The Association between Diabetes Status and Survival following an Out-of-Hospital Cardiac Arrest: A Retrospective Cohort Study
Principal Investigators: M. Parry, L. Morrison
Co-Investigators: K. Danielson, S. Brennenstuhl, I.R. Drennan
Funding: This study was possible through grants from the Canadian Institutes of Health Research (CIHR), the Laerdal Medical Foundation and the Heart and Stroke Foundation of Canada. Kyle Danielson was supported by a Canada Graduate Scholarship Master’s Award from CIHR and Ian Drennan was supported by a CIHR Banting and Best Doctoral Research Award. The RescuNet Epistry dataset was funded by the Laerdal Foundation, CIHR, the Heart and Stroke Foundation of Canada, Defence Research and Development Canada and the US National Institutes of Health funding for the Resuscitation Outcomes Consortium.
BACKGROUND AND OBJECTIVE: Sudden cardiac arrest (SCA), confirmed absence of cardiac mechanical activity, is the leading cause of heart-related death in the US. Almost 85% of SCA occur out-of-hospital (OHCA), with very poor rates of return of spontaneous circulation (ROSC) and survival to hospital discharge. We sought to determine if diabetes status was associated with survival or ROSC following an OHCA.
METHODS: We completed a retrospective cohort study using data from the Toronto Regional RescuNet Epistry dataset, based upon data definitions defined by the Resuscitation Outcomes Consortium (ROC) Epistry-Cardiac Arrest and the Strategies for Post Arrest Resuscitation Care (SPARC) network datasets. Adults ≥ 18 years of age who experienced an OHCA, had data on diabetes status, and were treated by Emergency Medical Services (EMS) between 2012-2014 were included in the analysis (n=10,097). We used bivariate analyses to examine relationships between diabetes status, Utstein elements and outcomes, and logistic regression to determine predictors of survival.
RESULTS: Diabetes prevalence was 27.8% (95% CI: 27.0–28.7). A larger proportion of those with diabetes had a non-shockable initial rhythm (28.8% vs. 25.1%; p < 0.01) and did not survive to hospital discharge (92.1% vs. 89.2%, p < 0.001). Diabetes status is associated with a decrease in survival, independent from a number of Utstein elements (adjusted OR = 0.76; 95% CI: 0.64-0.91, p = 0.003).
CONCLUSIONS: This is the first Canadian study to examine the association between diabetes status and OHCA outcomes. Our findings suggest that diabetes status prior to arrest is associated with decreased survival. The growing prevalence of diabetes globally suggests a future burden related to OHCAs.
Translation and Validation of the Canadian Diabetes Risk Assessment Questionnaire in China
Principal Investigator: J. Guo
Co-Investigators: Z. Chen, J. Dixon, J. Wiley, S. Tang, M. Parry
Funding: Jin’an Research Grant, Nursing Faculty Research Grant from China Medical Board, contract grant number: 13-168-201410; and the National Nature Science Fund of China, contract grant number: 81502901.
OBJECTIVE: The objective of this study was to translate and adapt the Canadian Diabetes Risk Assessment Questionnaire (CANRISK), validate the content of the revised questionnaire (CHINARISK), and evaluate the ability of CHINARISK to detect dysglycemia in China.
DESIGN AND METHODS: Six diabetes experts assessed content validation of the translated and adapted CHINARISK questionnaire. Criterion and construct validation of CHINARISK was assessed in a convenience sample of 194 individuals aged 35 to 74 years from October 2014 to April 2015. Results of 2-hour 75g oral glucose tolerance tests (OGTT) were used to determine criterion validity and the Finnish Diabetes Risk Score (FINDRISC) was used to determine construct validity.
