Correlation of internal jugular vein/common carotid artery ratio to central venous pressure: a pilot study in pediatric burn patients.

The purpose of this pilot study was to identify the relationship between the ratio of the diameter/cross-sectional area of the internal jugular vein (IJV) and carotid artery and the central venous pressure (CVP). After obtaining approval from our Institutional Review Board, ultrasound images were repeatedly obtained from participants on consecutive days when a thoracic central line was in place. The CVP was then measured in standardized fashion, using our bedside monitors. A blinded observer measured the diameter of the common carotid artery and IJV, for comparison. Similarly, digital images were analyzed to compare an estimate of the cross-sectional areas of the same vessels. Six patients met enrollment criteria, and one patient was excluded after enrollment before any measurements being made. The remaining five patients had a mean age of 7 years (range: 9 months to 15 years) and mean burn size of 64% (SD, ±15), and no patients had inhalation injuries. All patients in this study were mechanically ventilated. Measurements were made from one patient while spontaneously breathing. One patient reading occurred while on vasopressor support (levophed at 2 μg/kg/hr). CVP values ranged from 1 to 25 mm Hg. Comparison of the ratio of the IJV/common carotid artery cross-sectional area with CVP revealed that a ratio of 2 or greater was associated with a CVP of at least 8 mm Hg (P < .001). These preliminary results suggest that if the cross-sectional area of the vein is at least twice that of the artery, then the CVP seems to be ≥8 mm Hg.