Transfusion practice and complications after laparotomy – an observational analysis of a randomized clinical trial K. Nielsen, 1 C. S. Meyhoff, 1 P. I. Johansson, 2 L. N. Jorgensen, 3 L. S. Rasmussen 1 & The PROXI Trial Group 1 Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark 2 Section for Transfusion Medicine, Capital Region Blood Bank, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark 3 Department of Surgery, Bispebjerg Hospital, University of Copenhagen, Copenhagen, Denmark Received: 16 January 2012, revised 17 May 2012, accepted 22 May 2012 Background Transfusion of allogeneic red blood cells (RBC) may be associated with side effects. This study aimed to assess whether an association could be detected between transfusion practice and the occurrence of complications after laparotomy. Study design and methods This study is an observational analysis of data from a randomized trial in 1400 patients who underwent laparotomy. A subgroup of 224 transfused patients with an intraoperative blood loss ‡200 ml were included in the analysis. Logistic regression analysis was used to investigate risk factors for postoperative complications. The ratio of intraoperative RBC transfusion to blood loss was computed, and patients grouped by the median into a liberal transfusion practice (ratio equal to or above the median) and a restrictive transfusion practice group (ratio below the median). Results Surgical site infection occurred in 27% of patients in the liberal group vs. 20% of patients in the restrictive group with an OR of 1Æ5 [95% CI: 0Æ8–2Æ9] (P =0Æ18) and an OR of 1Æ2 [95% CI: 0Æ5–2Æ9] (P =0Æ73) when adjusting for known confounding variables. Pneumonia occurred in 14% vs. 8% in the liberal and restrictive group, respectively (adjusted P =0Æ07), and admission to the intensive care unit was 15% vs. 7%, respectively (adjusted P =0Æ02), but no other significant differences were found. Conclusion A liberal transfusion practice was not significantly associated with postoperative complications, but pneumonia tended to be more common in the liberal group, which was more often admitted to the intensive care unit. Key words: postoperative complication, red blood cell transfusion, surgery, surgical site infection, transfusion practice. Introduction Blood loss during abdominal surgery may require replace- ment with allogeneic red blood cells (RBC) to preserve oxy- gen delivery and may even be lifesaving, but carries a risk of non-immunologic as well as immunologic side effects [1,2]. The risk of postoperative bacterial infection may be increased in patients receiving RBC transfusion, the pro- posed mechanism being an immunomodulating effect occurring when antigens from the donor are introduced into the circulatory system of the recipient along with the RBC. The antigens interact with the recipient’s immune sys- tem, which results in either alloimmunization or induction of tolerance, the latter suspected of increasing the risk of infection. The donor antigens affect the naive T lympho- cytes of the recipient, and the usual activation of the T helper lymphocytes is altered, and down regulation of T lymphocytes, macrophages, and natural killer cells leads to a reduced ability to eliminate bacteria [3–7]. Survival of Correspondence: Kamilla Nielsen, Department of Anaesthesia, Centre of Head and Orthopaedics, Copenhagen University Hospital, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark E-mail: kamilla.nielsen.kn@gmail.com Vox Sanguinis (2012) ORIGINAL PAPER ª 2012 The Author(s) Vox Sanguinis ª 2012 International Society of Blood Transfusion DOI: 10.1111/j.1423-0410.2012.01626.x 1