- Email: [email protected]
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Research Forum Abstracts case groups were: (1) Patients diagnosed with SAH by CT (CT⫹) and (2) Patients diagnosed with SAH by LP after a negative CT (LP⫹), while the control group was (3) Patients whose workup for SAH was negative after CT and LP (CT/LP-). An abstracter blinded to the goal of the study abstracted data from all identified LP⫹ charts and a randomly selected sample of CT⫹ and CT/LP- charts. Comparisons using cross tabulations and a multinomial logistic regression were performed between the demographic characteristics and the clinical presentations of each group. Results: A total of 567 SAH were identified, of which 50 cases were LP⫹. To provide adequate statistical power, 150 CT⫹ and 89 CT-/LP- cases were reviewed. There was no difference in race and sex between the groups, however age was greater in CT⫹ when compared to LP⫹ and CT/LP- respectively (median age⫽55, 46, 38, p ⬍ 0.001). Historically, CT⫹ were more likely to present ⬍ 6 hours from onset of headache when compared to LP⫹ and CT/LP- (69%, 34%, 35%, p ⬍ 0.001), more likely to have had syncope (37%, 6%, 7%, p ⬍ 0.001) and a history of an altered level of consciousness (46%, 6%, 10%, p ⬍ 0.001). On exam, CT⫹ was more likely to have an altered level of consciousness (37%, 6%, 3%, p ⬍ 0.001) and a focal neural deficit (27%, 6%, 3%, p ⬍ 0.001). CT⫹ had the worst Glascow Coma Scale (p ⬍ 0.001) and Hunt and Hess Score (p⫽0.002) when compared to LP⫹ and CT/LP-. GCS did not differ for LP⫹ and CT/ LP-. There was increased risk for CT⫹ and LP⫹ to have sudden onset of headache (ORCT⫹⫽50.0; ORLP⫹⫽22.2), not resolving prior to full evaluation (ORCT⫹⫽29.8; ORLP⫹⫽5.2), stiff neck (ORCT⫹⫽5.2; ORLP⫹⫽9.9), family history of SAH (ORCT⫹⫽20.0; ORLP⫹⫽62.5), and focal neural deficit (ORCT⫹⫽55.6; ORLP⫹⫽23.3). There was increased risk for LP⫹ to having a warning headache within the previous two weeks (ORLP⫹⫽9.1). Conclusion: Patients with SAH that is diagnosed with CT are more likely to have exam findings suggestive of an intracranial event when compared to those diagnosed with LP, although they share similar historical features.
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Acute Stroke: A Descriptive Study of Mode of Arrival, Pre-Hospital Diagnosis, Duration of Symptoms, and Treatment
Cronin KA, Johnson S, Thode HC Jr, Henry MC/Stony Brook University, Stony Brook, NY
Study Objectives: To investigate mode of arrival, performance of EMS providers, duration of symptoms, and treatment for patients with acute stroke. Methods: Design: Retrospective chart review. Setting: Academic suburban hospital emergency department (ED) with annual census of 75,000. Subjects: Patients presenting with principal diagnosis of stroke (ICD-9430-438) during a 10 month period. Measures: Patient demographics, duration of symptoms, mode of arrival, EMS response time and diagnosis, stroke type, treatment. Data Analysis: Descriptive statistics, chi-squared tests. Results: 113 patients were diagnosed with cerebral vascular events. The mean age was 63 years, 58% were female. 57% of strokes were ischemic, 22% hemorrhagic, and 21% were transient ischemic attacks (TIA). 74% of the strokes that came by ambulance were ischemic, compared to 16% of transfers and 56% of the patients who walked in (p ⬍ .001). 84% of the transfers were hemorrhagic strokes and 71% of patients with TIA walked in to the ED. 64% of patients with symptoms ⱕ 2 hrs arrived via ambulance and 65% of those with symptoms lasting ⬎ 6hrs walked in (p⫽.021). The mean EMS response time was 14 minutes. For patients arriving by ambulance, EMS providers accurately diagnosed stroke 60% of the time and 55% had a positive finding on the Cincinnati stroke scale. 62% of patients received MRI. 6% of patients with ischemic strokes received intravenous thrombolysis (TPA) and 25% were treated with unfractionated heparin. 4% of patients died and 7% of patients required surgery. There was no statistically significant difference in treatment with TPA, heparin, need for operation, or death based on the mode of arrival to the ED. Conclusions: Type of stroke correlates with mode of arrival to the ED and with the pre-hospital duration of stroke symptoms. Patients with acute ischemic stroke symptoms, particularly those with duration of symptoms less than 2 hours utilize EMS. Mode of arrival to the ED does not correlate with treatment provided for stroke.
