1. pediatric syncope“>Sharma N, Chauhan S, Faruqi S, et al. Snake envenomation in a north Indian hospital. Emerg Med J 2005;22:118-20.
2. Lewis RL, Gutmann L. Snake venoms and the neuromuscular junction. Semin Neurol 2004;24:175-9.
3. Warrell DA. Crisis in snake anti-venom supply for Africa. Lancet 2000;356:2104.
4. Warrell DA. Animal toxins. In: Cook GC, Zumla A, editors. Manson’s tropical diseases. London: WB Saunders; 2003. p. 581-618.

ED management of pediatric syncope

To the Editor,

We read with interest the article by Goble and colleagues

[1] entitled “ED management of pediatric syncope: searching for a rationale.” The authors highlighted 2 findings: “the interpretation of ECGs by a pediatric cardiologist before planning admission may have adverted up to 5 of the 11 admissions”, and “a high rate of non cardiologic testing,” particularly head computed tomography (58% of patients, all with normal findings). We performed an observational cohort study that confirmed the first and original point and illustrated the second one with a very different pattern of procedures performed in a French multidisciplinary pediatric emergency department (ED) of a university hospital.

The aim of our study was to evaluate management of childhood syncope, focusing on diagnostic tests ordered, and the interest of cardiologist electrocardiogram (ECG) inter- pretation. Data of all consecutive children aged 2 to 15 years, who were referred for syncope or near-syncope, were prospectively collected during 1 year. Permanent medical supervision was provided by pediatricians. Standard ECG was the only compulsory investigation. The attending pediatrician decided if any other investigation was needed. One hundred fifty-nine children (mean age, 11 +- 4 years; sex ratio = 0.9) were included. Forty-eight percent had syncope, 52% had near-syncope. The most common cause was neurocardiogenic syncope (62%), followed by neurologic causes (seizure and migraine, 18%).

In the series of Goble and colleagues, 6 among the 11 hospital admissions were arranged because of equivocal ECGs. All but one of these ECGs (which showed Wolff- Parkinson-White syndrome) was later read as normal by a pediatric cardiologist. In our series, ECG was performed and blindly interpreted by a pediatric cardiologist in 149 cases (94%). There were discrepancies between cardiolo- gists’ and ED pediatricians’ ECG interpretations in 9% (n

= 13) of cases. The main significant discordant ECGs were the 5 long QT syndrome suspicions, all excluded by the cardiologist. The 8 other discordant ECGs were not clinically significant. The 2 studies cited by Goble and colleagues for reporting discrepancy rates from 13% to 24% for ECG interpretation in pediatric EDs concerned different clinical conditions: chest pain, arrhythmias, apparent life-threatening event, drug exposure, with only

11% and 18 % of “syncope and seizure” [2,3]. Our data clearly confirm the conclusion of Goble and colleagues that “ED interpretation of ECGs suspected of being abnormal should be verified if possible before planning admission based on that ECG” [1].

The second point is the very different pattern of procedures performed in our study. Like Goble and colleagues, we found a high rate for noncardiologic testing for pediatric syncope in the ED but with a lower rate of head CT. The most commonly ordered tests except ECG in our study were electrolytes (44% vs 90% [1]), EEGs

(33%), urinary drug screen (18%), chest x-ray (17% vs

37% [1]), and head computed tomography (8% vs 58% [1]). The 2 other recent studies of pediatric syncope cited by Goble and colleagues reported a high rate of EEG (58% and 39%, respectively) and head CT (23% and 27%) [4,5]. In no case was disease-related syncope diagnosed by head CT in our study, as in the others [1,4]. In the study by Steinberg and Knilans, Neuroimaging studies diagnostic yield was not precisely described but was also low [5]. All these data are consistent with the recommendation that “patients with Prolonged LOSs of consciousness, Seizure activity, and a postictal phase be referred for neurologic evaluation and an electroencephalogram, but that a head CT is not indicated unless focal neurologic deficits are found” [1,4].

Our data confirm the value of the interpretation of all

ECGs suspected of being abnormal by a pediatric cardiol- ogist and the limited indications of neuroimaging for pediatric syncope.

Valerie Hue MD Odile Noizet-Yvernaux MD Guy Vaksmann MD Francois Dubos MD

Alain Martinot MD Department of Pediatric Emergency Care Salengro Hospital, CHRU Lille

59037 Lille cedex, France E-mail address: [email protected]

doi:10.1016/j.ajem.2008.05.019

References

1. Goble MM, Benitez C, Baumgardner M, et al. ED management of pediatric syncope: searching for a rationale. Am J Emerg Med 2008;26:66-70.
2. Wathen JE, Rewers AB, Yetman AT, et al. Accuracy of ECG interpretation in the pediatric emergency department. Ann Emerg Med 2005;46:507-11.
3. Horton LA, Mosee S, Brenner J. Use of the electrocardiogram in a pediatric emergency department. Arch Pediatr Adolesc Med 1994;148: 184-8.
4. Massin MM, Bourguignont A, Coremans C, et al. Syncope in pediatric patients presenting to an emergency department. J Pediatr 2004;145: 223-8.
5. Steinberg LA, Knilans TK. Syncope in children: diagnostic tests have a high cost and low yield. J Pediatr 2005;146:355-8.

