Application of EBM in Emergency Medicine

Transcription

1 Application of EBM in Emergency Medicine Tzong-Luen Wang, MD, PhD, FESC, FACC, FAPSC Chief, ED, Shin-Kong Wu Ho-Su Memorial Hospital President, Society of Critical and Emergency Medicine CEO, National Resuscitation Council, Taiwan What is EBM? The integration of: Best Research Evidence with Clinical Expertise and Patient Values Sackett et al., Evidence-Based Medicine Questions: PICO Develop a focused clinical question concerning the patient's problem(s) Search secondary databases and the primary literature for relevant articles Access the validity and usefulness of those articles Judge the relevance to the individual patient Implement the findings in patient care PICO Problem Model 3 Centre for EBM: Search for the Best Evidence Review articles Community/professional standards Systematic reviews Original results Search for the Best Evidence 6

2 Search for the Best Evidence What are the Sources of Good Evidence? 7 Evidence-Based Medicine Diagnosis / Screening Outcome Risk Stratification Patient Safety Cost-Effectiveness Practice Guidelines Emergency Medicine? Disaster Medicine? Spectrum of EBEM STRONG Mortality Cost Effectiveness Risk Stratification Diagnosis Outcome Practice Guidelines ED Crowding Other General Issues Disaster Medicine WEAK 9 10 Evidence-Based Disaster Medicine Priority Journals Almost epidemiological studies Cannot be randomized, double-blind intervened Full of myths and fallacies No Evidence, No Truth/Belief. Agency for Health Care Quality and Research 11 12

3 1. How often do disasters occur in the world today? A. Once per day B. Once per week C. Once per month D. Once per year 1. Mahoney LE: Catastrophic disasters and the design of medical care systems. Ann Emerg Med 1987; De Boer J: Order in Chaos What is the most common type of disaster in the world today? A. Geological (e.g., earthquakes, volcanic eruptions) B. Hydrological-meteorological (e.g., floods, hurricanes) C. Transportation (e.g., air, train, marine disasters) D. Industrial (e.g., chemical release, fire, structural collapse) E. Complex humanitarian emergency (e.g., Darfur, Bosnia) Which of the following was a health disaster? A Tokyo Subway Sarin Attack B World Trade Center Attack C London bombing D Hurricane Katrina E. All of the above Severe Demand-Supply Mismatch due to EMS/Hospital Shutdown True or false: The number of dead is the best measure of the magnitude of a health disaster A. True Severely Injured instead of the Deceased is the Point! True or false: Victims of disasters often panic. A. True 1942 Fire Year Disaster Observation Coconut Grove Nightclub Massachusetts, USA 1945 Atomic bomb explosion Hiroshima, Japan 1953 Tornado Waco, TX USA 1964 Earthquake Anchorage, AK USA 1977 Fire Beverly Hills Supper Club Kentucky, USA Most persons calmly gathered their friends and evacuated (Quarantelli, 1972; 68) No evidence of mass panic. Many tried to help others (Fritz 1961; 671) No evidence of panic (Moore 1958; 7) No panic in patients or staff in hospitals at any time (Yutzy 1969: 68) No evidence of panic (Keating 1989; 89) 6. Who performs the most search and rescue in large-scale, sudden impact disasters? A. YearPolice Disaster Observation 1976 Earthquake B. Fire Tangshan, China C. EMS 1980 Earthquake 90% of search and rescue by D. Military Campania-Irpinia, Italy untrained, uninjured survivors 1985 Earthquake, E. Victims Mexico Citythemselves rescue and other 1989survivors Loma Prieta Earthquake San Francisco, CA USA ,000 survivors rescued themselves and then rescued 80% of others >1.2 million involved in search and >31,000 in 2 counties involved in search and rescue; 5% of Santa Cruz and 3% of San Francisco population 17 18

