47 Feasibility and Utility of Infrared Thermography to DistinguishBetween Acute Presentations of Cellulitis and Deep VenousThrombosis in the Emergency Department

Allen TL, Lee DN, Gardner SC, Allen BJ, Snow GL/LDS Hospital, Salt Lake City, UT

Study objectives: Specific illnesses may manifest with unique regional heat

variations and patterns in body surface temperature that can be detected by infrared

thermography. Although there is some experience described in the literature with

infrared thermography in burns and cancer, there is little experience with infrared

thermography in other disease states. This study attempted to determine the

feasibility and utility of infrared thermography to distinguish between lower-

extremity cellulitis and deep venous thrombosis.

Methods: This is a case-control study of infrared thermography using

a ThermaCAM P60 device (FLIR Systems, North Billerica, MA). Infrared

thermography images were obtained before diagnostic duplex imaging in 2 patients

presenting to the emergency department of a tertiary hospital with acute pain, swelling,

and erythema of a leg. The camera has a spatial resolution of 3203240 pixels in focal

plane array, scan integration rate of 60 Hz, and thermal sensitivity of 0.08oC per pixel.

Focal distance was 1 meter, with a set emissivity of 0.98. Images are acquired in JPEG

format. Body surface temperature in each extremity was analyzed using specialized

software across an area 4 cm2, placed over the area of interest. The mean temperature

change in the combined left-right (dT/dx), and up-down (dT/dy) directions in the

affected versus normal extremities were calculated using the formula:

+ dTdx

þ dTdy

� �

N

where N equals the number of pixels in the analyzed area.

Results: For the patient with cellulitis of the leg, the maximum dT/dx and dT/dy

values for the affected leg were 0.68 and 0.56, respectively, versus 0.19 and 0.22 in

the normal extremity. The mean temperature change in the combined directions was

0.35 in the affected extremity versus 0.09 in the normal extremity. For the patient

with deep venous thrombosis of the leg, the maximum dT/dx and dT/dy values for

the affected leg were 0.55 and 0.34, respectively, versus 0.26 and 0.17 in the normal

extremity. The mean temperature change in the combined directions was 0.14 in the

affected extremity versus 0.09 in the normal extremity.

Conclusion: The infrared thermography images of an extremity affected by

cellulitis versus deep venous thrombosis are visually quite different. Mathematical

models of these 2 clinical entities using infrared thermography also appear to

present distinct results. Because infrared thermography is easily and rapidly

obtained and poses no risk or radiation to the patient, this technology may prove

useful in distinguishing between cellulitis and deep venous thrombosis in the

clinical setting. Further study is required to determine the operating characteristics

of the infrared thermography test.

48 Deep Venous Thrombosis Caused by Iliac Vein CompressionSyndrome

Kim MR, Kwak Y, Jung S, Suh G/Seoul National University Hospital, Seoul, Korea

Study objectives: Iliac vein compression syndrome (IVCS) is a clinical condition

accompanied by deep venous thrombosis secondary to the compression of the left

common iliac vein between the right common iliac artery and the lumbar vertebrae.

We reviewed cases of IVCS in the emergency department (ED) compared with the

other patients of deep venous thrombosis for the analysis of its clinical

characteristics and therapeutic outcomes.

Methods: A total of 140 patients with deep venous thrombosis visited the ED of

Seoul National University Hospital from January 2000 to December 2002. Of these

patients, 20 patients were diagnosed with IVCS. The medical records of the IVCS

group (N=20) were retrospectively reviewed and compared with those of the other

deep venous thrombosis group (N=120).

