ABSTRACTS

with AOM in their pediatric practice took part.]

Douglas McOaniel, MD

Noninvasive ventilation for acute exacerbations of chronic obstructive pulmonary disease Brochard L, Mancebo J, Wysocki M, et al

N Engl J Med 333:817-822 September 1995

This prospective European study was de- signed to investigate noninvasive pressure- support ventilation in hospitalized patients with acute exacerbation of chronic obstruc- tive pulmonary disease (COPD), in compari- son with standard therapy. It is the authors' contention that in patients with COPD, non- invasive ventilation by face mask may be used in an attempt to avoid endotracheal intubation and the complications associat- ed 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 crite- ria were used by all five hospitals to enroll patients in the study. Patients were includ- ed if they had acute exacerbation with res- piratory acidosis but did not require imme- diate 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 non- invasive ventilation to provide an arterial oxygenation saturation higher than 90%. All the participating hospitals used the same noninvasive ventilation delivery appa- ratus. 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

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 consis- tent among the five centers. There were significant improvements in encephalopa- thy score, respiratory rate, partial pressure of arterial oxygen, and pH during the first hour of treatment in the noninvasive venti- lation 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 noninva- sive ventilation (23 days). The authors con- clude that the mortality rate was signifi- cantly reduced and hospital stay was significantly shortened with the use of non- invasive 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 phospho- kinase (CPK) and its MB isoenzyme, contin- uous cardiac monitoring, and radiologic imaging studies. The authors of this prospective study wanted to determine what subset of blunt trauma patients con- sidered at risk for myocardial contusion could safely undergo a limited cardiac eval- uation (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 crash- es at more than 30 mph, falls of more than

30 feet, pedestrians struck by motor vehi- cles 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 crite- ria: (1) age, (2) hemodynamic stability, (3) results of baseline ECG, (4) history of heart disease, and (5) need for surgery or neuro- logic observation. Those patients with a normal ECG, hemodynamic stability (sys- tolic 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 admis- sion ECG, simply received 24 hours of con- tinuous 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) ST- segment elevations, T-wave inversions, or conduction disturbances on serial ECGs; (2) significant arrhythmias on continuous car- diac monitoring; (3) one or more CPK-MB fractions greater than 4%; (4) right ventric- ular 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-seg- ment elevations, T-wave inversions, postin- farction 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-

27 8 ANNALS OF EMERGENCY MEDICINE 27:2 FEBRUARY 1996