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Limiting cardiac evaluation in patients with suspected myocardial contusion
ABSTRACTS
with AOM in their pediatric practice took part.] Douglas McOaniel, MD
Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease Brochard L, ManceboJ, WysockiM, et al N Engl J Med 333:817-822 September 1995 This prospective European study was designed to investigate noninvasive pressuresupport ventilation in hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (COPD), in comparison with standard therapy. It is the authors' contention that in patients with COPD, noninvasive ventilation by face mask may be used in an attempt to avoid endotracheal intubation and the complications associated with mechanical ventilation. Between September 1990 and November 1991, 85 patients were randomly and prospectively recruited from a larger group of 275 patients with COPD, all of whom were admitted to five intensive care units. The same specific inclusion and exclusion criteria were used by all five hospitals to enroll patients in the study. Patients were included if they had acute exacerbation with respiratory acidosis but did not require immediate intubation. Patients assigned to the standard treatment group received oxygen limited to a maximal flow rate of 5 L/minute by nasal cannula in order to achieve an arterial oxygenation saturation higher than 90%. Medications included subcutaneous heparin, antibiotic agents, and bronchodilators. Patients assigned to the noninvasive group received the same medications as the patients in the standard treatment group, with the addition of noninvasive ventilation to provide an arterial oxygenation saturation higher than 90%. All the participating hospitals used the same noninvasive ventilation delivery apparatus. The primary outcome variable was the need for endotracheal intubation and mechanical ventilation at any time during the study. Thirty-one (74%) of the 42
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patients in the standard treatment group required endotracheal intubation, compared with only 11 (26%) of the 43 patients in the noninvasive group. The results were consistent among the five centers. There were significant improvements in encephalopathy score, respiratory rate, partial pressure of arterial oxygen, and pH during the first hour of treatment in the noninvasive ventilation group, whereas the opposite was found in the standard treatment group. The hospital stay was significantly longer in the group receiving standard treatment (35 days) than in the group receiving noninvasive ventilation (23 days). The authors conclude that the mortality rate was significantly reduced and hospital stay was significantly shortened with the use of noninvasive ventilation. They further conclude that, in light of the rapidly reversible nature of most episodes of acute decompensation and the presence of ventilatory failure rather than hypoxemic lung failure, the results of this and previous studies suggest that patients with acute exacerbations of COPD should benefit from this approach.
Douglas McDaniel, MD
Limiting cardiac evaluation in patients with suspected myocardial contusion fildes Jd, getlej TM, Manglano R, et al Am Surg 61:832-835 September 1995 The evaluation of patients with suspected myocardial contusion can include serial ECGs, determinations of creatine phosphokinase (CPK)and its MB isoenzyme, continuous cardiac monitoring, and radiologic imaging studies. The authors of this prospective study wanted to determine what subset of blunt trauma patients considered at risk for myocardial contusion could safely undergo a limited cardiac evaluation (specifically, admission ECG and 24 hours of cardiac monitoring). The patient population consisted of 100 people who had mechanisms of injury consistent with myocardial contusion: motor vehicle crashes at more than 30 mph, falls of more than
30 feet, pedestrians struck by motor vehicles traveling at more than 30 mph, and home or industrial accidents in which myocardial injury was considered likely. All patients had a baseline ECG on admission. They were then assigned to one of two groups on the basis of the following criteria: (1) age, (2) hemodynamic stability, (3) results of baseline ECG, (4) history of heart disease, and (5) need for surgery or neurologic observation. Those patients with a normal ECG, hemodynamic stability (systolic blood pressure greater than 100), no history of heart disease, and no need for surgery or neurologic observation and who were younger than 55 years old were assigned to group 1 (n=74). All other patients were assigned to group 2 (n=19). Group 1 patients, in addition to the admission ECG, simply received 24 hours of continuous cardiac monitoring. Group 2 patients had a full cardiac evaluation, including an admission ECG, at least 24 hours of cardiac monitoring, serial ECGs, cardiac enzyme determinations, and either a multigated angiography scan (MUGA) or two-dimensional echocardiography (ECHO). Cardiac evaluation was considered to be positive for myocardial contusion if one or more of the