Correlation of internal jugular and subclavian vein diameter variation on bedside ultrasound with invasive right heart catheterization

Accurate estimation of fluid status is paramount in patients with heart failure. We hypothesized that bedside ultrasound assessment of the internal jugular vein (IJV) and subclavian vein (SCV) could reliably estimate right atrial pressure (RAP). Prospectively enrolled patients were positioned supine. IJV was imaged at the apex of the right sternocleidomastoid muscle and SCV was imaged at the lateral third of the right clavicle. Using M-mode on a portable ultrasound machine, the maximum (Dmax) and minimum (Dmin) anteroposterior diameters were noted during normal breathing. Respiratory variation in diameter (RVD) was calculated as [(Dmax – Dmin)/Dmax] and expressed as percent. Collapsibility was assessed with sniff maneuver. Patients then underwent right heart catheterization and their findings were correlated with above. Total of 72 patients were enrolled with mean age 61 years, mean BSA 1.9 m2, and left ventricular ejection fraction 45 ± 20%. Elevated RAP≥ 10 mmHg was associated with dilated IJV Dmax(1.0 vs. 0.7cm, p = 0.001), less RVD with resting respiration (14% vs. 40% for IJV, p = 0.001 and 24% vs. 45% for SCV, p = 0.001), and reduced likelihood of total collapsibility with sniff (16% vs. 66% patients for IJV, p = 0.001 and 25% vs. 57% patients for SCV, p = 0.01). For RAP ≥10 mmHg, lack of IJV complete collapsibility with sniff had a sensitivity of 84% while IJV Dmax > 1cm and RVD <50% had a specificity of 80%. The IJV and SCV diameters and their respiratory variation are reliable in estimating RA pressure.