Evaluation of water immersion level on respiratory function of tetraplegic patients undergoing hydrotherapy

Background: Hydrotherapy plays an important role in the rehabilitation of patients with spinal cord injury (SCI). In healthy subjects, immersion reduces pulmonary volumes. The effects of immersion on tetraplegic SCI subjects (a population with potential respiratory failure and increased abdominal compliance) are not as well known. Study aim: To observe the influence of two levels of immersion on the pulmonary function of tetraplegic SCI subjects, undergoing hydrotherapy as a part of their rehabilitation program. Methods: Ten adult spinal cord injury tetraplegic subjects (level of injury ranging from C4 to C7, ASIA A), at least three months post injury were included in a prospective open label study. Evaluation of pulmonary function was carried out in air, and in water in two levels of immersion (cervical and xyphoid). Lung volumes, forced ventilatory flows and static mouth pressures were measured. Respiratory comfort was evaluated. Results: Functional residual capacity increasingly and significantly decreased with immersion level, resulting from a fall of both residual volume and expiratory reserve volume while vital capacity remained stable. Maximal respiratory pressures remained stable regardless level of immersion while respiratory comfort tended to decrease with increasing depth of immersion. Conclusions: Lung volumes changes observed in SCI tetraplegic patients follow a similar pattern to that observed in healthy subjects. Water immersion level does not seem to be a limiting factor for the use of hydrotherapy in this population.