Background: Emerging evidence suggests that post-procedure chest radiography (CXR) is unnecessary if ultrasound confirms catheter position and excludes pneumothorax. We performed a prospective observational study using an ultrasound-guided protocol to confirm central venous catheter (CVC) position and exclusion of pneumothorax. The diagnostic accuracy of bedside ultrasound versus CXR for confirmation of CVC position and exclusion of pneumothorax, performed by ultrasound non-experts, is assessed.<
Methods: The study included a convenience sample of Emergency Department (ED) and Intensive Care Unit (ICU) patients who had internal jugular vein or subclavian vein CVCs placed. Emergency medicine senior residents and critical care fellows performed an ultrasound-guided protocol for CVC confirmation after CVC insertion and before the CXR. The ultrasound guided CVC confirmation protocol consisted of three elements: 1) evaluation of pleural slide; 2) identification of turbidity in the right atrium with a saline flush; and 3) absence of turbidity in neck vessels (internal jugular vein and carotid artery) with saline flush. Descriptive analysis was used to compare ultrasound to CXR for CVC position confirmation and exclusion of pneumothorax.
Results: 255 patients were enrolled; 65 patients were excluded because of incomplete ultrasound protocol. 199 patients were included in the final analysis. There were a total of 2.5% CVC malpositions and 3% pneumothorax on CXR. Mean total US time for CVC confirmation was 9.0 minutes (95% confidence interval [CI], 9-10) compared to 55 minutes (95% CI, 38-72) for CXR to be performed after being ordered. 74 patients with CVCs performed in the ED had sensitivity of catheter malposition of 1.00, specificity of 0.98 (95% CI, 0.96 – 1.01). 115 patients with CVCs were performed in the ICU with sensitivity of catheter malposition at 0.25, specificity of 0.98 95 (95% CI, 0.92 – 0.99). For pneumothorax detection, the negative predicative value was 0.951.0 (95% CI, 1.0- 1.0) and 0.98 97 (95% CI, 0.94 – 1.00) for patients in the Emergency Department and Intensive Care Unit respectively.
Conclusion: An ultrasound-guided protocol at the end of the CVC insertion can confirm CVC position and rule out an iatrogenic pneumothorax much faster than CXR, reserving CXR for positive findings on ultrasound or ongoing clinical concern.