Results: Of the 221 chest radiographs reviewed in the retrospective derivation set,

low malposition (\2 cm above the carina) of the endotracheal tube was noted in 46

(21%), including unrecognized mainstem endobronchial intubation in 14 (30% of

the low malpositioned tubes; 6% of the total intubations). In the prospective

validation set, 78 postintubation procedure cards were completed for 75 RSI patients

by 20 PBCCB-trained emergency physicians. Fifty-two RSI procedures (66%)

included the attempted application of the PBCCB technique, whereas it was not

attempted in one third (26 patients). For patients who did not undergo PBCCB

assessment, 9 patients (35%) required endotracheal tube repositioning, 8 of which

were repositioned according to postintubation chest radiograph alone, and 1 of

which was repositioned according to asymmetrical breath sounds alone. For the 52

patients undergoing pilot balloon assessment, 16 (31%) endotracheal tubes were

repositioned postintubation, 6 by PBCCB technique alone, and 10 by chest

radiograph alone; in all 10 of those patients, emergency physicians noted that the

endotracheal tube cuff could not be localized by PBCCB, intimating that the

endotracheal tube was indeed placed too low in the trachea.

Conclusion: Although additional work is warranted, these preliminary

observations demonstrate that the use of the PBCCB of the endotracheal tube could

add to the emergency physician’s airway skills armamentarium to assist in location

of the endotracheal tube location within the trachea, avoiding prolonged

endobronchial intubation. If validated, the technique could apply to alternative

settings in which chest radiograph is not immediately available or in which bedside

clinical auscultation skills are compromised by ambient noise or patient transport

(eg, emergency medical services or military field medical care).

385 The Impact of Blood Pressure in the Emergency Departmenton Survival in Transient Ischemic Attack

Stead LG, Peake B, Weaver AL, Brown Jr RD, Decker WW/Mayo Clinic, Rochester, MN

Study objectives: The role of blood pressure in acute brain ischemia has been long

been a subject of controversy. Although it is generally accepted that too high a blood

pressure can harm survival, the lower end of the spectrum is seldom considered. Is

there a range of blood pressure below which chances of survival are again poorer so

that the survival curve is no longer a linear one? We determine how the mean

arterial pressure (MAP), systolic blood pressure, or diastolic blood pressure in the

emergency department (ED) correlates with mortality in transient ischemic attack

(TIA).

Methods: The records of all patients with a final diagnosis of TIA (International

Classification of Diseases, Ninth Revision code 435) presenting to the Saint Mary’s

Hospital ED in a 6-month period was performed. Data on ED blood pressure

measurements and dates of death and last follow-up were abstracted. All consecutive

patients in the mentioned period were captured; all but 1 patient (subsequently

deceased) had blood pressure measurements recorded. Associations with survival

were evaluated according to fitting univariate Cox proportional hazards models and

summarized by calculating risk ratios (RR, risk/10-unit decrease) and 95% confidence

intervals (CIs). This study was approved by the authors’ institutional review board.

Results: Among the 72 patients with TIAs, 8 deaths occurred, with mean time

until death of 196.3 deaths (median, 173 days). The 8 deaths occurred at 17, 17, 61,

145, 201, 321, 377, and 431 days after the initial ED visit. Among the remaining 64

patients who were alive at last follow-up, the mean duration of follow-up was 275.6

days (median 310; range 0 to 463 days). According to univariate Cox models,

patients with low systolic blood pressure were more likely to have poorer survival

(RR 1.4, 95% CI 1.02 to 1.8, P=.036). Likewise, patients with low MAP were more

likely have poorer survival (RR 2.0, 95% CI 1.1 to 3.5, P=.026). There was also

a trend for patients with low diastolic blood pressure to have poorer survival (RR

2.1, 95% CI 0.99 to 4.7, P=.054).

Conclusion: Low MAP, systolic blood pressure, or diastolic blood pressure in the

ED in the setting of a TIA all appear to be associated with poorer survival. These

findings argue for judicious use of antihypertensive medications to patients with TIA

in the acute setting.

