ULTRAFRED – Ultrasound Facilitated Removal of Intercostal Drain

Abstract

Background While clinicians agree that ultrasound has proven as accurate or better than chest x-rays in diagnosing pneumothorax and hemothorax, the utilization of ultrasound as an adjunct to clinical findings in the decision algorithm for intercostal drain removal in posttraumatic injuries has not been thoroughly researched. Methods Patients undergoing treatment by drainage for traumatic chest injuries received two surgeon-operated ultrasound examinations in addition to standard care; one chest x-ray (CXR) before drain removal and one after. All decisions regarding patient treatment were based on based on clinical findings and CXR results. Ultrasound results were compared to the results of the CXRs, to establish if safe removal of drainage could be determined through ultrasound instead of CXR. Results Attempts were made to calculate Kappa Agreement, to test significance with Fisher’s Exact test and McNemar’s test as well as post hoc Power. For the examinations before drain removal specificity was found to be 100 %, sensitivity 0 %, negative predictive value (NPV) 75% and positive predictive value (PPV) 0 %. For the total amount of examinations specificity was 92.9 %, sensitivity 0%, NPV 86.7 % and PPV 0 % (p=1.00, post hoc power 8.3%). Kappa agreement was - 0.091 (p = 0.696). When clinical relevance was incorporated specificity reached 93.8 %, sensitivity 0 %, NPV 100 % and PPV 0 %. Conclusion Ultrasound results does not differ from the results of CXR (p = 1.000), but with a post hoc power of 8.3 %, this statement lacks statistical basis. So far, ultrasound seems promising as an adjunct to clinical findings however, low numbers of included patients considerably prevented the statistical analyses desired for proper conclusions to be drawn. Further research is required to correctly assess the exchangeability between CXR and ultrasound in the evaluation for intercostal drain removal.