In-hospital mortality following treatment with red blood cell transfusion or inotropic therapy during early goal-directed therapy for septic shock: a retrospective propensity-adjusted analysis

Abstract

Introduction: We sought to investigate whether treatment of subnormal (<70%) central venous oxygen saturation (ScvO2) with inotropes or red blood cell (RBC) transfusion during early goal-directed therapy (EGDT) for septic shock is independently associated with in-hospital mortality.

Methods: Retrospective analysis of a prospective EGDT patient database drawn from 21 emergency departments with a single standardized EGDT protocol. Patients were included if, during EGDT, they concomitantly achieved a central venous pressure (CVP) of ≥8 mm Hg and a mean arterial pressure (MAP) of ≥65 mm Hg while registering a ScvO2 < 70%. Treatment propensity scores for either RBC transfusion or inotrope administration were separately determined from independent patient sub-cohorts. Propensity-adjusted logistic regression analyses were conducted to test for associations between treatments and in-hospital mortality.

Results: Of 2,595 EGDT patients, 572 (22.0%) met study inclusion criteria. The overall in-hospital mortality rate was 20.5%. Inotropes or RBC transfusions were administered for an ScvO2 < 70% to 51.9% of patients. Patients were not statistically more likely to achieve an ScvO2 of ≥70% if they were treated with RBC transfusion alone (29/59, 49.2%, P = 0.19), inotropic therapy alone (104/226, 46.0%, P = 0.15) or both RBC and inotropic therapy (7/12, 58.3%, P = 0.23) as compared to no therapy (108/275, 39.3%). Following adjustment for treatment propensity score, RBC transfusion was associated with a decreased adjusted odds ratio (aOR) of in-hospital mortality among patients with hemoglobin values less than 10 g/dL (aOR 0.42, 95% CI 0.18 to 0.97, P = 0.04) while inotropic therapy was not associated with in-hospital mortality among patients with hemoglobin values of 10 g/dL or greater (aOR 1.16, 95% CI 0.69 to 1.96, P = 0.57).

Conclusions: Among patients with septic shock treated with EGDT in the setting of subnormal ScvO2 values despite meeting CVP and MAP target goals, treatment with RBC transfusion may be independently associated with decreased in-hospital mortality.

Figure 1

Early goal-directed therapy eligibility flowchart, Kaiser Permanente Northern California. Patients presenting with suspected infection and either two or more indicators of a systemic inflammatory response syndrome (SIRS) OR altered mental status are assessed for early goal-directed therapy eligibility based on both (1) initial venous lactate and (2) systolic blood pressure (SBP) as above. WBC, white blood cells.

Figure 2

Early goal-directed therapy treatment flowchart, Kaiser Permanente Northern California. Patients are considered for central venous oxygenation saturation (ScvO₂)-guided therapies once their central venous and mean arterial pressures have been optimized with fluid and vasopressor therapies as indicated. Patients with ScvO₂ values less than 70% are transfused with red blood cells (RBCs) until the hematocrit is 30% or greater, followed by dobutamine administration if ScvO₂ remains <70%.

Figure 3

Study subject selection flowchart. CVP, central venous pressure; DO₂, oxygen delivery; EGDT, early goal-directed therapy; MAP, mean arterial pressure; RBC, red blood cell; ScvO₂, central venous oxygen saturation.