Lit Bits: June 19, 2008

From the recent medical literature...

1. Sensitivity of Noncontrast Cranial CT for the ED Diagnosis of Subarachnoid Hemorrhage

Byyny RL, et al. Ann Emerg Med 2008;51:697-703.

Study objective
Emergency physicians use noncontrast cranial computed tomographic (CT) imaging of headache patients to identify subarachnoid hemorrhage caused by aneurysms or arteriovenous malformations. Given sufficiently high sensitivity, CT imaging could be used as a definitive diagnostic study in these patients. The purpose of this study is to determine the sensitivity of noncontrast cranial CT in detecting all spontaneous subarachnoid hemorrhages and those caused by aneurysm or arteriovenous malformation.

Methods
This was a retrospective review performed at an urban tertiary academic emergency department (ED). Using a combination of noncontrast cranial CT radiology coding, lumbar puncture results, International Classification of Diseases, Ninth Revision discharge diagnosis, and medical record review, we identified all patients who presented to a tertiary care academic ED from August 1, 2001, to December 31, 2004, with spontaneous subarachnoid hemorrhage. We determined whether patients were diagnosed by cranial CT or lumbar puncture, the presence of headache and level of consciousness at ED presentation, and whether or not they had an aneurysm or arteriovenous malformation.

Results
We identified 149 patients who were diagnosed with spontaneous subarachnoid hemorrhage during the study period. Noncontrast cranial CT scan diagnosed 139 patients, and 10 were diagnosed with lumbar puncture. This yielded an overall CT scan sensitivity of 93% (95% confidence interval [CI] 88% to 97%). Of the 149 with subarachnoid hemorrhage, 117 (79%) had aneurysm or arteriovenous malformation; cranial CT scan demonstrated subarachnoid hemorrhage in 110 of the 117, for a sensitivity of 94% (95% CI 88% to 98%). For the 67 patients presenting with headache and normal mental status who had a subarachnoid hemorrhage and vascular lesions (either aneurysm or arteriovenous malformation), the sensitivity of cranial CT scan was 91% (95% CI 82% to 97%).

Conclusion
Noncontrast CT imaging exhibits inadequate sensitivity to serve as a sole diagnostic modality in detecting spontaneous subarachnoid hemorrhage caused by aneurysm or arteriovenous malformation.

2. Is the Combination of Negative CT Result and Negative LP Result Sufficient to Rule Out SAH?

Perry JJ. Ann Emerg Med; 2008;51:707-7134.

Study objective
Current clinical practice assumes a negative computed tomography (CT) head scan result and a negative lumbar puncture result together are adequate to rule out subarachnoid hemorrhage in patients with acute headache. Our objective is to determine the sensitivity of a negative CT result combined with a negative lumbar puncture result to exclude subarachnoid hemorrhage.

Methods
This prospective cohort study was conducted at 2 tertiary care emergency departments (EDs) during 3 years. We enrolled all patients who were older than 15 years, had a nontraumatic acute headache and normal neurologic examination result, and who had a CT head scan and a lumbar puncture if the CT result was negative (ie, no blood in the subarachnoid space). Patients were followed up with a structured telephone questionnaire 6 to 36 months after their ED visit and electronic hospital records review to ensure no missed subarachnoid hemorrhage. We calculated sensitivity, specificity, and likelihood ratios of the strategy of CT and then lumbar puncture for subarachnoid hemorrhage.

Results
Five hundred ninety-two patients were enrolled, including 61 with subarachnoid hemorrhage. The mean patient age was 43.6 years, with 59.1% female patients. All cases of subarachnoid hemorrhage were identified on initial CT or lumbar puncture. One patient without subarachnoid hemorrhage was subsequently diagnosed with cerebral aneurysm, requiring surgery. The strategy classified patients with subarachnoid hemorrhage with sensitivity, specificity, and positive and negative likelihood ratios (with 95% confidence intervals [CIs]) of 100% (95% CI 94% to 100%), 67% (95% CI 63% to 71%), 3.03 (95% CI 2.69 to 3.53), and 0. For diagnosis of subarachnoid hemorrhage or aneurysm, these were 98% (95% CI 91% to 100%), 67% (95% CI 63% to 71%), 2.98 (95% CI 2.63 to 3.38), and 0.02 (95% CI 0.00 to 0.17), respectively.

Conclusion
To our knowledge, this is the largest prospective study evaluating the accuracy of a strategy of CT and lumbar puncture to rule out subarachnoid hemorrhage in alert ED patients with an acute headache. This study validates clinical practice that a negative CT with a negative lumbar puncture is sufficient to rule out subarachnoid hemorrhage.

3. Mild Hypothermia Therapy Subject of Comprehensive Lancet Review Article

Caroline Cassels. June 17, 2008 — Growing evidence for the use of mild hypothermia therapy, which is cooling of the body from 37°C to 32 to 35°C to prevent or mitigate permanent neurologic damage from a variety of causes, is the subject of a comprehensive review article in the June 7 issue of The Lancet.