RESULTS: Scores of CHINARISK were positively related to results of 2-hour 75g OGTT (r=0.343, p﹤0.001) and there were positive correlations between CHINARISK and FINDRISC scores (r=0.738, p﹤0.001). The area under receiver operating characteristic curve (AUC) of the CHINARISK was 0.705 (95% CI, 0.632-0.778), demonstrating medium diagnostic value and the AUC of FINDRISC was 0.665 (95% CI, 0.587-0.742), demonstrating low diagnostic value. At a cut-off score of 30, the sensitivity of the CHINARISK was 73%, positive predictive value (PPV) was 57%, and negative predictive value (NPP) was 78% for this threshold, which were higher than the indicators of FINDRISC.
CONCLUSION: Diabetes lack of awareness and subsequent lack of treatment will cause an epidemic of diabetes-related complications in China. CHINARISK has the potential to be a universal screening tool for diabetes. Before an organized approach to diabetes screening using a risk assessment tool can be implemented in China, a prospective cross-sectional screening study to evaluate the accuracy and discrimination of CHINARISK needs to be undertaken.
Her Heart, Her Story: A Grassroots Approach to Understanding Cardiac Pain in Women with Arthritis
Principal Investigator: M. Parry
Co-Investigators: AK Bjoernnes, L. Cooper, L. Eder, P. Harvey, C. Lalloo, J. Price, D. Richards, J. Stinson, J. Watt-Watson, L. Wilhelm
Collaborators: Canadian Arthritis Patient Alliance, The Arthritis Society, Canadian Pain Coalition, Heart and Stroke Foundation of Canada
Funding: The Women’s Xchange (2017 – 2018)
BACKGROUND AND OBJECTIVE: Inflammatory arthritis is associated with an increased risk of coronary artery disease (CAD) morbidity and mortality but little is known about the clinical presentations associated with cardiac pain in women with IA. Physicians/health care professionals (HCP) may underestimate the actual cardiac risk of women with IA by attributing symptoms to musculoskeletal disorders. Our project is the first to understand how women with IA understand, discuss, recognize and manage cardiac pain related to CAD.
METHODS: We partnered with The Arthritis Society, Canadian Arthritis Patient Alliance (CAPA), Canadian Pain Coalition, and the Heart and Stroke Foundation of Canada to: 1) complete a comprehensive review of the evidence on cardiac pain in women with inflammatory arthritis, 2) conduct a needs assessment using focus groups, 3) integrate and analyze this data, and 4) translate this grassroots knowledge to health care providers, researchers, and women with inflammatory arthritis through publication, presentation (professional and public), on-line technologies (video, virtual interactive case [VIC] presentation), social media, and websites (The Arthritis Society, CAPA).
RESULTS: In total, 519 studies were included for full text assessment. However, no study described the self-management of cardiac pain or associated cardiac pain equivalents (e.g., fatigue, dyspnea, and exhaustion) in women with IA. A total of five women were recruited using women’s social media health groups (Facebook). Women ranged in age from 56 to 73 years (X = 62.6, SD = 6.3), all (n = 5, 100%) were married or in a cohabitant relationship, and most (n = 4, 80%) were retired or working part-time. Eighty percent (n = 4) of women had mild/moderate or high stress at home, reduced physical function (X = 4.6, SD = 2.1), moderate pain scores (X = 6.0, SD = 2.0, range 4.0 – 8.5), and had high IA disease activity (n = 3, 60%). Most women (n = 3, 60%) were also the primary person responsible for housework in the home, completing an average of 18.2 hours (SD = 8.0) of housework per week (range 8 – 30 hours per week). The thematic content analysis identified five major themes from the women`s narratives: 1) arthritis pain experiences, 2) chest pain experiences, 3) decision-making processes, 4) impact on daily life and emotional responses, and 5) self-management behaviours. Our results suggest women with IA have a high burden of disease activity related to IA. Most women described their IA pain as episodic and associated with the intensity of their daily activities. They experienced a cascade of diffuse cardiac symptoms and early symptoms were often undifferentiated and difficult to interpret by healthcare personnel and the women themselves.
