Elsevier

Journal of Critical Care

Volume 31, Issue 1, February 2016, Pages 101-109
Journal of Critical Care

Cardiovascular/Thoracic
Thoracic ultrasound: Potential new tool for physiotherapists in respiratory management. A narrative review,☆☆

https://doi.org/10.1016/j.jcrc.2015.10.014Get rights and content

Abstract

The use of diagnostic ultrasound by physiotherapists is not a new concept; it is frequently performed in musculoskeletal physiotherapy. Physiotherapists currently lack accurate, reliable, sensitive, and valid measurements for the assessment of the indications and effectiveness of chest physiotherapy. Thoracic ultrasound may be a promising tool for the physiotherapist and could be routinely performed at patients' bedsides to provide real-time and accurate information on the status of pleura, lungs, and diaphragm; this would allow for assessment of lung aeration from interstitial syndrome to lung consolidation with much better accuracy than chest x-rays or auscultation. Diaphragm excursion and contractility may also be assessed by ultrasound. This narrative review refers to lung and diaphragm ultrasound semiology and describes how physiotherapists could use this tool in their clinical decision-making processes in various cases of respiratory disorders. The use of thoracic ultrasound semiology alongside typical examinations may allow for the guiding, monitoring, and evaluating of chest physiotherapy treatments. Thoracic ultrasound is a potential new tool for physiotherapists.

Introduction

The use of diagnostic ultrasound by physiotherapists is not a new concept [1]; it is frequently performed in musculoskeletal physiotherapy. Diagnostic ultrasound is noninvasive, is ionization-free, and can be performed rapidly at the patient's bedside for assessment and monitoring. The use of ultrasound for lung examination is increasingly gaining wide acceptance in emergency and critical care medicine [2], [3]. A recent narrative review by Leech et al [4] notes that physiotherapists typically use pulmonary auscultation and chest x-rays to assess and monitor their interventions. However, based on previous studies regarding auscultation, Leech et al [4] report a low interrater reliability and a low accuracy for identifying pleural effusion, alveolar consolidation, and alveolar interstitial syndrome (61%, 36%, and 55%, respectively). Those authors also highlight the fact that chest x-ray sensitivity and specificity are low at detecting pleural effusion (42% and 89%, respectively), interstitial syndrome (53% and 90%, respectively), and lung consolidation (53% and 90%, respectively) [4]. Finally, chest x-rays are not necessarily performed during a physiotherapist's intervention, which could yield inaccurate information about lung status. Thus, the limits of auscultation and chest x-rays are well described: the real effectiveness of chest physiotherapy is probably underestimated or overestimated, leading to excessive or inadequate treatment [4]. Thus, physiotherapists currently lack accurate, reliable, sensitive, and valid measurements for patient monitoring and assessments of the indications and effectiveness of chest physiotherapy [5]. The use of lung ultrasound (LUS) examination by physiotherapists to evaluate lung status in real time offers new insights [6]. The assessment of diaphragm function is another promising application of ultrasound, particularly in intensive care units (ICUs) during weaning from mechanical ventilation [7]. Leech et al [4] discuss the benefits for critical care physiotherapists of implementing LUS in their clinical practices and briefly propose applications in certain clinical situations. For example, LUS could be used to differentiate pleural effusion from lung collapse in the case of chest x-ray opacity. In this situation, LUS allowing a physiotherapist to know if a lung is recruitable or not could have the potential to influence physiotherapy treatment.

The objective of this narrative review is to detail the development of LUS for physiotherapists. This review refers to lung and diaphragm ultrasound semiology, and how thoracic ultrasound should be used at the patient's bedside for lung and diaphragm assessment. This review explores the literature and the LUS experiences of the authors to describe how physiotherapists may use this potential new tool in their clinical decision-making process.

Section snippets

Examination protocol

A simple machine with a microconvex probe (with a frequency of 2-4 MHz) is sufficient for performing a LUS examination. To explore the entire thorax, it is necessary to define examination areas. Two lines delimit the axillary space: the anterior and posterior axillary lines [8]. These lines define areas of investigation for each hemithorax—anterior, lateral, and posterior—each of which is divided into upper and lower parts. Each hemithorax includes 6 examination areas [2], [8]. The locations of

Maximal diaphragm excursion

One method to assess diaphragm function using ultrasound is to measure its displacement. The most commonly used method involves an anterior subcostal approach between the anterior axillary line and the midclavicular line [31], [32], [33], [34], [35]. B mode is initially used to determine the best approach and select the exploration line. The liver and spleen serve as an acoustic window that allows the visualization of the diaphragm (ie, bright lines that border these organs; Fig. 3A). After the

Guiding chest physiotherapy with LUS

Chest physiotherapy aims to improve airway clearance, alveolar recruitment, and ventilation/perfusion matching [43]. It typically involves many techniques that are often used in combination [44], and the selection of interventions depends on the type of pulmonary dysfunction assessed. For example, in the case of retained airway secretions, airway clearance techniques may be used to promote secretions removal, reducing airway resistance, optimizing lung compliance, and decreasing work of

Limitations

First, lung disorders that do not reach the pleura cannot be assessed by ultrasound. Second, dressings, subcutaneous emphysema, and obesity are obstacles to using LUS. The use of inadequate probes or settings and noncompliance with examination conditions are also limitations [3]. Finally, LUS must be used alongside clinical evaluations and should not be the only outcome measure used in clinical practice. As suggested by Leech et al [4], LUS may be used to answer a focused clinical question. The

Perspectives and research

For physiotherapists to perform LUS evaluations, they must possess extensive knowledge of anatomy, pulmonary physiopathology, and LUS semiology. Rigorous training and experience are required for LUS use [4]. Lung ultrasound is currently a diagnostic tool for intensivists, emergency physicians, and pulmonologists [8]. It is quite conceivable that a physiotherapist may use LUS to detect lung abnormalities and not to provide a medical diagnosis in order to select and reassess his/her physiotherapy

Conclusions

Diagnostic ultrasound performs significantly better than chest x-rays or auscultation at diagnosing lung deficiencies. Lung ultrasound provides relevant information about the lung and diaphragm statuses, which may indicate chest physiotherapy (eg, alveolar-interstitial syndrome and lung consolidation) or require the patient to be reviewed by the medical team (eg, pneumothorax and pleural effusion). Because the usual evaluation tools of physiotherapist (ie, clinical review, chest-x-ray, and

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    Support was provided solely by departmental sources.

    ☆☆

    None of the authors have any financial interest in the subject matter, materials, or equipment discussed or in any competing materials.

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