following were present: (1) STsegment elevations, T-wave inversions, or conduction disturbances on serial ECGs;(2) significant arrhythmias on continuous cardiac monitoring; (3) one or more CPK-MB fractions greater than 4%; (4) right ventricular ejection fraction less than 40%, left ventricular ejection fraction less than 50%, or a regional wall motion abnormality on ECHO or MUGA. None of the patients in group 1 patients had cardiac complications that required treatment. There were no crossovers to group 2. Follow-up was obtained in 24% of group 1, and in all cases the ECG remained normal. None of these patients had complaints referable to a cardiac injury. Group 2 patients were so categorized for the following reasons: 9 (47.4%) had abnormal baseline ECGs, including Mobitz type I AV block, ST-segment elevations, T-wave inversions, postinfarction patterns, or multiple premature ventricular contractions; 7 (36.8%) had a history of heart disease; 4 (21%) underwent laparotomy; 1 (.5%) was admitted for neu-
ANNALS OF EMERGENCY MEDICINE 27:2 FEBRUARY 1996
ABSTRACTS
rological observation; 10 (52.6%) were older than 55 years of age. Nine patients (47.3%) had more than one indication for entry into group 2. The cardiac evaluations of group 2 revealed 14 patients (73.6%)who had at least one test suggestive of myocardial contusion. Of these 14 patients, 9 (62.4%) had two or more positive tests, 7 had ECG abnormalities, and 1 had a positive MUGA. All ECHOresults were normal. Nine patients had one or more positive CPK-MB results. In no group 2 patient did cardiac complications requiring therapy develop. Follow-up was completed in 32%. All patients with normal ECGsduring hospitalization had normal follow-up ECGs. In only one patient with a normal baseline ECG did T-wave inversions develop during hospitalization, and these persisted on follow-up. The authors conclude that it is safe to limit the cardiac evaluation in patients who are hemodynamically stable, are younger than 55 years old, have a normal admission ECG, have no history of heart disease, and do not require surgery or neurologic observation. Specifically, their study suggests that only an admission ECG and 24 hours of cardiac monitoring are required. [Editor's note: Weaknessesof this study include the facts that follow-up was very limited in both groups and that group 2 was small and included no contusions requiring intervention. We still need better information on which of these patients can be managed as outpatients.] Marie Olson, MD
Tetanus immunization and its association to hepatitis B vaccination in patients with chronic renal failure Girndt M, Pietsch M, K~hler H Am J Kidney Dis 26:454-460 September 1995 This prospective, controlled study was designed to demonstrate that a percentage of patients with chronic kidney failure have an inadequate immunologic response to tetanus toxoid vaccination. The extensive study of antibody titers in hepatitis
B-immunized patients with chronic kidney failure demonstrates only a 50% to 60% efficacy. Four groups of seronegative patients were immunized with three scheduled doses of tetanus toxoid. Patients with chronic kidney failure not requiring dialysis, patients requiring intermittent hemodialysis, patients with successful kidney transplantation, and a control group of patients with essential hypertension but normal kidney function were compared for tetanus prophylaxis. Exclusion criteria before immunization included acute infectious disease, a history of allergy, immunosuppressive drug treatment (except transplant patients), blood transfusion less than 4 weeks before vaccination, and presence of acute forms of immunologically mediated glomerulonephritis or the nephrotic syndrome. The dialysis patients all had been on maintenance hemodialysis for longer than 2 years, and transplant patients all had had documented stable kidney function for longer than 1 year. Immunosuppressive therapy for all transplant patients consisted of triple therapy with prednisolone, cyclosporine, and azathioprine. A protective antibody response was identified in only 11 (55%) of 20 patients with chronic kidney failure and 16 (69%) of 23 patients undergoing chronic intermittent hemodialysis; on the other hand, 6 (86%) of 7 patients with stable kidney transplants and 13 (100%)of 13 agematched control patients seroconverted. A comparison was made between responsiveness to tetanus toxoid and previous hepatitis B vaccination. Patients with a history of adequate antibody titers to hepatitis B were more likely to have an adequate response to the tetanus immunization.The converse was also true: nonrespondersto hepatitis B were more likely to have an insufficient antibody responseto the tetanus toxoid administration. The antibody concentrations of all patient groups who seroconvertedwere significantly less than those of the control group. The authors conclude that patients with underlying chronic kidney failure need more frequent tetanus vaccination boosters, with a low threshold for revaccination and measurement of tetanus toxoid levels in the event of injury. Nancy Trangmoe, MD
