Do diabetic patients have higher in-hospital complication rates when admitted from the emergency department for possible myocardial ischemia?

OBJECTIVE: To compare in-hospital complication rates for diabetic and nondiabetic patients admitted from the emergency department (ED) for possible myocardial ischemia. METHODS: This was a prospective, observational study of consecutive consenting patients presenting to a suburban university hospital ED during study hours with typical and atypical symptoms consistent with cardiac ischemia. Demographic, historical, and clinical data were recorded by trained research assistants using a standardized, closed-question, data collection instrument. Inpatient records were reviewed by trained data abstractors to ascertain hospital course and occurrence of complications. Final discharge diagnosis of acute myocardial infarction (AMI) was assigned by World Health Organization criteria. Categorical and continuous data were analyzed by chi-square and t-tests, respectively. All tests were two-tailed with alpha set at 0.05. RESULTS: There were 1,543 patients enrolled who did not have complications at initial presentation; 283 were diabetic. The rule-in rate for AMI was 13.8% for nondiabetic patients and 17.7% for diabetic patients (p = 0.09). Times to presentation were similar for nondiabetic vs diabetic patients [248 minutes (95% CI = 231 to 266) vs 235 minutes (95% CI = 202 to 269); p = 0.32]. Nondiabetic patients tended to be younger [56.6 years (95% CI = 55.8 to 57.4) vs 61.6 years (95% CI = 60.2 to 63.1); p = 0.001] and were less likely to be female (34.3% vs 48.1%; p = 0.001). The two groups had similar prevalences for initial electrocardiograms diagnostic for AMI (5.5% vs 7.4%; p = 0.21). There was no significant difference between nondiabetic and diabetic patients for the occurrence of the following complications after admission to the hospital: congestive heart failure (1.3% vs 1.1%, p = 0.77); nonsustained ventricular tachycardia (VT) (1.3% vs 1.2%, p = 0.93); sustained VT (1.2% vs 1.1%, p = 0.85); supraventricular tachycardia (1.7% vs 3.2%, p = 0.12); bradydysrhythmias (1.9% vs 1.1%, p = 0.33); hypotension necessitating the use of pressors (0.9% vs 1.1%, p = 0.76); cardiopulmonary resuscitation (0.2% vs 0.7%, p = 0.10); and death (0.3% vs 0.7%, p = 0.34). One or more complications occurred with similar frequencies for patients in the two groups (6.3% vs 5.7%; p = 0.70). CONCLUSIONS: No statistically significant difference was found in the postadmission complication rates for initially stable diabetic vs nondiabetic patients admitted for possible myocardial ischemia. Based on these results, the presence or absence of diabetes as a comorbid condition does not indicate a need to alter admitting decisions with respect to risk for inpatient complications.

Clinical characteristics of diabetic vs nondiabetic patients who "rule-in" for acute myocardial infarction.

OBJECTIVE: To compare the clinical characteristics of diabetic vs nondiabetic patients who present to the ED with acute myocardial infarction (AMI). METHODS: This was a prospective, observational study at a suburban, university hospital ED of patients presenting to the ED during study hours between December 1993 and October 1996 with typical and atypical symptoms consistent with cardiac ischemia. Diabetic and nondiabetic patients with AMI were compared. Demographic, historical, and clinical data were recorded by trained research assistants using a standardized, closed-question, data collection instrument. Final discharge diagnosis of AMI was assigned by WHO criteria. Continuous variables were analyzed by t-tests. Clinical variables were analyzed by chi-square tests. All tests were two-tailed with alpha preset at 0.05. RESULTS: There were 216 patients with AMI during the study period; 51 of these patients (24%) were diabetic. For diabetic vs nondiabetic patients with AMI, there was no significant difference in age (64.0 +/- 13 vs 60.0 +/- 14 years, p = 0.13), female gender (37% vs 26%, p = 0.13), and time to presentation from symptom onset (192 +/- 238 vs 251 +/- 456 minutes, p = 0.41). Hypertension was the only cardiac risk factor significantly more prevalent in diabetic vs nondiabetic patients with AMI (77% vs 50%, OR = 1.54, 95% CI = 1.24 to 1.91, p = 0.001), though elevated cholesterol (48% vs 33%, OR = 1.47, 95% CI = 1.02 to 2.12, p = 0.06) tended to be more prevalent in the diabetic group. There was no statistically significant difference between the two groups in terms of the frequency of chest pain (OR = 1.04, 95% CI = 0.95 to 1.14, p = 0.30), associated symptoms, and diagnostic ECGs (OR = 1.16, 95% CI = 0.76 to 1.79, p = 0.53). CONCLUSION: Diabetic patients with AMI may have similar symptoms upon presentation as do nondiabetic patients with AMI. Of the cardiac risk factors, hypertension is more prevalent in diabetic vs nondiabetic patients with AMI.

