Diagnostic accuracy of prehospital ultrasound in detecting lung injury in patients with trauma: a systematic review and meta-analysis

Background Ultrasound is now readily available in the prehospital setting and its use has been highlighted as one of the top research priorities in prehospital care. Clinical examination remains the standard care for diagnosing lung injury in the prehospital setting, yet this can be challenging and has poor diagnostic accuracy. This review evaluates the accuracy of prehospital ultrasound for the diagnoses of pneumothorax, haemothorax and pulmonary contusions in patients with trauma. Methods A systematic review and meta-analysis was conducted. MEDLINE/PubMed, CINAHL, Embase and the Cochrane Library were searched. Only papers reporting on the diagnostic accuracy of lung ultrasound for traumatic pneumothorax, haemothorax or pulmonary contusions; in a prehospital or helicopter emergency medical service setting; and with CT or operative findings as a reference standard, were included. Non-English studies or articles that reported on animal studies were excluded. The Quality Assessment of Diagnostic Accuracy Studies-2 was used to assess the methodological quality of the included studies. Results Six observational studies, four with low risk of bias and two with some concerns, reporting on 1908 thoracic ultrasound examinations in patients with trauma, were included. For pneumothorax, meta-analysis yielded pooled sensitivity of 29% (95% CI 22% to 37%, I 2 =0%) and pooled specificity of 98% (95% CI 97% to 99%, I 2 =0%). Insufficient data were reported for a reliable meta-analysis on the presence of haemothorax. Only one study reported on the presence of pulmonary contusions and therefore no analysis was conducted. Conclusion Prehospital ultrasound is highly specific but has a lower sensitivity for the presence of pneumothorax when compared with hospital studies. Further research is required, alongside education and training of prehospital providers, to further explore the factors that account for the differences observed in this review. PROSPERO registration number CRD42023365034.