FEBRUARY 1996 2 7 : 2 ANNALS OF EMERGENCY MEDICINE
Myocardial infarction in young adults: Angiographic characterization, risk factors, and prognosis (Coronary Artery Surgery Study registry) Zimmerman FH, CameronA, Fisher I D, et al J Am Coil Cardiol 26:654-661 September 1995 The CoronaryArtery Surgery Study (CASS) included a registry of 24,958 patients undergoing diagnostic cardiac catheterization between August 1974 and May 1979 for suspected coronary artery disease at 15 institutions in the United States and Canada.The 8,839 patients who were determined to have had a history of myocardial infarction (MI) at entry formed the study group for this analysis, which examined the angiographic characteristics, coronary risk factors, and prognosis in younger versus older men and women with a history of MI. Patients were classified into four groups: men 35 years of age or younger (n=294), men older than 35 years of age (n=7,210),women 45 years of age or younger (n=210), and women older than 45 years of age (n=1,125).Analysis of coronary angiograms in the four groups showed that both younger men and younger women had a higher prevalence of angiographically normal coronary arteries and nonobstructive coronary artery disease (P<.0001)than older patients, and they were more likely than older patients to have single-vessel rather than multiplevessel disease (P<.0001).Risk factor analysis demonstrated that younger patients were more likely to be smokers at the time of study enrollment (P<.0001). Diabetes was more common in older men (P=-.0005)and older women (P=.0356).Hypertensionwas also more common in the older groups (P<.0001). Prognosisfor survival was better for younger men and younger women. Younger men had an 84% survival rate at 7 years, compared with a 75% survival rate in older men (P=.0094).The rates for younger women and older women at 7 years were 90% and 77%, respectively (P=-.0004).This favorable survival prognosis remained even after adjustment for other variables, including coronary anatomy, left ventricular function, and treatment. The
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with AOM in their pediatric practice took part.] Douglas McOaniel, MD
Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease Brochard L, ManceboJ, WysockiM, et al N Engl J Med 333:817-822 September 1995 This prospective European study was designed to investigate noninvasive pressuresupport ventilation in hospitalized patients with acute exacerbation of chronic obstructive pulmonary disease (COPD), in comparison with standard therapy. It is the authors' contention that in patients with COPD, noninvasive ventilation by face mask may be used in an attempt to avoid endotracheal intubation and the complications associated with mechanical ventilation. Between September 1990 and November 1991, 85 patients were randomly and prospectively recruited from a larger group of 275 patients with COPD, all of whom were admitted to five intensive care units. The same specific inclusion and exclusion criteria were used by all five hospitals to enroll patients in the study. Patients were included if they had acute exacerbation with respiratory acidosis but did not require immediate intubation. Patients assigned to the standard treatment group received oxygen limited to a maximal flow rate of 5 L/minute by nasal cannula in order to achieve an arterial oxygenation saturation higher than 90%. Medications included subcutaneous heparin, antibiotic agents, and bronchodilators. Patients assigned to the noninvasive group received the same medications as the patients in the standard treatment group, with the addition of noninvasive ventilation to provide an arterial oxygenation saturation higher than 90%. All the participating hospitals used the same noninvasive ventilation delivery apparatus. The primary outcome variable was the need for endotracheal intubation and mechanical ventilation at any time during the study. Thirty-one (74%) of the 42
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patients in the standard treatment group required endotracheal intubation, compared with only 11 (26%) of the 43 patients in the noninvasive group. The results were consistent among the five centers. There were significant improvements in encephalopathy score, respiratory rate, partial pressure of arterial oxygen, and pH during the first hour of treatment in the noninvasive ventilation group, whereas the opposite was found in the standard treatment group. The hospital stay was significantly longer in the group receiving standard treatment (35 days) than in the group receiving noninvasive ventilation (23 days). The authors conclude that the mortality rate was significantly reduced and hospital stay was significantly shortened with the use of noninvasive ventilation. They further conclude that, in light of the rapidly reversible nature of most episodes of acute decompensation and the presence of ventilatory failure rather than hypoxemic lung failure, the results of this and previous studies suggest that patients with acute exacerbations of COPD should benefit from this approach.