387 Very Early Risk of a Significant Cardiac Event After aTransient Ischemic Attack or Acute Ischemic Stroke

McGregor A, Panagos P, Reinert S/Brown Medical School, Rhode Island Hospital,

Providence, RI

Study objectives: Current guidelines generally recommend the admission of

patients with a transient ischemic attack (TIA) and acute ischemic stroke (AIS) to

the hospital for evaluation. The short-term risk (90-day) of recurrent stroke and TIA

after index TIA and AIS is approximately 13%; however, there are few studies

delineating the short-term risk for cardiac morbidity after these neurologic

events. This study determines the very early short-term risk (\48 hours from

admission) of a significant cardiac event (SCE) for patients admitted to

the hospital with TIA or AIS and identifies independent predictors of cardiac

complications.

Methods: We included all patients admitted to a large tertiary teaching hospital

with the diagnosis of TIA and AIS from January 2002 to July 2002. Patients were

identified by International Classification of Diseases, Ninth Revision, Clinical

Modification (433 to 435) discharge codes verified by a neurologist. An SCE was

defined as (1) ECG changes consistent with new-onset arrhythmia or ischemia; (2)

elevated troponin I level; and (3) death directly related to a cardiac event.

Institutional review board approval was obtained for this study.

Results: One hundred ninety-eight patients were admitted with the diagnosis of

TIA (n=27) and AIS (n=171); an SCE occurred in 16% (n=32) of patients. The mean

age was 70 years, and 55% were women. Comorbidities included cerebrovascular

disease (35%), cardiovascular disease (23%), hypertension (70%), hyperlipidemia

(41%), diabetes (26%), current smoker (27%), atrial fibrillation (20%), and a family

history of heart disease (30%). Those with an SCE were more likely to have

diabetes (P=.02), hypertension (P=.05), current smoking (P=.04), or cardiovascular

disease (P=.002). Baseline demographics and other major vascular risk factors were

the same in SCE and non-SCE groups. Stroke subtypes by Trial of Org 10172 in

Acute Stroke Treatment (TOAST) criteria were large-artery atherothromboembolic

32%, cardioembolic 26%, small-vessel thrombotic 32%, and other etiology 10%.

Patients with cardioembolic stroke were significantly more likely to have an SCE

(P\.05).

Conclusion: Short-term cardiac morbidity is substantial after a TIA or AIS. For

patients admitted to our hospital with the diagnosis of TIA or AIS, the independent

risk factors of cardiovascular disease, diabetes, hypertension, smoking, and

suspected cardioembolic stroke subtype predicted the short-term risk for SCE. These

5 identifiers may help to determine a subset of high-risk patients who require

admission to telemetry.

R E S E A R C H F O R U M A B S T R A C T S

386 Utility of Perfusion-Weighted Computed Tomography in AcuteIschemic Stroke Treated With Thrombolytic Therapy

Kim H, Kim HS, Oh BS, Kim JH/Wonju College of Medicine, Conju, South Korea

S 1 2 0

Study objectives: Intravenous administration of tissue plasminogen activator

(tPA) is recommended if there is no contraindication to fibrinolytic therapy and

if the drug can be administered within 3 hours of the onset of stroke symptoms.

We perform this study to evaluate the utility of perfusion-weighted computed

tomography (CT) and perfusional status after thrombolytic therapy with

intravenous tPA.

Methods: We conducted a prospective study of 24 patients (men 17, mean age

62614 years) who presented within 3 hours of the onset of stroke symptoms. We

perform a neurologic examination and perfusion-weighted CT before and after

thrombolytic therapy.

Results: The middle cerebral artery territory infarction was in 16 patients (67%),

brain stem infarction was in 5 patients (20%), and posterior cerebral artery territory

infarction was in 3 patients (13%). Mean Glasgow Coma Scale score and National

Institutes of Health stroke scale were significantly different before and after

thrombolytic therapy (13.961.6 versus 14.561.1, P=.013, and 11.665.1 versus

5.865.9, P=.001). The mean cerebral blood flow and mean transit time were

significantly different before and after thrombolytic therapy (11.767.6 versus

23.667.7 mL/100 g/min, P=.002, and 13.964.3 versus 5.262.0 seconds, P=.001).

The mean cerebral blood volume did not differ (1.460.4 versus 1.560.4 mL/100 g,

P=.311).

Conclusion: Perfusion-weighted CT imaging is a useful modality to detect

reperfusion status in acute ischemic stroke treated with thrombolytic

therapy.

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