4 7. True or false: Most injured survivors are brought to hospitals by EMS in disasters. A. True 19 Implication = little decontamination occurs in the field in a chemical emergency True or false: Victims are usually evenly distributed to nearby hospitals in sudden-onset emergencies Distribution of victims with serious injuries to hospitals Oklahoma City bombing A. True Number of hospitalized injured survivors hospitals Maldistribution Distance from related Murrah Federal to distance Building from (miles) site Metrolink Train Collision, Chatsworth 2008 Shariat S. Data from Injury Prevention Service, Oklahoma City, Oklahoma State Health Department Distribution of victims to hospitals - 20 November 2003 Istanbul bombings medical facilities TERSH 160 Private hospital Private clinic Number of 120 injured survivors who sought emergency care Government hospital Government clinic AH Street distance from HSBC headquarters (km) Maldistribution related to patient preference True or false: The first victim usually arrives at the hospital about one hour after a sudden-onset emergency A. Mass True Casualty Terrorist Bombing London Old Bailey 1973 Type Time (min) Number hospital s Reference Open air 5 1 Caro D. Lancet 1973; 1 Buenos Aires 1994 Collapse mins 1 Biancolini CA. J Trauma 1997; 47 New York City 2001 Collapse mins 5 CDC. MMWR 2002; 51 Cu Chi 1969 Mixed 15 2 Henderson, JV. JWAEDM 1986; 2 Tel Aviv 1995 Open Air 15 1 Paran H. J Trauma 1996; 40 London Victoria 1991 Open Air 16 3 Madrid 2004 Collapse 17 1 Johnstone DJ. Injury 1993; 24 Gutierriez de Ceballos U. CritiCare 2005; 8 Tower of London 2011/9/21 Conf space 20 1 Tucker K. BMJ 1975; Okl h Cit 1995 C ll Anteau CM. Crit Care Nurs

5 10. Which statement best characterizes victim mortality in sudden-onset emergencies? A. Relatively few victims die in EDs B. About 25% of victims die in EDs C. About 50% of victims survivors die in EDs D. About 75% of victims die in EDs E. Almost all victims die in EDs A. Few victims die in emergency departments 1995 Tokyo Subway sarin attack 640 victims presented to St. Luke s International Hospital 500 victims arrived at ED in minutes 3 (<1%) victims arrived in cardiac arrest 1 victim in cardiac arrest survived 25 Okumura T. Report on 640 victims of the Tokyo Subway Sarin Attack. Ann Emerg Med 1996;28: What is the usual disposition of most victims reaching hospitals in sudden-impact impact disasters? A. Most victims are hospitalized B. Most victims receive critical care C. Most victims receive operative care D. Most victims are transferred to other hospitals E. Most victims are treated and released from emergency departments 12. True or false: Disaster Medical Assistance Teams (DMATs( DMATs) ) usually provide substantial emergency medical care during disasters A. True Which pathogen did not pose a significant infectious disease risk after Hurricane Katrina? A. Rotavirus B. Vibrio cholera C. West Nile virus D. Clostridium tetani E. Vibrio vulnificus No Pathogens, No Epidemics. We are gravely concerned about the potential for cholera, typhoid and dehydrating diseases that could come as a result of the stagnant water and the conditions. - Secretary Michael Leavitt, US Department of Health and Human Services, 1 September /9/ True or false: Early critical incident stress debriefing (CISD) helps prevent post-traumatic traumatic stress disorder (PTSD) after disasters Study Study group Study type A. True 11 RCTs Suzanna RO. Cochrane Database Syst Rev 2002 Persons exposed to traumatic event < 1 month Single session psychological debriefing v no intervention Metaanalysis Outcomes PTSD at 3-5 months PTSD at 6 months psychological morbidity, depression, or anxiety Key results No difference No difference No difference Study weakness es Small number Aulagnier M. Review PTSD No study Not formal 8 controlled studies Rev suggested. metaanalysis Persons exposed to Epidemiol 1 study traumatic event < 1 month Sante suggested Single session Publique psychological 2004;52 Depression, 1 study debriefing v no intervention anxiety, suggested 2011/9/21 30 alcohol dependence

