Strong correlation between doppler snuffbox resistive index and systemic vascular resistance in septic patients

Purpose: To compare systemic vascular resistance index (SVRI) as measured by invasive transpulmonary indicator dilution (TPID) and non-invasive Doppler-derived resistive index in septic patients. Methods: We measured the snuffbox resistive index (SBRI) in both hands of septic patients who received hemodynamic monitoring by TPID prospectively. Results: Thirty-six patients with septic shock were enrolled (median acute physiology and chronic health evaluation II score: 23; median age: 64 years). Four SBRI values were measured in each patient, for a total of 96 patient days and 951 ultrasound measurements. The correlation coefficients between SVRI and the four SBRI values were all higher than 0.87 (p <.001). A higher SVRI was associated with sharp waveforms and reversed diastolic flow. A resistive index (RI) of 0.97 was the lower limit of normal SVRI (1700 dyn*s*cm⁻⁵*m²), and an RI of 1.1 was the upper limit of normal SVRI (2400 dyn*s*cm⁻⁵*m²). Conclusions: Using ultrasound to measure RI is a noninvasive, inexpensive, reliable method to evaluate peripheral vascular resistance in septic patients, and it is highly correlated with SVRI. In addition, SBRI can be used to evaluate peripheral circulatory disturbances in septic patients.