CAEP/ACMU 2000 Scientific Abstracts: 4-7

CAEP Abstracts

CJEM 2001;2(3):169-187

004 Predictors of Good Quality of Life in Prehospital Cardiac Arrest Survivors.
Stiell IG, De Maio VJ, Nichol G, Spaite DW, Ward RE, Martin M, Blackburn J, O'Brien J-A, for the OPALS Study Group. Clinical Epidemiology Unit, University of Ottawa, Ottawa.

OBJECTIVES: To evaluate the prehospital factors associated with optimal quality of life for survivors of out-of-hospital cardiac arrest, within the Ontario Prehospital Advanced Life Support (OPALS) Study.
METHODS: The OPALS Study is a large EMS trial that evaluates BLS-D and ALS interventions for cardiac arrest, trauma, and respiratory distress in 20 communities. This prospective cohort sub-study included all adult out-of-hospital cardiac arrest patients during the rapid defibrillation or ALS phases of the OPALS Study (1995­99) and who survived to one year. Patients were evaluated for the Health Utilities Index (HUI) Mark 3, which describes health as a utility score on a scale from 0 (dead) to 1.0 (perfect health). Analyses included appropriate univariate tests and stepwise logistic regression to model HUI scores >0.80. RESULTS: The 5,022 consecutive cardiac arrest patients had overall survival rates of 5.1% to hospital discharge and 4.0% to one year. This sub-study included 189 (93.6%) of 1-year survivors: mean age 64.0 (range 16­94), bystander-witnessed 60.0%, EMS-witnessed 24.6%, citizen-initiated CPR 34.4%, initial rhythm VF/VT 89.1%, response with defibrillator <8 minutes 98.9%, and best CPC category 86.9%. The overall median HUI score was 0.88 (IQR 0.74­0.95) which compares well to age adjusted values for the general population (0.85). Logistic regression identified 3 factors independently associated with good quality of life and their odds ratios (95% CIs): male gender 2.3 (1.1­5.2), EMS-witnessed arrest 3.1 (1.4­7.2), and citizen-initiated CPR 2.6 (1.3­5.4) (Hosmer­Lemeshow goodness-of-fit statistic 0.57).
CONCLUSIONS: This represents the largest known study of 1-year survivors and is the first to demonstrate that citizen-initiated CPR is strongly and independently associated with better quality of life for out-of-hospital cardiac arrest survivors.
Key words: cardiac arrest, resuscitation, health related quality of life

005 Feasibility Evaluation of Chest Pain Patients in the OPALS Study.
Easo J, Stiell I, Wells G, Spaite D, O'Brien J-A, Martin M, Kennedy D, for the OPALS Study Group. Clinical Epidemiology Unit, University of Ottawa, Ottawa.

OBJECTIVES: The Ontario Prehospital Advanced Life Support (OPALS) Study will be the largest prehospital study yet conducted and will evaluate the impact of prehospital ALS programs on the outcomes of cardiac arrest, trauma, and other patients. The purpose of this study was to assess feasibility and methodological issues required for a clinical trial of chest pain patients within the OPALS Study.
METHODS: This cohort study was conducted over a 6-month period in a city of 750,000 and included all adults transported to one of 5 hospitals with a primary complaint of chest pain. Data were collected from ambulance, dispatch, ED, and hospital records. Analyses included descriptive statistics with 95% CIs and univariate associations. RESULTS: 905 consecutive patients were enrolled: mean age 65.8, female 52.7%, NTG prior to EMS arrival 48.1%. Hospital survival was 95.2% and the immediate adverse outcome rate 16.0% (ED MI 13.7%, ED lethal arrhythmia 2.6%, ED pulmonary edema 1.7%, ED hypotension 1.5%, EMS- witnessed cardiac arrest 0.3%). Lengths of stay, in days, were: hospital 8.6, special care unit 2.8, telemetry unit 3.7. Cardiac procedures performed: angiography 18.6%, angioplasty 4.8%, CABG 3.9%, pacemaker 1.2%. The overall survival rate was 95.2%; 71.9% rated "good" at discharge on the CPC scale. The ICD-9 based final diagnoses were: chest pain NYD 17.6%, MI 17.1%, unstable angina 14.6%, stable angina 9.5%, G.I. 8.8%, cardiac dysrhythmias 6.0%, respiratory 5.9%, cardiac other 5.2%. For the proposed clinical trial, a sample size of 13,000 would afford 80% power to detect a 1% difference in hospital survival and a 2% difference in the immediate adverse outcome rate.
CONCLUSIONS: This comprehensive in-hospital review provides an in-depth profile of prehospital chest pain patients and was vital for the design and funding of the chest pain component of the OPALS study, which will evaluate the benefits of prehospital ALS.
Key words: chest pain, emergency medical services

