Simulated hydrodynamics study on rationality of placement of pancreatic drainage after pancreaticoduodenectomy

Objective 　To explore a rational method of placing appropriate pancreatic drainage after pancreaticoduodenectomy, and evaluate its safety and feasibility. Methods 　Classic Bernoulli's flowing mechanics energy equation (Bernoulli's equation) was used to calculate the dynamics of pancreatic juice flowing inside of the drainage tube. With given constant flowing velocity and density of pancreatic juice, four related factors on ΔP(pressure difference between entrance and exit planes of drainage tube) were investigated viarehearsing the formula. Effects on draining velocity by diameter and length of the tube were further verified by use of self-made pancreas drainage simulator, as well as the impact of liquid level difference on ΔP. Results 　Data obtained from calculation elucidated that the rank of 4 related factors was as follows: inner diameter﹥liquid level difference﹥liquid viscosity﹥tube length. The experiment also verified that the influence of draining velocity depended more on diameter rather than length. Liquid level difference was identified as major independent impact factor on ΔP. Conclusions 　Tube calibre ranging 1.5-2.0mm to allow a continuity of liquid flow is an essential factor to promise a fluent drainage. A 1.4m-length drainage tube is recommended for external draining, however, intraintestinal drainage of the pancreatic duct may be the best option. DOI: 10.11855/j.issn.0577-7402.2014.03.03