Joseph Fisher

Research Synopsis

Over the last 15 years Dr. Fisher’s laboratory has developed the theory and technology for control of blood gases in spontaneously breathing and ventilated subjects.  This work has facilitated a number of scientific and clinical advances.  First, using controlled changes of carbon dioxide and oxygen, plus MRI imaging, his team developed unique functional images of cerebral blood flow, or cerebrovascular reactivity.  They also developed new image processing methods, which in turn let to new understandings of how brain blood flow is controlled, and has enabled the evaluation of the risk of stroke and the effectiveness of brain vascular bypass surgery in patients with cerebrovascular disease.  Second, Dr. Fisher’s research team applied blood gas control to develop a novel fully automated respiratory Fick measure of cardiac output.  They believe this is the most accurate known method of measuring cardiac output (see Klein et al. BJA 2015; PMID 25488304).  Third, they have developed methods to accelerate the respiratory elimination of hydrocarbons such as anesthetics and carbon monoxide, without affecting the carbon dioxide levels.  Finally, they developed the world’s first digitally controlled anesthetic delivery system, and applied it for the first time in patients, at the UHN. 

For the last decade Dr. Fisher has been the Chief Scientist at Thornhill Research Inc., a spin-off company from UHN.  TRI has developed a compact rugged life-support system for treating and transporting critically injured personnel in war and disaster conditions. In addition, he developed the world’s first FDA approved clinical digital in-line vaporizer for the administration of anesthetics.

Recent Publications

1. Duffin, J., Sobczyk, O., Crawley, A. P., Poublanc, J., Mikulis, D. J., & Fisher, J. A. (2015). The dynamics of cerebrovascular reactivity shown with transfer function analysis. NeuroImage. doi:10.1016/j.neuroimage.2015.04.029
2. Klein, M., Minkovich, L., Machina, M., Selzner, M., Spetzler, V. N., Knaak, J. M., . . . Fisher, J. A. (2015). Non-invasive measurement of cardiac output using an iterative, respiration-based method. Br J Anaesth, 114(3), 406-413. doi:10.1093/bja/aeu377
3. Poublanc, J., Crawley, A. P., Sobczyk, O., Montandon, G., Sam, K., Mandell, D. M., . . . Fisher, J. A. (2015). Measuring cerebrovascular reactivity: the dynamic response to a step hypercapnic stimulus. J Cereb Blood Flow Metab. doi:10.1038/jcbfm.2015.114
4. Sobczyk, O., Battisti-Charbonney, A., Fierstra, J., Mandell, D. M., Poublanc, J., Crawley, A. P., . . . Fisher, J. A. (2014). A conceptual model for CO-induced redistribution of cerebral blood flow with experimental confirmation using BOLD MRI. Neuroimage. doi:S1053-8119(14)00081-0 [pii];10.1016/j.neuroimage.2014.01.051 [doi]
5. Sobczyk, O., Battisti-Charbonney, A., Poublanc, J., Crawley, A. P., Sam, K., Fierstra, J., . . . Fisher, J. A. (2015). Assessing cerebrovascular reactivity abnormality by comparison to a reference atlas. J Cereb Blood Flow Metab, 35(2), 213-220. doi:10.1038/jcbfm.2014.184

Appointments

Staff, Department of Anesthesiology, University Health Network
Senior Scientist, Division of Advanced Diagnostics, Cardiovascular, Toronto General Research Institute
Full member, Institute of Medical Science, University of Toronto
Chief Scientist, Thornhill Research Inc.