6 Medicine (EBEM) Respiratory Cardiology General Medical Conditions Injury Genitourinary and Abdominal Neuroscience ENT Minor Procedures Public Health Medicine (EBEM) Knowledge Translation Critical Appraisal Continuing Education Quality Improvement Medication Adherence ED Triage ED Overcrowding Utilization of EBM in Emergency Medicine Find the relevant answers if others have already evaluated the evidences and answered the clinical questions or issues. Go to the process of evidence evaluation if the clinical questions or issues remains unanswered or the previous answers are irrelevant. If still no answer, do the research~ Q1: In hospital EDs, how is overcrowding defined? A1: Definitions for ED overcrowding vary within and between health systems, and even within institutions in the same health system, adding to the complexity of describing and studying the problem. Q2: In hospital EDs, does overcrowding impact on patient care compared to periods when no crowding exists? A2: There is increasing evidence that ED overcrowding negatively process of care and quality of care measures, some of which are known to be important predicators of patient outcome. There is some evidence that hospital and ED overcrowding may also increase mortality

7 Q2: In hospital EDs, does overcrowding impact on patient care compared to periods when no crowding exists? MEDLINE: (ED OR emergency department) AND )overcrowding OR crowding) AND outcome (mortality OR morbidity) 18 papers cited and reviewed Q2: In hospital EDs, does overcrowding impact on patient care compared to periods when no crowding exists? In-hospital mortality: all positive findings Care of quality: mixed results STEMI NSTEMI CAP Hip fracture/pain assessment and management Leave without seeing/aborted ED visits: positive results Ambulance diversion: negative results EBEM in Canada: General Issues ED Overcrowding (Q2) Q3: In hospital EDs experiencing overcrowding, do interventions to reduce overcrowding improve patient flow and care compared to status quo? A3: Within the ED changes in staffing numbers and processes can reduce waits. The impact on triage systems on waiting times is still contentious. Improving access to diagnostic tests does improve waits. Schull MJ et al. Ann Emerg Med Q4: In hospital EDs experiencing overcrowding, do system-wide interventions to reduce overcrowding improve patient flow and care compared to status quo? A4: Further research is urgently required in this field. Q5: In hospital EDs experiencing overcrowding, does the 4-h rule reduce overcrowding and improve patient flow and care compared to status quo? A5: The 4-h rule introduced in England appears to have improved patient satisfaction and the number of patients in EDs; however, there is no convincing evidence regarding its effect on quality of care or patient outcomes

8 Q6: In hospital EDs experiencing overcrowding, does a full-capacity protocol reduce overcrowding and improve patient flow and care compared to status quo? A6: The introduction of an FCP may improve ED LOS for admitted patients and improve flow in the ED; however, there is no convincing evidence regarding its effect on quality of care or patient outcomes. ED Crowding --PDCA Strategies Occupancy 77.5% 43 Plan ED Crowding --PDCA Strategies Definition of ED Overcrowding Impact of ED Overcrowding Ambulance Diversion System-Wide Interventions ED Interventions 4-h Rule Full-Capacity Protocol Do ED Crowding --PDCA Strategies Monitoring and Supervision of all beds Mandatory release of more than half beds if occupancy is less than 75% Full Capacity Protocol Bed control by ED in non-official hours 90% 80% 70% 60% 79.1% 71.5% 98 年 99 年 一般病房佔床率 83.7% 83.2% 69.2% 81.6% 86.0% 81.1% 82.9% 79.2% 99 年 7 月 1-29 日佔床率 87% 84.5% 81.6% 1 月 2 月 3 月 4 月 5 月 6 月 Check ED Crowding --PDCA Strategies 滿床次數 由於今年以來, 確實落實急診通報滿床時之全院調床機制, 初步已將急診對外通報滿床次數較前二年度降低約三分之一 全院佔床率提升至 95% 以上 年度 98 年度 99 年 1-6 月 年度 34% 就診人次 報滿床次數 (1 年合計 ) 月平均就診人次