134
Bias Introduced by the Informed Consent Process on Pulmonary Embolism Prevalence
Mitchell A, Kline J/Carolinas Medical Center, Charlotte, NC
Study Objective: To determine the potential bias introduced by the written informed consent process on prevalence studies of pulmonary embolism (PE) in the emergency department (ED) setting.
S42 Annals of Emergency Medicine
Methods: Consecutive ED patients (August 10, 2005 through Oct 9, 2005) undergoing evaluation for PE by D-dimer measurement and/or computed tomography (CT) of the chest with venography, in a single ED were approached for written informed consent for participation in an ongoing study. This study involved the collection of a 10 mL plasma sample and telephone and medical record follow-up. Patients were identified via partial waiver of consent to screen ED charts, D-dimer logs and CT logs. The trigger for screening for enrollment was the ordering of a Ddimer or CT to rule-out PE by the evaluating ED physician. Exclusion criteria for this study included age ⬍ 18 yrs, chronic hemodialysis, cardiac catheterization within 28 days, active heart failure and anticoagulation for known PE. Patients with any exclusion criteria were screened but not approached for enrollment. All plasma samples were collected concurrent with standard blood draws performed for usual care. All written consents were obtained by a study coordinator with sufficient intrainstitutional training recognized by the institutional review board to be able to obtain written informed consent. Study coordinators were not physicians, did not participate in patient care, and were not authors of any study related manuscripts. All patients were approached for consent prior to the availability of the results of diagnostic tests. Study coordinators maintained a sequential log of consents and refusals for all patients approached for enrollment, in which the date and, if volunteered by the patient, the reason for refusal. No patient identifiers were recorded. For patients enrolled, the time of enrollment was also recorded. The prevalence of PE was defined by the number ED CTs interpreted as positive for venous thromboembolism, by board certified radiologists, during the study period. Results: A total of 298 patients were eligible for enrollment. During the study period, 260 (87%, confidence interval [95%CI]: 83 to 91%) patients, were approached and consent was obtained in 185/298 (62%, 95%CI: 56 to 68%) patients. Of those approached for consent and refused, 15/260 (6%, 95%CI: 3 to 9%) cited the blood draw, 14/260 (5%, 95%CI: 3 to 9%) stated a general dislike or distrust for research, 16/260 (6%, 95%CI: 4 to 10%) related fatigue, 3/260 (1%, 95%CI: 0 to 3%) refused over concern for privacy of their medical records, and 2/ 260 (1%, 95%CI: 0 to 3%) desired financial reimbursement. Fifteen (6%, 95%CI: 3 to 9%) patients could not be consented because of medical acuity. The remainder of those that refused (10/260; 4%, 95%CI: 2 to 7%) did not volunteer a reason for refusal. The prevalence of PE among those enrolled in the study was 8/185 (4%, 95%CI: 2 to 8%) and 13/113 (12%, 95%CI: 6 to 19%) among those who were not approached or refused to consent, which is a difference of 7% (95%CI of the difference: 1 to 15%). Conclusion: The overall prevalence of PE was low, but significantly lower for patients in which written informed consent was obtained. This difference does suggest that the informed consent process may represent an important source of systematic bias, especially in this low prevalence population. The effect of age, gender and race could not be determined.
