Purpose: Patients living with advanced heart failure experience dyspnea, fatigue, poor quality of life, depression and cognitive impairment which may threaten their ability to provide informed consent to undergo heart transplant (HTx) or mechanical support (LVAD). Using qualitative and quantitative methods, we asked how patients with advanced heart failure make decisions regarding HTx and LVAD. The variables chosen to reflect the elements of consent included quality of life and symptom severity (voluntariness), depression and cognitive impairment (capacity) and treatment preferences (decision-making). Methods: 76 patients enrolled in the quantitative arm completed the Minnesota Living with Heart Failure Questionnaire; Visual Analog scales for dyspnea, fatigue and overall health; Beck Depression Inventory; Montreal Cognitive Assessment; Standard Gamble and Time Tradeoff. Qualitative methods were used to discover concepts, relationships and decision-making processes described by 17 of the 76 patients considering HTx and LVAD. Results: Patients reported poor quality of life and high symptom severity scores which compelled them to consider surgery as a way to relieve unpleasant symptoms and improve quality of life. Although 30% of patients had evidence of depression and/or cognitive impairment, no patient was deemed incapable of decision-making. Patients were willing to take considerable risk (35%) and trade considerable time (4months) to improve their health. While heart failure-related concepts were important to the decision, entrustment emerged as the meaningful process for decision-making. Conclusions: Patients who participated in this study were capable of decision-making and understood the risks associated with the surgery. Voluntariness was diminished by disease but not absent, and decisions were free of coercion. These results suggest the entrustment model of decision-making is the dominant process for patients considering high-risk surgical procedures and meets criteria for informed consent. Understanding the process of decision-making will help clinicians support and enable treatment decisions made by patients living with advanced heart failure.

Cerebral autoregulation is an intrinsic physiological response that maintains a constant cerebral blood flow (CBF) despite dynamic changes in the systemic blood pressure. Autoregulation is achieved through changes in the resistance of the small blood vessels in the brain through reflexive vasodilatation and vasoconstriction. Cerebrovascular reactivity (CVR) is a measure of this response. CVR is defined as a change in CBF in response to a given vasodilatory stimulus. CVR therefore potentially reflects the vasodilatory reserve capacity of the cerebral vasculature to maintain a constant cerebral blood flow. A decrease in CVR (which is interpreted as a reduction in the vasodilatory reserve capacity) in the vascular territory downstream of a larger stenosed supply artery correlates strongly with the risk of a hemodynamic stroke. As a result, the use of CVR studies to evaluate the state of the cerebral autoregulatory capacity has clinical utility. Application of CVR studies in the clinical scenario depends on a thorough understanding of the normal response. The goal of this thesis therefore was to map CVR throughout the brain in normal healthy individuals using Blood Oxygen Level Dependant functional Magnetic Resonance Imaging (BOLD MRI) as an index to CBF and precisely controlled changes in end-tidal partial pressure of carbon dioxide (PETCO2) as the global flow stimulus.

Spinal cord injury (SCI) remains a significant cause for morbidity and mortality in North America. Bladder dysfunction following SCI is very common and could lead to severe complications including renal failure and autonomic dysreflexia (AD). AD involves life threatening episodes of hypertension in patients with SCI above T6 level. Current management protocols for AD are symptomatic and usually ineffective. Botulinum toxin-A (BTX-A), has been successfully used recently in SCI patients because it reduces the detrusor contractility via inhibiting acetylcholine release from efferent nerve endings. Recent evidence, however, suggests a sensory involvement via modulation of sensory neuropeptides, neurotransmitters, and receptors. It is still, however, unclear whether BTX-A can affect putative spinal neurons involved in AD. In this study we demonstrated that intravesical BTX-A treatment has blocked AD in rats with T4-SCI, and also provided a novel mechanism for the control of autonomic dysreflexia via a minimally invasive treatment modality.