9 Act 急診留觀大於 72 小時率 留觀大於 72 小時率 中位數 (1.63) 平均數 (1.6) What Are Clinical Prediction or Clinical Decision Rules (CPR; CDR) Tools that quantify the individual contributions that various components of history, physical examination, and basic lab results make toward the diagnosis, prognosis, or likely response to treatment in a patient Attempt to formally test, simplify, and increase the accuracy of clinicians diagnostic and prognostic assessments Most likely to be useful where decision making is complex, or there are opportunities to achieve cost savings without compromising patient care JAMA, 2000; 284:79~84 Three Steps for Putting CDR into Clinical Practice Step 1. Derivation Identification of factors with predictive power Step 2. Validation Evidence of reproducible accuracy Narrow Validation Application of rule in a similar clinical setting and population as in Step 1 Broad Validation Application of rule in Multiple clinical settings with varying prevalence and outcomes of disease Step 3. Impact Analysis Evidence that rule changes physician behavior and improves Patient Outcomes and/or reduces costs Level of Evidence Methodological standards for derivation of a clinical prediction rule Were all important predictors included in the derivation process? Were all important predictors present in a significant proportion of the study population? Were all the outcome events and predictors clearly defined? Were those assessing the outcome event blinded to the presence of the predictors and vice versa? Was the sample size adequate (including adequate number of outcome events? Does the rule make clinical sense? JAMA 2000; 284: Methodological standards for validation of a clinical prediction rule Were the patients chosen in an unbiased fashion and do they represent a wide spectrum of severity of disease? Was there 100% follow up of those enrolled? Was there a blinded assessment of the criterion standard for all patients? Was there an explicit and accurate interpretation of the predictor variables and the actual rule without knowledge of the outcome? JAMA 2000; 284: Current State for ILCOR Evidence Evaluation

10 Recommendations for Triage and Transfer for PCI (for STEMI) AHA Level of Evidence and Strength of Recommendation NEW Recommendation I IIaIIb IIbIII III Each community should develop a STEMI system of care following the standards developed for Mission Lifeline including: Ongoing multidisciplinary team meetings with EMS, non-pcicapable hospitals (STEMI Referral Centers), & PCIcapable hospitals (STEMI Receiving Centers) Proposed Future State for ILCOR Evidence Evaluation BMJ 2008; 336:924 What is GRADE? Grading of Recommendations Assessment, Development and Evaluation system Increasingly used by organizations around the world including: World Health Organization American College of Chest Physicians UpToDate Surviving Sepsis American College of Physicians The Cochrane Collaboration Society of Critical Care Medicine Infectious Diseases Society of America Emergency Medical Services for Children National Resource Center Assigning Level of Evidence Randomized trials start as high level evidence. May be downgraded (study limitations, inconsistency of results, indirectness of evidence, imprecision, reporting bias, etc.) Observational studies start as low level evidence May be upgraded (very large treatment effect, dose-response relationship, all plausible biases would decrease magnitude of apparent treatment effect) Fig 1 Hierarchy of outcomes according to importance to patients to assess effect of phosphate lowering drugs in patients with renal failure and hyperphosphataemia. Guyatt G H et al. BMJ 2008;336: by British Medical Journal Publishing Group

11 Fig 1 Two generic ways in which a test or diagnostic strategy can be evaluated. GRADE Allows Consideration of Resources Schünemann H J et al. BMJ 2008;336: by British Medical Journal Publishing Group In what way do costs differ from other health outcomes? Patients receive health benefits and bear the burden of adverse health outcomes, but healthcare costs are typically shared by society as a whole (as represented by the government), employers, and patients Attitudes differ as to whether costs should influence a doctor s decision about treating individual patients Healthcare costs may vary widely among and even within jurisdictions and quickly change over time What societies can purchase if they forego use of healthcare resources (opportunity cost) varies widely between countries. A year s supply of an expensive drug may pay a nurse s salary in the US and 30 nurses salaries in China When healthcare expenditures demand foregoing expenditures elsewhere, attitudes differ as to whether the health system, public expenditures, or society as a whole should bear the burden Matters relating to resource use are highly political and may result in conflict of interest for a guideline panel (for example, panellists may have an association with industry or government) Final Quality Judgment on PICO Question High quality Further research is very unlikely to change our confidence in the estimate of effect Moderate quality Further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate Low quality Further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate Very low quality Any estimate of effect is very uncertain Recommendation Types Strong: the evidence is high quality and the desirable effects clearly outweigh the undesirable effects. Weak: There is a close or uncertain balance. Strength of Recommendation GRADE grid Strong: the desirable effects of an intervention clearly outweigh the undesirable effects, or clearly do not. For patients most people in your situation would want the recommended course of action and only a small proportion would not; request discussion if the intervention is not offered For clinicians most patients should receive the recommended course of action Weak: the trade-offs are less certain either because of low quality evidence or because evidence suggests that desirable and undesirable effects are closely balanced. For patients most people in your situation would want the recommended course of action, but many would not For clinicians you should recognise that different choices will be appropriate for different patients and that you must help each patient to arrive at a management decision consistent with her or his values and preferences

