Prospective comparison of point‐of‐care international normalised ratio measurement versus plasma international normalised ratio for acute traumatic coagulopathy

Abstract

Early detection of acute traumatic coagulopathy (ATC) might be useful to guide trauma resuscitation. This study aimed to compare results from a point-of-care (POC) international normalised ratio (INR) measuring device with plasma INR in acute trauma patients. This was a single-centre, prospective, blinded comparative study. All trauma patients meeting trauma call-out criteria in a major trauma centre were screened. Patients predicted to have ATC were identified by the Coagulopathy of Severe Trauma score and a convenience sample of 72 patients included in this study. Whole blood was used to measure INR at the bedside, whereas blood from the same sample was sent to the hospital laboratory for plasma INR testing. Agreement between the laboratory and bedside INR was determined using a Bland-Altman plot. There were 38 (52.8%) patients with ATC by laboratory measure, defined as INR >1.5 or activated partial thrombin time >60 s, whereas the POC system identified 28 (38.9%) patients with an INR >1.5. Assuming the laboratory measure as the gold standard, the POC system had a specificity of 88.2% (95% confidence interval 71.6-96.2) and a sensitivity of 63.1% (95% confidence interval 46.0-77.7). Bland-Altman plots demonstrated inadequate agreement between the two methods of INR measurement for the major trauma patient. POC INR measurements using this method during the trauma reception and resuscitative phases cannot be used to identify or exclude patients with ATC. Further studies are required to determine if there is any role for POC INR measures during trauma resuscitation.