INFLUENCE OF DIFFERENT VOLUME THERAPY REGIMENS ON REGULATORS OF THE CIRCULATION IN THE CRITICALLY ILL

Various vasoactive substances are involved in the regulation of the ma cro- and microcirculation. We have investigated if these regulators ch ange during long-term volume therapy with human albumin (HA) or hydrox yethylstarch solution (HES) in trauma and sepsis patients. To maintain pulmonary capillary wedge pressure (PCWP) at 10-15 mm Hg, either 20% HA (HA-trauma, n=14; HA-sepsis, n=14) or 10% low-molecular weight HES solution (HES-trauma, n=14; HES-sepsis, n=14) were infused for 5 days, otherwise patient management did nor differ between the two groups (t rauma/sepsis). Mean arterial pressure (MAP), heart rate (HR), PCWP and cardiac index (CI) were monitored In all patients. Liver function was assessed using the monoethylglycinexylidide (MEGX) test, and gastric intramucosal pH (pH(i)) was monitored by tonometry to assess splanchni c perfusion. Plasma concentrations of vasopressin, endothelin-1, adren aline, noradrenaline, atrial natriuretic peptide and 6-keto-prostaglan din F-1 alpha were measured from arterial blood samples. All measureme nts were carried out on the day of admission to the intensive care uni t (trauma patients) or on diagnosis of sepsis, and daily over the next 5 days at 12:00. MAP, HR and PCWP did not differ between the correspo nding subgroups (trauma/sepsis). CI increased significantly more in th e HES than in the HA groups. pH(i) and MEGX plasma concentrations did not differ in the trauma patients throughout the study. Both were lowe r than normal in the sepsis groups and increased more markedly in the HES than in the albumin-treated patients (P<0.05). In the trauma patie nts, concentrations of all vasoactive regulators were very similar in both groups. In both sepsis groups, vasopressors (vasopressin, endothe lin-1, noradrenaline and adrenaline) were significantly increased abov e normal at baseline and decreased more markedly in HES than in HA pat ients. Concentrations of atrial natriuretic peptide increased only in the HA patients (from 159 (SD 31) to 215 (38) pg ml(-1) on day 2). Pla sma concentrations of 6-keto-prostaglandin F-1 alpha decreased signifi cantly only in the HES sepsis patients (from 112 (25) to 47 (15) pg ml (-1)).