Inter-rater reliability of a wright respirometer to measure vital capacity in neuromuscular disorders

[Purpose] We examined the inter-rater reliability of the Wright respirometer between therapists who assessed the vital capacity of patients with neuromuscular disorders. [Participants and Methods] We examined 18 patients with neuromuscular disorders. We performed a test-retest method after measuring their vital capacities. Two physical therapists experienced in the use of the Wright respirometer, specifically, therapist A with six years of clinical experience and therapist B with one, each took one measurement of the vital capacity of the same patients. The measurements between the therapists were taken at intervals of 3–7 days. We made a manual to standardize the measurements between the therapists. [Results] The vital capacities were 905 ± 490 mL for therapist A and 897 ± 483 mL for therapist B. The inter-rater reliability of ICC(2,1) was 0.96 (95% CI: 0.89–0.98). Bland-Altman analyses revealed neither a fixed nor proportional bias. [Conclusion] These results demonstrated good to excellent inter-rater reliability of the Wright respirometer for patients with neuromuscular disorders using a manual and instructions.