Douglas McDaniel, MD
Limiting cardiac evaluation in patients with suspected myocardial contusion fildes Jd, getlej TM, Manglano R, et al Am Surg 61:832-835 September 1995 The evaluation of patients with suspected myocardial contusion can include serial ECGs, determinations of creatine phosphokinase (CPK)and its MB isoenzyme, continuous cardiac monitoring, and radiologic imaging studies. The authors of this prospective study wanted to determine what subset of blunt trauma patients considered at risk for myocardial contusion could safely undergo a limited cardiac evaluation (specifically, admission ECG and 24 hours of cardiac monitoring). The patient population consisted of 100 people who had mechanisms of injury consistent with myocardial contusion: motor vehicle crashes at more than 30 mph, falls of more than
30 feet, pedestrians struck by motor vehicles traveling at more than 30 mph, and home or industrial accidents in which myocardial injury was considered likely. All patients had a baseline ECG on admission. They were then assigned to one of two groups on the basis of the following criteria: (1) age, (2) hemodynamic stability, (3) results of baseline ECG, (4) history of heart disease, and (5) need for surgery or neurologic observation. Those patients with a normal ECG, hemodynamic stability (systolic blood pressure greater than 100), no history of heart disease, and no need for surgery or neurologic observation and who were younger than 55 years old were assigned to group 1 (n=74). All other patients were assigned to group 2 (n=19). Group 1 patients, in addition to the admission ECG, simply received 24 hours of continuous cardiac monitoring. Group 2 patients had a full cardiac evaluation, including an admission ECG, at least 24 hours of cardiac monitoring, serial ECGs, cardiac enzyme determinations, and either a multigated angiography scan (MUGA) or two-dimensional echocardiography (ECHO). Cardiac evaluation was considered to be positive for myocardial contusion if one or more of the following were present: (1) STsegment elevations, T-wave inversions, or conduction disturbances on serial ECGs;(2) significant arrhythmias on continuous cardiac monitoring; (3) one or more CPK-MB fractions greater than 4%; (4) right ventricular ejection fraction less than 40%, left ventricular ejection fraction less than 50%, or a regional wall motion abnormality on ECHO or MUGA. None of the patients in group 1 patients had cardiac complications that required treatment. There were no crossovers to group 2. Follow-up was obtained in 24% of group 1, and in all cases the ECG remained normal. None of these patients had complaints referable to a cardiac injury. Group 2 patients were so categorized for the following reasons: 9 (47.4%) had abnormal baseline ECGs, including Mobitz type I AV block, ST-segment elevations, T-wave inversions, postinfarction patterns, or multiple premature ventricular contractions; 7 (36.8%) had a history of heart disease; 4 (21%) underwent laparotomy; 1 (.5%) was admitted for neu-
ANNALS OF EMERGENCY MEDICINE 27:2 FEBRUARY 1996
ABSTRACTS
rological observation; 10 (52.6%) were older than 55 years of age. Nine patients (47.3%) had more than one indication for entry into group 2. The cardiac evaluations of group 2 revealed 14 patients (73.6%)who had at least one test suggestive of myocardial contusion. Of these 14 patients, 9 (62.4%) had two or more positive tests, 7 had ECG abnormalities, and 1 had a positive MUGA. All ECHOresults were normal. Nine patients had one or more positive CPK-MB results. In no group 2 patient did cardiac complications requiring therapy develop. Follow-up was completed in 32%. All patients with normal ECGsduring hospitalization had normal follow-up ECGs. In only one patient with a normal baseline ECG did T-wave inversions develop during hospitalization, and these persisted on follow-up. The authors conclude that it is safe to limit the cardiac evaluation in patients who are hemodynamically stable, are younger than 55 years old, have a normal admission ECG, have no history of heart disease, and do not require surgery or neurologic observation. Specifically, their study suggests that only an admission ECG and 24 hours of cardiac monitoring are required. [Editor's note: Weaknessesof this study include the facts that follow-up was very limited in both groups and that group 2 was small and included no contusions requiring intervention. We still need better information on which of these patients can be managed as outpatients.] Marie Olson, MD
