Monitoring the post surgery inflammatory host response
The human response to surgery is meant to be protective and to promote healing. The cascade of events that ensue following tissue injury is highly complicated and involves an interplay of the metabolic, hemodynamic, hormonal and immunological systems. The release of biomolecules known as damage-associated molecular patterns (DAMPs) activates the pro-inflammatory innate and anti-inflammatory adaptive responses, which are designed to defend and contain the inflammatory process locally. The magnitude of tissue injury influences the scale of the inflammatory response. Further, patient factors as well as medical therapy influences this response. An imbalance between the pro-inflammatory and anti-inflammatory response or an exaggerated response may culminate with organ dysfunction, an increased susceptibility for infections or death. Cell mediated immunity (CMI) is often suppressed post surgery and patients are predisposed to the development of postoperative infections and complications. Mapping the immune response would be useful in terms of adjudging the patient’s response to surgery, alerting clinicians to the occurrence of complications thereby providing the opportunity to implement appropriate management timeously if necessary. There is a vast overlap in the surgical inflammatory response with that of the pathogen-associated molecular patterns (PAMPs) induced response that follows sepsis. This presents a challenge in the postoperative period in terms of distinguishing between infectious and non-infectious complications. Biomarkers have thus emerged as attractive contenders to map the immune response. Taking into account the complexity of the inflammatory response, it is unlikely that a single biomarker will ever be utilised to achieve this. In the era of personalised medicine, where our patient populations are quite heterogeneous, future directions point towards the use of multiple panels of novel biomarkers. Currently the procalcitonin (PCT) and C-reactive protein (CRP) are available for general use. This review explores the inflammatory response to surgery and the utility of CRP and PCT in the postoperative period. It highlights the importance of using biomarker kinetics coupled with the clinical response and the principle of individualised interpretation.