Is Prolonged Slow Expiration a Reproducible Airway Clearance Technique?

Abstract

Abstract Background Prolonged slow expiration (PSE) is a manual chest physical therapy technique routinely performed in clinical practice. However, the reliability and agreement of the technique have not been tested. Objective The objective of this study was to assess reliability and agreement between physical therapists during the application of PSE in infants with wheezing. Design This was a cross-sectional study. Methods Infants with a mean age of 59 weeks (SD = 26 weeks) were included in this study. Two physical therapists (physical therapist 1 and physical therapist 2) randomly performed 3 PSE sequences (A, B, and C). The expiratory reserve volume (ERV) was measured with a pneumotachograph connected to a face mask. ERV was used to evaluate the reproducibility of the technique between sequences and between physical therapist 1 and physical therapist 2. Results The mean ERV of the infants was 63 mL (SD = 21 mL). There was no statistically significant difference between the ERV values in the 3 sequences for physical therapist 1 (A: mean = 46.6 mL [SD = 17.8 mL]; B: mean = 45.7 mL [SD = 19.9 mL]; C: mean = 53.3 mL [SD = 26.3 mL]) and physical therapist 2 (A: mean = 43.5 mL [SD = 15.4 mL]; B: mean = 43.2 mL [SD = 18.3 mL]; C: mean = 44.8 mL [SD = 25.0 mL]). There was excellent reliability between the sequences for physical therapist 1 (ICC = 0.88 [95% CI = 0.63–0.95]) and physical therapist 2 (ICC = 0.82 [95% CI = 0.48–0.93]). Moderate agreement was observed between physical therapist 1 and physical therapist 2 (ICC = 0.67 [95% CI = 0.01–0.88]). According to Bland-Altman analysis, the mean difference between physical therapist 1 and physical therapist 2 was 4.1 mL (95% CI = −38.5 to 46.5 mL). Limitations The data were collected in infants with wheezing who were not in crisis. This decreased lung mucus; however, it also reduced evaluation risks. Conclusions PSE was a reproducible chest physical therapy technique between physical therapists.