Internal Jugular Vein Distensibility with Passive Leg Raise: A Diagnostic Approach to Dehydration

Evaluating volume status is crucial in emergency medicine, especially for detecting dehydration. The internal jugular vein distensibility index (IJVDI) has been proposed as a noninvasive ultrasound-based marker for hypovolemia, but its diagnostic accuracy remains uncertain.

To evaluate the diagnostic accuracy of IJVDI combined with passive leg raise (PLR) in detecting dehydration.

This single-center prospective diagnostic accuracy study investigated the ability of IJVDI combined with PLR to detect dehydration using a Ramadan fasting-induced dehydration model. Dehydration was simulated by a 12-hour fasting period without food or water. IJVDI and cardiac output (CO) were measured at baseline and after PLR. The diagnostic value of ΔIJVDI, ΔCO, and ΔVTI (velocity-time integral) for dehydration was assessed.

This study included 90 participants (30 with fasting-induced dehydration and 60 controls). IJVDI was higher in the hypovolemic group than in controls (18.9 ± 12.3 vs. 11.8 ± 4.82, p < 0.001). The diagnostic cut-off for IJVDI was ≥11.8% (Sens: 73.3%, Spec: 58.3%, PPV: 46.8%, NPV: 81.4%, area under the curve [AUC]: 0.690, p = 0.003), while for ΔIJVDI it was -2.1% (Sens: 70%, Spec: 60%, PPV: 46.6%, NPV: 80%, AUC: 0.654, p = 0.017). The highest diagnostic accuracy was observed for ΔCO and ΔVTI, with ΔCO ≥500 mL (Sens: 100%, Spec: 96.7%, AUC: 0.999, p < 0.001) and ΔVTI ≥2.2 cm (Sens: 93.3%, Spec: 80%, AUC: 0.928, p < 0.001). Optimal cut-off values were determined using Youden's index.

While IJVDI measurements differed between dehydrated and control groups, their diagnostic accuracy was limited. In contrast, ΔCO and ΔVTI demonstrated superior predictive value for dehydration. Bedside ultrasonographic evaluation of CO and VTI, combined with PLR, maybe a more reliable approach in emergency settings.