doi:10.1186/cc13956engLorente, L.Martín, M. M.López-Gallardo, E.Iceta, R.Blanquer, J.Solé-Violán, J.Labarta, L.Díaz, C.Jiménez, A.Montoya, J.Ruiz-Pesini, E.Higher platelet cytochrome oxidase specific activity in surviving than in non-surviving septic patientsART-2014-98813Introduction: In a previous study with 96 septic patients, we found that circulating platelets in 6-months surviving septic patients showed higher activity and quantity of cytochrome c oxidase (COX) normalized by citrate synthase (CS) activity at moment of severe sepsis diagnosis than non-surviving septic patients. The objective of this study was to estimate whether COX specific activity during the first week predicts 1-month sepsis survival in a larger cohort of patients.Methods: Using a prospective, multicenter, observational study carried out in six Spanish intensive care units with 198 severe septic patients, we determined COX activity per proteins (COXact/Prot) in circulating platelets at day 1, 4 and 8 of the severe sepsis diagnosis. Endpoints were 1-month and 6-months mortality.Results: Survivor patients (n = 130) showed higher COXact/Prot (P 0.30 mOD/min/mg at day 1 (P = 0.002), 4 (P = 0.006) and 8 (P = 0.02) was associated independently with 1-month mortality. Area under the curve of COXact/Prot at day 1, 4 and 8 to predict 30-day survival were 0.70 (95% CI = 0.63-0.76; P < 0.001), 0.71 (95% CI = 0.64-0.77; P < 0.001) and 0.71 (95% CI = 0.64-0.78; P < 0.001), respectively.Conclusions: The new findings of our study, to our knowledge the largest series reporting data about mitochondrial function during follow-up in septic patients, were that septic patients that survive 1-month have a higher platelet cytochrome oxidase activity at moment of sepsis diagnosis and during the first week than non-survivors, and that platelet cytochrome oxidase activity at moment of sepsis diagnosis and during the first week could be used as biomarker to predict the clinical outcome in septic patients.2014http://zaguan.unizar.es/record/13040610.1186/cc13956http://zaguan.unizar.es/record/130406oai:zaguan.unizar.es:130406Critical care 18, 3 (2014), R136 [17 pp]byhttp://creativecommons.org/licenses/by/3.0/es/info:eu-repo/semantics/openAccess