successful procedure. As evidenced in Table 10, we can say with 95% confidence that the Grandview allows for a statistically significant reduction in number of attempts necessary for success compared with the Miller.

Ideally physicians would be able to compare multiple blades and visualizations on the same patient, thus making anatomical variances obsolete. This is neither practical nor ethical when dealing with emergent endotracheal intubation. In only 5 of 28 cases were we able to collect data that incorporated multiple attempts with more than 1 blade on the same patient, so analysis of data collected about second blade used was limited to draw valid conclusions [11,12].

The limited number of completed data questionnaires made it difficult to draw absolute conclusions when comparing 3 different blades. Although general trends and comparisons can be followed, a higher volume of data would be necessary to improve validity.

The study successfully introduced and evaluated the Grandview Laryngoscope blade compared with traditional Macintosh and Miller blades in emergent endotracheal intubation. With the given data, this study did show that the Grandview blade provides improved airway visualization and improved ease of intubation than the Macintosh and the Miller blades.

Martha A. Kelley DO, LCDR, USN Stephen Boskovich DO, CAPT, USAF

Midwestern University/ Chicago College of Osteopathic Medicine Provident Hospital of Cook Country

Chicago, Ill 60615, USA

Paul J. Allegretti DO, FACOEP, FACOI Emergency Medicine, Midwestern University/ Chicago College of Osteopathic Medicine Provident Hospital of Cook Country

Chicago, Ill 60615, USA E-mail address: [email protected]

doi:10.1016/j.ajem.2008.02.028

References

1. Marks RR, Hancock R, Charters P. An analysis of Laryngoscope blade shape and design: new criteria for laryngoscope evaluation. Can J Anaesth 1993;40(3):262-70.
2. Cook TM, Tuckey JP. A comparison between the Macintosh and the McCoy laryngoscope blades. Anaesthesia 1996;51(10):977-80.
3. Papageorgiou E, Kokkinis K, Goumas P, Mochloulis G, Alexapoulos

C. Objective evaluation of the difficulty of endotracheal intubation. A comparative study of two different laryngoscope blades. Anaesth Intensive Care 1997;25(6):655-8.

1. Gerlach K, Wenzel V, von Knobelsdorff G, Steinfath M, Dorges V. A new universal laryngoscope blade: a preliminary comparison with Macintosh laryngoscope blades. Resuscitation 2003;57(1):63-7.
2. Arino JJ, Velasco JM, Gascoc, Lopez-Timoneda F. straight blades improve visualization of the larynx while curved blades increase ease

of intubation: a comparison of the Macintosh, Miller, Belscope and Lee-Fiberview blades. Can J Anesthesiol 2003;50(10):1078-9.

1. Nowicki T, London S. Management of the difficult airway. Emerg Med

Rep 2005;26(17).

1. Sagarin MJ, Barton ED, Chng Y, Wall RM. Airway management by US and Canadian emergency medicine residents: a multicenter analysis of more than 6,000 endotracheal intubation attempts. Ann Emerg Med 2005;46(4):328-36.
2. Rassam S, Wilkes AR, Hall JE, Mecklenburgh JS. A comparison of 20 laryngoscope blades using an intubating manikin: visual analogue scores and forces exerted during laryngoscopy. Anaesthesia 2005;60: 384-94.
3. Yardeni IZ, Gefen A, Smolyarenko V, Zeidel A, Beilin B. Design evaluation of commonly used rigid and levering laryngoscope blades. Acta Anaesthesiol Scand 2002;46:1003-9.
4. Perera CN, Wiener PC, Harmer M, Vaughan RS. Evaluation of the use of the Flexiblade. Anaesthesia 2000;55:890-3.
5. Maleck WH, Koetter KP, Lenz M, Piper SN, Triem J, Boldt J. A randomized comparison of three laryngoscopes with the Macintosh. Resuscitaion 1999;42:241-5.
6. Amour J, Marmion F, Birenbaum A, Nicolas-Robin A, Coriat P, Riou B, et al. Comparison of plastic single-use and metal reusable laryngoscope blades for orotracheal intubation during rapid sequence induction of anesthesia. Anesthesiology 2006;104:60-4.

