Gregory Hare


Associate Scientist, Li Ka Shing Knowledge Institute


Dr. Gregory Hare is a Staff Anesthesiologist at St. Michael’s Hospital and a Professor in the Department of Anesthesia at the University of Toronto. His clinical focus is to develop multimodal and inter-professional approaches to optimize patient outcomes through patient blood management strategies. His long term research goal is to define mechanisms of anemia-induced morbidity and mortality; and to design novel treatment strategies to prevent these adverse outcomes.

Dr. Hare’s research is focused on defining adaptive, and maladaptive, cardiovascular mechanisms in experimental models of acute anemia using integrative whole animal models. These translational studies have defined mechanism of anemia-induced tissue hypoxia and mortality. His laboratory has identified integrative adaptive cellular (nNOS and HIF) and physiological mechanisms which promote organism survival during acute anemia. In addition, their laboratory has demonstrated that acute beta-blockade interferes with adaptive cardiovascular mechanisms, which sustain cerebral oxygen delivery during anemia. This could possibly explain the negative interaction between acute anemia and beta-blockade and the increased incidence of stroke in perioperative patients.

The laboratory is currently focused on translational approaches to identify patient specific biomarkers of anemia-induced tissue hypoxia in order to identify when patients are at risk of anemia induced morbidity and mortality; and to derive patient specific therapies which can reduce morbidity and mortality associated with both anemia and red blood cell transfusion. The overall clinical goal is to reduce morbidity and mortality associated with acute and chronic anemia in perioperative patients.

Recent Publications

  1. Cahill, LS, Pilmeyer, J, Yu, LX, Steinman, J, Hare, GMT, Kassner, A et al.. Ultrasound Detection of Abnormal Cerebrovascular Morphology in a Mouse Model of Sickle Cell Disease Based on Wave Reflection. Ultrasound Med Biol. 2019; :. doi: 10.1016/j.ultrasmedbio.2019.08.017. PubMed PMID:31563480 .
  2. Bao, J, Shore, EM, Simpson, AN, Hare, GMT, Sholzberg, M, Robertson, D et al.. Delphi Approach for the Design of an Intraoperative Blood Conservation Pathway for Open Myomectomy. J Obstet Gynaecol Can. 2019; :. doi: 10.1016/j.jogc.2019.04.023. PubMed PMID:31296447 .
  3. Ho, A, Zaltzman, J, Hare, GMT, Chen, L, Fu, L, Tarlo, SM et al.. Severe and near-fatal anaphylactic reactions triggered by chlorhexidine-coated catheters in patients undergoing renal allograft surgery: a case series. Can J Anaesth. 2019; :. doi: 10.1007/s12630-019-01441-5. PubMed PMID:31264193 .
  4. Garg, AX, Badner, N, Bagshaw, SM, Cuerden, MS, Fergusson, DA, Gregory, AJ et al.. Safety of a Restrictive versus Liberal Approach to Red Blood Cell Transfusion on the Outcome of AKI in Patients Undergoing Cardiac Surgery: A Randomized Clinical Trial. J. Am. Soc. Nephrol. 2019;30 (7):1294-1304. doi: 10.1681/ASN.2019010004. PubMed PMID:31221679 PubMed Central PMC6622429.
  5. Hare, GMT, Mazer, CD. A one-shot solution for improved patient blood management in cardiac surgery?. Lancet. 2019;393 (10187):2177-2178. doi: 10.1016/S0140-6736(18)32979-9. PubMed PMID:31030985 .
  6. Kei, T, Mistry, N, Curley, G, Pavenski, K, Shehata, N, Tanzini, RM et al.. Efficacy and safety of erythropoietin and iron therapy to reduce red blood cell transfusion in surgical patients: a systematic review and meta-analysis. Can J Anaesth. 2019;66 (6):716-731. doi: 10.1007/s12630-019-01351-6. PubMed PMID:30924000 .
  7. Pavenski, K, Ward, SE, Hare, GMT, Freedman, J, Pulendrarajah, R, Pirani, RA et al.. A rationale for universal tranexamic acid in major joint arthroplasty: overall efficacy and impact of risk factors for transfusion. Transfusion. 2019;59 (1):207-216. doi: 10.1111/trf.14995. PubMed PMID:30383292 .
  8. Mazer, CD, Whitlock, RP, Fergusson, DA, Belley-Cote, E, Connolly, K, Khanykin, B et al.. Six-Month Outcomes after Restrictive or Liberal Transfusion for Cardiac Surgery. N. Engl. J. Med. 2018;379 (13):1224-1233. doi: 10.1056/NEJMoa1808561. PubMed PMID:30146969 .
  9. Shehata, N, Mistry, N, da Costa, BR, Pereira, TV, Whitlock, R, Curley, GF et al.. Restrictive compared with liberal red cell transfusion strategies in cardiac surgery: a meta-analysis. Eur. Heart J. 2019;40 (13):1081-1088. doi: 10.1093/eurheartj/ehy435. PubMed PMID:30107514 PubMed Central PMC6441852.
  10. McAuliffe, N, Nicholson, S, Rigamonti, A, Hare, GMT, Cusimano, M, Garavaglia, M et al.. Awake craniotomy using dexmedetomidine and scalp blocks: a retrospective cohort study. Can J Anaesth. 2018;65 (10):1129-1137. doi: 10.1007/s12630-018-1178-z. PubMed PMID:29978278 .
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Affiliations & Other Activities


  • Staff Anesthesiologist, Department of Anesthesia, St. Michael’s Hospital
  • Professor, Department of Anesthesia, University of Toronto
  • Professor, Physiology, University of Toronto
  • Associate Member, Institute of Medical Science, University of Toronto