Subcutaneous interstitial pressure measurement during early septic shock: an exploratory study

Fluid therapy is crucial in managing septic shock but may result in harmful fluid overload due to capillary leakage, causing interstitial fluid accumulation. Burns and endotoxemia models demonstrate that interstitium can reduce its hydrostatic pressure, increasing permeability, but this has not been clinically investigated in human sepsis. This study aimed to examine the changes in subcutaneous interstitial pressure (SIP) during sepsis. This prospective observational study involved adult patients admitted to the Intensive Care Unit (ICU) within 24 h, under sedation and mechanical ventilation, and who received < 50 ml/kg resuscitation. The septic shock group met the septic shock criteria, whereas the control group lacked sepsis or shock criteria (admission for non-traumatic coma). The SIP was measured using a subcutaneous transducer-tip probe. SIP was measured in 30 patients and was not significantly lower in septic shock: 1.69 ± 2.99 vs. 2.51 ± 2.39 mmHg in controls (p = 0.410). Among the 6 patients with a negative SIP, all but one were in the septic shock group, although the absolute difference was not significant (5 (33%) vs. 1 (7%), p = 0.169). Subcutaneous interstitial pressure was not significantly lower in septic shock patients, but sub-atmospheric SIP was more prevalent in this group, despite higher fluid balance. Further studies are required to clarify the role of interstitial pressure in capillary leakage during sepsis.