Background: An accurate and readily available biomarker for identifying patients with complicated intra-abdominal infection needing special attention in critical care units because of their greater risk of dying would be of value for intensivists.
Methods: A multi-center, observational, retrospective study explored blood lactate, C-reactive protein (CRP), and procalcitonin (PCT) concentrations, and also Sequential Organ Failure Assessment (SOFA) and Simplified Acute Physiology Score (SAPS II) as mortality predictors in all adult patients with complicated intra-abdominal infection (cIAI) admitted to Surgical Critical Care Units (SCCUs) for ≥48 h in four Spanish hospitals (June 2012-June 2013). Logistic regression models (step-wise procedure) were constructed using as dependent variables "intra-SCCU mortality" or "overall mortality," and variables showing differences (p≤0.1) in bivariate analyses as independent variables.
Results: One hundred twenty-one cases were included. Mortality intra-SCCU (R(2)=0.189, p=0.001) was associated with SAPS II (categorized as high if ≥47) (OR=9.55; 95% CI, 1.09-83.85; p=0.042) and 24 h-lactate (≥5.87 categorized as high) (OR=6.90; 95% CI, 1.28-37.08). Overall mortality (R(2)=0.275, p=0.001) was associated with peak PCT (≥100 categorized as high) (OR=11.28; 95% CI, 1.80-70.20), peak lactate (≥1.8 categorized as high) (OR=8.86; 95% CI, 1.51-52.10) and SOFA at admission (≥7 categorized as high) (OR=8.14; 95% CI, 1.69-39.20), but was predicted better (R(2)=0.275, p=0.001) by a single dummy variable (high peak PCT-high peak lactate concentrations) (OR=99.11; 95% CI, 5.21-1885.97; p=0.002).
Conclusions: In the present study, SAPS II and 24 h-lactate concentrations predicted intra-SCCU mortality whereas overall mortality was predicted better by concurrent high PCT and lactate peak concentrations than by clinical scores or by each biomarker separately.