Abstract Body: Introduction: Septic shock is defined by systemic hypotension, tissue hypoperfusion, and elevated lactate levels. Although lactate is widely used to assess tissue oxygenation, it may not always reflect real-time hemodynamic changes. Capillary refill time (CRT) and the transcutaneous-to-arterial carbon dioxide gap (tc-artCO2 gap) have recently emerged as alternative markers of peripheral perfusion, but their comparative performance against lactate during resuscitation has not been fully elucidated.
Objective: To evaluate the responsiveness of CRT and tc-artCO2 gap compared to lactate in monitoring therapeutic effects during septic shock resuscitation.
Methods: Eighteen pigs were randomized into three groups (n = 6 each): control, sepsis, and treatment. Sepsis was induced via intravenous endotoxin. The control group received saline only, while the treatment group underwent goal-directed resuscitation—initiated when mean arterial pressure remained below 60 mmHg for 30 minutes—using fluid infusion and norepinephrine. CRT, tc-artCO2 gap, and lactate were measured serially over a four-hour period. Hemodynamic and perfusion parameters were analyzed using repeated-measures ANOVA.
Results: In the control group, mean arterial pressure (MAP), CRT, tc-artCO2 gap, and lactate levels remained stable during the 4-hour anesthesia period. In the sepsis group, MAP significantly decreased, while CRT, tc-artCO2 gap, and lactate levels significantly increased, with a 4-hour survival rate of only 16.7%. In contrast, all animals in the treatment group survived. Both CRT and the tc-artCO2 gap decreased immediately after treatment, closely corresponding with improvements in cardiac output and oxygen delivery. However, lactate levels remained elevated despite the recovery of hemodynamics.
Conclusions: CRT and tc-artCO2 gap are more sensitive and timely indicators of hemodynamic improvement during the early phase of septic shock resuscitation than lactate. These findings underscore the value of incorporating peripheral perfusion parameters into clinical monitoring protocols and caution against sole reliance on lactate levels to guide therapy.