The correlation between postoperative pancreatic fistula and volume of amylase discharge in drainage fluid after pancreaticoduodenectomy

Introduction:The operative morbidity and mortality associated with pancreaticoduodenectomy (PD) remains relatively high. Despite a recent study showing that removing prophylactic drains early reduced the incidence of infective post-PD complications, most surgeons hesitate to do so. We determined the correlation between postoperative pancreatic fistula(PF)and the volume of amylase discharge in post-PD drainage fluid. Patients and methods: Subjects were 73 consecutive cases of PD conducted between 2006 and 2008. PF was defined and scored based on criteria of the International Study Group on Pancreatic Fistulas, i.e., any appreciable drainage from a drain placed during surgery with an amylase activity greater than three times the upper limit of normal serum amylase activity measured on or after postoperative day (POD) 3 (grade A, called " transient fistula," it has no clinical impact)grade B, required a change in management or adjustment in the clinical pathway)grade C, a major change in clinical management or deviation from the normal clinical pathway: And in this study, we defined PF as grade B/ C. Drain data, including amylase levels of drainage fluid (D-Amy) and the product of D-Amy and drainage volume, was compared between a group with PF(PF(+)) and one without PF(PF-)) Results:The incidence of PF in all patients was 27%. The incidence of PF was 49% in subjects with a soft pancreas and 6% in those with a hard pancreas. Risk factors for PF were obesity and soft pancreatic texture. D-Amy was significantly higher in the PF(+) group than in the PF(-) group on POD 1, 3, 5, and 7. The product of D-Amy and drainage volume was significantly higher in the PF(+) group than in the PF(-)group on POD 1 and 7, but no statistically significant difference was seen in that on POD 3and5. Conclusion:The product of D-Amy and drainage volume equals the volume of amylase discharge in drains. PF appears to develop on POD 7 in many cases, so care must be taken in the early removal of prophy-lactic drains in patients with a soft pancreas.