC . FRC returned to pre-CPAP values by the first minute after removal of 5 and 10 cm H2O of CPAP. We were unable to measure CVs in any subject s. It was concluded that 5 and 10 cm H2O of CPAP increase FRC in healt hy tetraplegic individuals, but that these increases are rapidly lost with the subsequent removal of CPAP. These results suggest that CPAP m ay have a role in the treatment and prevention of respiratory complica tions in tetraplegics.