Quantification of changes in lung aeration associated with physiotherapy using lung ultrasound in mechanically ventilated patients: a prospective cohort study

Abstract

Background: Lung ultrasound (LUS) is a novel and emerging tool for physiotherapists in ICU and may provide a way of monitoring lung aeration change in response to respiratory physiotherapy treatment during a patient's ICU stay. Objective: To measure change in the LUS score associated with a respiratory physiotherapy treatment; to determine whether change in LUS score correlates with other physiological measures. Design and setting: A single-centre prospective cohort study was undertaken in a tertiary teaching hospital in Sydney, Australia. Patients: Adult mechanically ventilated patients in ICU with suspicion of atelectasis. Measurements: Primary outcome: pre-post difference in LUS score. Secondary outcomes: PaO2/FiO2 (PF) ratio, tidal volume (VT), lung auscultation score, driving pressure (DP) and the modified radiological atelectasis score (mRAS) on CXR. Results: 43 patients were included. There was a mean improvement in total LUS score after physiotherapy treatment of − 2.9 (95%CI −4.4, −1.4), and a mean improvement in LUS of the right and left lungs of − 1.6 (−2.5, −0.7) and − 1.3 (−2.5, −0.1) respectively. There was a mean improvement in PF ratio, VT and auscultation score of 10.4 (−11.89, 32.7), 19 (−7.4, 44.5) and − 1.8 (−2.6, −1.0) respectively. There was no improvement in mRAS or DP. There was a weak correlation between change in LUS score compared with change in mRAS score. Limitations: Limitations included the prospective cohort single site design and the small sample size. Conclusions: The LUS score can be used to detect changes in lung aeration associated with respiratory physiotherapy treatment for acute lobar atelectasis in mechanically ventilated patients. Australian and New Zealand Clinical Trials Registry Number: ACTRN12619000783123. Contribution of the Paper: • Assessment and measurement tools currently used by physiotherapists lack diagnostic accuracy. Lung ultrasound has high diagnostic accuracy in detecting pathologies pertinent to physiotherapists and may be helpful in monitoring treatment response. • The lung ultrasound score detects changes in lung aeration associated with respiratory physiotherapy treatment. • This study highlights lung ultrasound as a potential new tool for lung monitoring for physiotherapists in ICU.