Comparison of Bedside Ultrasound With Chest X-ray for Confirmation of Central Venous Catheter Position

Overview

Background: Insertion of a central venous catheter (CVC) could lead to a variety of complications. To detect those complications, Chest X-ray (CXR) is still the reference standard. However, there are major limitations in performing CXR's in the critical care setting. Aim/objectives: The objective of this study is to compare the use of bedside ultrasound (US) to conventional CXR in visualization of accuracy and safety of the CVC placement. The aim is to eventually replace X-ray with bedside ultrasound as gold standard for the confirmation of CVC-placement in critically ill patients, thereby reducing radiation exposure and unnecessary delay before CVC use. Methods: The bedside US will be performed by the student or attending physician, who is blinded for CXR findings. After US examination, the attending physician (or student) will fill in a structured form, based on an established protocol. CXR will be performed before or after US examination and assessed by a radiologist. The radiologist will be blinded for the findings of the bedside ultrasound to prevent any biases. Final diagnosis will be determined after examination of the complete medical chart.

Most patients admitted to an intensive care unit undergo central venous catheterization (CVC) or already have received a CVC. Over 5 million CVC placements are performed each year in the United States. An indication of central venous access is for example when peripheral veins are inaccessible or for the administration of potent vasoactive drugs such as norepinephrine or dopamine. Three anatomical sites are frequently used to insert a CVC: the subclavian, jugular and femoral site. Although central venous catheterization offers multiple advantages, it is associated with adverse events that could be hazardous for patients. Mechanical, infectious or thrombotic complications could occur. Most common mechanical complications include arterial puncture, hematoma and pneumothorax. Besides mechanical complications, malposition of a CVC could also lead to complications, including phlebitis, perforation, and venous thrombosis or occlusion. Malposition of the CVC tip into the right atrium could also lead to arrhythmias. The frequency of primary mal-positioning has been shown to be up to 3.7%. A recent multicenter trial, which included 3471 catheters in 3027 patients, showed that subclavian-vein catheterization was associated with a lower risk of bloodstream infection and symptomatic thrombosis but involved a higher risk of pneumothorax as compared to jugular-vein or femoral-vein catheterization. The risk of mechanical complications in subclavian, jugular or femoral catheterization was 2.1%, 1.4% and 6% respectively. To date, the post-procedural chest X-ray (CXR) has been the reference standard to detect these mechanical complications. Some studies suggest that it should not be considered a reliable procedure for detecting complications in the absence of clinical symptoms. In addition, reading of a bedside CXR alone is not very accurate to identify intra-atrial tip position. The exceedingly low complication rate after right internal jugular vein catheterization suggests that, to detect pneumothorax and intra-atrial malposition, routine post-procedure CXR is neither necessary nor accurate and causes delay until catheter use. Omitting the need for CXR could reduce healthcare costs as well. Due to some clear advantages, there has already been an increasing role for ultrasonography in the critical care setting. In comparison to radiography, an advantage of ultrasound is that the patient is not exposed to radiation, and is often faster performed. Compared to the traditional 'blind' landmark method, ultrasound-guided subclavian cannulation reduces failed catheterizations and complications associated with subclavian catheterization. Advantages of ultrasound-guided cannulation include correct identification of the vein, detecting variable anatomy and reducing events of arterial puncture. Due to the developing knowledge and techniques in ultrasound, is has been suggested that it would be a suitable method to replace CXR in the role of detecting pneumothorax and identifying CVC tip position. A small number of studies already demonstrated this effect. In this study we evaluate the use of ultrasound as diagnostic modality in patients after CVC placement in the subclavian or jugular vein. This research proposal aims to evaluate US examination as diagnostic tool for misplacement, bleeding and pneumothorax after CVC-placement. Combining the different strategies from previous studies. we developed "tHe UltraSound evaluation of Cvc Insertion" i.e. HUSCI-protocol. Hereby, we aim to improve accuracy The outcome measure will be the sensitivity and specificity of US. In addition, diagnostic concordance between US and CXR in patients after CVC placement will be studied. If US catches clinical relevant findings accurately we can replace standard expensive and harmful CXR as standard diagnostic tool in patients after CVC-placement in the future. We hypothesize that US can confirm correct CVC placement and detect potential associated complications accurately.