CONCLUSION: Our results confirm a lack of evidence related to how women with IA self-manage and make decisions about cardiac pain and more research is needed to better target treatment and follow-up support for these women.
Self-Management Programs for Women with Cardiac Pain: An Integrated Mixed Methods Systematic Review
Principal Investigators: M. Parry, H. Clarke
Co-Investigators: AK Bjoernnes, L. Cooper, A. Gordon, P. Harvey, C. Lalloo, M. Leegaard, S. LeFort, J. McFetridge-Durdle, M. McGillion, S. O’Keefe-McCarthy, J. Price, J. Stinson, JC Victor, J. Watt-Watson
Collaborators: P. Ayala, E. Lenton, K. Bernard, C. De Angelis, Alpha Phi Xi Chapter, Ontario Women’s Health Network, Centre for Global eHealth Innovation
Funding: Canadian Institutes of Health Research (CIHR) (2017 – 2018)
BACKGROUND AND OBJECTIVE: The overall goal of this program of research is to develop and systematically evaluate an integrated smartphone and web-based intervention (HEARTPA♀N) that will help women self-manage cardiac pain. The aim of Phase 1 (current work) was to conduct an integrated mixed methods systematic review of self-management programs for women who have cardiac pain.
METHODS: We used methods described by the Evidence for Policy and Practice Information (EPPI) and the Coordinating Centre at the Institute of Education to systematically search the literature on the self-management of cardiac pain in women. We consulted with key end-user stakeholders to discuss and re-confirm priorities and search terms for a comprehensive review of the literature and summarized the findings of the overall quantitative and qualitative reviews using a mixed methods synthesis.
RESULTS: Our systematic review of self-management interventions yielded 22,402 articles titles and abstracts. Of these, 57 RCTs were included in a final quantitative synthesis, comprising data from 5,299 women. Results indicated that self-management interventions for cardiac pain were more effective if they included a greater proportion of women (standardized mean difference [SMD], -0.01; standard error, 0.003; P=0.02), goal setting (SMD, -0.26; 95% confidence interval [CI], -0.49 to -0.03), and collaboration/support from health care providers (SMD, -0.57; 95% CI, -1.00 to -0.14). A total of 35 qualitative studies were included in a final meta-summary, comprising data from 437 women. Results also support individualized intervention strategies that promote goal setting and action planning, management of physical and emotional responses, and social facilitation provided through social support.
Cardiac Home Education and Support Trial (CHEST): A Pilot Study
Principal Investigators: M. Parry
Co-Investigators: J. Watt-Watson, E. Hodnett, J. Tranmer, CL. Dennis, D. Brooks
Funding: Heart and Stroke Foundation of Canada, Canadian Institutes of Health Research FUTURE Program for Cardiovascular Nurse Scientists, Cardiac Science Medtronic Research Grant/Kingston General Hospital, Canadian Council of Cardiovascular Nurses Research Grant, Nurse Practitioner Association of Ontario, Cardiovascular Acute Care Nurse Practitioner Pfizer Award, Canadian Pain Society Nursing Research Award.
BACKGROUND AND OBJECTIVE: Coronary artery bypass graft (CABG) surgery is performed more frequently in individuals who are older and sicker than in previous years. Increased patient acuity and reduced hospital length of stays leave individuals ill prepared for their recovery. To test the feasibility of a peer support program and determine indicators of the effects of peer support on recovery outcomes of individuals following CABG surgery.
METHODS: A pre-post test pilot randomized clinical trial design enrolled men and women undergoing first-time nonemergency CABG surgery at a single site in Ontario. Patients were randomly assigned to either usual care or peer support. Patients allocated to usual care (n=50) received standard preoperative and postoperative education. Patients in the peer support group (n=45) received individualized education and support via telephone from trained cardiac surgery peer volunteers for eight weeks following hospital discharge (Clinical Trial Registration NCT00275340).
