Respiratory muscle pressures in non-CF bronchiectasis: repeatability and reliability.

Area of Science:

• Pulmonology
• Respiratory Medicine
• Clinical Physiology

Background:

• Respiratory muscle strength is a key diagnostic and outcome measure in chronic lung diseases.
• Limited data exists on the repeatability of respiratory muscle strength testing in non-cystic fibrosis bronchiectasis.
• This study addresses the need for repeatability data in this patient population.

Purpose of the Study:

• To assess the repeatability of maximal inspiratory pressure (P(I)max) and maximal expiratory pressure (P(E)max) measurements.
• To determine the reliability of these measures as outcome indicators in stable, moderate-to-severe non-CF bronchiectasis.
• To inform clinical practice and trial design regarding respiratory muscle strength assessment.

Main Methods:

• Twenty participants with stable, moderate-to-severe non-CF bronchiectasis were enrolled.
• Respiratory muscle strength was measured on two separate days using a standardized protocol.
• Three technically acceptable and reproducible readings (within 10% difference) were obtained for P(I)max and P(E)max.

Main Results:

• Maximal inspiratory pressures (P(I)max) demonstrated good repeatability (ICC=0.93, p=0.14).
• Maximal expiratory pressures (P(E)max) showed significant variability between tests (ICC=0.90, p=0.02).
• Limits of agreement indicated acceptable repeatability for P(I)max but not for P(E)max.

Conclusions:

• Maximal inspiratory pressure (P(I)max) is a repeatable measure in stable non-CF bronchiectasis, suitable as an outcome measure.
• A single baseline measurement for P(I)max may suffice, eliminating the need for a second visit.
• Maximal expiratory pressure (P(E)max) repeatability is questionable, necessitating further research into optimal testing protocols.