Subcutaneous interstitial pressure measurement during early septic shock: a case-control study

Abstract Background Fluid therapy is the cornerstone of septic shock management, but it is also responsible of a deleterious fluid overload, corresponding to accumulation of fluid in the interstitium due to capillary leakage. Interstitium contributes directly to capillary leakage by decreasing interstitial pressure during inflammation. This phenomenon was thoroughly described in burns and other models of inflammation including endotoxemia, but its role during sepsis was never explored in a clinical study. Our objective was to explore the subcutaneous interstitial pressure (SIP) changes during sepsis. Methods This case-control study included adult patients admitted in ICU since less than 24h, under sedation and mechanical ventilation, without overt subcutaneous edema and with crystalloid resuscitation < 50ml/kg. In the septic shock group, additional criteria were presence of septic shock since less than 24h, and in the control arm absence of current severe infection. Interstitial pressure was measured using a subcutaneous transducer-tipped probe. Results The SIP was measured in 31 patients and was not significantly different between septic shock and control patients: 1.64 ± 2.89 versus 2.51 ± 2.39 mmHg, respectively (p = 0.370). Patients with a strictly negative SIP were all in the septic shock group but one, although the absolute difference was not significant (5 (31%) vs 1 (7%) respectively, p = 0.172). Conclusion Subcutaneous interstitial pressure was not significantly lower in patients with septic shock, but sub-atmospheric SIP was prevalent only in the septic shock group, despite higher fluid balance. Further studies are required to demonstrate the role of interstitial pressure in increasing capillary leakage during sepsis.