RESULTS: Most (93%) peer volunteers believed they were prepared for their role, with 98% of peer volunteers initiating calls within 72 h of the patient’s discharge. Peer volunteers made an average of 12 calls, less than 30 minutes in duration over the eight-week recovery period. Patients were satisfied with their peer support (n=45, 98%). The intervention group reported statistical trends toward improved physical function (physical component score) (t [89]=—1.6; P=0.12) role function (t [93]=—1.9; P=0.06), less pain (t [93]=1.30; P=0.20) and improved cardiac rehabilitation enrollment (x2=2.50, P=0.11).
CONCLUSIONS: These preliminary results suggest that peer support may improve recovery outcomes following CABG. Data from the present pilot trial also indicate that a home-based peer support intervention is feasible and an adequately powered trial should be conducted.
Peer Support Intervention Trials for Individuals with Heart Disease: A Systematic Review
Principal Investigators: M. Parry
Co-Investigators: J. Watt-Watson
Funding: Heart and Stroke Foundation of Canada, Canadian Institutes of Health Research FUTURE Program for Cardiovascular Nurse Scientists, Cardiac Science Medtronic Research Grant/Kingston General Hospital, Canadian Council of Cardiovascular Nurses Research Grant, Nurse Practitioner Association of Ontario, Cardiovascular Acute Care Nurse Practitioner Pfizer Award, Canadian Pain Society Nursing Research Award.
BACKGROUND AND OBJECTIVE: Heart disease is a major cause of illness, disability and death worldwide with high personal, community and healthcare costs. Social support affects psychological and physical morbidity, mortality, and adjustment to chronic disease. Peer support, a specific type of social support, has been shown to be an effective intervention for a variety of populations. The aim of this study was to critically examine the effects of peer support interventions on health outcomes in individuals with heart disease.
METHODS: Searches were made of ACP Journal Club, EBM, CDSR, DARE, CCTR (1982–2005), MEDLINE (1966–2005), PsycINFO (1975-July 2005), HealthSTAR (1975-June 2005), and CINAHL (1982-July 2005) using text words and MeSH headings.
RESULTS: Electronic and hand searching yielded 27 studies and reviews. Six studies met the inclusion criteria and were assessed using guidelines from The Evidence-Based Medicine Working Group and The Cochrane Collaboration. Inferences about the results were limited to critical appraisal. The trials demonstrated some positive effects of peer support for individuals with heart disease, including higher levels of self-efficacy, improved activity, reduced pain, and fewer emergency room visits.
CONCLUSIONS: Despite some evidence supporting peer support for individuals with heart disease,methodological problems preclude generalizations. Further research with greater methodological rigor is warranted.
Cardiac Enhancing Postoperative Recovery of Cardiac Surgery Patients: A Randomized Clinical Trial of an Advanced Practice Nursing Intervention
Principal Investigator: M. Parry
Co-Investigator: J. Tranmer
Funding: Canadian Nurses Foundation/Kingston General Hospital Foundation.
OBJECTIVE: To determine the effectiveness of advanced practice nursing support on cardiac surgery patients’ during the first 5 weeks following hospital discharg
METHODS: Patients (n=200) were randomly allocated to two groups: (a) an intervention group who received telephone calls from an advanced practice nurse (APN) familiar with their clinical condition and care needs, twice during the first week following discharge then weekly thereafter for 4 weeks, and (b)a usual care group. Measures of health-related quality of life (HRQL), symptom distress, satisfaction with recovery care, and unexpected health care contacts were obtained at 5 weeks following discharge.
RESULTS: There were no significant group differences in HRQL, unexpected contacts with the health care system, or symptom distress.
CONCLUSIONS: The provision of APN support via telephone follow-up after cardiac surgery is feasible. However, further randomized trials of single and multicomponent advanced practice nursing interventions are needed to prove effectiveness.
Quality Improvement Strategies Utilized by Health Care Providers to Provide Diabetes Care in Ontario: A Literature Review
Principal Investigators: M. Parry, P. Segal
Co-Investigators: N. Green and Members of the Banting & Best Diabetes Centre QUEST Committee
Funding: Supported through the Banting & Best Diabetes Centre.