Tetanus immunization and its association to hepatitis B vaccination in patients with chronic renal failure Girndt M, Pietsch M, K~hler H Am J Kidney Dis 26:454-460 September 1995 This prospective, controlled study was designed to demonstrate that a percentage of patients with chronic kidney failure have an inadequate immunologic response to tetanus toxoid vaccination. The extensive study of antibody titers in hepatitis
B-immunized patients with chronic kidney failure demonstrates only a 50% to 60% efficacy. Four groups of seronegative patients were immunized with three scheduled doses of tetanus toxoid. Patients with chronic kidney failure not requiring dialysis, patients requiring intermittent hemodialysis, patients with successful kidney transplantation, and a control group of patients with essential hypertension but normal kidney function were compared for tetanus prophylaxis. Exclusion criteria before immunization included acute infectious disease, a history of allergy, immunosuppressive drug treatment (except transplant patients), blood transfusion less than 4 weeks before vaccination, and presence of acute forms of immunologically mediated glomerulonephritis or the nephrotic syndrome. The dialysis patients all had been on maintenance hemodialysis for longer than 2 years, and transplant patients all had had documented stable kidney function for longer than 1 year. Immunosuppressive therapy for all transplant patients consisted of triple therapy with prednisolone, cyclosporine, and azathioprine. A protective antibody response was identified in only 11 (55%) of 20 patients with chronic kidney failure and 16 (69%) of 23 patients undergoing chronic intermittent hemodialysis; on the other hand, 6 (86%) of 7 patients with stable kidney transplants and 13 (100%)of 13 agematched control patients seroconverted. A comparison was made between responsiveness to tetanus toxoid and previous hepatitis B vaccination. Patients with a history of adequate antibody titers to hepatitis B were more likely to have an adequate response to the tetanus immunization.The converse was also true: nonrespondersto hepatitis B were more likely to have an insufficient antibody responseto the tetanus toxoid administration. The antibody concentrations of all patient groups who seroconvertedwere significantly less than those of the control group. The authors conclude that patients with underlying chronic kidney failure need more frequent tetanus vaccination boosters, with a low threshold for revaccination and measurement of tetanus toxoid levels in the event of injury. Nancy Trangmoe, MD
FEBRUARY 1996 2 7 : 2 ANNALS OF EMERGENCY MEDICINE
Myocardial infarction in young adults: Angiographic characterization, risk factors, and prognosis (Coronary Artery Surgery Study registry) Zimmerman FH, CameronA, Fisher I D, et al J Am Coil Cardiol 26:654-661 September 1995 The CoronaryArtery Surgery Study (CASS) included a registry of 24,958 patients undergoing diagnostic cardiac catheterization between August 1974 and May 1979 for suspected coronary artery disease at 15 institutions in the United States and Canada.The 8,839 patients who were determined to have had a history of myocardial infarction (MI) at entry formed the study group for this analysis, which examined the angiographic characteristics, coronary risk factors, and prognosis in younger versus older men and women with a history of MI. Patients were classified into four groups: men 35 years of age or younger (n=294), men older than 35 years of age (n=7,210),women 45 years of age or younger (n=210), and women older than 45 years of age (n=1,125).Analysis of coronary angiograms in the four groups showed that both younger men and younger women had a higher prevalence of angiographically normal coronary arteries and nonobstructive coronary artery disease (P<.0001)than older patients, and they were more likely than older patients to have single-vessel rather than multiplevessel disease (P<.0001).Risk factor analysis demonstrated that younger patients were more likely to be smokers at the time of study enrollment (P<.0001). Diabetes was more common in older men (P=-.0005)and older women (P=.0356).Hypertensionwas also more common in the older groups (P<.0001). Prognosisfor survival was better for younger men and younger women. Younger men had an 84% survival rate at 7 years, compared with a 75% survival rate in older men (P=.0094).The rates for younger women and older women at 7 years were 90% and 77%, respectively (P=-.0004).This favorable survival prognosis remained even after adjustment for other variables, including coronary anatomy, left ventricular function, and treatment. The
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