hypoxemia or change in Coronary blood flow. However, it was neither sensitive nor specific for left-sided pneu- mothorax in this study. Phasic QRS voltage variation was probably due to the intrathoracic air adjacent to the heart that underwent phasic alteration in size with respiration. It was very specific for left-sided pneumothorax, but the specificity was only 40% in this study.

In conclusion, QRS voltage ratio (aVF/I) greater than 2 was a simple and accurate ECG finding to differentiate left- sided pneumothorax from prior anterior MI.

Satoshi Kurisu MD Ichiro Inoue MD Takuji Kawagoe MD Masaharu Ishihara MD Yuji Shimatani MD Yasuharu Nakama MD

Department of Cardiology, Hiroshima City Hospital

Hiroshima 730-8518, Japan E-mail address: skurisu@nifty.com

doi:10.1016/j.ajem.2008.03.032

References

1. Walston A, Brewer DL, Kitchens CS, Krook JE. The electrocardio- graphic manifestations of spontaneous left pneumothorax. Ann Intern Med 1974;80:375-9.
2. Copeland R, Omenn GS. Electrocardiographic changes suggestive of coronary artery disease in pneumothorax. Arch Intern Med 1970;125: 151-3.
3. Werne CS, Sands MJ. Left Tension pneumothorax masquerading as anterior myocardial infarction. Ann Emerg Med 1985;164:166.
4. Ruo W, Rupani G. Left tension pneumothorax mimicking myocardial ischemia after percutaneous central venous cannulation. Anesthesiology 1992;76:306-8.
5. Dimitar R. A case of spontaneous left-sided pneumothorax with ECG changes resembling acute myocardial infarction. Int J Cardiol 1996;56: 197-9.
6. Kozelj M, Rakovec P, Sok M. Unusual ECG variations in left-sided pneumothorax. J Electrocardiol 1997;30:109-11.
7. DePace NL, Colby J, Hakki AH, et al. Poor R wave progression in the precordial leads: clinical implications for the diagnosis of myocardial infarction. J Am Coll Cardiol 1983;2:1073-9.
8. Gami AS, Holly TA, Rosenthal JE. Electrocardiographic poor R-wave progression: analysis of multiple criteria reveals little usefulness. Am Heart J 2004;148:80-5.

Clinical questions in the ED

To the Editor,

We read with great interest the article by Graber et al [1]. Capturing clinical questions in the emergency department (ED) is an important area of research, fundamental to developing resources that better meet the information needs of ED physicians. Earlier research has demonstrated broadly

similar findings to those of Graber et al in relation to number of questions asked, sought, answered, and sources used. How- ever, it additionally examined such factors as motivation and, crucially, impact on present and future patient management [2]. This earlier study was conducted in 3 phases and examined the information behavior (ie, information needs, seeking, and use) of 13 ED physicians in a Canadian tertiary care-level pediatric ED. During the first phase, physicians completed an initial questionnaire designed to describe their current information management (including an estimate of the number of questions they anticipated asking during each shift). Secondly, using a microcassette recorder, each physician recorded questions arising over three 8-hour shifts and indicated how quickly answers were needed. Finally, a follow-up questionnaire solicited responses relating to several issues, including whether or not answers were sought and found, if answers were found within specified time frames, which sources were used, and present and future

impact on patient management.

Physicians estimated that they would ask an average of

4.8 questions per shift, but in actual practice raised 3 questions per shift. Most questions were treatment-related and drawn from the specialty topic areas of infectious disease and orthopedics. Participants pursued answers to 66% of their questions and found answers to 58% of pursued questions. Urgent questions were more likely to be pursued. Print and human sources were consulted most frequently, with physical accessibility and credibility the major determinants of source selection. In seeking answers, physicians were motivated by a variety of factors including the needs of patient care, for confirmation, curiosity, uncertainty, and generalizability. Reasons for not seeking an answer were similar to those in the study of Graber et al, including lack of time and the answer not immediately applicable to patient care. Factors resulting in questions remaining unanswered included lack of time and problems experienced in retrieving answers.

This earlier study confirms the findings of Graber et al that ED physicians ask fewer questions but pursue a higher proportion of them than in other clinical specialties. However, Talbot’s study determined additionally that the information retrieved changed both present and future patient management in approximately 50% of cases. In both present and future management, the most common categories identified were drug treatment, “other” (such as expanding the differential diagnosis), and choice of tests. These findings underscore the significance of the supposition of Graber et al that, “it is possible, although unlikely, that cognitive gaps have no impact on patient outcome (p 147). Talbot’s study further showed that questions are raised not just for immediate patient management, suggesting that patient care episodes may prompt questions that are indicative of general learning need (a “want to know” as opposed to a “need to know”). A more detailed exploration of these questions is likely to enhance future disease management, educational benefit, and quality improvement.