Evaluation of CK-MB isoform analysis for early diagnosis of myocardial infarction.

Measurement of CK-MB and its isoforms by high-voltage electrophoresis has been proposed as a sensitive test for early detection of myocardial infarction (MI). We performed a prospective study of this test in 231 patients presenting to the Emergency Department with symptoms consistent with ischemic chest pain. Blood specimens were obtained at 0, 1, and 3 h following presentation, and plasma was immediately frozen and analyzed within 1 week by high-voltage electrophoresis for total CK-MB and isoforms. The test was considered positive whenever total CK-MB was elevated (>6 U/L) or the cardiac isoform MB2 was relatively increased (MB2 > 2 U/L and MB2/MB1 > 1.7). This test had a sensitivity of 68% overall and 55% for specimens collected within 3 h of symptom onset. It was positive within 3 h of presentation in 36/39 (92%) of patients with confirmed MI. Specificity was 92% overall and did not vary with time after symptoms. The CK-MB alone, at the cutoff of 6 U/L, had lower sensitivity overall (56%; p = 0.01) and within 3 h of onset (39%; p = 0.03), and higher specificity overall (98%; p < 0.001). Lowering the cutoff for CK-MB alone to match the sensitivity of the isoform test caused a greater loss of specificity. It is concluded that analysis of CK-MB by high-voltage electrophoresis is an effective method for rapid diagnosis of MI, with the isoform analysis enhancing early sensitivity.

Cardiac marker point-of-care testing in the Emergency Department and Cardiac Care Unit.

There has been much interest in improving the accuracy and speed with which chest pain patients presenting to the emergency department are diagnosed and treated. Recently, attention has been directed toward alternative site or point-of-care testing for biochemical markers of myocardial cell necrosis in addition to traditional diagnostic methodologies. The various point-of-care cardiac marker devices available and their potential applications are discussed. Regulatory and quality management issues related of point-of-care testing are reviewed.

Effect of duration from symptom onset on the negative predictive value of a normal ECG for exclusion of acute myocardial infarction.

STUDY OBJECTIVE: We hypothesized that the negative predictive value of the ECG would improve with time and assessed the effect of time elapsed from symptom onset to ED presentation on the negative predictive value, sensitivity, specificity, and positive predictive value of the initial ECG in patients presenting with symptoms suggestive of acute myocardial infarction (AMI). METHODS: We conducted a cross-sectional study in a university teaching hospital. Our structured data instrument, completed at the time of presentation included demographics, time of onset of symptoms, history, laboratory, and ECG findings. AMI was diagnosed with the use of international diagnostic criteria. Patients were stratified according to duration of time from symptom onset at 3-hour intervals. RESULTS: We enrolled 526 patients in the study group. The mean age was 59 years; 40% were female. The mean time elapsed from symptom onset to presentation was 185 minutes. A diagnosis of AMI was made in 104 patients (20%). The negative predictive values of a normal ECG for exclusion of AMI, stratified by duration of time from symptom onset, were: 0 to 3 hours, 93.2% (95% confidence interval [CI], 87.4% to 96.1%); 3 to 6 hours, 93.0% (95% CI, 83.0% to 98.1%); 6 to 9 hours, 92.6% (95% CI, 75.8% to 99.1%); and 9 to 12 hours, 94.1% (95% CI, 71.3% to 99.9%) (P = 1.0). The sensitivity, specificity, and positive predictive value of the ECG were similar in all groups. CONCLUSION: The negative predictive value of a normal ECG for exclusion of AMI does not improve as the duration of time from symptom onset to presentation increases. Normal ECG findings cannot be used to rule out an AMI, even those obtained up to 12 hours after symptom onset.

Are monitored telemetry beds necessary for patients with nontraumatic chest pain and normal or nonspecific electrocardiograms?

We evaluated the frequency of cardiovascular complications in chest pain patients with normal or non-specific electrocardiograms admitted to noncardiac care unit monitored beds and found that none of 261 patients had life-threatening dysrrhythmias requiring treatment.

Academic associate program: integrating clinical emergency medicine research with undergraduate education.