Ultrasound-assisted localization for lumbar puncture in the ED

To the Editor,

We read with great interest the article by Ferre et al [1] regarding the use of ultrasound by emergency physicians for identifying the anatomical landmarks of lumbar puncture. In this study, 76 patients enrolled were more obese with a mean body mass index of 31.4 (95% confidence interval, 29.1- 33.6). Despite nearly half (47%) of the subjects having difficult- or impossible-to-palpate landmarks, ultrasound is very sensitive in identifying the spinous process (100%, 76/ 76 subjects) and ligamentum flavum (97.4%, 74/76) by using curved array from midline approach. Although the identifi- cation rates of dural matter and epidural space by ultrasound are much lower, 85.5% (65/76) and 77.6% (59/76), respectively, we found that simply identifying the spinous process and ligamentum flavum through bedside ultrasono- graphy had been sufficient enough for successfully obtaining cerebrospinal fluid (CSF). This finding is rather interesting. We hereby present a case of a 25-year-old male patient with a body mass index of 34 (a body weight of 100 kg and a height of 1.7 m) who underwent an uneventful lumbar puncture using ultrasound-assisted landmarks localization.

This patient was presented to the emergency department with 1-day history of fever, conscious alteration, and Nuchal rigidity suggestive of meningitis. Antibiotics were given before performing spinal tapping on this obese patient.

The patient’s body surface landmarks, such as the lumbar spinous processes, were difficult to palpate even after being

Fig. 1 A, Sagittal view of the sonographic image of the lumbar spine. The 2 convex bright line with acoustic casting represent spinous processes. L4 and L5 indicate the spinous processes of fourth and fifth lumbar vertebrae, respectively. Arrow indicates the ligamentum flavum. B, Picture of the patient’s back. L4 and L5 indicate the spinous processes of fourth and fifth lumbar vertebrae, respectively.

placed in a lateral decubitus fetal position for lumbar puncture. A 2-dimensional ultrasound scan of his lumbosa- cral spine with a Terason T3000 machine using a variable frequency (2-5 MHz) curvilinear transducer (Terason, Boston, Mass) was done. The spinous processes of L4, L5 (Fig. 1A, the 2 convex acoustic casting), the interspinous space (the gap in between), and the ligmentum flavum (Fig. 1A, arrow) were identified through sagittal midline approach. A distance of 6 cm between skin and the spinous process of L4 and 10.5 cm between skin and the ligmentum flavum were shown. After centering the interspinous space on the image, 2 points were marked as L4 and L5 on the midline of the patient’s back (Fig. 1B). The puncture site was in the middle of the 2 skin marks, and the standard process of lumbar puncture was carried out afterward. Confirmation of the skin marks by repetitive sonography is necessary if the patient moved between ultrasonography localization and the puncture procedure. Fig. 2 illustrates the model route of needle advancement (dotted line), passing through the interspinous space to the Spinal canal. The CSF of this patient was successfully obtained without difficulty by a single attempt, and the diagnosis of meningitis was later proven by the CSF study.

According to a preliminary report by Pisupati et al [2], in cases with easy-to-palpate spinal landmarks, there were no significant differences regarding the success rate of lumbar puncture between those undergoing ultrasonographic loca- lization and those with “blind” palpation alone. By using ultrasound-assisted landmark localization, the success rate, however, could be improved in those with spinal landmarks that are either difficult-to-palpate or nonpalpable, whereas the significance remained unclear owing to insufficient case numbers. Furthermore, the report by Ferre et al also showed a mean time for obtaining the best scan is 54.7 +- 58.0 seconds (95% confidence interval, 41.3-68.1) using the 3-

MHz curved array probe by midline approach [1], suggesting that the use of ultrasound in landmarks identification is not time-consuming. Based on our clinical experiences, we suggest a “2-end point” approach when using ultrasound for those patients with difficult- or impossible-to-palpate landmarks. First of all, localize the skin landmarks as well as establish the route of needle advancement by identifying spinous processes and liga- mentum flavum. Secondly, determine the needle length by measuring the distance between skin and ligamentum flavum. We strongly believe that the time for successfully obtaining the useful landmarks will be even further reduced by using our 2-end point method.

Fig. 2 The dotted line illustrates the imaginary route of needle advancement, passing through the interspinous space to the spinal canal.

Ming-Yuan Huang MD Aven P. Lin MD

Wen-Han Chang PhD

Emergency Department, Mackay Memorial Hospital

Taipei, Taiwan E-mail address: [email protected]

doi:10.1016/j.ajem.2008.03.007

References

1. Ferre RM, Sweeney TW. Emergency physicians can easily obtain ultrasound images of anatomical landmarks relevant to lumbar puncture. Am J Emerg Med 2007;25:291-6.
2. Pisupati D, Heyming TW, Lewis RJ, Peterson MA. Effect of ultrasonography localization of spinal landmarks on lumbar puncture in the emergency department. Ann Emerg Med 2004;44:s38.

