Regional citrate anticoagulation for hemorrhage experiments in rats James L. Atkins, MD, PhD,* Elizabeth Barrows, MS, Stephen A. Byzek, BS, Chae-Hyuk Lee, MD, Jeffrey Keesee, BS, Andrea Edwards, BS, and James D. Oliver III, MD, PhD Walter Reed Army Institute of Research, Silver Spring, Maryland 20910 article info Article history: Received 14 December 2011 Received in revised form 30 January 2012 Accepted 9 February 2012 Available online 3 April 2012 Keywords: Hemorrhagic shock Heparin Citrate Regional anticoagulation Catheter abstract Introduction: Hemorrhage alone without concomitant trauma often results in a hypercoag- ulable state that makes it difficult to prevent clotting within the blood withdrawal cathe- ters. Although systemic administration of heparin can ameliorate this problem, heparin use has many additional actions that may confound interpretation of the hemorrhage experiments. The problem can be resolved by the use of a dual lumen catheter that anti- coagulates only the blood within the withdrawal circuit. We describe the design of such a catheter and evaluate its function in studies of hemorrhagic shock in rats. Materials and methods: Construction directions are provided for the dual lumen catheter along with a commercial source. The catheters were connected to computer controllable infusion syringes. Either citrate or heparin was used for regional extracorporeal anti- coagulation. Rats were anesthetized and hemorrhaged to 40 mm Hg for more than 15 min through the use of a computer program written in Labview. Ionized calcium measurements were obtained pre- and posthemorrhage. Results: The catheters remained patent throughout the experiments. There was no signif- icant difference in the ionized calcium whether citrate or heparin was used for extracor- poreal anticoagulation. Conclusion: The dual lumen catheters are suitable for the study of hemorrhagic shock in rats without the need for systemic anticoagulation. The catheters can be used with computer- controlled hemorrhage procedures. ª 2013 Elsevier Inc. All rights reserved. 1. Introduction It is difficult to maintain patent catheters for blood with- drawal during studies of hemorrhagic shock (HS) in rodents. Wiggers [1] used systemic anticoagulation with heparin in his studies, and that was the standard method for the study of HS until the practice was called into question by the findings of Rana et al. [2] and Wang et al. [3], which demonstrated that the systemic administration of heparin preserved microvascular patency and afforded protection in HS. The Chaudry group Part of this work was presented as an abstract: Atkins, J. L., Lee, C., Barrows, E., Quinn, P., Gonzales, R., and Oliver, J. D. Dual Lumen catheter for heparin-free hemorrahge in rats: design, construction and use. The FASEB Journal 22:1227.13.2008. * Corresponding author. Nephrology Division, Department of Medicine, Uniformed Services University of the Health Sciences, 4301 Jones Bridge Road, Bethesda, Maryland 20814, U.S.A. Tel: þ1301-814-0785. E-mail address: Jim.atkins@us.army.mil (J.L. Atkins). Available online at www.sciencedirect.com journal homepage: www.JournalofSurgicalResearch.com journal of surgical research 179 (2013) e197 ee202 0022-4804/$ e see front matter ª 2013 Elsevier Inc. All rights reserved. doi:10.1016/j.jss.2012.02.019