Role of Combined Post-Operative Venous Lactate and 48 Hours C-Reactive Protein Values on the Etiology and Predictive Capacity of Organ-Space Surgical Site Infection after Elective Colorectal Operation.

Background: C-reactive protein (CRP) has been assessed to detect organ-space surgical site infection (OSI). Nevertheless, data about peri-operative oxygen debt and surgical stress-elicited biologic markers to explain and allow for the early detection of OSI are lacking. We analyzed immediate post-operative venous lactate, early CRP levels, and intra-operative hemodynamic values on the capacity to predict OSI after elective colorectal operation.

Patients And Methods: Patients undergoing an elective colorectal surgical procedure with anastomosis between March 2013 and August 2014 were included and assessed prospectively. Post-operative lactate values at L-0, L-6, and L-24 hours, CRP (basal and 48 h), and the percentage of operative time (POT) with systolic blood pressure below 100 mm Hg and heart rate above 90 beats per minute in patients with and without OSI were compared. Binary logistic regression was constructed for L-0 and CRP-48, and receiver-operating characteristic (ROC) was analyzed for sensitivity (S), specificity (Sp), positive (PPV) and negative (NPV) predictive values.

Results: Patients with OSI (11 of 100) showed higher L-0 and L-24 (3.2 ± 2.5 vs. 1.6 ± 0.8; p = 0.025 and 1.9 ± 1.2 vs. 1.2 ± 0.4 mmol/L; p = 0.025) and CRP-48 (188 ± 80 vs. 74 ± 52 mg/L; p = 0.001). The ROC from logistic regression showed area under the curve of 0.899 (95% confidence interval [CI] 0.805-0.992), S of 72% (95% CI 43.2%-90.5%), Sp of 95% (95% CI 88.6%-98.4%), PPV of 66% (95% CI 38.9%-86.4%) and NPV of 0.96 (95% CI 90%-99%). L-0 was higher in those patients with hypotension during more than 60% of the POT (2.4 ± 2.1 vs. 1.6 ± 0.8; p = 0.038). Patients with OSI had a higher POT with hypotension (50 ± 28% vs. 30 ± 28%; p = 0.032) and tachycardia (18 ± 27% vs. 5 ± 16%; p = 0,024).

Conclusions: The combination of immediate post-operative lactate and CRP at 48 hours proved to be useful in predicting OSI after elective colorectal operation. Assessment of peri-operative lactate is a potential target for intra-operative goal-oriented management aimed at improving post-operative outcomes.