135
Attitudes Toward Waiver of Consent Studies
Triner W, Jacoby L, Shelton W, McGee G/Albany Medical College, Albany, NY
Study Objectives: This study was undertaken to examine attitudes toward clinical trials involving waiver of informed consent, the degree of awareness and understanding of such a study being undertaken in the community, mechanisms of learning about this study and the effect demographic characteristics have on attitudes toward such studies. Additionally, the effect of media attention questioning the ethical behavior of a study sponsor had on attitudes was studied. Methods: Study Design: This was a cross-sectional observational study. Setting: The study took place in an academic tertiary care emergency department with an annual census of 65,000. Study participants: A convenience sample of patients and visitors was studied between January 6th, 2006 and April 3rd, 2006. Interventions: A self-administered survey was administered during an emergency department visit. The survey assessed attitudes and awareness of an ongoing waiver of consent study, and demographics of the respondents. Questions related to attitudes of waiver of consent studies and willingness to participate in them, were assessed by sixpoint Likert scales. Results: 497 surveys were completed out of 725 patients present during study periods. 162 patients presented with exclusion criteria and 66 refused participation. There were 39 respondents who reported awareness of the ongoing waiver of consent study. Yet only 19 (4% of all respondents) were able to demonstrate recollection of a single risk or benefit listed during the community consultation and notification. Television was the most commonly reported method of learning of the study (53%).
Volume , . : October
133
Acute Stroke: A Descriptive Study of Mode of Arrival, Pre-Hospital Diagnosis, Duration of Symptoms, and Treatment
Cronin KA, Johnson S, Thode HC Jr, Henry MC/Stony Brook University, Stony Brook, NY
Study Objectives: To investigate mode of arrival, performance of EMS providers, duration of symptoms, and treatment for patients with acute stroke. Methods: Design: Retrospective chart review. Setting: Academic suburban hospital emergency department (ED) with annual census of 75,000. Subjects: Patients presenting with principal diagnosis of stroke (ICD-9430-438) during a 10 month period. Measures: Patient demographics, duration of symptoms, mode of arrival, EMS response time and diagnosis, stroke type, treatment. Data Analysis: Descriptive statistics, chi-squared tests. Results: 113 patients were diagnosed with cerebral vascular events. The mean age was 63 years, 58% were female. 57% of strokes were ischemic, 22% hemorrhagic, and 21% were transient ischemic attacks (TIA). 74% of the strokes that came by ambulance were ischemic, compared to 16% of transfers and 56% of the patients who walked in (p ⬍ .001). 84% of the transfers were hemorrhagic strokes and 71% of patients with TIA walked in to the ED. 64% of patients with symptoms ⱕ 2 hrs arrived via ambulance and 65% of those with symptoms lasting ⬎ 6hrs walked in (p⫽.021). The mean EMS response time was 14 minutes. For patients arriving by ambulance, EMS providers accurately diagnosed stroke 60% of the time and 55% had a positive finding on the Cincinnati stroke scale. 62% of patients received MRI. 6% of patients with ischemic strokes received intravenous thrombolysis (TPA) and 25% were treated with unfractionated heparin. 4% of patients died and 7% of patients required surgery. There was no statistically significant difference in treatment with TPA, heparin, need for operation, or death based on the mode of arrival to the ED. Conclusions: Type of stroke correlates with mode of arrival to the ED and with the pre-hospital duration of stroke symptoms. Patients with acute ischemic stroke symptoms, particularly those with duration of symptoms less than 2 hours utilize EMS. Mode of arrival to the ED does not correlate with treatment provided for stroke.
134
Bias Introduced by the Informed Consent Process on Pulmonary Embolism Prevalence
Mitchell A, Kline J/Carolinas Medical Center, Charlotte, NC
Study Objective: To determine the potential bias introduced by the written informed consent process on prevalence studies of pulmonary embolism (PE) in the emergency department (ED) setting.
