Physiotherapy-led Lung Ultrasounds in Preterm Infants

Aim

This study aimed to evaluate the impact of lung ultrasound (LUS) compared to currently used tools in guiding chest physiotherapy (CPT) decision-making in critically unwell neonates. It was hypothesised that LUS would improve diagnostic decision-making, thereby enhancing safety and efficacy of CPT.

Outcomes

Primary outcome:

Net reclassification improvement (NRI), quantifying how frequently CPT diagnosis and treatment were changed following the addition of a LUS assessment to standard CPT assessment tools.

Secondary outcomes:

1. Diagnostic concordance (agreement) between standard tools and LUS

2. Physiotherapist confidence in diagnoses

Results:

From 30 included cases, the NRI was 40% (p=0.238), indicating LUS did not have a statistically significant effect on physiotherapist decision-making, but was similar to that found in adult CPT study. Diagnostic concordance was significant (0.595 p<0.001) and observed in 21 (70%) cases. In 9 cases (30%) CPT diagnosis and treatment was changed as a result of LUS. Confidence increased significantly by 1.16/7 points (p<0.001) after LUS.

Background

Chest physiotherapy (CPT) plays a pivotal role in managing certain lung pathologies in preterm neonates (1). CPT utilises various manual and positioning techniques to clear airway secretions, thereby reducing resistance to breathing and improving lung expansion and oxygenation. Delivering CPT in unwell preterm infants is not without risk however and inappropriate or incorrect use can be of no benefit, or at worst, potentially harmful.

To ensure CPT is appropriately and effectively administered in preterm infants, neonatal physiotherapists require measurement tools that can accurately and quickly identify the location, severity, and type of lung pathology to determine the necessity for, and consequence of undertaking CPT treatment (2). This is of particular importance in the Neonatal Intensive Care Unit where infants are physiologically very fragile and where lung pathology can develop or change rapidly. Discerning, reliable, and feasible measurement tools are therefore essential to neonatal physiotherapists to ensure CPT delivery is effective, safe, and individualised to each baby. To date, however, no recognised ‘gold standard’ measurement tool has been identified to guide CPT use in preterm infants, and research has raised concerns around the clinimetric strength of standardly used measurement tools in this cohort (3,4).

Typically, neonatal physiotherapists rely on auscultation and chest xray (CXR) to make decisions about the presence. location and type of lung pathology. These tools give have either poor accuracy, (auscultation), expose the infant to radiation (CXR) or lack clinical utility (CT scan). Lung ultrasound (LUS), however, has emerged as a tool that is radiation-free, has robust clinimetric properties and can be used by the bedside to provide real-time information to guide CPT intervention with minimal patient disruption. LUS has been used successfully as a CPT tool in adult and paediatric cohorts, however no data exists about its use and benefit in preterm infants. This study therefore aimed to investigate whether the addition of LUS to standard assessment tools in preterm infants improved physiotherapist diagnosis and treatment decisions, and whether this additional information also impacted therapist confidence.

The potential benefits of this study were felt to be manifold, the most significant of these being the emergence of LUS as a new, more robust and accurate tool for neonatal physiotherapists, to improve CPT efficiency, individualise intervention, and minimise the risk of unnecessary or inappropriate interventions in this incredibly fragile population.

Discussion

To succeed, this study required the support of the Mater Physiotherapy and NICU multidisciplinary teams. This support was achieved as a result of the value that was felt to be gained from developing a more accurate understanding of individualised CPT prescription through the use of LUS as a new and promising assessment tool for NICU physiotherapists.

Furthermore, all parents approached for eligibility of their infant consented. A key strength of this study was the identification of LUS as a feasible CPT assessment tool that led to significant improvements in physiotherapist clinical decision-making confidence levels, regardless of whether it changed the diagnosis or treatment plan. The addition of an additional, real-time image of lung pathology to the standard tools of CXR and auscultation, was noted to be of significant benefit to neonatal physiotherapists, regardless of their level of experience. There were a number of limitations to this study and these present opportunities to undertake future studies and refine which infants are most likely to benefit the most from the addition of physiotherapy-led LUS assessments.

While the NRI did not prove statistically significant across all cases, in a third of cases LUS led to clinically important changes in diagnosis and treatment, that was more appropriate or effective following the addition of LUS. It is possible that the sample size was not large enough in this study to identify statistical significance, and/ or that the NRI was not the most appropriate, or sensitive measure to identify clinically significant effects. Another possible consideration in interpreting results is that infants were consented into the study in a consecutive manner and included infants who had lung pathology and expected to require active CPT treatment, as well as infants who had no lung pathology. As CPT is not indicated for all infants, cases where LUS could be considered clinically significant may have been diluted in the statistical analysis as a result of the study design.

Furthermore, it is likely that infants with lung pathology amenable to CPT will benefit more from the addition of LUS findings and are the most at-risk if treated incorrectly or unnecessarily. Future, larger scale studies, allowing for stratification of infants depending on severity of lung disease and need for active CPT intervention are recommended. The applicability of this study is far-reaching as it is the first time LUS has been used to guide CPT in preterm infants. While CPT is not indicated routinely in the management of all preterm infants, there is a cohort who will benefit from CPT and where it forms an important part of their treatment and potentially long-term lung health. Preterm infants are some of the sickest and most fragile patients cared for by physiotherapists and the benefits of being able to quickly and accurately deliver individualised CPT is essential. As a newly emerging technique, it is proposed that physiotherapy-led LUS in preterm infants will continue to be investigated and educational resources developed and provided to facilitate it use statewide, as a routine skill rather than extended-scope practice.

References

1. Abeer ESH, Rabab Salah El Din M. The effectiveness of chest physiotherapy on mechanically ventilated neonates with respiratory distress syndrome: a randomized control trial. Journal of Medicine in Scientific Research. 2022;5(2):129-41.

2. Lauwers E, Ides K, Van Hoorenbeeck K, Verhulst S. Outcome measures for airway clearance techniques in children with chronic obstructive lung diseases: a systematic review. Respiratory Research. 2020;21(1):217-33.

3. Fukuhara S, Yamaguchi Y, Uetani Y, Akasaka Y. Lung Ultrasound in Children with Acute Respiratory Failure: Comparison between Chest X-ray, Chest Computed Tomography, and Lung Ultrasound: A Case Series. Indian journal of critical care medicine : peer-reviewed, official publication of Indian Society of Critical Care Medicine. 2019;23(2):95-8.

4. McAlinden BM, Hough JL, Kuys S. Measuring the effects of airway clearance in mechanically ventilated infants and children: A systematic review. Physiotherapy. 2022;117:47-62.

5. Brat R, Yousef N, Klifa R, Reynaud S, Aguilera SS, De Luca D. Lung Ultrasonography Score to Evaluate Oxygenation and Surfactant Need in Neonates Treated With Continuous Positive Airway Pressure. JAMA Pediatr. 2015;169(8):8.