BACKGROUND AND OBJECTIVE: Providing health care practitioners with best practice information to support decision making at the point of care helps to improve outcomes. Our objectives were to: 1) conduct a literature review to identify recent interventions, innovations, models and quality improvement strategies utilized by health care providers to deliver diabetes care in Ontario; and 2) identify gaps in diabetes care delivery in Ontario.
METHODS: This review is based on a systematic, comprehensive search of the Cochrane Library (Cochrane Database of Systematic Reviews [CDSR], the Database of Reviews of Effectiveness [DARE], and the Cochrane Central Register of Controlled Trials [CENTRAL] (2011-2016). MEDLINE, Ovid Health Star, CINAHL, PubMed, Scopus and Web of Science was searched using a combination of ‘text words’ and Medical Subject Headings (MeSH) (2011-2016). Other databases searched included Academic OneFile, Google Scholar, Biosis and Up-to-Date.
RESULTS: Our search yielded 1029 citations. Removal of duplicates resulted in a total of 347 article titles and abstracts. Of these, 191 articles were included in a full-text review. Following an iterative process for article selection, 46 articles were included in the final narrative synthesis. Six themes of provider-level navigation were organized using the Chronic Care Model (CCM): 1a) The Team – Interprofessional Collaboration (IPC) and Team Composition, 1b) Delivery Systems Design: Team Roles – Leadership and Coaching, 2) Self-Management Support – Personalized Support, 3) Decision Support – Guideline Harmonization and Guideline Implementation, 4) Clinical Information Systems – E-Assessments, E-Delivery, E-Audit/Feedback, and E-Reminders, 5) Community – Partnering and Transitioning, and 6) Health Systems – Incentives.
CONCLUSIONS: Results of this review could be utilized by providers to assist in the planning and coordination of diabetes care and expanded to incorporate interventions, innovations, models and quality improvement strategies across all aspects of the chronic care model.
Does the Speed of Sternal Retraction During Cardiac Surgery Affect Postoperative Pain Outcomes: A Randomized Controlled Trial
Principal Investigators: T. Saha, D. Petsikas
Co-Investigators: M. Parry, A. Hamilton, D. Payne, E. VanDenKerkhof, B. Milne
Funding: Southeastern Ontario Medical Association (SEAMO) Innovation Fund.
BACKGROUND AND OBJECTIVE: In North America, almost ½ million people undergo coronary artery bypass graft surgery annually and over one third develop chronic chest pain. We will compare slow sternal retraction for heart exposure (over 15 minutes) to the standard-of-care (over 30 seconds) and examine the incidence of chronic post-sternotomy pain (CPSP) and quality-of life at 3, 6 and 12 months post-operatively.
METHODS: Following institutional ethics approval and signed consent, eligible patients scheduled for elective coronary artery bypass graft surgery will be randomly assigned (stratified by gender and surgeon to ensure equality between groups) either to the Standard Group (in which sternal retraction occurs over ~30s) or the Slow Group in which sternal retraction occurs over 15 minutes. Patients and research personnel performing the postoperative assessments will remain blinded to group assignment until conclusion of the investigation. All other intra-operative variables will be performed as per standard practice by the cardiac surgeons. The extent of sternal retraction will be to the surgeon’s discretion to enable appropriate exposure of the heart and allow safe conduct of the operation but will be recorded in all cases. The primary outcome measure will be the incidence of post-sternotomy chest pain at 6 months following CABG with median sternotomy. We will also measure the incidence of post-sternotomy chest pain at 3 and 12 months. Secondary outcomes will include pain intensity (NRS scale) at rest and while coughing daily while in hospital until discharge and at 1 week postoperatively. Analgesic consumption (morphine equivalents) daily while in hospital until discharge, 1 week post-operatively and then at 3, 6, and 12 months postoperatively. Pain quality, quality of life, and pain interference with daily function at 3, 6 and 12 months post-operatively. All assessments following discharge from the hospital will be via telephone calls from a research nurse blinded to randomization assignment. In-hospital assessments will also be done by a research nurse blinded to group assignment.
