Spirometry--acceptability and reproducibility in spinal cord injured subjects

Area of Science:

• Pulmonary Medicine
• Neurology
• Rehabilitation Science

Background:

• The American Thoracic Society (ATS) provides guidelines for spirometry.
• Individuals with spinal cord injury (SCI) may have impaired respiratory muscle function, potentially affecting spirometry results.
• Hypothesis: SCI subjects exhibit poor spirometry test acceptability and reproducibility due to respiratory muscle weakness.

Purpose of the Study:

• To evaluate the acceptability and reproducibility of spirometry in individuals with SCI according to ATS criteria.
• To identify factors influencing spirometry test performance in SCI.
• To determine the feasibility of longitudinal respiratory function studies in SCI.

Main Methods:

• Seventy-eight subjects with SCI (39 with complete SCI) completed a respiratory questionnaire.
• Subjects performed spirometry maneuvers.
• Data were analyzed to assess adherence to ATS criteria, identify reasons for non-adherence, and evaluate reproducibility of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC).

Main Results:

• The proportion of complete SCI subjects meeting ATS criteria decreased with higher injury levels.
• Poor test performance was not linked to age, respiratory symptoms, or muscle fatigue.
• Excessive back extrapolated volumes (EBEV) was the most common reason for failing ATS acceptability criteria.
• Efforts failing only on EBEV and/or exhalation duration < 6 seconds showed reproducible FEV1 and FVC values.
• Reproducibility was comparable to other reported cohorts.

Conclusions:

• Standard ATS spirometry criteria may exclude SCI individuals with otherwise reproducible FEV1 and FVC.
• Spirometry in SCI subjects can yield reproducible results, even with minor deviations from ATS acceptability criteria.
• Longitudinal studies of respiratory function in SCI are feasible.