Comparison of Predictive Ability of Macrocirculation and Microcirculation Markers on Outcomes of Patients with Septic Shock During Initial Fluid Resuscitation: A Prospective Observational Study

Abstract Introduction This study aimed to compare the predictive abilities of macrocirculation markers (mean arterial pressure, heart rate, and central venous pressure), microcirculation markers (capillary refill time and peripheral perfusion index), as well as fluid balance, lactate level, and lactate clearance on the outcomes of patients with septic shock during initial resuscitation. Methods In this prospective, single-center observational study, adult patients with septic shock admitted to the intensive care unit (ICU) at Shohada Hospital in Tabriz, Iran, between December 2020 and September 2021, were included. Receiver operating characteristic (ROC) curve analysis and multivariate logistic regression were used to assess the associations between macrocirculation markers (heart rate, mean arterial pressure, central venous pressure, and fluid balance) and microcirculation markers (capillary refill time, peripheral perfusion index, mottling score, lactate level, and lactate clearance level) with outcomes such as ICU length of stay, need for renal replacement therapy (RRT), vasopressor requirements, duration of mechanical ventilation (MV), and mortality rate. Assessments were performed at baseline, 6 h, and 24 h after fluid resuscitation. Results A total of 100 patients with septic shock (55 men and 45 women) were enrolled in the study. The area under the curve (AUC) values for the macrocirculation and microcirculation markers in predicting mortality ranged from 0.517 to 0.770 and 0.695 to 0.993, respectively. Among the macrocirculation markers, central venous pressure and mean arterial pressure at baseline showed the best predictive values for mortality, with AUCs of 0.770 and 0.753, respectively. Conclusion In patients with septic shock, microcirculation markers, particularly the peripheral perfusion index (PPI), demonstrated better predictive accuracy for mortality compared to macrocirculation markers. Furthermore, the combination of markers had a higher AUC, sensitivity, and specificity for predicting outcomes compared to individual markers alone.