Targeting skeletal muscle tissue oxygenation (StO2) in adults with severe sepsis and septic shock: a randomised controlled trial (OTO-StS Study)

Objective Evaluation of the ratio of oxyhaemoglohin to total haemoglobin in skeletal muscle (StO(2)) using near-infrared spectroscopy may aid in the monitoring of patients with sepsis. This study assessed the benefits and risks of targeting StO(2) in adults with severe sepsis or septic shock. Design A European randomised controlled trial was performed on two parallel groups. Setting Five intensive care units (ICU) in France, Greece, Spain and Germany were used for the study. Participants A total of 103 adults with severe sepsis or septic shock on ICU admission were randomised (54 subjects in the experimental arm and 49 subjects in the control arm). Interventions Haemodynamic management using an algorithm that was adapted from the 2004 Surviving Sepsis Campaign guidelines with (experimental arm) or without (control arm) targeting an StO(2) value greater than 80% at a minimum of two different sites. Outcomes The primary outcome was a composite: 7-day all-cause mortality or worsening of organ function, defined as a positive difference in Sepsis-related Organ Failure Assessment (SOFA) score between day 7 and randomisation (ie, delta SOFA >0). Secondary endpoints: 30-day mortality, duration of mechanical ventilation and vasopressor therapy up to 30 days from randomisation. Results The study ended prematurely due to lack of funding after enrolment of 103/190 patients. Eighteen patients (33.3%) in the experimental arm and 14 (28.6%, P=0.67) in the control arm died or exhibited delta SOFA >0 on day 7. The mean number of days on mechanical ventilation was 12.2 +/- 10.6 in the experimental group and 7.6 +/- 7.9 in the control group (P=0.03). Thirty-one (57%) patients in the experimental arm and 14 (29%) patients in the control arm received red cells by day 7 (P=0.01). Conclusion Despite the limitation related to premature termination, this study provides no data to support the routine implementation of resuscitation protocols incorporating StO(2) >80% at two or more muscle sites as a target. StO(2)-guided therapy may be associated with prolonged use of mechanical ventilation and an increased number of red blood cell transfusions.