Predictive value of perianastomotic drain fluid biomarkers in anastomotic leak: a cohort study

Justification for conduct of this study

• Anastomotic leak (AL) occurs when there is anastomosis dehiscence followed by leakage of intestinal contents into the peritoneum. The incidence of AL ranges from 2% to 20%.
• AL is one of the catastrophic complication following bowel anastomosis. Even though there several techniques of anastomosis described, none provide a leak proof outcomes. AL entails a complex post-operative course with increased morbidity and high short-term mortality (10 – 20%).
• AL usually presents with systemic inflammatory syndrome (SIRS), while the presentation may occasionally be asymptomatic. Patients are often taken up for imaging or damage control surgery when they present with clinical features of AL.
• Imaging has varying sensitivity and specificity for AL, and is not diagnostic. However, it can potentially delay the surgical procedure owing to its false negative findings.
• Despite several established risk factors and the numerous studies on this subject, AL is still difficult to predict, and on the contrary, AL with SIRS may rapidly worsen and despite intervention it may progress rapidly to mortality.
• In order to make diagnosis of AL at an early stage (prior to presentation), different methods other than imaging, like biomarkers of inflammation in serum and drain fluid are under investigations
• Serum biomarkers [such as total leucocyte count, C-reactive protein (CRP), cytokines (e.g., TNF-α, IL-6, IL-1β), serum lactate, and Procalcitonin (PCT)] have been utilised to detect AL.  However, they were found be non-specific, had variable cut-off for values (e.g., CRP, PCT etc), and these became significantly positive (increased) only after the appearance of symptoms or SIRS.
• From the available literature, the pH, lactate and CRP of drain fluid has been investigated by a few, and have concluded that it is a promising tool in predicting AL. However, none of these biomarkers have yet been verified in large scale clinical trials and lacks validation. Additionally, these were tested for colorectal surgeries only, and not following small bowel anastomosis.
• Hence, this study is trying to find if drain fluid biomarkers could help in detecting AL prior to presentation (or SIRS) so that an intervention can be performed in a time frame that can reduce morbidity and save lives.