Prof. Tae-Yop KIM
Professor, Konkuk University School of Medicine, Korea
Dr. Tae-Yop Kim is a Professor of Anesthesiology at the Konkuk University School of Medicine, Seoul, Korea. He is now serving as Director of Academic Affairs of the Korean Society of Anesthesiologists (KSA), Chair of KSA’s Patient Safety Initiatives, Director of International Cooperation of the Korean Society of Cardiovascular and Thoracic Anesthesiologists, Director of Planning of the Korean Society of Geriatric Anesthesia and Pain Medicine, and Director of Research Affairs in the Korean Society of Patient Blood Management.
He is also the Board Member of the WFSA-Asia Australia Regional Section representing KSA, and the member of the Committee of Scientific Affairs of WFSA.
He has been organizing the KoreAnesthesia, the annual scientific congress of the KSA, in 2017-2020.
He serves to provide up-to-date Cardiothoracic Anesthesia Service with his long-time expertise in managing patients undergoing cardiovascular and thoracic surgery.
He has expertise in perioperative transesophageal/transthoracic echocardiography and its use for evaluating cardiac performance. His interest also includes fast-track cardiac anesthesia, goal-directed intraoperative IV volume optimization, patient blood management, and 3-D TEE for pre- and post-procedural assessment of cardiac procedures.
He published many original articles and case reports in international journals, lectured on many topics regarding perioperative TEE application, transfusion and bleeding management for cardiac surgery in many international and domestic scientific programs.
Blood is the mass of red blood cells (RBCs). As RBC has hemoglobin, the carrier of O2 to organ and tissue, hematocrit (Hct) reflects the size of the O2 carrying capacity of the unit blood volume.However, the real amount of O2 delivery is dependent on the overall amount of blood volume.
The ratio of Hct to whole blood viscosity (WBV, Hct/WBV ratio) has been employed to evaluate the blood rheological property as an index for O2 delivery potential. Due to non-Newtonian characteristics of blood, WBV is determined by the vascular shear rate (SR), which is continuously changing throughout the circulation. The optimum Hct/WBV ratio of human blood was variable and hugely dependent on the vascular SR. The SR at the medium-to-large-sized arteries with higher vascular shear stress is 300 sec-1 and the SR in the microcirculation with low shear stress is 1-5 sec-1, respectively. The low shear WBVs affects microcirculatory blood flow to the myocardium. Therefore, for evaluating the changes in the microvascular Hct/WBV ratio, as an indicator of the change in O2 delivery potential to the myocardial tissue, it may be necessary to employ the low shear WBVs.
Many studies demonstrated the compensatory responses to acute hemodilution: vasodilation, increased cardiac output (CO), and increased O2 extraction.
Hemodilution-induced reduction in WBV reduces vascular-flow resistance and increases CO, and increasing the blood flow to the myocardium and brain even in patients with coronary artery disease.
It would be beneficial to integrate the hemorheological concept and to adopt various point-of-care viscometers in patient blood management.
1. Nemeth N, et al. Inter-species differences in hematocrit to blood viscosity ratio. Biorheology 2009;46:155-65
2. Jung JM, et al. Reference intervals for whole blood viscosity using the analytical performance-evaluated scanning capillary tube viscometer. Clin Biochem 2014;47:489-93