Early resuscitation of septic shock to different levels of arterial blood pressure

Overview

Objective:
The optimal target mean arterial pressure (MAP) in the resuscitation of septic shock is undetermined. The aim of this study was to assess the effect of different levels of MAP on splanchnic organ perfusion/ function and lactate metabolism.

Design:
Prospective, randomized, clinical trial.

Setting:
St. Anna University Hospital, Brno, Department of Anaesthesia and Intensive Care.

Materials and methods:
Patients in the first 6 hours of septic shock were randomized to target MAP of 65 (G65) or 85 (G85) mm Hg. The target MAP was achieved by the admisnistration of fluids and norepinephrine. A set of measurements was taken during the first 2 hours of the study (T1) and repeated 6 hours later (T2). Lactate metabolism was assessed by the exogenous lactate challenge test (ELCT). Cardiac output (CO), SvO₂, gastric tonometry (pCO₂gap), clearance of ICG (ICG-PDR) and creatinine clearance were measured. The data are presented as median (range); appropriate non-parametric tests were used.

Results:
16 patients were included in the study – 8 in the G65 and 8 in the G85 groups. APACHE II and SOFA scores were comparable between the groups. Patients randomized to G65 tended to higher age than G85 (p = 0.065). No differences in the volume of infused fluids, norepinephrine dose, CI and SvO₂ were observed during the study. Values of pCO₂gap, ICG-PDR and creatinine clearance did not differ between the groups at T1 or T2. No differences in lactate production and elimination were recorded but the G65 patients tended to an increased lactate turnover between T1 and T2.

Conclusion:
Resuscitation of septic shock patients to different MAP level (65 or 85 mm Hg) did not influence the global or splanchnic haemodynamics or lactate metabolism.

Key words:
septic shock – norepinephrine – perfusion pressure – lactate – haemodynamics