Microcirculation impairment and blood pressure in sepsis

Blood pressure is crucial for the tissue perfusion, oxygenation and elimination of metabolites in normal tissue. In septic patients it may be altered by several mechanisms. Endothelial lesions and impaired vasoregulation resulting from bacteriemia may produce vasodilatation, hypotension, tissue hypoxia and decrease in the blood velocity. These events may favour disseminated intravascular coagulation in septic patients, and thus pronounce perfusion misdistribution. Since hypotension is commonly treated by vasoactive drugs to increase vascular tone toward normal values, more pronounced peripheral tissue ischemia may result. During, the process of blood pressure regulation in septic patients a diversity of physiological parameters should be encountered, i.e. age, body weight, core temperature, overall patients' cardiovascular performance, anemia, and protein status. In a healthy, adult person, in the absence of other causes of hypotension systolic blood pressure of > 90 mmHg or mean arterial pressure > 70 mmHg should maintain adequate tissue perfusion. Together with specific antibiotics, therapeutic procedures like haemodilution, use of vasoconstrictors, vasopressin and its analogue terlipressin, corticosteroids are currently used to improve outcome of hypotensive septic patients. Numerous studies were undertaken to point the values of the biochemical tests suggesting a need for prompt intervention. The arterial lactate, cortisol response, TNF, interleukin (IL) 6, IL-12p70 and IL-12p40 production, together with submucosal (gastric intramucosal or sublingual) CO2 values were proven as indicative. These may suggest whether microcirculatory impairment is reversible or not, and which therapeutic maneuver should be appropriate.