Written by Kees H. Polderman, MD, of the University Medical Centre Utrecht, in Utrecht, the Netherlands, the article provides clinicians with an overview of the growing body of evidence supporting the use of mild hypothermia for a variety of indications including fever control, traumatic brain injury (TBI), ischemic stroke, and acute myocardial infarction (MI), among others.

Dr. Polderman points out that neurologic injuries are an important cause of morbidity and mortality. In particular, TBI is a leading cause of death and neurologic disability in young people.

In addition, he also notes that subarachnoid hemorrhage and ischemic stroke frequently result in severe disability and death and notes that only 10% to 20% of patients who have postanoxic encephalopathy as a result of cardiac arrest leave the hospital with no substantial neurologic impairment.

Given the growing body of evidence supporting hypothermia as "a highly promising treatment in neurocritical care," it is, "likely that physicians caring for patients with neurological injuries, both in and outside the intensive care unit, are likely to be confronted with questions about temperature management more frequently."

For the past 15 years, hypothermia therapy has been tested in many neurologic emergencies. However, although some studies have provided clear evidence of its protective effects, others have yielded mixed or conflicting results.

Current evidence, writes Dr. Polderman, suggests that hypothermia may be more effective the sooner it is applied, which could translate into better outcomes if the treatment is applied in the ambulance or in the emergency department.

He also notes that fever, regardless of the cause, has the potential to contribute to adverse neurologic outcomes. Therefore, he suggests that there may be a role for hypothermia therapy outside of the intensive care unit in high-dependency or general hospital wards.

More research to establish optimum depth and duration of cooling is needed. In particular, writes Dr. Polderman, the rate of rewarming seems to be an important factor in establishing successful use of hypothermia in the treatment of neurologic injuries and requires additional investigation.

"Hypothermia remains widely underused in many countries, especially in the USA [United States of America] and (to a lesser extent) the UK [United Kingdom] and Germany; therefore, applying the existing evidence and working on implementation strategies should be a priority," he concludes.

Dr. Polderman has disclosed no relevant financial relationships.

Lancet. 2008;371:1955-1969. Abstract: http://www.thelancet.com/journals/lancet/article/PIIS0140673608608375/abstract

4. MRSA Main Cause of S. Aureus Community Pneumonia During Flu Season

By Anthony J. Brown, MD

NEW YORK (Reuters Health) Jun 06 - During the 2006 to 2007 influenza season in the US, 79% of community-acquired pneumonia cases caused by Staphylococcus aureus were due to MRSA, according to a report in the June 3rd online issue of the Annals of Emergency Medicine.

Many of the cases occurred with or after influenza and often involved otherwise healthy young people, according to the report. Just over half of the cases proved fatal.

"I think the most interesting findings were the large proportion (of cases) that were MRSA, the large number that were not empirically treated for this organism and the potential association between co-infection with influenza and a worsened outcome," lead author Dr. Alexander J. Kallen, from the Centers for Disease Control and Prevention in Atlanta, told Reuters Health.

A number of S. aureus community-acquired pneumonia cases reported to public health authorities in early 2007 led Dr. Kallen's team to seek out additional case reports nationwide, in an effort to better characterize the cases seen during the 2006 to 2007 influenza season. The study period ran from November 1, 2006 to April 30, 2007.

A total of 51 cases were identified in 19 states, of which 47 had known susceptibility results, the authors note. The median patient age was 16 years; 44% had no history of pertinent medical problems. Twenty-four (51%) patients died at a median of 4 days after symptom onset.

Thirty-seven (79%) of the 47 cases were due to MRSA, the report indicates. Just 16 (43%) of MRSA-infected patients were treated empirically with recommended antimicrobial agents.

In 22 (47%) of the 47 cases, the S. aureus infection arose during or after a viral infection. Influenza infection was confirmed in 11 (33%) of 33 patients who were tested.

"The main take-home messages for clinicians," Dr. Kallen said, "are that this disease (S. aureus pneumonia with onset in the community, including MRSA) is seen during the winter months, it can be severe, and it should be considered in people presenting with pneumonia during the winter."

He added, "Obviously consideration should be given to influenza vaccination for those who may wish to increase their chances of avoiding influenza and its potential complications."

Ann Emerg Med 2008. In press. Abstract: http://www.annemergmed.com/article/S0196-0644(08)00773-7/abstract

5. Sonography May be Useful as the First Imaging Study for Suspected Appendicitis

NEW YORK (Reuters Health) May 29 - Color Doppler ultrasound should be the first imaging examination in adult patients with suspected acute appendicitis, according to a study in Israel. The authors recommend that computed tomography be reserved for patients with inconclusive findings on ultrasound and for those with classical signs and symptoms for whom clinical suspicion remains high.

Dr. Diana E. Gaitini, at Rambam Health Care Campus in Haifa, and her colleagues evaluated the accuracy of color Doppler sonography and contrast-enhanced multidetector computed tomography (CT) in 420 consecutive adult patients presenting with lower abdominal pain. They report their findings in the May issue of the American Journal of Roentgenology.