12 Determinants of Strength of Recommendation Factor Comment Balance between desirable and undesirable effects Quality of evidence Values and preferences Costs (resource allocation) The larger the difference between the desirable and undesirable effects, the higher the likelihood that a strong recommendation is warranted. The narrower the gradient, the higher the likelihood that a weak recommendation is warranted The higher the quality of evidence, the higher the likelihood that a strong recommendation is warranted The more values and preferences vary, or the greater the uncertainty in values and preferences, the higher the likelihood that a weak recommendation is warranted The higher the costs of an intervention that is, the greater the resources consumed the lower the likelihood that a strong ILCOR vs GRADE Factor ILCOR GRADE Comment Levels of evidence 5 (LOE 1 5) 4 (high, moderate, low, very low) Judgment of study quality 3 (good, fair, poor) Strength of recommendation Essentially AHA classes (1, IIa, IIb, none, III) 5 (strong in favor, weak in favor, none/research only; weak against, strong against) Factor Other systems GRADE Advantages of GRADE system* Definitions Implicit definitions of quality (level) of evidence and strength of recommendation Explicit definitions Makes clear what grades indicate and what should be considered in making these judgments Judgments Implicit judgments regarding which outcomes are important, quality of evidence for each important outcome, overall quality of evidence, balance between benefits and harms, and value of incremental benefits Sequential, explicit judgments Clarifies each of these judgments and reduces risks of introducing errors or bias that can arise when they are made implicitly Conclusion Key components of quality of evidence Other factors that can affect quality of evidence Overall quality of evidence Relative importance of outcomes Balance between health benefits and harms Whether incremental health benefits are worth the costs Summaries of evidence and findings Extent of use Systematic and explicit consideration of study Not considered for each important outcome. design, study quality, consistency, and directness Ensures these factors are considered Judgments about quality of evidence are often of evidence in judgments about quality of appropriately based on study design alone evidence Explicit consideration of imprecise or sparse data, reporting bias, strength of association, evidence Not explicitly taken into account Ensures consideration of other factors of a dose response gradient, and plausible confounding Based on the lowest quality of evidence for any of Reduces likelihood of mislabeling overall quality Implicitly based on the quality of evidence for the outcomes that are critical to making a of evidence when evidence for a critical outcome benefits decision is lacking Explicit judgments about which outcomes are Ensures appropriate consideration of each critical, which ones are important but not critical, Considered implicitly outcome when grading overall quality of and which ones are unimportant and can be evidence and strength of recommendations ignored Explicit consideration of trade offs between important benefits and harms, the quality of Clarifies and improves transparency of Not explicitly considered evidence for these, translation of evidence into judgments on harms and benefits specific circumstances, and certainty of baseline risks Explicit consideration after first considering Ensures that judgments about value of net health Not explicitly considered whether there are net health benefits benefits are transparent Ensures that all panel members base their Consistent GRADE evidence profiles, including Inconsistent presentation judgments on same information and that this quality assessment and summary of findings information is available to others Builds on previous experience to achieve a Seldom used by more than one organization and International collaboration across wide range of system that is more sensible, reliable, and widely little, if any empirical evaluation organizations in development and evaluation applicable EBM has been widely applied in emergency medicine. It is encouraged that EBM should be routinely and consistently undergoing in the field of emergency medicine. Different methodologies for evidence evaluation should be implemented and compared in development of EBEM. *Most other approaches do not include any of these advantages, although some may incorporate some of these advantages.