An educational program that teaches undergraduate students about clinical research related to emergency medicine is described. The students work as research assistants within the ED, thus providing a departmental framework for the enrollment of patients in clinical studies. Volunteers interested in the program undergo a physical examination, vaccination history, and standard serologic testing, and sit through a formal blood and body fluid exposure course offered by the university prior to their clinical research participation. A didactic curriculum on clinical research concepts and course examinations is provided. Over the 4 years since the department established its departmental research goals and this educational program, the departmental publication rate has increased from 2 to 20 manuscripts. While there was only 1 faculty member with a research publication in 1992, there were 9 faculty with manuscripts accepted for publication in the first 6 months of 1996. Similarly, more nurses and ancillary staff have become involved in prospective clinical research. Much of this success is attributed to the novel use of resources through the academic associate program.

Evaluation of a new assay for cardiac troponin I vs creatine kinase-MB for the diagnosis of acute myocardial infarction. Biochemical Markers for Acute Myocardial Ischemia (BAMI) Study Group.

OBJECTIVE: To compare a new assay for cardiac troponin 1 (cTn-1) with an assay for creatine kinase-MB (CK-MB) for the diagnosis of acute myocardial infarction (AMI). METHODS: A prospective cross-sectional study of patients presenting with symptoms consistent with cardiac ischemia was performed at a university teaching hospital. Serum sampling for cTn-1 and CK-MB was performed at 0, 1, 3, 8, and 16 hours after presentation. Normal values were defined as CK-MB < or = 7 ng/mL and a relative index < or = 2%, cTn-I < or = 1.4 ng/mL. Final diagnosis was made using World Health Organization criteria, including standard enzyme sampling. Consecutive patients with AMI were compared with a randomly selected subset of patients without AMI to determine the sensitivity and specificity of cTn-I and CK-MB assays for AMI, stratified by time from symptom onset. The ability of the biochemical cardiac markers obtained within 6 hours of symptom onset to predict later complications or need for interventions was assessed using odds ratios (ORs). RESULTS: Thirty-five patients who had AMI were compared with 136 patients who did not have AMI. The sensitivities and specificities of the cTn-I and CK-MB assays, stratified by time from symptom onset, were: [table: see text]. Patients who had elevations in either CK-MB or cTn-I within 6 hours of symptom onset were at increased risk for cardiovascular complications and/or interventions (CK-MB, OR 5.8; cTn-I, OR 6.3). CONCLUSION: cTn-I was as sensitive and specific for AMI as was CK-MB in ED patients who presented within 24 hours of symptom onset. However, cTn-I was more sensitive in patients who presented > or = 24 hours after symptom onset. Elevations of either marker within 6 hours of symptom onset predict an increased risk of complications and/or need for interventions.

Comparison of wound infection rates using plain versus buffered lidocaine for anesthesia of traumatic wounds.

Buffered lidocaine has been shown to be less painful than plain lidocaine for anesthetizing wounds. However, the effect of a buffering agent on the local host defenses has not been evaluated. The infection rates of wounds anesthetized with plain lidocaine versus buffered lidocaine were compared in an observational cohort study. Consecutive emergency department patients with traumatic wounds that required sutures had a closed-question wound registry sheet prospectively completed. Follow-up data were obtained at the time of the return visit. Patients failing to return were contacted by telephone. Data were analyzed for wound infection rates comparing plain lidocaine with buffered lidocaine. Chi-squared or Fisher exact tests were used for statistical analysis. Of 2,711 patients analyzed, 2,279 had received plain and 432 had received buffered lidocaine. The infection rate for patients treated with plain lidocaine was 3.5%, versus that for patients treated with buffered lidocaine, 3.9% (P = .63). After adjustment for confounding variables, the infection rate did not differ between plain and buffered lidocaine. The infection rates of wounds repaired after anesthesia with either plain or buffered lidocaine are similar.

Evaluation of cardiac STATus CK-MB/myoglobin device for rapidly ruling out acute myocardial infarction.

The Cardiac STATus CK-MB/Myoglobin device is highly sensitive and has a high negative predictive value within 3 hours of patient presentation. The device may play a role in the re-triage of patients from the CCU to less intensive settings, resulting in a net cost savings.

Improved specificity of myoglobin plus carbonic anhydrase assay versus that of creatine kinase-MB for early diagnosis of acute myocardial infarction.

