Noninvasive Central Venous Pressure Measurement by Controlled Compression Sonography at the Forearm

OBJECTIVES: We sought to validate a new noninvasive technique to determine central venous pressure (CVP) using high-resolution compression sonography. BACKGROUND: Information concerning CVP is crucial in clinical situations, including cardiac failure, volume overload, and sepsis. The measurement of CVP, however, requires puncture of a vein with attendant risk of complication. METHODS: After a proof-of-concept study in healthy subjects, a prospective blinded evaluation was performed comparing CVP measurement using a central venous catheter with measurement using compression sonography in critically ill (intensive care unit) patients. RESULTS: In healthy subjects with experimentally induced venous hypertension with a wide range of pressure values, a strong correlation (r = 0.95; p < 0.001) between noninvasive and invasive peripheral venous pressure at the forearm was shown. High interobserver agreement with an intraclass correlation coefficient of 0.988 shows excellent reliability of the system. Noninvasive peripheral venous pressure measurement at the forearm showed a good correlation with CVP in 50 intensive care unit patients with the forearm positioned both below heart level (r = 0.84; p < 0.001) and at heart level (r = 0.85; p < 0.001). The mean difference between invasive and noninvasive measurement was negligible (-0.1 +/- 3.5 cm H2O and -0.7 +/- 3.4 cm H2O, respectively). CONCLUSIONS: Controlled-compression sonography is a valuable tool for measuring venous pressure in peripheral veins and allows reliable indirect assessment of CVP without intravenous catheterization.