Original Study Journal of Veterinary Emergency and Critical Care 23(5) 2013, pp 517–522 doi: 10.1111/vec.12093 Comparison of heparinized saline and 0.9% sodium chloride for maintaining peripheral intravenous catheter patency in dogs Yu Ueda, DVM; Adesola Odunayo, DVM, MS, DACVECC and F.A. Mann, DVM, MS, DACVS, DACVECC Abstract Objective – To determine whether heparinized saline would be more effective in maintaining the patency of peripheral IV catheters in dogs compared to 0.9% sodium chloride. Design – Prospective blinded randomized study. Setting – University Veterinary Teaching Hospital. Animals – Thirty healthy purpose bred dogs, intended for use in the junior surgery laboratory, were utilized. The dogs were randomized into 1 of 3 groups, 2 treatment groups and a control group. Interventions – An 18-Ga cephalic catheter was placed in the cephalic vein of each dog. Each dog in the treatment group had their catheter flushed with either 10 IU/mL heparinized saline or 0.9% sodium chloride every 6 hours for 42 hours. The dogs in the control group did not have their catheters flushed until the end of the study period. Immediately prior to flushing catheters, each catheter was evaluated for patency by aspiration of blood and the catheter site was evaluated for phlebitis. Measurements and Main Results – All dogs in the heparinized saline and 0.9% sodium chloride group had catheters that flushed easily at each evaluation point. More dogs in the saline group had catheters from which blood could not be aspirated, but there was no significant difference between these groups. All dogs in the control group had catheters that flushed easily at the end of the assigned 6 hour interval except in 1 dog. Phlebitis was not detected in any dog. Conclusions – Flushes of 0.9% sodium chloride were found to be as effective as 10 IU/mL heparinized saline flushes in maintaining patency of 18-Ga peripheral venous catheters in dogs for up to 42 hours. For peripheral catheters placed with the intention of performing serial blood draws, heparinized flushes may be warranted. (J Vet Emerg Crit Care 2013; 23(5): 517–522) doi: 10.1111/vec.12093 Keywords: catheter care, blood sampling, thrombophlebitis Introduction Peripheral IV catheters are indispensable lifesaving tools commonly used in hospitalized human and veterinary patients to administer fluids, medications, and par- enteral nutrition. 1–7 Medical personnel in the ICU work From the Department of Clinical Sciences, Auburn University, Auburn, AL 36849 (Ueda, Odunayo); Department of Veterinary Medicine and Surgery, University of Missouri, MO 65211 (Mann). Dr. Ueda’s current address is School of Veterinary Medicine, University of California, Davis, CA. Dr. Odunayo’s current address is College of Veterinary Medicine, University of Tennessee, Knoxville, TN 37996. The authors declare no conflict of interests. Address correspondence and reprint requests to Dr. Adesola Odunayo, College of Veterinary Medicine, University of Ten- nessee, Knoxville, TN 37996. Email: adesolaodunayo@yahoo.com Submitted December 15, 2011; Accepted August 1, 2013. to ensure that these devices remain patent during the patient’s stay in the hospital. Loss of IV catheter patency may lead to compromised patient care, increased costs associated with replacing the catheters, and increased patient discomfort. 3, 8, 9 Occlusion and catheter site phlebitis are 2 common complications associated with peripheral IV catheters in human and veterinary patients. 10, 11 Catheter occlusion is thought to occur due to factors such as catheter site infection, duration of catheterization, or patient-related risk factors. Those factors ultimately lead to thrombus formation. 12 A great deal of work has been devoted to develop different catheter materials that minimize activation of coagulation. 13 Catheter clot formation has also traditionally been addressed by filling and flushing catheters with solutions with anticoagulant properties such as heparin, citrate, and vitamin C. 12 In C  Veterinary Emergency and Critical Care Society 2013 517