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Abstract

Introduction: Tissue hypoperfusion(TH), a crucial process in severe sepsis(SS) associated with higher morbidity and mortality, can be recognized early using central venous oxygen saturation(ScvO2) and lactate levels. However, both are invasive and underutilized. Tissue oxygen saturation(StO2) is a non-invasive method to detect TH. Studies have shown that low StO2 values(LSV) are associated with low ScvO2 and higher mortality in patients with SS/septic shock(SSK). The purpose of this study was to determine the incidence of LSV in non-intensive care unit(ICU) patients with suspected SS and association with disease progression, ICU transfer and length of stay(LOS). Hypothesis: LSV are associated with a higher incidence of disease progression, ICU transfer and prolonged LOS. Methods: This was a prospective, non-interventional study in patients with suspected SS from the non-ICU floors. An automated sepsis alert system identified patients based on systemic inflammatory response syndrome criteria, laboratory values and parameters indicating organ dysfunction. Pertinent baseline characteristics that might affect StO2 measurements were collected to control for confounding factors. All enrolled patients had StO2 measured to identify incidence of TH, defined as values less than 75%. The LSV were further evaluated to identify association with percentage of patients progressing to SS or SSK, transfer to the ICU, hospital LOS, and in-hospital mortality(IHM). Results: The incidence of TH identified by StO2 screening among 244 patients was 20% with a mean StO2 value of 67% vs 84% in the normal StO2 value(NSV) group. Most of the baseline characteristics between the LSV and NSV groups were similar except for a higher incidence of pre-existing liver disease in the NSV group. There was no difference in the percentage of patients progressing to SS(31% vs 35%,p=0.62) or SSK(6% vs 1%,p=0.056), number of patients requiring ICU transfer(12% vs 6%,p=0.21), hospital LOS(12.85 vs 14.4 days,p=0.44) and IHM(6% vs 11%,p=0.43) between patients with LSV and NSV, respectively. Conclusions: The incidence of LSV was similar to previous studies in SS/SSK. There was a strong trend of higher SSK incidence in patients identified with TH by StO2 measurement.