A new tool that allows real-time, three-dimensional ultrasound may help cut down on errors while placing central lines, without adding precious time to the procedure, researchers have found. When anesthesiologists attempted the technique on a sample of 10 patients undergoing heart surgery, they cannulated the internal jugular vein in every patient—and, in nine of the 10 patients, with the first needle pass (Figure). No back wall passes or inadvertent punctures of the carotid artery occurred.

The cases required an average of 15 seconds to scan the blood vessels, and the average time to insert the needle into the internal jugular vein was 14 seconds, according to the study, which the researchers presented at the 2011 annual meeting of the Society of Cardiovascular Anesthesiologists, in Savannah, Ga.Traditional ultrasound techniques take approximately the same amount of time to find the vein, said David Auyong, MD, of Virginia Mason Medical Center in Seattle. The new technique “didn’t take longer, and it potentially showed that we could follow the needle better, by avoiding the back wall passes and arterial punctures.” However, one patient required six needle passes, likely because the internal jugular vein was relatively deep, Dr. Auyong said.

Many anesthesiologists now rely on ultrasound when inserting a central line, but the traditional technique cannot always rigorously track the tip of the needle, as evidenced by the lingering risk for complications such as pneumothorax and inadvertent arterial puncture.

The new “4-D” technique uses a probe that wobbles slightly (roughly four times per second) over a three-dimensional area such as the internal jugular vein, creating a three-dimensional image in real time—with time representing the fourth dimension, Dr. Auyong explained. “The ultimate goal here is a way to track the needle more reliably,” he said.

Dr. Auyong, who has lectured for SonoSite, which supplied the ultrasound equipment used in the study, said that the biggest hurdle for uptake of the technology is learning how to use it. When he demonstrates it to other anesthesiologists, he said they often struggle with having to follow four images simultaneously in order to track the needle. “It is not something that is necessarily intuitive the second you pick it up.” Dr. Auyong said he, too, struggled at first, but grew more comfortable after an estimated 10 practice insertions of a needle. Cost is another barrier, said Paul Barash, MD, professor of anesthesiology at Yale University School of Medicine, in New Haven, Conn., and a member of the Anesthesiology News editorial board. Ultrasound helps reduce the risk for complications associated with vascular catheterization, Dr. Barash said, but the physicians who do not use it often attribute their hesitation to the expense of the equipment.