The association of cardiovascular toxins and electrocardiographic abnormality in Poisoned patients

To the Editor,

Poisoned patients frequently present in the ED. According to the Center for Disease Control, approximately 1 million of the 110 million annual ED visits are related to ingestions, poisonings, and other toxic effects [1]. Furthermore, at least 2 million cases are reported to poison centers (PC) each year. The PC data demonstrate that cardiovascular drugs as a specific group rank 11th among the most frequent ingested materials. However, many drugs in overdose can have effects on the electrocardiogram (ECG), not just those specifically marketed for those effects. Other Medication classes which are more frequently encountered in poisonings include antidepressants, antipsychotics, antihistamines, and seda- tives-all of which have potential Cardiovascular effects [2,3]. Overall, agents with potential impact on the ECG are frequently encountered in the poisoned patient presenting to the ED. The range of abnormalities in the poisoned patient is potentially great, including both rhythm and P-QRS-T cycle morphological abnormalities [4-6].

In the poisoned patient, the ECG is used in 2 forms-the electrocardiographic rhythm strip and the 12-lead ECG. The ECG is used in the ED to establish the diagnosis, assess for end-organ toxicity, and guide therapeutic interventions. Patients presenting with significant cardiotoxicity mani- fested by dysrhythmia are assessed with the electrocardio- graphic monitor-essentially, a diagnosis of the rhythm. “Stable” patients are commonly evaluated with the 12-lead ECG-which considers not only the rhythm but also various abnormalities, potentially indicative of ingestion.

The 12-lead ECG has been studied in relation to specific abnormalities that serve as diagnostic clue in the character-

ization of an unknown ingestion. For instance, prolongation of the QRS complex along with an rSR? wave in Lead aVR suggests Sodium channel blocker toxicity (ie, tricyclic antidepressant overdose), whereas QTc interval prolongation and a Torsades de pointes arrhythmia suggest poisoning by a potassium efflux blocking agent (ie, phenothiazine toxicity). As a result of this conclusion that electrocardiographic abnormalities can guide the diagnostic workup of an unknown ingestion, it is now routine in many EDs to obtain a 12-lead ECG as part of the initial workup of a patient with a potentially toxic ingestion. The diagnostic impact in the potentially poisoned patient, however, has not been inves- tigated-in fact, little clinical information is found in the literature to address the general use of the ECG in the poisoned patient.

As such, we explored the association of cardiovascular toxins and electrocardiographic abnormalities in poisoned patients. The study occurred in the ED of a university teaching hospital with approximately 600 inpatient beds and an annual ED census of 60 000 patients. Patients entered in the study were ED patients, seen within 6 hours of ingestion, and managed by the toxicology service over an 18-month period. The ECGs were reviewed for both rhythm and morphological diagnoses by 5 clinicians, composed of 4 emergency physicians and one cardiologist. Intervals and durations were also measured using the ECG machine- provided measurements-the majority opinion prevailed as the final study interpretation in each category. Electrocardio- gram abnormality was scored using a point system. Each abnormality was given a score of 1; the patient’s ECG abnormality score was a summation of these assigned points. The toxins were identified and considered either a cardio- vascular toxin or cardiovascular nontoxin. A total number of cardiovascular (CV) toxins were identified for each patient presentation. The study was considered retrospective and therefore exempted by the institution’s internal review board. In this study, we reviewed 624 ED patients who were seen by the medical toxicology service; 277 (44%) patients underwent ECG and were used for data analysis. The mean age of study patients was 35.4 years with a range of 0.8 to 84 years. The mean number of toxins per patient in the study group was 1.9 (range, 1-5) toxins; considering CV toxins per patient, the mean number of CV toxins was 0.5 (range, 0-3). One hundred twenty-three (68%) patients demonstrated an Abnormal ECG. Electrocardiogram abnormality was rarely encountered in patients without CV toxin poisoning (P =

.0007). Electrocardiogram abnormality was associated with ingested CV toxin (P b .0001). The degree of abnormality was associated with increasing numbers of ingested CV toxins (P b .0001).

Of the abnormal ECG findings, 62% had a rhythm abnormality and 38% had a morphological abnormality. Rhythm disturbances (Fig. 1) included sinus tachycardia (47%), Sinus bradycardia (6%), atrioventricular block (4%), nonsinus atrial tachycardia (3%), and nodal bradycardia (3%). Morphological abnormalities (Fig. 2) included