ORIGINAL ARTICLESThe effect of N-acetylcysteine on blood coagulation and platelet function in patients undergoing open repair of abdominal aortic aneurysmNiemi, Tomi T; Munsterhjelm, Edward; Pöyhiä, Reino; Hynninen, Marja S; Salmenperä, Markku T Author Information Department of Anaesthesiology and Intensive Care Medicine, Helsinki University Central Hospital, Finland Received 23 August, 2005 Revised 7 October, 2005 Accepted 7 October, 2005 Correspondence and requests for reptints to Tomi Niemi, MD, Department of Anaesthesiology and Intensive Care Medicine, PO Box 340, FIN-00029 HUS, Finland. Tel: +358 9 47176476; fax: +358 9 47176477; e-mail: [email protected] Sponsorship: Supported by the Helsinki University Hospital HUS-EVO funding and a grant from the Instrumentarium Science Foundation, Helsinki, Finland. Blood Coagulation & Fibrinolysis: January 2006 - Volume 17 - Issue 1 - p 29-34 doi: 10.1097/01.mbc.0000195922.26950.89 Buy Metrics Abstract N-acetylcysteine (NAC) may offer renal and hepatic protection during surgery, but in experimental studies it has been shown to impair coagulation. Since very little is known about the effects of NAC on blood coagulation in surgical patients, we studied its effects during abdominal aortic reconstruction. NAC (a bolus of 150 mg/kg followed by a continuous 24-h infusion of 150 mg/kg) or the same volume of placebo was given intravenously, in a randomized double-blinded fashion, to 20 patients undergoing abdominal aortic aneurysm repair. The haematocrit, platelet count, prothrombin time, thromboelastometry, and platelet aggregation were studied during and after surgery. Total blood loss was also measured. The median (25th–75th percentiles) decrease of the prothrombin time value was 33.0% (30–37%) after NAC treatment and 6.5% (4–8%) after placebo (P < 0.001). Postoperative prothrombin time values remained lower in the patients receiving NAC. In thromboelastometry tracings the coagulation time was more prolonged after the bolus of NAC (P = 0.02). Platelet aggregation induced with adenosine diphosphate decreased after NAC but not after placebo. Low prothrombin time values before and after bolus infusions were associated with increased blood loss (P = 0.008 and P = 0.015, respectively). NAC has anticoagulant and platelet-inhibiting properties in patients undergoing major vascular surgery. This abnormal haemostatic activity should be considered when NAC is administered to patients with increased bleeding risk. © 2006 Lippincott Williams & Wilkins, Inc.