Objectives: To describe the use of standardized protocols (SPs) in emergency departments (EDs) across Ontario for childhood asthma and analyze the association of SPs with hospital admissions, 7-day ED re-visits, and outpatient follow-up visits. Methods: Population-based retrospective cohort study using health administrative data and survey data. EDs were categorized as having the optimal, other, or no SP for each outcome. Associations were tested with generalized estimating equations. Results: Between 2006/04/14-2009/02/28, 46,510 children with asthma were seen in 146 EDs, with 43 (29.5%) having SPs. Children treated in EDs with the optimal SP compared to no SP had no significant differences in hospital admissions (AOR 1.17; 95% CI 0.91, 1.49) or ED re-visits (AOR 1.09; 95% CI 0.85, 1.40) but were more likely to have follow-up visits (AOR 1.27; 95% CI 1.02, 1.59). Conclusions: SPs for childhood asthma are not common in Ontario EDs and had little impact on outcomes measured.

Spinal cord injury (SCI) remains a significant cause for morbidity and mortality in North America. Bladder dysfunction following SCI is very common and could lead to severe complications including renal failure and autonomic dysreflexia (AD). AD involves life threatening episodes of hypertension in patients with SCI above T6 level. Current management protocols for AD are symptomatic and usually ineffective. Botulinum toxin-A (BTX-A), has been successfully used recently in SCI patients because it reduces the detrusor contractility via inhibiting acetylcholine release from efferent nerve endings. Recent evidence, however, suggests a sensory involvement via modulation of sensory neuropeptides, neurotransmitters, and receptors. It is still, however, unclear whether BTX-A can affect putative spinal neurons involved in AD. In this study we demonstrated that intravesical BTX-A treatment has blocked AD in rats with T4-SCI, and also provided a novel mechanism for the control of autonomic dysreflexia via a minimally invasive treatment modality.

Cerebral autoregulation is an intrinsic physiological response that maintains a constant cerebral blood flow (CBF) despite dynamic changes in the systemic blood pressure. Autoregulation is achieved through changes in the resistance of the small blood vessels in the brain through reflexive vasodilatation and vasoconstriction. Cerebrovascular reactivity (CVR) is a measure of this response. CVR is defined as a change in CBF in response to a given vasodilatory stimulus. CVR therefore potentially reflects the vasodilatory reserve capacity of the cerebral vasculature to maintain a constant cerebral blood flow. A decrease in CVR (which is interpreted as a reduction in the vasodilatory reserve capacity) in the vascular territory downstream of a larger stenosed supply artery correlates strongly with the risk of a hemodynamic stroke. As a result, the use of CVR studies to evaluate the state of the cerebral autoregulatory capacity has clinical utility. Application of CVR studies in the clinical scenario depends on a thorough understanding of the normal response. The goal of this thesis therefore was to map CVR throughout the brain in normal healthy individuals using Blood Oxygen Level Dependant functional Magnetic Resonance Imaging (BOLD MRI) as an index to CBF and precisely controlled changes in end-tidal partial pressure of carbon dioxide (PETCO2) as the global flow stimulus.

Objectives: To describe the use of standardized protocols (SPs) in emergency departments (EDs) across Ontario for childhood asthma and analyze the association of SPs with hospital admissions, 7-day ED re-visits, and outpatient follow-up visits. Methods: Population-based retrospective cohort study using health administrative data and survey data. EDs were categorized as having the optimal, other, or no SP for each outcome. Associations were tested with generalized estimating equations. Results: Between 2006/04/14-2009/02/28, 46,510 children with asthma were seen in 146 EDs, with 43 (29.5%) having SPs. Children treated in EDs with the optimal SP compared to no SP had no significant differences in hospital admissions (AOR 1.17; 95% CI 0.91, 1.49) or ED re-visits (AOR 1.09; 95% CI 0.85, 1.40) but were more likely to have follow-up visits (AOR 1.27; 95% CI 1.02, 1.59). Conclusions: SPs for childhood asthma are not common in Ontario EDs and had little impact on outcomes measured.