Pain Experiences of Men and Women After Coronary Artery Bypass Graft Surgery
Principal Investigator: M. Parry
Co-Investigators: J. Watt-Watson, E. Hodnett, J. Tranmer, C.L. Dennis, D. Brooks
Funding: Heart and Stroke Foundation of Canada, Canadian Institutes of Health Research FUTURE Program for Cardiovascular Nurse Scientists, Cardiac Science Medtronic Research Grant/Kingston General Hospital, Canadian Council of Cardiovascular Nurses Research Grant, Nurse Practitioner Association of Ontario, Cardiovascular Acute Care Nurse Practitioner Pfizer Award, Canadian Pain Society Nursing Research Award.
BACKGROUND AND OBJECTIVE: Individuals with coronary artery disease undergo coronary artery bypass graft (CABG) surgery to relieve symptoms, improve quality of life, and reduce early death. Pain is the most prevalent symptom identified by persons after CABG surgery. The objective of the study was to compare the prevalence and severity of pain and pain-related interference with activities in men and women 9 weeks after CABG surgery.
METHODS: This was a secondary data analysis using data obtained from the Cardiac Home Education and Support Trial (CHEST): A Pilot Study (Registration NCT00275340). Participants included men (n = 78) and women (n = 17) who were having first-time nonemergency CABG surgery. Pain outcome data were collected via telephone using the McGill PainQuestionnaire and the Brief Pain Inventory Interference Subscale.
RESULTS: Forty-seven percent of the women (n = 8) had moderate to severe pain described as the ‘‘worst pain in previous 24 hours with movement’’ 9 weeks following discharge from CABG surgery. More women were divorced, widowed, or single (P=0.0002). There was a statistically significant between-groups difference, with more women reporting moderate to severe pain with movement (P=0.03), as well as greater interference with walking (P=0.01) and sleeping (P=0.01) due to pain.
CONCLUSIONS: Further research with larger sample sizes should investigate what conditions lead to the sex differences in the pain experience after CABG surgery, what mechanisms and support structures underlie these differences, and how these differences can inform the clinical management of pain.
Women’s Recovery from Sternotomy – Extension Study (WREST-E) Study: Examining Long-Term Pain and Discomfort Following Sternotomy and Their Predictors
Principal Investigator: K. King
Co-Investigators: M. Parry, R. Tsuyuki, R. Collins-Nakai, P. Maitland, P. Faris, G. Currie
Funding: Gender and Sex Determinants of Circulatory and Respiratory Diseases: Interdisciplinary Enhancement Team Grant Program (CIHR/Gender and Health and HSFC).
OBJECTIVE: To examine incision and breast pain and discomfort, and their predictors in women 12 months following sternotomy.
METHODS: This study was an extension of the Women’s Recovery from Sternotomy (WREST) Trial (Registration ISRCTN 47669580) that examined the use of a novel compression undergarment in women following first-time median sternotomy. Pain and discomfort data (numeric rating scales) was collected by standardised interview at 5 days, 12 weeks and 12 months following sternotomy in women (n=326) across 10 Canadian centres.
