Drain fluid biomarkers for the diagnosis of clinically relevant postoperative pancreatic fistula: a diagnostic accuracy systematic review and meta-analysis

Drain Fluid Amylase as an Early Negative Predictor of Salivary Fistula Following Free Flap Reconstruction

OBJECTIVES

Salivary fistula is a known complication following head and neck free flap reconstruction involving the aerodigestive tract. We sought to examine the association between surgical drain fluid amylase and salivary fistula formation during postoperative hospitalization.

METHODS

Eighty patients who underwent head and neck reconstruction involving the aerodigestive tract at our institution between 2019 and 2023 were included. Amylase concentration (IU/L) was measured from a Jackson-Pratt drain located along the mucosal closure line on postoperative days 1-5.

RESULTS

Twelve patients (15%) developed salivary fistulas. The change in drain amylase concentration between postoperative day 1 and day 2 was found to be significantly higher in those who developed a fistula during postoperative hospitalization. A receiver operating characteristic curve found that a threshold of 15% provided a sensitivity of 58.3% and specificity of 80.6% (area under the curve 0.767) to predict salivary fistula. This threshold remained significant on multivariate analysis (odds ratio 5.35, 95% confidence interval 1.79-24.3) when controlling for prior radiation, perioperative transfusion, and total laryngectomy. When retrospectively applied to our cohort, a cutoff of 15% resulted in a positive predictive value of 35% and a negative predictive value of 91.5%.

CONCLUSION

Change in surgical drain fluid amylase from postoperative day 1 to 2 was associated with fistula formation following free flap reconstruction of the aerodigestive tract. Importantly, a change in amylase of < 15% from postoperative day 1 to 2 was best at identifying patients who are at low risk of developing salivary fistula during postoperative hospitalization, with a negative predictive value of 91.5%.

Biochemical Early Detection of Postoperative Pancreatic Fistula

Introduction

Clinically relevant postoperative pancreatic fistula (CR-POPF) is a severe complication following pancreatic surgery, leading to increased mortality, morbidity, and healthcare burden. This review focuses on the role of drain amylase and lipase as biomarkers for predicting and diagnosing CR-POPF and explores perspectives considering novel markers and their clinical applicability.

Methods

A comprehensive literature review was conducted using Medline via PubMed, Scopus via Elsevier, and Web of Science via Clarivate, selecting studies from 2019 to 2024. Search terms included pancreatic fistula, drainage, amylase, lipase, biomarkers, and corresponding MeSH terms. Studies were screened and selected for their assessment of biomarker accuracy, sensitivity, specificity, and postoperative timing of drain fluid collection.

Results

A total of 13 studies met the inclusion criteria, analyzing amylase, lipase, or other biomarkers in drain fluid for CR-POPF prediction. Both amylase and lipase consistently showed high diagnostic accuracy, with AUC values above 0.8. However, variability in optimal cut-off values across studies complicated standardization. Other drain biomarkers such as CRP or drain fluid culture positivity as well as amylase/lipase ratio and the temporal drain amylase-level progression were found to be promising predictors of CR-POPF.

Conclusion

Drain fluid amylase and lipase remain valuable diagnostic tools for CR-POPF, though variabilities and inconsistencies still pose challenges. Combining these with dynamic biomarker progression analysis and emerging markers as well as standardizing protocols could advance prediction and management. Further research is needed to verify the usefulness of supplementary novel biomarkers and to establish their clinical application in order to improve postoperative outcomes.

Non-Surgical Interventions for the Prevention of Clinically Relevant Postoperative Pancreatic Fistula-A Narrative Review

Clinically relevant postoperative pancreatic fistula (CR-POPF) is the leading cause of morbidity and mortality after pancreatic surgery. Post-pancreatectomy acute pancreatitis (PPAP) has been increasingly understood as a precursor and exacerbator of CR-POPF. No longer believed to be the consequence of surgical technique, the solution to preventing CR-POPF may lie instead in non-surgical, mainly pharmacological interventions. Five databases were searched, identifying eight pharmacological preventative strategies, including neoadjuvant therapy, somatostatin and its analogues, antibiotics, analgesia, corticosteroids, protease inhibitors, miscellaneous interventions with few reports, and combination strategies. Two further non-surgical interventions studied were nutrition and fluids. New potential interventions were also identified from related surgical and experimental contexts. Given the varied efficacy reported for these interventions, numerous opportunities for clarifying this heterogeneity remain. By reducing CR-POPF, patients may avoid morbid sequelae, experience shorter hospital stays, and ensure timely delivery of adjuvant therapy, overall aiding survival where prognosis, particularly in pancreatic cancer patients, is poor.