STUDY OBJECTIVE: Carbonic anhydrase III (CA-III) is an enzyme released from skeletal muscle in a fixed ratio with myoglobin during cell injury, but unlike myoglobin it is not found in cardiac muscle. This study compared the clinical utility of serum myoglobin (S-Mgb) in conjunction with the ratio of S-Mgb to CA-III (S-Mgb/CA-III) versus creatine kinase-MB (CK-MB) for the early diagnosis of acute myocardial infarction (AMI). METHODS: This prospective observational study set at a university teaching hospital emergency department enrolled 251 consecutive consenting patients who presented with symptoms consistent with cardiac ischemia or infarction of less than 12 hours' duration. Patients with trauma or kidney failure were excluded. Standardized history and physical examination data were recorded, as were the results of serial blood sampling for S-Mgb, CA-III, and CK-MB at 0, 1, and 3 hours after patient presentation. A positive test for the study assays was defined as an S-Mgb concentration of more than 110 ng/mL with an S-Mgb/CA-III of 3.21 or higher by receiver operating characteristic analysis. Data were analyzed with McNemar's chi 2 test for symmetry and confidence intervals (CIs), using the exact method. RESULTS: Thirty (12%) of the 251 patients were found to have AMI by World Health Organization criteria. Mean time from symptom onset to presentation was 3.2 hours. The use of S-Mgb plus S-Mgb/CA-III compared with CK-MB for identification of AMI in patients presenting within 3 hours of symptom onset yielded respective sensitivities of 47.8% versus 17.4% (P = .02); specificities of 98.9% versus 100% (P = NS); positive predictive values of 84.6% (95% CI, 54.6% to 98.1%) versus 100% (95% CI, 39.8% to 100%); and negative predictive values of 93.5% (95% CI, 90.0% to 96.6%) versus 90.0% (95% CI, 84.8% to 93.9%). CONCLUSION: S-Mgb in conjunction with S-Mgb/CA-III was significantly more sensitive than CK-MB yet equally as specific for the early diagnosis of patients with AMI.

Chest pain associated with cocaine: an assessment of prevalence in suburban and urban emergency departments.

STUDY OBJECTIVE: Chest pain and myocardial infarction following the use of cocaine have been well documented. We assessed the prevalence of cocaine use in patients who presented to the emergency department with chest pain of possibly ischemic origin. DESIGN: During times of research assistant availability, consecutive adults with the chief complaint of chest pain unexplained by trauma or radiographic abnormality were questioned about cocaine use in the preceding week. Urine was tested for the presence of cocaine or cocaine metabolites with a highly accurate bedside urine test kit (specificity, 100%; sensitivity 98%). Anonymous unlinked data-collection methods were used. Therefore we could not determine whether the patients who used cocaine had sustained myocardial infarctions. SETTING: One suburban and three urban EDs. RESULTS: We enrolled 359 patients with a mean age of 51 years, 8% of whom sustained myocardial infarctions. Sixty patients (17%) had cocaine or cocaine metabolites in urine. The likelihood of testing positive for cocaine varied by age group: 18 to 30 years, 29%; 31 to 40 years, 48%; 41 to 50 years, 18%; 51 to 60 years, 3%; 61 years or older, 0% (P < .0001). Of the 60 patients who tested positive for cocaine, only 43 (72%) admitted recent use. CONCLUSION: Many ED patients with chest pain have recently used cocaine. Because the recent use of cocaine is not uncommon in patients with chest pain up to 60 years old, such patients should be questioned about cocaine use. When treatment or disposition may be altered, consideration should be given to objective assessment of cocaine use because patient self-report does not appear reliable.

Comparison of plain, warmed, and buffered lidocaine for anesthesia of traumatic wounds.

STUDY OBJECTIVE: To compare pain on infiltration, need for additional anesthesia, and pain on suturing in patients given plain, warm, and buffered lidocaine preparations before the suturing of traumatic wounds in the emergency department. DESIGN: Randomized, prospective, single-blinded convenience sample. SETTING: University hospital ED. PARTICIPANTS: Patients with traumatic lacerations. Patients allergic to lidocaine and patients with abnormal mental status or altered pain sensorium were excluded. INTERVENTIONS: All wounds were anesthetized by use of a standard injection technique. Wound margins were anesthetized with plain, buffered, or warm lidocaine in a randomized fashion. Pain of infiltration was recorded for each margin by means of a previously validated visual-analogue pain scale. RESULTS: The main outcome parameter was pain of infiltration. Need for additional anesthesia and pain on suturing were secondary outcome parameters. We evaluated 45 patients. Pain on injection varied by the type of lidocaine (mean pain scores: plain, 8.2; buffered, 4.7 [P < .05 versus plain]; warm, 4.9 [P < .05 versus plain]). There was no significant difference between the mean pain scores of the groups given warm and buffered lidocaine (P = NS). Need for additional anesthesia and pain on suturing did not vary by the type of anesthesia. The order of injection was not found to influence results. Mean pain scores were not different for margins 1 and 2 in any of the groups (P = NS). CONCLUSION: Both buffered and warmed lidocaine were as efficacious as plain lidocaine, and they had significantly less pain associated with infiltration than did plain lidocaine. In EDs with fluid warmers, warmed lidocaine may be the most convenient, well-tolerated, efficacious lidocaine preparation for anesthesia of traumatic wounds.

