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 (ScvO2) 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 ScvO2 < 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 ScvO2 > 70% within 6 hours (G5). RESULTS In the RBC group, after one unit of RBC transfusion, ScvO2 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 ScvO2 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.