S42 Annals of Emergency Medicine
Methods: Consecutive ED patients (August 10, 2005 through Oct 9, 2005) undergoing evaluation for PE by D-dimer measurement and/or computed tomography (CT) of the chest with venography, in a single ED were approached for written informed consent for participation in an ongoing study. This study involved the collection of a 10 mL plasma sample and telephone and medical record follow-up. Patients were identified via partial waiver of consent to screen ED charts, D-dimer logs and CT logs. The trigger for screening for enrollment was the ordering of a Ddimer or CT to rule-out PE by the evaluating ED physician. Exclusion criteria for this study included age ⬍ 18 yrs, chronic hemodialysis, cardiac catheterization within 28 days, active heart failure and anticoagulation for known PE. Patients with any exclusion criteria were screened but not approached for enrollment. All plasma samples were collected concurrent with standard blood draws performed for usual care. All written consents were obtained by a study coordinator with sufficient intrainstitutional training recognized by the institutional review board to be able to obtain written informed consent. Study coordinators were not physicians, did not participate in patient care, and were not authors of any study related manuscripts. All patients were approached for consent prior to the availability of the results of diagnostic tests. Study coordinators maintained a sequential log of consents and refusals for all patients approached for enrollment, in which the date and, if volunteered by the patient, the reason for refusal. No patient identifiers were recorded. For patients enrolled, the time of enrollment was also recorded. The prevalence of PE was defined by the number ED CTs interpreted as positive for venous thromboembolism, by board certified radiologists, during the study period. Results: A total of 298 patients were eligible for enrollment. During the study period, 260 (87%, confidence interval [95%CI]: 83 to 91%) patients, were approached and consent was obtained in 185/298 (62%, 95%CI: 56 to 68%) patients. Of those approached for consent and refused, 15/260 (6%, 95%CI: 3 to 9%) cited the blood draw, 14/260 (5%, 95%CI: 3 to 9%) stated a general dislike or distrust for research, 16/260 (6%, 95%CI: 4 to 10%) related fatigue, 3/260 (1%, 95%CI: 0 to 3%) refused over concern for privacy of their medical records, and 2/ 260 (1%, 95%CI: 0 to 3%) desired financial reimbursement. Fifteen (6%, 95%CI: 3 to 9%) patients could not be consented because of medical acuity. The remainder of those that refused (10/260; 4%, 95%CI: 2 to 7%) did not volunteer a reason for refusal. The prevalence of PE among those enrolled in the study was 8/185 (4%, 95%CI: 2 to 8%) and 13/113 (12%, 95%CI: 6 to 19%) among those who were not approached or refused to consent, which is a difference of 7% (95%CI of the difference: 1 to 15%). Conclusion: The overall prevalence of PE was low, but significantly lower for patients in which written informed consent was obtained. This difference does suggest that the informed consent process may represent an important source of systematic bias, especially in this low prevalence population. The effect of age, gender and race could not be determined.
135
Attitudes Toward Waiver of Consent Studies
Triner W, Jacoby L, Shelton W, McGee G/Albany Medical College, Albany, NY
Study Objectives: This study was undertaken to examine attitudes toward clinical trials involving waiver of informed consent, the degree of awareness and understanding of such a study being undertaken in the community, mechanisms of learning about this study and the effect demographic characteristics have on attitudes toward such studies. Additionally, the effect of media attention questioning the ethical behavior of a study sponsor had on attitudes was studied. Methods: Study Design: This was a cross-sectional observational study. Setting: The study took place in an academic tertiary care emergency department with an annual census of 65,000. Study participants: A convenience sample of patients and visitors was studied between January 6th, 2006 and April 3rd, 2006. Interventions: A self-administered survey was administered during an emergency department visit. The survey assessed attitudes and awareness of an ongoing waiver of consent study, and demographics of the respondents. Questions related to attitudes of waiver of consent studies and willingness to participate in them, were assessed by sixpoint Likert scales. Results: 497 surveys were completed out of 725 patients present during study periods. 162 patients presented with exclusion criteria and 66 refused participation. There were 39 respondents who reported awareness of the ongoing waiver of consent study. Yet only 19 (4% of all respondents) were able to demonstrate recollection of a single risk or benefit listed during the community consultation and notification. Television was the most commonly reported method of learning of the study (53%).
Volume , . : October