Evaluation of a new rapid quantitative immunoassay for serum myoglobin versus CK-MB for ruling out acute myocardial infarction in the emergency department.

STUDY OBJECTIVE: To compare the predictive values of serum myoglobin and creatine kinase (CK)-MB for ruling out acute myocardial infarction in the emergency department. DESIGN: Prospective, observational study. SETTING: University teaching hospital. PARTICIPANTS: One hundred eighty nine consecutive patients aged 30 years and older who presented within 12 hours from onset of chest discomfort, dyspnea, syncope, congestive heart failure, symptomatic dysrhythmia, pulmonary edema, or epigastric pain were entered into the study. Patients with trauma or renal failure were excluded. INTERVENTIONS: Standardized history and physical examination and blood sampling for serum myoglobin (S-Mgb) and CK-MB were done at the time of presentation (T0) and 1 hour later (T1). RESULTS: Using World Health Organization criteria, 22 acute myocardial infarction patients were identified. Mean time from symptom onset to presentation was 3.2 hours. S-Mgb was more sensitive than CK-MB at T0 and T1, 55% versus 23% (P < .05) and 73% versus 41% (P < .05), respectively. Respective specificities of S-Mgb versus CK-MB were 98% versus 99% (P = NS) at T0 and 97% versus 99% (P = NS) at T1. Negative predictive values of S-Mgb versus CK-MB were 94% versus 91% (P = NS) at T0 and 96% versus 93% (P = NS) at T1. The S-Mgb assay yielded quantitative results allowing the difference between the T0 and T1 values to be analyzed. A difference of 40 or more ng/mL between T0 and T1 was considered positive. When using a positive result in either the T0 or T1 value or a difference between the two values of 40 or more ng/mL, the sensitivity of S-Mgb was 91% (P < .05 versus CK-MB), the specificity was 96% (P = NS versus CK-MB), and the negative predictive value was 99% (95% confidence interval for S-Mgb, 97.0 to 100 versus CK-MB, 95% confidence interval, 88.9 to 96.6). CONCLUSION: In the first hour of presentation to the ED, the rapid quantitative assay for S-Mgb was statistically more sensitive than CK-MB and had an excellent negative predictive value for ruling out acute myocardial infarction in patients with typical or atypical symptoms. Due to the relatively small sample size, we could not exclude the possibility that differences in specificity might become statistically significant (beta error) with a larger sample size of acute myocardial infarction patients.

"Abnormal" electrocardiograms in patients with cocaine-associated chest pain are due to "normal" variants.

"Abnormal" electrocardiograms are found in 56% to 84% of patients with cocaine-associated chest pain. This study was designed to assess whether these findings can be explained by "normal" variations in young patients' electrocardiograms. This cross-sectional study was conducted in a municipal hospital emergency department and walk-in clinic. History and results of an electrocardiogram for consecutive patients with cocaine-associated chest pain, aged 18 to 35 years, were compared to normal controls matched for age, race, and gender. Electrocardiograms underwent detailed analysis by two physicians blinded to both the study protocol and the hypothesis. Interphysician concordance for electrocardiographic diagnosis was substantial. There were 112 patients enrolled, 56 in each group. There was no significant difference found in the mean frequency of electrocardiographic diagnoses between the cocaine-associated chest pain patients and controls. The early repolarization variant was common. In conclusion, "normal" variations (J point and ST segment elevations) account for many of the "abnormal" electrocardiograms observed in young patients with cocaine-associated chest pain. Further study is needed to define the prevalence of these "normal" variations, and to determine if standard electrocardiographic criteria for thrombolysis apply to young patients.

The enlarging clinical spectrum of Lyme disease: Lyme cerebral vasculitis, a new disease entity.

The case of a patient with cerebral vasculitis with a right thalamic infarct associated with cerebral spinal fluid Lyme disease is presented. This entity has not been described in the United States, and only one similar case in the world literature could be found. The patient presented with a progressive headache and subsequent development of grand mal seizure activity. Lyme disease has been associated with cranial nerve palsies, peripheral and cranial radiculopathies, aseptic meningitis, encephalitic symptoms, chorea, and demyelinating polyneuropathy presenting like Guillain-Barré syndrome. These syndromes can occur separately or in combination. Stroke and strokelike syndromes have been attributed to Lyme disease. The literature concerning the neurologic manifestations of Lyme disease is reviewed.