Simple Ultrasound Measurement of the Internal Jugular Vein Accurately Estimates Central Venous Pressure Target in Critically III Patients

Background:

Early goal‐directed therapy (EGDT) for severe sepsis or septic shock requires placement of a central venous catheter (CVC) to measure central venous pressure (CVP), with the aim of maintaining CVP ≥ 8‐12 mm Hg. This requirement may delay timely resuscitation, possibly leading to worse patient outcomes, and places the patient at risk for complications related to the CVC. Our objective was to determine if CVP can be accurately assessed using noninvasive ultrasound to measure the aspect ratio (height ÷ width) of the internal jugular vein (IJV), assuming a flat IJV (lower aspect ratio) would correlate with a lower CVP, whereas a circular IJV (higher aspect ratio) would correlate with higher CVP. Our specific goal was to determine if this method could accurately estimate a CVP ≥ 8 mm Hg.

Methods:

Following a feasibility study with 19 healthy, euvolemic volunteers, we conducted a 2‐center blinded, prospective comparison between ultrasound imaging of the IJV and traditional invasive CVP measurement in 44 critically ill patients.

Results:

For the healthy volunteers, age (mean ± standard deviation) was 42.6 ± 10.6 years, and BMI was 26.4 ± 4.5 kg/m². Bland‐Altman analysis revealed good intra‐ and interobserver agreement. The mean aspect ratio of both the right and left IJV for all volunteers was 0.81 ± 0.14, and there was no difference between either side or for male versus female patients. For the critically ill patients, age was 65.6 ± 13.6 years, and BMI was 28.8 ± 9.1 kg/m². Ultrasound imaging of the IJV accurately estimated the CVP target of 8 mm Hg for EGDT with area under the receiver operator characteristic curve of 0.84 (95% CI 0.72‐0.96). A threshold aspect ratio of 0.83 gave a sensitivity of 78% for discriminating CVP ≥ 8 mm Hg and a specificity of 77% for discriminating CVP < 8 mm Hg.

Conclusions:

Noninvasive ultrasound imaging of the IJV aspect ratio accurately estimated a CVP ≥ 8 mm Hg for spontaneously breathing critically ill patients. This technique is simple to perform at the bedside with minimal training and provides real‐time results, and the ultrasound equipment is readily available at most hospitals. If validated in an independent sample, ultrasound measurement could substitute for the EGDT CVP target in critically ill patients and allow early aggressive resuscitation without the need for a CVC. Such a measurement technique would be useful for emergency medicine physicians, hospitalists, and intensivists.

Author Disclosure:

A. S. Keller, Mayo Clinic; R. Melamed, Abbott Northwestern; R. John, Capitol Care Associates.; O. Gajic, Mayo Clinic; D. Tierney, Abbott Northwestern; M. Malinchoc, Mayo Clinic.