Laboratory Research Program

​The purpose of our program is to identify and address specific gaps in our knowledge of basic integrative physiology that have long retarded progress in patient care. Our research examines:

• Acceleration of elimination of volatile hydrocarbons such as carbon monoxide and inhalational anesthetic agents.

  Carbon monoxide, the 'silent killer', (the most common cause of poisoning death in the world), along with deliberately administered poisons such as inhaled anesthetics, and self-administered poisons such as alcohol, methanol and accidental ingestions by children share the requirement for rapid detoxification.   

  What they have in common is being volatile – they are able to evaporate.  As such, they evaporate from the blood into the lungs.  Their elimination from the lungs then becomes the limiting factor for their elimination from the body.   

  We have devised a means of accelerating their elimination from the lung (and hence the rest of the body).

  Our research now is focused on assessing the extent of the clinical benefits of this detoxification method.  

• Development and validation of new non-invasive cardiac output models: bench to bedside

  'Cardiac output,' the rate of circulation of the blood in the body, is responsible for providing the nutrients required to sustain life.

  In health, it is regulated according to the needs of the body.  In the case of heart disease, severe illness, and during some operations, the blood flow to the body can be inadequate to meet its needs, therefore depriving vital organs of the blood flow they need to maintain normal function.

  Cardiac output is difficult to measure accurately.  Currently, its measure first requires the insertion of a long tube that courses through the heart, with its tip sitting in a major vessel in the lungs.  Even so, the measures have many drawbacks in risk, expense, reliability of data and practicality.  Its use is therefore reserved for specific life-threatening occasions.  As a result, it is not available for more liberal use where it would improve patient well-being and outcome. 

  For many years there has been a quest to provide accurate, practical, non-invasive means for measuring cardiac output.  Some such means (many are only semi-invasive) are already commercially available.  We have developed several related non-invasive, accurate, clinically practical methods of measuring cardiac output.   

  We are currently testing new commercial devices, as well as investigating and validating the various assumptions of our new methods and configuring them to be suitable for clinical testing.

• Assessment of breathing mechanics, predictions of respiratory failure; non-invasive approaches to increasing ventilatory reserve

  Severely ill patients lose their ability to maintain ventilation ('ventilatory failure') and have to fall back on mechanical support (requiring a mechanical ventilator) for their breathing.  Similarly, even after the acute systemic illness begins to resolve, it is often difficult to wean them off mechanical support.

  We study the contribution of various breathing muscle groups to provide the ventilatory reserve, to prevent ventilatory failure.  This understanding provides some insights into what could be done non-invasively to boost the reserve, and therefore avoid mechanical ventilation. Our studies test the efficacy of these non-invasive aids. 

  We are currently doing our preliminary studies on healthy volunteers, using exercising to exhaustion as a surrogate for respiratory failure. 

• Vascular reactivity in the brain and eye

  We have developed a new method of inducing changes in arterial partial pressure of carbon dioxide (PaCO₂), and oxygen (PaO₂), as means of stimulating changes in blood flow in various organs such as the brain, eye, kidney, heart and liver.  

  With imaging methods that detect changes in blood flow in these organs, we can test the health of their blood supply.   

  We have ongoing, extensive studies in healthy volunteers and patients, addressing issues related to stroke, subarachnoid bleed, brain trauma, radiation and brain tumours, obstructive sleep apnea, glaucoma, diabetic retinopathy and other conditions.

• Control, and non-invasive determination, of arterial partial pressures of oxygen (PaO₂) and carbon dioxide (PaCO₂)

  PaO₂  and PaCO₂ are sensitive indicators of breathing ability and acid-base status of the blood.  The determination of these values is one of the most common blood tests in the Emergency Department, Intensive Care Unit and operating room.  These determinations can only be performed through a puncture of an artery.  We study the efficacy of a new, non-invasive method of determining these values.

• Effects of acute and chronic hypoxia (at high altitude) on breathing patterns, brain blood flow and novel in-vivo measures of oxyhemoglobin dissociation curve. 

  As anesthesiologists and intensive care specialists dealing with severely ill patients, it is important for us to understand the physiology of response to acute and chronic lack of oxygen.

  We study the effects of hypoxia on breathing and brain blood-flow.  We are unique in studying how the hemoglobin's affinity for oxygen changes with oxygen-lack while in the body, as opposed to in a test tube, after it has been extracted from the body.

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