Point of care-Ultraschall versus Röntgen-Thorax zur Lagekontrolle zentralvenöser Katheter

Abstract

Background: Central venous catheter (CVC) placement is a standard procedure in critical care environments. Ultrasound guidance during CVC placement is recommended by current guidelines, but there is no consensus on the best method for the evaluation of correct CVC tip position. Recently, the “rapid atrial swirl sign” (RASS) has been investigated in a limited number of studies. Methods: We performed a prospective clinical trial in the Intensive Care Unit (ICU) and Intermediate Care Unit (IMC) at the University Medical Center Göttingen in 100 consecutive adult patients. The first ten subjects were assessed by one investigator (test cohort), the remaining 90 patients by different residents (validation cohort). All patients received a post-procedural chest radiograph as gold standard. CVC tip positions were assessed with focused echocardiography performed by residents after a short training session. An opacification of the right atrium (RASS) within two seconds after rapid injection of 10 mL of normal saline was considered a “positive” test. Flush appearance after two seconds was defined as “delayed”, no flush was regarded a “negative” test. Results: Sensitivity of the RASS was excellent in all patients 100% (95% CI 73,54-100%). Overall specificity was 94,32% (95% CI 87,24-98,13%) and varied from 91-97% between residents. Positive and negative predictive values were 70,59% (CI 44,04-89,69%) and 100% (CI 95,65-100%), respectively, in all patients. Median time needed to perform the echocardiography was 5 (1-28) minutes in all patients, chest radiographs were available after a median time of 49,5 (13-254) minutes. Interrater agreement of the RASS was good with Cohen’s kappa of 0,772, chest radiograph interpretation of CVC tip position correlated well between two observers (r2=0,8665). Importantly, test characteristics were similar among differently experienced residents. Conclusions: Focused echocardiography using the RASS for CVC tip position assessment reached excellent sensitivity and specificity and was equally well performed among residents after minimal training. After a positive RASS, routine post-procedural chest radiography can be safely omitted, reducing time, costs and radiation exposure. A negative RASS should lead to sonographic screening for misplaced catheters and/or chest radiography.