RESULTS: More women reported having incision or breast discomfort (46.6%) than pain (18.1%) at 12 months postoperatively. No symptoms at 5 days postoperatively were significantly associated with symptom presence at 12 postoperative months. However, having incision pain and discomfort as well as breast pain and discomfort at 12 postoperative weeks was associated with incision pain (odds ratio (OR)=3.26, 95% confidence interval (CI) 1.51 to 7.07), incision discomfort (OR=4.87, 95% CI 3.01 to 7.88), breast pain (OR=9.36, 95% CI 3.91 to 22.38) and breast discomfort (OR=6.42, 95% CI 3.62 to 11.37), respectively, at 12 postoperative months. Increasing chest circumference was associated with having ongoing incision pain (OR=1.12, 95% CI 1.03 to 1.21) and breast pain (OR=1.10, 95% CI 1.00 to 1.22). Harvesting of bilateral internal mammary arteries (IMAs) was associated with having ongoing incision pain (OR=4.71, 95% CI 1.54 to 14.3), while harvesting only the left IMA was associated with having ongoing breast pain (OR=2.78, 95% CI 1.06 to 7.32) and breast discomfort (OR 1.80, 95% CI 1.02 to 3.19).
CONCLUSIONS: Women reported incision and breast pain and discomfort as long as 12 months post-sternotomy. Improved management of postoperative pain and discomfort up to at least 12 weeks following surgery may render reduced long-term pain and discomfort symptoms.
The Initial Systolic Time Interval (ISTI) as a Measure of Sympathetic Nervous System Function in Heart Failure
Principal Investigator: M. Parry
Funding: Connaught New Researcher Award and a Bertha Rosenstadt Small Research Grant, University of Toronto.
OBJECTIVE: To evaluate the utility of using the initial systolic time interval (ISTI) to measure pre-ejection period (PEP) and sympathetic nervous system (SNS) function in persons with reduced ejection fraction heart failure.
METHODS: In the original descriptive study, men and women (n=28) with reduced ejection fraction heart failure were recruited from an outpatient device clinic at a tertiary care hospital in Southeastern Ontario, Canada. Participants completed a sit-to-stand posture protocol wearing an ambulatory blood pressure device and the VU-AMS version 5fs impedance cardiography system. Although the Vrije Universiteit Ambulatory Monitoring System (VU-AMS) version 5fs detected anticipated SNS changes to postural shift in persons with reduced ejection fraction heart failure, 64% of the sample had to be eliminated due to scoring difficulties. Reliability of PEP scoring is sensitive to the selection of correct landmarks, and the tedious manual inspection of Q-onset and B-point detection threatens the validity of the results and limits its use in clinical practice settings. We completed a secondary data analysis to evaluate the utility of using the ISTI to measure PEP and SNS function in persons with reduced ejection fraction heart failure.
RESULTS: Five participants were excluded from the analysis due to poor signal quality and two were excluded due to technical difficulties. The remaining participants (n=21, 75%) were male (n=18, 86%) with a mean age of 71 years (SD = 8 years). Most (67%, n = 14) had Grade 3 or 4 left ventricular function with a mean ejection fraction of 30% (SD = 12). Response to the sit-to-stand posture protocol included a 3% increase in heart rate (p = 0.002), a 12% increase in SNS activity (p = 0.004), and a 14% decrease in systolic blood pressure (p = 0.000).
CONCLUSIONS: When compared to standard PEP scoring practices using Q-onset and B-point determination, ISTI offered more accurate PEP scoring using the R-wave peak on the ECG and the dZ/dt (min) peak (C-point) on the ICG for participants with reduced ejection fraction heart failure. Given that the information between PEP and ISTI overlap empirically and theoretically, ISTI may be a better marker of SNS activity in persons with reduced ejection fraction heart failure in clinical practice settings. However, before these technologies can be integrated into clinical practice settings, validation of these results in a larger sample of men and women with HF is warranted.
Ambulatory Impedance Cardiography in Heart Failure: A Validation Study
Principal Investigator: M. Parry
Funding: Connaught New Researcher Award and a Bertha Rosenstadt Small Research Grant, University of Toronto.
OBJECTIVE: The purpose of this pilot study was to evaluate the sensitivity of the Vrije Universiteit Ambulatory Monitoring System (VU-AMS) version 5fs to detect hemodynamic and sympathetic nervous system changes associated with postural shift in persons with reduced ejection fractin heart failure.
