BLOOD-PRESSURE AND ARTERIAL LACTATE LEVEL ARE EARLY INDICATORS OF SHORT-TERM SURVIVAL IN HUMAN SEPTIC SHOCK

Objective: To identify early prognostic markers of septic shock among catheterization-derived hemodynamic and metabolic data. Design: Prospe ctive cohort study. Setting: A medical intensive care unit in a univer sity hospital. Patients: Thirty-two consecutive patients; with septic schock, separated into two groups according to short-term (10-day) evo lution: 18 acute survivors and 14 fatalities. Measurements: Usual hemo dynamic and metabolic variables were measured at the onset of shock, i .e. when the catheter was inserted (TO): and 24 h later (T24). The val ues collected for each group at TO and T24 and their 24-h changes were compared. Results: On admission, no difference was found between acut e survivors and eventual fatalities. After 24 h, fatalities presented with significantly lower mean arterial pressure (p < 0.01), left ventr icular stroke work: index (p < 0.05) and higher lactate levels (p < 0. 01) than acute survivors. Moreover, the 24-h changes of lactate and bl ood pressure were also of prognostic value (p < 0.05). Oxygen delivery and oxygen consumption did not differ statistically between the two g roups. At T24, a mean arterial pressure of less than 85 mmHg and a lac tate level equal to or greater than 3.5 mmol/l were independently asso ciated with poor survival (37.5% and 30.7%, respectively). Day 10 surv ival was only 12.5% when both criteria were present at T24. Conclusion s: Changes in mean arterial pressure and arterial blood lactate within the first 24 h of treatment are strong prognostic indicators of short -term survival in patients with septic shock. After 24 h of treatment, maintenance of a mean blood pressure equal to or greater than 85 mmHg correlates with survival at day 10. Data suggest that early reduction s in both cardiac function and vascular tone play a determining role i n the hypotension observed in fatalities. Persistence of hyperlactatem ia in hypotensive patients bodes particularly ill. Blood pressure and lactate level are simple bedside parameters that can enable the clinic ian to identify patients with a high risk of mortality.