Regional microvascular function and vascular reactivity in patients with different degrees of multiple organ dysfunction syndrome

The pathophysiology of multiple organ dysfunction syndrome (MODS) is believed to be related to that of microcirculatory dysfunction. We hypothesized that the severity of MODS is determined by measuring regional variables of microvascular function and vascular reactivity in critically ill patients. Therefore, we compared (a) reactive hyperemia response in the forearm using transcutaneous PO2/PCO2 electrodes and laser Doppler velocimetry, (b) microvascular permeability assessed by strain-gauge plethysmography in legs, and (c) variables derived from gastric tonometry in hemodynamically stable patients with moderate (n = 15) and severe (n = 15) MODS. There were no differences in systemic oxygen delivery, consumption, and oxygen extraction ratio between the groups. Mortality was 20% in patients with moderate MODS and 60% in patients with severe MODS (P = 0.025). Patients with a high MODS score had significantly larger arterial lactate concentrations (3.81 +/- 2.7 mmol/L) than patients with moderate MODS (1.66 +/- 0.82 mmol/L; P = 0.006). No significant differences in gastric pHi, gastric regional-to-arterial PCO2 difference, capillary filtration coefficient, isovolumetric venous pressure, and skin reactive hyperemia response were observed between patients with moderate and severe MODS. Once MODS is established, regional variables of microvascular function and vascular reactivity measured in this study do not reflect severity of organ dysfunction.