Static respiratory pressures in patients with post-traumatic tetraplegia.

The purpose of this study was to examine ventilatory muscle strength as represented by static respiratory pressures in 30 tetraplegic patients with a complete lesion between the fifth and the eighth cervical vertebrae. The Inspiratory/Expiratory Pressure Meter was used to obtain maximum static expiratory mouth pressure (PEmax) and maximum static inspiratory mouth pressure (PImax) measurements. The PEmax was measured at vital capacity and the PImax at residual volume. The measurements were effected while the patient was in the supported sitting position. The mean PEmax for the group was 50 cm H2O and the mean PImax was -65 cm H2O. There was a significant difference between the PEmax and PImax values. Unlike normal individuals most tetraplegic subjects in this study showed PImax values to be much higher than their PEmax values.