104 The Journal of Emergency Medicine

department (ED). They then tested the algorithm in a pro- spective trial of 280 patients. The algorithm was to be based on the most probable diagnoses encountered in penetrating truncal injuries and then formulated into a one-page deci- sion tree. However, they required several pages of notes detailing the specific management criteria of the 34 sepa- rate steps. The authors then entered 280 consecutive pa- tients with stab or GSW likely to have injured thoracic or abdominal contents and managed them according to the algorithm. Of the 280 patients, 31 were dead on arrival, 12 were alive on admission, and expired in the hospital. There were 209 patients whose management complied with the algorithm. Of these 209, 4 (1.9%) died. Forty (40) patients had major deviations from the algorithm; of these, 8 (20%) died. The findings suggest that using a comprehensive algo- rithm in the emergency management of penetrating truncal trauma may reduce mortality and certainly warrants further investigation. [Elizabeth L. Mitchell, MD]

Editor’s Note: Since the judgment of what constituted a significant deviation from the algorithm was not prospec- tively established or blinded, these results should be viewed with some caution.

Cl TERMINAL40 MS FRONTAL PLANE QRS AXIS AS A MARKER FOR TRICYCLIC ANTIDEPRESSANT OVERDOSE. Wolfe TR, Caravati EM, Rollins DE. Ann Emerg Med. 1989;18:348-65.

The terminal 40-ms frontal plane QRS axis has been noted to be between 130 and 270 in tricyclic-antidepressant- (TCA)-poisoned patients. In this retrospective study, the terminal 40-ms frontal plane QRS axis was evaluated for its ability to discriminate between TCA-poisoned patients and non-TCA-poisoned patients. Symptomatic patients were di- vided into TCA-poisoned and non-poisoned groups by plas- ma and urine drug screening. Eighty-three percent of ‘lCA patients were noted to have the terminal 40-ms of the QRS between 130” and 270”. These changes were 8.6 times more common in TCA patients, and were more predictive of TCA toxicity than was QRS duration. Plasma concentration and the terminal QRS did not show any significant correlation. The authors conclude that the terminal 40 ms QRS axis is a more sensitive indicator of significant TCA overdose than QRS duration. [Tom S. Rives, MD]

0 THE SELECTIVE MANAGEMENT OF PENETRAT- ING WOUNDS OF THE BACK. Whalen G, Angorn IB, Robbs JV. J Trauma. 1989;29:509-11.

Fifty patients with penetrating wounds of the back were prospectively evaluated and managed selectively on the ba- sis of physical examination. Patients with additional ab- dominal wounds either anteriorly or in the flanks were ex- cluded. Forty-two patients sustained stab wounds, and eight had gunshot wounds. Eight patients had initial exami- nations that were considered abnormal: all eight patients were taken to surgery where six had significant injury. Six- teen patients were considered to have an equivocal initial exam: three were taken to surgery with no significant inju-

ries noted. Of the 13 other patients with equivocal initial exam, only one had significant injury. None of the patients with initial normal exam developed any significant compli- cations. The author concluded that clinical judgment based on careful history and physical examination may be used to guide management in penetrating back injuries.

[William E. Sandusky, MD]

Editor’s Note: This study fails to address the proper role of other diagnostic modalities (eg, computed tomography) in the management of these patients.

0 NONINVASIVE IMAGING FOR DEEP VENOUS THROMBOSIS. Borozan PG, Zukowski A, Thorpe L, et al. Am J Surg. 1989;156:474-6.

Having previously determined by review of the literature as well as by their own study that duplex ultrasonography (DU) compares favorably with venography for the diagnosis of deep venous thrombosis (DVT), these authors now set out to compare Doppler examination to DU. Over an 18- month-period, 96 out of 918 patients evaluated by DU were positive for DVT in 127 extremities. Doppler examinations were positive in 77 (61 X) of these 127. Of 103 extremities positive for above the knee or popliteal thrombi, 73 (71%) had abnormal Doppler. Of the 24 isolated tibia1 vein throm- bi, 4 (17%) had abnormal Doppler. In 87 extremities with totally occlusive thrombi at the popliteal area or above, 70 (80%) had positive Doppler, whereas Doppler was positive in only 3 (19%) of the 16 other nonocclusive above-the-knee or popliteal thrombi. Doppler was negative in all 4 nonoc- elusive isolated tibia1 thrombi. Therefore, using DU as the standard of diagnosis, the authors conclude that Doppler examination is not as sensitive, and that two major factors explain the discrepancy. These are 1) location, with more proximal thrombi more likely to have abnormal Dopplers, and 2) degree of occlusion, with totally occlusive thrombi also more likely to be abnormal on Doppler examina- tion. IRobert D. Schmidt, MD]

0 HOW ACCURATE ARE VENTILATION-PERFU- SION SCANS FOR PULMONARY EMBOLISM? Caracci BF, Rumbolo PM, Mainini S, et al. Am J Surg. 1988;156: 477-480.

Pulmonary angiography is the gold standard for diagnosing pulmonary embolism, yet has an associated 1% morbidity and mortality. Fifty angiograms were compared with the ventilation-perfusion scans at St. Louis University Medical Center to determine the accuracy of the ventila- tion-perfusion scans. The scans were read as normal, low, intermediate, or high probability as determined by classifi- cation standards. In general, low probability scans had small or matched defects, moderate contained single mis- matched segmental defects, and high probability scans not- ed two or more mismatched segmental defects. The five most common clinical characteristics of the patients in the study were tachypnea, tachycardia, dyspnea, abnormal chest x-ray study, and diaphoresis, all occurring in more than 80% of patients. All three patients with normal scans