That ED physicians ask fewer questions than other specialties may be due in part to the specific nature of ED practice. As one physician remarked, “As busyness goes up the level of questioning goes down… I do most of my thinking outside the ED. By the time I get into work, I’m going on established algorithms, on pathways formulated outside the ED…I ask my questions (outside the ED)” [2, p 77]. Other physicians noted their reliance on memory, a factor recognized as a potential source of error in clinical decision making [3,4]. Although electronic point-of-care systems appear an obvious solution (especially for drug questions), caution should be exercised in assuming that these systems will necessarily improve decision making in more complex situations. cognitive biases, for example, have been identi- fied as adversely affecting the quality of decision making while using information retrieval systems [5]. The complexity of information behavior and its elemental link with decision making highlights the need for more detailed research.

Although the conclusions of both ED studies suggest that information needs are not generic but vary across specialties, the finding that answering questions has a significant effect on patient management emphasizes the importance of questioning to clinical practice. Determining precise num- bers of questions may not be as important, however, as increasing awareness of individual behavior patterns and of establishing systems of collecting questions. As Smith observes, physicians currently “… have a machine for answering questions but no afferent loop to supply questions”[6]. Increasing awareness of questioning behavior patterns not only reinforces the concept of continuous learning but is a fundamental precursor to the first stage of practicing evidence-based medicine, that is, the formulation of answerable questions [7].

Andrea C. Talbot Learning Curve, Banbridge, Co. Down BT32 3LT, Northern Ireland

E-mail address: actalbot@btinternet.com

Michael B.H. Smith MB BCh Department of Paediatrics, Craigavon Area Hospital Craigavon, Co.Armagh, BT63 5QQ, Northern Ireland E-mail address: mike.smith@southerntrust.hscni.net

doi:10.1016/j.ajem.2008.04.001

References

1. Graber MA, Randles BD, Ely JW, et al. Answering questions in the ED. Am J Emerg Med 2008;26:144-7.
2. Talbot AC. Information behaviour of pediatric emergency department physicians [dissertation]. Halifax (NS), Canada: Dalhousie University; 2002.
3. Institute of Medicine, Committee on Quality of Health Care in America. Crossing the quality chasm: a new health system for the 21st century. Washington, DC: National Academy Press; 2001.
4. Kuhn GJ. diagnostic errors. Acad Emerg Med 2002;9:740-50.
5. Lau AYS, Coiera EW. Do people experience cognitive biases while searching for information? J Am Med Inform Assoc 2007;14:599-608.
6. Smith R. Answers descend, questions ascend. BMJ 2000;321:0.
7. Sackett DL, Richardson WS, Rosenberg W, et al. Evidence-based medicine. How to practice and teach EBM. Edinburgh: Churchill Livingstone; 1998.

Acute spinal ischemia might cause the pulmonary edema

To the Editor,

Mjahed et al [1] reported a very interesting case of accidental intra-arterial application of benzathine penicillin as a source of T9 through T10 spinal ischemia with the development of paraplegia and acute pulmonary edema. They implicated that an embolization of the Adamkiewicz artery, a nutritional vessel of T9 through T12 spinal cord levels, by crystals of penicillin salts, caused the spinal ischemia. They suspected an immunologically mediated mechanism as a source of the Noncardiogenic pulmonary edema. However, a subsequent allergologic examination was negative.

Although I would agree with their statement on the origin of the spinal ischemia, I would not be so sure about the immunologic mechanism of pulmonary edema development. I believe the edema described in this study would rather be Neurogenic pulmonary edema. In our laboratory, we performed a series of experiments on our model of neurogenic pulmonary edema in rat, and this clinical case report is similar in several aspects to our experiments [2-4]. In our model, pulmonary edema is elicited by an immediate thoracic Spinal cord compression at the T8 level [2,3]. Here, the spinal ischemia occurred also immediately after the application of benzathine penicillin, and it occurred

at the spinal level T9 through T10.

Mjahed et al. reported that the patient’s respiratory symptoms occurred immediately after the injection. In our studies, with the direct observation of the neurogenic pulmonary edema development through the thoracic wall, we observed the final picture of the edema–the darkening of the lung surface, enlargement of the lungs, and subpleural bleeding developed within 6 to 8 minutes [3]. However, the animals were anesthetized. We believe that when the experiment would be done in a conscious animal, the duration would be even shorter; however, because of ethical reasons, this was not possible. The x-ray finding was similar to ours [2,3]; the perihilar infiltrates were the dominating ones.

Mjahed et al. reported that the pulmonary edema was accompanied by a hemoptysis, occurring immediately after the injection. In most pulmonary edemas, the rapid development of Pulmonary hemorrhages is not present. However, it is specific to neurogenic pulmonary edema. In our experiments, pulmonary hemorrhages accompanied the neurogenic pulmonary edema in all cases [2,3].