Pediatric Transplantation. 2018;e13119. wileyonlinelibrary.com/journal/petr | 1 of 9 https://doi.org/10.1111/petr.13119 © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd Accepted: 13 December 2017 DOI: 10.1111/petr.13119 ORIGINAL ARTICLE Intraoperative blood transfusion in pediatric patients undergoing renal transplant—Effect of renal graft size Rakan I. Odeh 1 * | Martin Sidler 1,2 * | Teresa Skelton 3 | Fadi Zu’bi 1 | Naimet K. Naoum 1 | Ibraheem Abu Azzawayed 1 | Fahad A. Alyami 4 | Armando J. Lorenzo 1 | Walid A. Farhat 1 | Martin A. Koyle 1 Abbreviations: BP, blood pressure; CO, cardiac output; EBL, estimated intraoperative blood loss; Epo, erythropoietin; ESRD, end-stage renal disease; GFR, glomerular filtration rate; Hb, hemoglobin; KS, Kolmogorov-Smirnov; NKF-DOQI, National Kidney Foundation Kidney Disease Outcomes Quality Initiatives; OvR, oversize renal recipients; PRBC, packed red blood cell; RT, renal transplant; SMR, size-matched renal recipients. *Authors contributed equally in the construction of this manuscript. 1 Division of Pediatric Urology, The Hospital for Sick Children and University of Toronto, Toronto, ON, Canada 2 Department of Paediatric Surgery, Great Ormond Street Hospital for Children, London, UK 3 Department of Pediatric Anesthesia, The Hospital for Sick Children and University of Toronto, Toronto, ON, Canada 4 Division of Urology, Department of Surgery, King Saud University, Riyadh, Saudi Arabia Correspondence Martin Sidler, Department of Paediatric Surgery, Great Ormond Street Hospital for Children, London, UK. Email: martin.sidler@gosh.nhs.uk Abstract In pediatric RT, donor allograft size often exceeds the expected recipient norms, espe- cially in younger recipients. An “oversize” graft might not only present a technical- and space-related challenge, but may possibly lead to increased demands in perioperative volume requirements due to the disparity between donor and recipient in renal blood flow. We evaluated transfusion practices at a single tertiary institution with special consideration of kidney graft size, hypothesizing that oversize graft kidneys might lead to a quantifiable increased need of blood transfusion in smaller recipients. Retrospective analysis of all patients who underwent pediatric RT from January 2004 to June 2014 at a tertiary pediatric centre was performed. Variables analyzed included patient age, weight, pre- and postoperative Hb concentration, graft size, EBL, amount of intraop- erative blood transfusion, and preoperative use of erythropoietin. Based on graft size in relation to patient’s age, a SMR and an OvR were identified. A subcohort of age- matched pairs was used to allow for comparison between groups. We calculated the expected procedure- and transfusion-induced changes in Hb and compared these changes to the observed difference in pre- vs postoperative Hb to assess the influence of graft size on transfusion requirements. RT was performed in 188 pediatric recipi- ents during the study period. In the matched cohort, percentage of transfused patients during transplantation in the OvR group was more than double compared with SMR (89% vs 39%, P < .001); similarly, the median number of transfused PRBC units in OvR was 1, while the median of SMR did not receive transfusion (P < .001). The difference between expected (calculated) and observed change in Hb was significantly higher in OvR with a median of 1.9 g/dL compared with SMR with a median of 1.0 g/dL (P = .026). Correspondingly, the calculated median volume taken up by a regular size kidney was significantly higher with 213 mL compared with 313 mL (P = .031) taken up by an oversize graft kidney. Median estimated intraoperative blood loss was