Results: The IVCS group was 14.3% of total patients with deep venous

thrombosis, and mean age of the IVCS group was 55 years. The male to female ratio

in the IVCS group was 1:3 and had statistical significance (P=.019). In the IVCS

group, there was more cardiovascular disease (P=.029) and less malignancy (P=.044)

compared with the deep venous thrombosis group. There were no significant

differences between the IVCS group and the deep venous thrombosis group in

abnormality of coagulation and pulmonary embolism. Swelling confined to the left

lower extremity in all patients and abnormal coagulation panel in 50% of the IVCS

group were shown. For the treatment of IVCS, anticoagulation with heparin was

done in all patients and thrombolysis with urokinase in 95%. Additionally, balloon

angioplasty and metallic stent insertion were performed in 80% and 75% of patients,

respectively. Among the 15 patients treated by stent insertion, 10 patients showed no

relapse and 2 (13%) patients showed relapse. The remaining 3 patients were lost

during the mean follow-up period of 12.8 months. Among 5 patients who did not

undergo stent insertion, 2 patients did not have recurring disease, and 3 (60%)

patients had recurring disease during the mean follow-up period of 11.2 months.

Prognosis of the stent insertion group tended to be good but had no statistical

significance (P=.095).

Conclusion: IVCS was mainly manifested as swelling confined to the left lower

extremity and was more common in female patients. Of the appropriate

managements to prevent deep venous thrombosis, stent insertion treatment showed

a tendency to reduce the relapse. There needs to be a multicenter study for more

analysis of IVCS.

49 Concordance Between Emergency Department and DischargeDiagnoses in Patients Admitted With Right Lower QuadrantAbdominal Pain

Milling TJ, Lazarides A, Gaeta T, Birkhahn R/New York Methodist Hospital, Brooklyn,

NY

Study objectives: We compare emergency department (ED) diagnosis to discharge

diagnosis in patients presenting with right lower quadrant pain and examine factors

influencing agreement.

Methods: We conducted a 7-month prospective observational study enrolling

patients with right lower quadrant pain in an urban ED. Exclusion criteria were

recent trauma or previous appendectomy. Patients discharged from the ED were

followed up for 7 days (none required later admission). ED diagnosis, discharge

diagnosis, demographic data, diagnostic studies, and inhospital management were

recorded. Primary outcomes were agreement between ED diagnosis and discharge

diagnosis (excluding discharged patients). Secondary outcome was ED diagnosis

accuracy in appendicitis, controlling for age, race, sex, and insurance (sensitivity/

specificity calculated with discharged patients). Data are reported with 95%

confidence intervals (CIs).

Results: Four hundred twenty-nine patients enrolled; 269 patients were admitted

(63%). Agreement of ED diagnosis and discharge diagnosis was 80% (95% CI 75% to

85%). There was no difference in age groups ([65 versus\65), race, or insurance

status. Agreement in male patients was 90% (95% CI 85% to 95%). Agreement in

female patients was 75% (95% CI 70% to 80%). ED diagnosis of appendicitis in both

sexes (n=429) was as follows: accuracy 93% (95% CI 91% to 95%), sensitivity 92%

(95% CI 90% to 94%), and specificity 93% (95% CI 91% to 95%). ED diagnosis of

appendicitis in male patients was as follows: accuracy 95% (95% CI 91% to 99%),

sensitivity 97% (95% CI 93% to 100%), and specificity 94% (95% CI 90% to 98%).

ED diagnosis of appendicitis in female patients was as follows: accuracy 92% (95%

CI 89% to 95%), sensitivity 90% (95% CI 87% to 93%), and specificity 93% (95% CI

90% to 96%). Seven of the 21 observed diagnoses were female-specific pathology.

Agreement in patients with these diagnoses at discharge (n=26) was 58% (95% CI

39% to 77%; 7 of 11 misdiagnosed cases required operation). ED diagnosis of

appendicitis without computed tomographic (CT) scan (n=186) was as follows:

Table, abstract 46.

T1No. ofPatients

D-Dimer Valueat T1, ng/mL

D-Dimer Valueat T2, ng/mL

Normal 29 971.2561765 82261312Stable angina 14 532.786386 71861208Unstable angina 50 757.961064 79661108Myocardial infarction 26 958.4661143 114861322

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

S 1 6 A N N A L S O F E M E R G E N C Y M E D I C I N E 4 4 : 4 O C T O B E R 2 0 0 4

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