METHODS: In this descriptive study, participants (n=28) were recruited from an outpatient device clinic at a tertiary hospital in Ontario, Canada. They completed a sit-to-stand posture protocol wearing an ambulatory blood pressure (ABP) and a noninvasive VU-AMS 5fs impedance cardiography system.
RESULTS: Most (n=18, 64%) participants were eliminated from the final analyses in this sample because of difficulty in Q-onset and B-point identification in peculiar electrocardiogram and impedance cardiogram waveforms. The remaining participants (n=10) had a mean age of 69 years (SD=10 years) and responses to sit-to-stand posture protocol that included a 5% increase in heart rate (p=0.001), an 18% decrease in stroke volume (p=0.01), and an 8% decrease in left ventricular ejection time (p=0.01). Participants had an increased pre-ejection period (11%, p=0.01), a drop in cardiac output of 13% (p=0.02), and a reduced mean arterial pressure of approximately 4% (p=0.09) with standing.
CONCLUSIONS: Although the VU-AMS version 5fs system detected anticipated hemodynamic and sympathetic nervous system changes to postural shift in participants (n=10), the elimination of 64% (n=18) of the sample because of scoring difficulties limits the use of this impedance cardiography device using standard scoring algorithms in persons with reduced ejection fraction heart failure.
Ambulatory Impedance Cardiography: A Systematic Review
Principal Investigator: M. Parry
Co-Investigator: J. McFedridge-Durdle
Funding: Nursing Research Fellowship from the Heart and Stroke Foundation of Canada and a Doctoral Strategic Training Fellowship from the FUTURE Program for Cardiovascular Nurse Scientists (CIHR-ICRH/HSFC funded).
BACKGROUND AND OBJECTIVE: Standard noninvasive impedance cardiography has been used to examine the cardiovascular responses of individuals to a wide range of stimuli in critical care and laboratory settings. It has been shown to be a reliable alternative to invasive thermodilution techniques and an acceptable alternative to the use of pulmonary artery catheters. Ambulatory impedance cardiography provides a similar assessment of cardiac function to standard non-invasive impedance cardiography, but it does so while individuals engage in activities of daily living. We sought to critically examine through a literature analysis the validity, reliability, and sensitivity of ambulatory impedance cardiography for the assessment of cardiac performance during activities of daily living.
METHODS: The Cochrane Database of Systematic Reviews (CDSR), The Cochrane Database of Methodology Reviews (CDMR), The Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE), National Health Service Economic Evaluation Database (NHS EED), Health Technology Assessment (HTA), and The Cochrane Methodology Register (CMR; 1966-2005); MEDLINE (1950-2005); and CINAHL (1982-2005) were searched using the following terms: ambulatory cardiac performance, impedance cardiac performance, AIM cardiac performance monitor, thoracic electrical bio-impedance, impedance cardiography, ambulatory impedance monitor, bio-impedance technology, ambulatory impedance cardiography, bio-electric impedance; also included were reference lists of retrieved articles. Studies were selected if they used an ambulatory impedance monitor to examine one or more of the following cardiovascular responses: pre-ejection period (PEP), left ventricular ejection time (LVET), stroke volume (SV), or a combination of these.
RESULTS: Studies have been predominantly descriptive and have been focused on a young, male population with a normal body mass index (BMI; 25-29 kg/m2). Inconsistencies in determining specific markers of cardiac function (e.g., pre-ejection period and stroke volume) across studies necessitated that results be reported by outcome for each study separately.
CONCLUSIONS: Ambulatory impedance monitors are valid and reliable instruments used for the physiologic measurement of cardiac performance. Sensitivity is established utilizing within-individual measurements of relative change. This is especially important in light of an aging population and technical advances in healthcare. Further research is warranted using nursing interventions that focus on an older, female population who have a BMI greater than 30 kg/m2. Availability of noninvasive ambulatory measures of cardiac function has the potential to improve care for a variety of patient populations, including those with hypertension, heart failure, pain, anxiety, and depressive symptoms.