INTERNAL JUGULAR-VEIN AND CAROTID-ARTERY ANATOMIC RELATION AS DETERMINED BY ULTRASONOGRAPHY

Background: Cannulation of the internal jugular vein (IJV) is associat ed with a 95% success rate when external landmarks are used, Anatomic variability has been implicated as the cause for difficulty in cannula tion without ultrasound, In contrast to an IJV located lateral to the carotid artery (CA), an IJV overlying the CA may result in CA puncture , The authors' purpose in this study was to examine, using ultrasound, the anatomic relation of the IJV and CA as viewed from the perspectiv e of a cannulating needle. Methods: Ultrasound imaging was used in 1,1 36 patients to examine the relation between the IJV and CA. A 7.5-MHz transducer was placed in the direction of a cannulating needle on the right neck at the apex of the angle formed hy the division of the ster nocleidomastoid muscle. A Polaroid(R) photograph of the image was late r scored by three blinded investigators according to the percentage of the CA overlaid by the IJV (0 to 4). Results: Of the 1,136 Polaroid(R ) photographs of the ultrasound images, 1,009 were suitable for scorin g. Fifty-four percent of all patients received a score of 4, which ind icated that the IJV overlies more than 75% of the CA in an imaging pla ne positioned in the direction of a cannulating needle, Patients older than 60 yr were more likely to have this anatomy than patients younge r than 60 yr (P < 0.05), None of the other patient characteristics rec orded were predictive of this anatomic relation. Conclusions: In a maj ority of patients, the IJV is not lateral to the CA In an ultrasound i maging plane positioned in the direction of a cannulating needle, Inst ead, the IJV overlies the CA in 54% of patients overall, predisposing these patients to CA puncture if the cannulating needle traverses the IJV.