C-reactive protein kinetics post elective cranial surgery. A prospective observational study

Introduction: Post cranial surgery readmission, largely caused by surgical site infection (SSI), is a marker of patient-care quality requiring comprehensive discharge planning. Currently, discharge assessment is based on clinical recovery and basic laboratory tests, including C-reactive protein (CRP). Although CRP kinetics have been examined postoperatively in a handful of papers, the validity of CRP as a standalone test to predict SSI is yet to be explored. Methods: A prospective observational study was performed on adult patients undergoing elective cranial surgery over a 3-month period. Laboratory data; CRP, white cell count (WCC), neutrophil cell count (NCC), and clinical data were assessed pre and post-operatively and were evaluated as predictors for safe discharge. Readmission rates within 1 month were recorded. Results: In this study, 68 patients were included. About 8.6% were readmitted due to SSI. A postoperativepeak in CRP was seen on day 2 with a value of 57 in the non-readmitted group, and 115 in the readmitted group. CRP dropped gradually to normal levels by day 5 in the non-readmitted group. A secondary CRP rise at day 5 was noted in the readmitted group with a sensitivity, specificity, and negative predictive value of 71%, 90%, and 96%, respectively. Interestingly, our ROC analysis indicates that a CRP value of less than 65 predicts safe discharge with a sensitivity of 86%, specificity of 89% and negative predictive value of 98% of safe discharge (area under the curve, AUC: 0.782). No significant difference in other inflammatory markers was found between both groups. Conclusions: CRP increases postoperatively for 4-5 d which could be a physiological response to surgery, however, prolonged elevation or a secondary increase in CRP may indicate an ongoing infection. Our data validate the potential use of CRP levels to predict SSI. A multicentre study is warranted to investigate the role of CRP in predicting SSI.