Preoperative Aspirin Administration Improves Oxygenation in Patients Undergoing Coronary Artery Bypass Grafting* Rabin Gerrah, MD; Amir Elami, MD; Alon Stamler, MD; Asya Smirnov, Bsc; and Zeev Stoeger, MD Objectives: Release of thromboxane (Tx) A 2 by platelets may be one of multiple factors that are responsible for lung injury after cardiopulmonary bypass, leading to pulmonary vasoconstriction and impaired oxygenation. In experimental models, the inhibition of Tx receptor or its production improved lung function. The use of aspirin, which is used widely in the treatment of ischemic heart disease because of its antiplatelet activity, is usually discontinued a week before the patient undergoes the operation to restore normal platelet hemostatic function. The purpose of this study was to determine the relationship between the time of cessation of aspirin before coronary artery bypass surgery, and postoperative oxygenation and bleeding. Design: A prospective clinical study comparing the effect of aspirin on postoperative oxygenation in patients who had been treated or had not been treated with aspirin. Setting: Tx levels in the pericardial fluid, oxygenation, and bleeding were compared between the two groups. Patients: Thirty-two patients with coronary artery disease who were undergoing coronary artery bypass grafting. Fourteen of these patients received aspirin until the day of the operation, whereas 18 patients stopped receiving aspirin at least 1 week before undergoing the operation. Main results: Mean ( SD) Tx levels in the pericardial fluid were significantly lower in the aspirin group (117  47 pg/mL) compared to those in the control group (1,306  2,048 pg/mL; p  0.02). The duration of ventilation after the operation was significantly longer in the nonaspirin group (9.6  5.6 h vs 3.8  1.4 h, respectively; p  0.0004). PO 2 reached a higher level while patients breathed 100% O 2 in the aspirin group (235  54 mm Hg vs 176  27 mm Hg, respectively; p  0.001). The mean amount of bleeding during the first 24 h after surgery was increased in the aspirin group (710  202 mL) compared with the nonaspirin group (539  143 mL; p  0.01), but these patients did not require more transfusions. Conclusions: The administration of aspirin until the operation may improve oxygenation with only a slight increase in bleeding. This improvement is probably mediated by antiplatelet activity and Tx inhibition by aspirin. (CHEST 2005; 127:1622–1626) Key words: aspirin; cardiopulmonary bypass; coronary disease; oxygenation; thromboxane; ventilation Abbreviations: CABG  coronary artery bypass graft; CPB  cardiopulmonary bypass pump; Fio 2  fraction of inspired oxygen; Tx  thromboxane L ung injury is a frequent complication after car- diac surgery using cardiopulmonary bypass (CPB). 1,2 It has been shown that when the effects of general anesthesia and surgical injury are similar, the use of CPB may be the dominant factor worsening postoperative respiratory dysfunction. 1 Various in- flammatory mediators, produced or released during CPB, are believed to exert a damaging effect through the activation of WBCs. 3–5 The depletion of these activated leukocytes was performed in the clinical *From the Department of Cardiothoracic Surgery (Dr. Gerrah), Assuta Medical Center, Tel Aviv, Israel; the Department of Cardiothoracic Surgery (Dr. Elami), Hebrew University, Hadas- sah Medical School, Jerusalem, Israel; the Department of Car- diothoracic Surgery (Dr. Stamler), Rabin Medical Center, Sack- ler Medical School, Tel Aviv, Israel; and the Department of Internal Medicine (Ms. Smirnov and Dr. Stoeger), Kaplan Medical Center, Rehovot, Israel. Manuscript received July 30, 2004; revision accepted November 11, 2004. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal. org/misc/reprints.shtml). Correspondence to: Rabin Gerrah, MD, 15 Hagana St, Apart- ment 3, Holon 58275, Israel; e-mail: rabin@assuta.com 1622 Clinical Investigations Downloaded From: http://journal.publications.chestnet.org/ by a Breman National Medical Lib User on 04/10/2015