006 Emergency Physicians' Attitudes Towards an Early Discharge Clinical Prediction Rule for Patients with Chest Discomfort.
MacGougan CK, Christenson JM. St. Paul's Hospital, Vancouver, BC.

OBJECTIVE: To assess Canadian emergency physicians' (EPs') attitudes to a potential early discharge clinical prediction rule for patients with chest discomfort.
METHODS: An anonymous, cross-sectional mail survey of a random sample of 300 members of the Canadian Association of Emergency Physicians (CAEP).
RESULTS: 82% of the eligible CAEP members surveyed (235/288) responded. 193/216 (89%) estimated a mean LOS of >2 hours for those with acute coronary disease ruled out. Only 11/235 (5%) indicated any follow-up assessment of chest pain patients. Estimates of rates of missed AMIs ranged from 0.1%­10%. 70% of the EPs responding to the survey felt that a clinical prediction rule which identified patients with chest discomfort who are safe to discharge after a brief (~2 hour) assessment would be very useful, 18% felt it would be useful. 94% of the respondents felt that a rule which could identify more patients who are safe for discharge, while not increasing the current percentage of missed acute myocardial infarction (estimated ~2%), would be useful. 59% of respondents prefer a clinical prediction rule to convey a suggested course of action, while 30% prefer a rule to convey a probability of disease.
CONCLUSIONS: Canadian EPs are generally supportive of an early discharge clinical prediction rule for patients with chest discomfort. Most Canadian EPs believe that a clinical prediction rule which could improve efficiency of clinical decision-making for patients with chest discomfort, while maintaining current levels of safety, would be clinically useful.
Key words:chest pain, emergency department, clinical prediction rule

007 Obtaining Consensus for the Definition of "Clinically Important" Brain Injury in the CCC Study.
Stiell I, Lesiuk H, Vandemheen K, Clement C, Reardon M, Eisenhauer M, Wells G, Worthington J, Schull M, Morrison L, McKnight D, MacPhail I, Greenberg G, Dreyer J, Cass D, Brison R. Clinical Epidemiology Unit, University of Ottawa, Ottawa.

OBJECTIVES: The Canadian C-Spine/CT Head (CCC) Study is designed to develop clinical decision rules for imaging in head and neck trauma. This methodological sub-study was essential in order to define and obtain consensus for an outcome measure: "clinically important brain injury."
METHODS: This prospective cohort study/survey involved the CT film review of 273 brain injury cases from minor head injury patients (GCS 13­15) at 8 Canadian EDs. CT brain injuries were considered "clinically unimportant" if the patient was neurologically intact and required neither admission nor neurosurgical follow-up. A formal survey was then sent to 164 academic emergency physicians, neurosurgeons, and neuroradiologists at the 8 Canadian university study sites. Descriptive statistics with 95% CIs were calculated.
RESULTS: 57 of 2,536 CCC Study cases reviewed were considered to have "clinically unimportant" injuries: i) solitary contusion <5 mm in diameter (28 cases), ii) localized subarachnoid blood <1 mm thick (22), iii) smear subdural hematoma <4 mm thick (8), iv) isolated pneumocephaly (3), and v) closed depressed skull fracture not through the inner table (1). Surveys returned by 129 of 164 physicians (79.0%) showed the following % agreement with the proposed criteria.

CONCLUSIONS: Most neurosurgeons and neuroradiologists supported the proposed criteria. Emergency physicians were less supportive but often indicated that they would defer to the opinion of the "neuro" specialists. The secondary outcome measure for the CCC Study CT Head rule will be "clinically important brain injury," as developed by this sub-study. "Need for neurological intervention" remains the primary outcome.Key words: brain injury, computed tomography, clinical prediction rule