Abstract: We included 34 studies with 8635 participants in this review. Summary estimates of sensitivity and specificity were 0.74 (95% CI 0.65 to 0.81) and 0.96 (95% CI 0.94 to 0.98). Pooled positive and negative likelihood ratios were estimated at 18.5 (95% CI 10.8 to 40.5) and 0.27 (95% CI 0.19 to 0.37), respectively. There was substantial heterogeneity across studies, and the reported accuracy of POCS strongly depended on the population and affected body area. In children, pooled sensitivity of POCS was 0.63 (95% CI 0.46 to 0.77), as compared to 0.78 (95% CI 0.69 to 0.84) in an adult or mixed population. Associated specificity in children was 0.91 (95% CI 0.81 to 0.96) and in an adult or mixed population 0.97 (95% CI 0.96 to 0.99). For abdominal trauma, POCS had a sensitivity of 0.68 (95% CI 0.59 to 0.75) and a specificity of 0.95 (95% CI 0.92 to 0.97). For chest injuries, sensitivity and specificity were calculated at 0.96 (95% CI 0.88 to 0.99) and 0.99 (95% CI 0.97 to 1.00). If we consider the results of all 34 included studies in a virtual population of 1000 patients, based on the observed median prevalence (pretest probability) of thoracoabdominal trauma of 28%, POCS would miss 73 patients with injuries and falsely suggest the presence of injuries in another 29 patients. Furthermore, in a virtual population of 1000 children, based on the observed median prevalence (pretest probability) of thoracoabdominal trauma of 31%, POCS would miss 118 children with injuries and falsely suggest the presence of injuries in another 62 children. In patients with suspected blunt thoracoabdominal trauma, positive POCS findings are helpful for guiding treatment decisions. However, with regard to abdominal trauma, a negative POCS exam does not rule out injuries and must be verified by a reference test such as CT. This is of particular importance in paediatric trauma, where the sensitivity of POCS is poor. Based on a small number of studies in a mixed population, POCS may have a higher sensitivity in chest injuries. This warrants larger, confirmatory trials to affirm the accuracy of POCS for diagnosing thoracic trauma.

Plain-language summary: We searched for studies from the year in which the first paper about using ultrasound to diagnose trauma patients was published until 15 July 2017. We considered 2296 records and included 34 relevant studies that involved 8635 participants in this review. All 34 studies were published between 1992 and 2017, with the number of participants in each study ranging from 51 to 3181. Ten studies included only children, two studies only adults, and the remaining 22 studies included both children and adults. In many studies, important information about the selection of participants and choice of the diagnostic tests against which to compare POCS was not reported. We therefore rated the methodological quality of the available evidence mostly as unclear. Point-of-care sonography had a sensitivity (i.e. the ability to detect a person with the disease) of 74% and a specificity (i.e. the ability to exclude a person without the disease) of 96%. Sensitivity and specificity varied considerably across studies, which was due in part to variation in study, participant, and injury characteristics. In children, both the sensitivity and specificity of POCS were lower than in an adult or mixed population, meaning that POCS was less able to identify or rule out an injury. Based on our results, we would expect that amongst 1000 patients of a mixed-age population with suspected blunt trauma to the abdomen or chest, POCS would miss 73 patients with injuries, and would falsely suggest the presence of injuries in 29 patients who were unaffected. This result emphasises the need for additional imaging in trauma patients for whom POCS shows no injuries (i.e. a negative result), to check whether they are really injury-free.