Dr. Howard J. Nathan is Professor of Anesthesiology at the University of Ottawa and also practices cardiac anesthesiology and intensive care at the University of Ottawa Heart Institute. He obtained his MD at McGill University and after several years of rural family practice returned to McGill to ...
Dr. Howard J. Nathan is Professor of Anesthesiology at the University of Ottawa and also practices cardiac anesthesiology and intensive care at the University of Ottawa Heart Institute. He obtained his MD at McGill University and after several years of rural family practice returned to McGill to complete a clinical fellowship in anesthesiology. He then did a postdoctoral research fellowship in Physiology and Biophysics at the University of Washington in Seattle, supported by a Fellowship award from the Medical Research Council of Canada. After three years of postdoctoral training, he accepted a faculty position at the University of Ottawa and obtained a Career Scientist Award from the Ontario Ministry of Health which was extended for the maximum of ten years.
Dr. Nathan has enjoyed uninterrupted peer-reviewed grant support for the past 18 years. His early laboratory work focused on finding the safest anesthetic techniques for patients with coronary artery disease undergoing surgery. After several years he decided to directly address the problems of the patients he was caring for by turning to clinical investigation, which has focused on preventing or minimizing brain injury during heart surgery.
Coronary artery surgery is one of the most frequent surgical procedures with more than 600,000 operations performed yearly in North America. Advances in surgery and anesthesia have resulted in great improvements, with death rates of less than 2% in many institutions. Now that the procedure can be performed safely, attention has turned to some of the associated adverse effects. Prominent among these is brain injury. These range in severity from brain death and incapacitating stroke to deficits in intellectual ability. Typical complaints include dependence on calculators to do simple arithmetic and an increased reliance on agendas and directories to remember appointments and contacts. Some professionals, suffering from an inability to concentrate, feel forced to abandon successful careers.
Dr. Nathan and his colleagues at the University of Ottawa Heart Institute were the first to recognize the important effect of intraoperative temperature on the brain. They discovered that, while on the heart-lung machine, the brain was inadvertently being heated to abnormally high temperatures. A survey of Canadian cardiac centers documented that this brain hyperthermia was a widespread occurrence. Dr. Nathan initiated a clinical trial, funded by the Heart and Stroke Foundation of Ontario, which demonstrated that patients whose brains were kept slightly cooler than normal had better cognitive function. With funding from the Canadian Institutes of Health Research (CIHR), the team is currently conducting a trial designed to verify and extend these findings. With worldwide recognition of the importance of brain temperature during heart surgery, many centers have modified their practices to the benefit of their patients.
Most recently, funding has been obtained from the Heart and Stroke Foundation of Ontario to discover underlying changes in the brain following heart surgery. Magnetic resonance imaging (MRI) is used to examine the brain while subjects perform cognitive tests. It is also possible to measure the chemical structure of the brain using the same machine. By examining consenting patients in this way before and after heart surgery, the team hopes to uncover the nature and significance of any resulting brain injury. It is expected that these observations will also add to our understanding of how the brain learns new tasks. Dr. Nathan feels privileged to have the opportunity to undertake research that may not only lead to improved patient care but may also reveal fundamental aspects of brain functioning.