The relationship between systemic vascular resistance index and snuff-box resistive index in patients with septic shock

Introduction: Sepsis and septic shock are the leading causes of mortality worldwide. Fluid management is a crucial step in the treatment of sepsis. Effect of fluid therapy may be negative for the patients who are not fluid responsive. Search for methods that can be an alternative to hemodynamic monitoring systems, which are expensive or invasive systems, for vasopressor use and efforts to optimize existing monitoring systems continue today. This study aims to examine the relationship between the systemic vascular resistance index (SVRI) calculated by cardiac output measurement methods and the resistive index (SBRI) measured by ultrasound on the distal radial artery (anatomical snuffbox). Materials and Methods: Our study was planned as a prospective observational study in patients older than 18 years of age, who were being followed up in the intensive care unit for septic shock, also receiving invasive mechanical ventilation support, vasopressor or inotrope support. Patients who had intervention in both radial arteries same time within the last 12 hours, body mass index >35, atrial fibrillation, and were receiving continuous hemodiafiltration therapy were excluded. Baxter Starling monitor electrodes were connected while the patients were lying in a 45o head-up position. Demographic data of the patient were set to the device. Information about the patient's current treatment was checked from the patients file and bedside monitor and noted. After the calibration measurement, the fluid responsiveness test was started with the passive leg raising test option. Parameters such as blood pressure and heart rate were recorded from the bedside monitor. Meanwhile, resistive index was measured over the anatomical snuffbox from the side without arterial cannula. When the baseline measurement of the test was completed, the passive leg raising test, which lasted for 3 minutes, was initiated. For this, the patient was positioned with the bed in a trendelenburg maneuver with head 0o and feet 45o degrees. In the last 30 seconds of the test, resistive index was measured again from the same point. Hemodynamic data were recorded. Following the end of the test, the data were recorded, and the study was completed. Results: After normality analysis, demographic and study-related data of the patients were divided into subgroups according to fluid responsiveness and noradrenaline dose. A significant correlation has found between SBRI and SVRI values at T0 and T1 and at all times. In addition, a significant correlation was found between the percentage change in stroke volume (▲SVI) calculated as a result of the test and the percentage change in SBRI (▲SBRI) at T0 and T1. Conclusion: In our study, we demonstrated a strong correlation between Doppler SBRI and SVRI measured by bioreactance in septic patients. We also observed that dynamic measurements, which form the basis of personalized shock therapy, can be applied quickly and easily with bedside ultrasound.