Wheezy patient with heart failure and chronic obstructive pulmonary disease: what to treat with?

To the Editor,

The role of ?-agonists in patients with coronary artery disease and chronic obstructive pulmonary disease has always been a matter of controversy [1]. We are tempted to give ?-agonists in such patients who have evidence of wheeze. There is now a substantial body of evidence that cardiac disease can precipitate airway narrowing. This has been attributed to interstitial pulmonary edema and sub- mucosal airway edema causing compression and obstruction of airways, respectively [2,3]. In addition, bronchial hyperreactivity has also been demonstrated in heart failure that may contribute to wheezy dyspnea in such patients [4]. Clinicians should be aware of this fact and judiciously use ?- agonists in such patients. The management of a wheezy patient with coronary artery disease and chronic obstructive pulmonary disease is challenging to every clinician and the treatment should be tailored to each patient.

Chandrasekar Palaniswamy MD

New York Medical College, Westchester Medical Center

Valhalla, NY 10595, USA E-mail address: [email protected]

Randeep Guleria DM Anant Mohan MD

All India Institute of Medical Sciences

New Delhi, India

Dhana Rekha Selvaraj MD

PGIMER, Chandigarh, India

doi:10.1016/j.ajem.2008.06.008

References

1. Parker H, Brenya R, Zarich S, Manthous CA. Beta-agonists for patients with chronic obstructive pulmonary disease and heart disease? Am J Emerg Med 2008;26(1):104-5.
2. Light RW, George RB. Serial pulmonary function in patients with acute heart failure. Arch Intern Med 1983;143:429-33.
3. Peterman W, Barth J, Entzian P. Heart failure and airways obstruction. Int J Cardiol 1987;17:207-9.
4. Cabanes LR, Weber SN, Matran R, Regnard J, Richard MO, Degeorges ME, et al. Bronchial hyper responsiveness to methacholine in patients with left ventricular failure. N Engl J Med 1989;320:1317-22.

Effect of sample volume for the measurement of osmolality by using the Advanced 3250 osmometer

To the Editor,

Osmolality is a count of the total number of osmotically active particles in a solution and is equal to the sum of the molalities of all the solutes present in that solution. The osmolality of a solution can be measured using an osmometer. The most commonly used instrument in modern laboratories is a freezing point depression osmometer. This instrument measures the change in freezing point that occurs in a solution with increasing osmolality.

Freezing point depression is one of the oldest and easiest methods for determination of the osmotic concentration of biological fluids. By this method, the specimen is placed in a cooling chamber that is maintained at a temperature well below the freezing point of the solution. During the analysis, samples are supercooled, at which time crystallization is initiated in a process called seeding. The crystal formation results in release of the heat of fusion of water (80 cal/g [334.9 kJ/kg] water), causing the sample to warm to a point at which ice and solution exist in equilibrium; and the temperature remains constant for a period of time.

The Advanced 3250 osmometer (Norwood, MA) was used for the measurement of osmolality in our Stat laboratory. According to the manufacturer’s instruction, the recommended sample volume is about 0.20 to 0.25 mL. In this study, we aim to investigate whether one half of the sample volume affects the result of osmolality by using the Advanced 3250 osmo- meter. Therefore, we collected blood samples in a blood collection tube containing lithium heparin anticoagulant (Vacutainer Plasma Separator Tube II [Vacutainer Tube, Beckton Dickinson, Franklin Lakes, NJ]) during a single veni- puncture of 30 patients admitted to our emergency department (ED). All blood samples were centrifuged immediately after collection, and aliquots of heparinized plasma samples of

0.2 and 0.1 mL were then assayed in singlicate for osmolality. Data were analyzed by simple linear regression.

In the present study, simple linear regression between the 0.2-mL (A) and 0.1-mL (B) sample volume from 30 patients provided a y-intercept of 0.96 and a slope of 11.09. The correlation was good (r = 0.99, P b .0001) (Fig. 1). Results for the 0.2-mL sample volume ranged from 275 to

320 mmol/kg, and those for the 0.1-mL sample volume ranged from 270 to 322 mmol/kg. The results were also not significantly different by Student t test.

The speed and simplicity of testing with a modern osmometer make it a very useful first step in the evaluation of cases presented to the ED, in monitoring response to fluid therapy and in monitoring the recovery from surgical procedures. Freezing point is the method of choice for osmometers in this field because they are sensitive to all types of solutes. The evaluation of cases includes drug intoxication monitoring (alcohol, methanol, or Ethylene glycol), head injury, monitoring mannitol therapy, coma, and also burns