Patients with acute myocardial infarction (AMI) are at high risk for reinfarction and death, with the highest rate of death and reinfarction occurring within 30 days of AMI. Therapies that have been shown to reduce these risks (secondary prevention) continue to be underutilized. Nurse practitioners are well positioned to provide secondary prevention during and following hospitalization. The purpose of this pilot study was to examine the feasibility, acceptability, and preliminary effects of an NP delivered secondary prevention intervention. The specific objectives were: 1) to describe NP activities when delivering the secondary prevention intervention; 2) to evaluate the effect of the NP intervention on the rate of implementation of evidence-based secondary prevention treatment strategies and the patients’ achievement of secondary prevention target goals; and, 3) to examine the relationship between the NP activities delivering the intervention and secondary prevention goal achievement by patients. A prospective cohort design was used, in which patients’ achievement of target goals were compared between patients who received secondary prevention care from an NP and those who received usual care. The sample of convenience consisted of 65 patients with AMI. Data on practice activities and implementation of secondary prevention by the NP were collected before discharge from hospital and one week, two weeks, six weeks and 3 months after discharge. Data on patients’ achievement of goals were obtained before discharge from hospital and 3 months after discharge from both groups. This study’s results provide preliminary evidence that an NP delivered secondary prevention intervention, beginning prior to discharge and continuing for three months post myocardial infarction, significantly improves the implementation and uptake of guideline based secondary prevention treatments and risk factor reduction strategies. NP-led interventions such as this warrant replication. The unique contribution of the NP with this patient population is the training and skills needed to deliver all aspects of secondary prevention, including pharmacological and nonpharmacological therapies, without the immediate availability of a physician.

Patients with acute myocardial infarction (AMI) are at high risk for reinfarction and death, with the highest rate of death and reinfarction occurring within 30 days of AMI. Therapies that have been shown to reduce these risks (secondary prevention) continue to be underutilized. Nurse practitioners are well positioned to provide secondary prevention during and following hospitalization. The purpose of this pilot study was to examine the feasibility, acceptability, and preliminary effects of an NP delivered secondary prevention intervention. The specific objectives were: 1) to describe NP activities when delivering the secondary prevention intervention; 2) to evaluate the effect of the NP intervention on the rate of implementation of evidence-based secondary prevention treatment strategies and the patients’ achievement of secondary prevention target goals; and, 3) to examine the relationship between the NP activities delivering the intervention and secondary prevention goal achievement by patients. A prospective cohort design was used, in which patients’ achievement of target goals were compared between patients who received secondary prevention care from an NP and those who received usual care. The sample of convenience consisted of 65 patients with AMI. Data on practice activities and implementation of secondary prevention by the NP were collected before discharge from hospital and one week, two weeks, six weeks and 3 months after discharge. Data on patients’ achievement of goals were obtained before discharge from hospital and 3 months after discharge from both groups. This study’s results provide preliminary evidence that an NP delivered secondary prevention intervention, beginning prior to discharge and continuing for three months post myocardial infarction, significantly improves the implementation and uptake of guideline based secondary prevention treatments and risk factor reduction strategies. NP-led interventions such as this warrant replication. The unique contribution of the NP with this patient population is the training and skills needed to deliver all aspects of secondary prevention, including pharmacological and nonpharmacological therapies, without the immediate availability of a physician.

Simulation and Web-based Learning (WBL) are both educational approaches that are increasingly applied in medical education. However, little is known about how these two instructional approaches may be integrated to improve learning outcomes. A prospective three-arm experimental study of different WBL preparation materials was conducted. Thirty undergraduate medical students with no prior experience in central venous catheterization (CVC) were randomly assigned to one of three preparatory interventions: tradition reading materials (TM), observational practice (OP), or OP and educational networking (OPEN). Participants then completed a simulation-based training workshop in CVC and a delayed retention test. Performance was assessed by a task-specific checklist, global rating scale (GRS) and by measuring time to competency. Main findings reveal a significant linear trend across the TM, OP and OPEN groups in time to competency. This exploratory study demonstrates the potential utility of Web-based observational practice and collaborative learning for improving the efficiency of simulation-based training.