Predictive value of blood gas parameters and hematologic indices on survival in critically ill sepsis patients

Abstract

Introduction: Sepsis is a life-threatening condition caused by an excessive immune response to infection, leading to severe tissue and organ damage. In resource-limited settings, early, low-cost, and readily available laboratory parameters may guide outcome prediction. This study aimed to evaluate the role of hematological indices and laboratory parameters in predicting mortality among intensive care unit (ICU) patients with sepsis.

Methodology: This retrospective study included adult sepsis patients admitted to the ICU between January 2018 and December 2023. Blood samples obtained within the first 6 hours of ICU admission were processed using standardized analyzers. Demographic data, laboratory results at admission, length of hospital stay, and mortality status were retrieved from the hospital database. Associations between hematological indices, laboratory parameters, and mortality were analyzed.

Results: A total of 180 patients were included; 40 died during hospitalization. No significant association was found between neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), or platelet-to-lymphocyte ratio (PLR) and mortality (NLR: p = 0.834, LMR: p = 0.895, PLR: p = 0.192). In contrast, pH levels showed a strong negative correlation with mortality (p < 0.001), while lactate levels were significantly positively correlated (p = 0.006). Carboxyhemoglobin and methemoglobin levels were not significantly related to mortality.

Conclusions: Low pH and high lactate levels were the strongest predictors of mortality in sepsis patients, highlighting the prognostic value of simple blood gas parameters, especially where advanced diagnostics are limited. Hematological indices showed no significant association with mortality. pH and lactate should be prioritized in clinical decision-making for sepsis patients.