Transfusion of Red Blood Cells Is Associated With Improved Central Venous Oxygen Saturation But Not Mortality in Septic Shock Patients

BACKGROUND: Although the optimum hemoglobin (H) concentration for patients with septic shock (SS) has not been specifically investigated, current guidelines suggest that H of 7 - 9 g/dL, compared with 10 - 12 g/dL, was not associated with increased mortality in critically ill adults. This contrasts with early goal-directed resuscitation protocols that use a target hematocrit of 30% in patients with low central venous oxygen saturation (ScvO(2)) during the first 6 hours of resuscitation of SS. METHODS: Data elements were prospectively collected on all patients with SS patients (lactic acid (LA) > 4 mmol/L, or hypotension). Out of a total of 396 SS patients, 46 patients received red blood cell (RBC) transfusion for ScvO(2) < 70% (RBC group). We then matched 71 SS patients that did not receive RBC transfusion (NRBC group) on the following goals (G): LA obtained within 6 hours (G1), antibiotics given within 3 hours (G2), 20 mL/kg fluid bolus followed by vasopressors (VP) if needed to keep mean arterial pressure > 65 mm Hg (G3), central venous pressure > 8 mm Hg within 6 hours (G4) and ScvO(2) > 70% within 6 hours (G5). RESULTS: In the RBC group, after one unit of RBC transfusion, ScvO(2) improved from average of 63% (± 12%) to 68% (± 10%) (P = 0.02). Sixteen patients required another unit of RBC, and this resulted in increase of ScvO(2) to 78% (± 11%) (P < 0.01). The RBC and NRBC groups were matched on sequential organ failure assessment (SOFA) scores and all five goals. There was no difference in mortality between the two groups: 41% vs. 39.4% (OR: 0.8, 95% CI: 0.4 - 1.7, P = 0.6). CONCLUSIONS: In our study, transfusion of RBC was not associated with decreased mortality in SS patients.