Reliability, validity and minimal detectable change of computerized respiratory sounds in patients with chronic obstructive pulmonary disease

INTRODUCTION

Computerized respiratory sounds (CRS) are closely related to the movement of air within the tracheobronchial tree and are promising outcome measures in patients with chronic obstructive pulmonary disease (COPD). However, CRS measurement properties have been poorly tested.

OBJECTIVE

The aim of this study was to assess the reliability, validity and the minimal detectable changes (MDC) of CRS in patients with stable COPD.

METHODS

Fifty patients (36♂, 67.26 ± 9.31y, FEV₁ 49.52 ± 19.67%predicted) were enrolled. CRS were recorded simultaneously at seven anatomic locations (trachea; right and left anterior, lateral and posterior chest). The number of crackles, wheeze occupation rate, median frequency (F50) and maximum intensity (Imax) were processed using validated algorithms. Within-day and between-days reliability, criterion and construct validity, validity to predict exacerbations and MDC were established.

RESULTS

CRS presented moderate-to-excellent within-day reliability (ICC_1,3  ≥ 0.51; P < .05) and moderate-to-good between-days reliability (ICC_1,2  ≥ 0.47; P < .05) for most locations. Negligible-to-moderate correlations with FEV₁ %predicted were found (-0.53 < r_s  < -0.28; P < .05), and the inspiratory number of crackles were the best discriminator between mild-to-moderate and severe-to-very severe airflow limitations (area under the curve >0.78). CRS correlated poorly with patient-reported outcomes (r_s  < 0.48; P < .05) and did not predict exacerbations. Inspiratory number of crackles at posterior right chest, inspiratory F50 at trachea and anterior left chest and expiratory Imax at anterior right chest were simultaneously reliable and valid, and their MDC were 2.41, 55.27, 29.55 and 3.98, respectively.

CONCLUSION

CRS are reliable and valid. Their use, integrated with other clinical and patient-reported measures, may fill the gap of assessing small airways and contribute toward a patient's comprehensive evaluation.

Effects of a respiratory physiotherapy session in patients with LRTI: a pre/post-test study

INTRODUCTION

The role of respiratory physiotherapy (RP) in lower respiratory tract infections (LRTI) has been questioned. However, studies have focused on hospitalised patients, and the presence/absence of an underlying disease has been neglected.

OBJECTIVES

To assess the effects of a RP session in community patients with LRTI and to explore the differences between patients with pneumonia (restrictive disease - AR) and those with exacerbations of an obstructive disease (AO).

METHODS

A pre/post-test study was conducted. A RP session was applied to patients with LRTI and crackles, wheezes, dyspnoea, perception of sputum and oxygen saturation were collected pre/post session. Comparisons were performed using paired t-tests or Wilcoxon tests.

RESULTS

Thirty patients (14 males, 55.23 ± 17.78 years) with pneumonia (AR, n = 12), exacerbations of chronic obstructive pulmonary disease, acute bronchitis and asthma (AO, n = 18) were enrolled. After treatment, the total sample presented lower wheeze rates at trachea (P = 0.02; r = -0.54) and less sputum (P = 0.01; r = -0.47). AR patients presented a decrease in the number of crackles (P < 0.05; 0.30 < d_z  < 0.26) and number and rate of wheezes at chest locations (P < 0.05; -0.56 < r < -0.48). AO patients showed an increase in the number of crackles (P < 0.05; 0.20 <d_z <0.31), wheeze frequency (P = 0.03; r = -0.27) and dyspnoea (P = 0.04; r = -0.55); and a decrease in the number of wheezes at trachea (P = 0.02; r = -0.54).

CONCLUSIONS

RP seems effective in reducing wheezes and perception of sputum in patients with LRTI. However, when considering AR and AO diseases separately, further changes in respiratory sounds and dyspnoea emerged. This highlights the importance of considering subgroups of patients with LRTI to develop RP evidence-base practice.