Ultrasonography: a novel approach to central venous cannulation

Abstract

Background: Portable ultrasound machines are highly valuable in ICUs, where a patient's condition might not permit shifting the patient to the USG department for imaging. Traditionally central lines are put blindly using anatomical landmarks, which often result in complications such as difficulty in access, misplaced lines, pneumothorax, bleeding from inadvertent arterial punctures, etc. Ultrasonography provides "real time" imaging, i.e., the needle can be visualized entering the vein.

Aims: We performed a study to compare USG guided central venous cannulation (CVC) and conventional anatomical landmark approach to CVC, in terms of ease of cannulation, time consumed, and associated complications.

Settings and design: The study was performed in a 16-bed open ICU. Eighty patients were randomly divided in two groups.

Materials and methods: The right internal jugular vein (IJV) was cannulated in all. In Group I, a portable ultrasound machine was used during cannulation. The vessels were visualized in the transverse section with the internal carotid artery (ICA) identified as a circular pulsatile structure, while the IJV as a lateral, oval nonpulsatile structure). The needle was inserted perpendicular to the skin under visualization on the US screen. Central venous line was then inserted by the Seldinger technique. In Group II, CVC was performed by the conventional landmark approach. The parameters studied included time for insertion, attempts required, and complications encountered.

Statistical analysis: The database of all parameters was analyzed using SPSS software version 10.5.

Results: The mean time to successful insertion was 145 and 176.4 sec in groups I and II, respectively (p = 0.00). An average of 1.2 attempts per cannulation was required for group I, while 1.53 for group II (p = 0.03): 10% witnessed arterial puncture and 2.5% pneumothorax in group I and none in group II.

Conclusion: USG-guided CVC is thus easier, quicker, and safer than landmark approach.

Keywords: central venous cannulation; intensive care unit; ultrasound.

Figure 1

IJV and ICA as seen normally on scan (IJV = internal jugular vein, ICA = internal carotid artery)

Figure 2

On applying pressure with US probe, IJV gets compressed while ICA remains as such