Their study encompassed the period from January 2003 to June 2006. The patients had been referred from the emergency department to sonography examination for suspected acute appendicitis. CT was performed in 132 patients when sonography findings were inconclusive or when there was a discrepancy between the clinical diagnosis and the sonography results.

Ultrasound correctly diagnosed appendicitis in 66 of 75 cases and correctly ruled out acute appendicitis in 312 of 326 cases. Sensitivity was 74.2% and specificity was 97%.

CT was inconclusive in only one case. It correctly diagnosed acute appendicitis in 38 of 39 patients and correctly ruled it out in the remaining 92 cases, yielding a sensitivity of 100% and specificity of 98.9%.

Alternative gynecologic, urologic, and gastroenterologic diagnoses were made in 82 patients who underwent ultrasound and in 42 patients who underwent CT.

Among 97 patients who underwent surgery for appendicitis, the appendix was normal in two. Five other patients underwent surgery for alternative diagnoses, which were confirmed.

"Lack of radiation exposure, especially significant in a population of mostly young patients, higher availability, and lower cost are the main reasons for trying sonography first," Dr. Gaitini's group recommends.

However, they advise that, "because of the relatively high false-negative rate, sonography should not be used to exclude acute appendicitis in patients with a high clinical suspicion based on classical signs and symptoms, and CT examination is warranted in these selected cases."

Am J Roentgenol 2008;190:1300-1306.

6. Algorithm Could Reduce Cranial CT in Minor Pediatric Head Trauma

NEW YORK (Reuters Health) May 26 - A new clinical decision rule with nearly 100% accuracy in ruling out intracranial injury in minor pediatric head trauma may help reduce unnecessary cranial CTs, a multicenter team of physicians reports.

Dr. Shireen M. Atabaki, at Children's National Medical Center in Washington, DC, and colleagues at four level 1 pediatric trauma centers conducted a prospective observational study of 1000 pediatric patients (mean age 8.9 years) with minor closed-head trauma undergoing cranial CT. Sixty-five (6.5%) had positive findings on CT, and six of these patients required neurosurgical intervention.

"Recursive partitioning resulted in the following rule for optimal prediction of intracranial injury: dizziness, sensory deficit, Glasgow Coma Scale score less than 15, mental status change, bicycle-related injury, age younger than 2 years, skull defect on examination, and evidence of a basilar skull fracture (Battle sign, rhinorrhea, hemotympanum, periorbital ecchymosis, or cerebrospinal fluid otorrhea)," the investigators report in the May issue of the Archives of Pediatrics and Adolescent Medicine.

The decision rule for detection of intracranial injury had a sensitivity of 95.4%, a specificity of 48.9%, and a negative predictive value of 99.3%.

In comparison, the sensitivity of clinicians' predictions of intracranial injury based on history and physical examination was 14.8%.

Dr. Atabaki and associates don't advise "blind application of the rule to all patients with minor head trauma." Instead, they recommend that it be used as "an additional tool to guide clinicians who are considering cranial CT in a child with minor head trauma."

The researchers also urge clinicians to continue follow-up for patients who are symptomatic despite negative CT findings. Eventually, they hope, "functional imaging and psychometric testing may replace CT for the assessment of the child with minor head trauma."

Arch Pediatr Adolesc Med 2008;162:439-445.

7. Corticosteroids reduce recurrence of ED Migraine

Evans RW. BMJ 2008;336:1320

In the accompanying systematic review, Colman and colleagues assess the effectiveness of parenteral corticosteroids for treating acute severe migraine and preventing recurrence. In Western Europe and the United States, about 12% of adults experience migraine each year, and 63% of these people have one to four migraines a month. Most people have nausea and moderate to severe pain, which results in severe impairment or requires bed rest, and one third have vomiting. If untreated, these headaches last for four to 72 hours, with a median duration of 24 hours.

In the US, only 56% of affected patients have received a medical diagnosis of migraine and instead believe that they have sinus, tension, or stress headache. About half of these people use over the counter drugs, which are effective in up to 59% of cases. But even with seven different types of triptans and various ways of giving them, 25% of patients do not respond.

When triptans are initially effective, the pain recurs in up to 40% of instances and a second dose may not be effective or not taken. All drugs for symptomatic migraine are more effective if taken when the pain is mild. However, patients often delay taking drugs, or they sometimes wake from sleep with intense pain or cannot retain the drug because of vomiting. As the pain progresses, central sensitisation can cause cutaneous allodynia (pain provoked by stimulation of the skin that would ordinarily not produce pain; this is seen especially in the head and face, but it can also be generalised) and triptans are unlikely to be effective.

Not surprisingly, people with migraine often seek help in the emergency department, where they account for around 2% of visits and may receive a less than warm welcome when they present with "just a headache." This challenging group of people is made up of those with their first or worst attacks, those who have not taken or not responded to drugs, frequent attendees, those with acute exacerbation of chronic migraine, and those with migraine with neurological symptoms and signs (with aura).

In the emergency department, evidence based guidelines recommend the first line use of dihydroergotamine, subcutaneous sumatriptan, dopamine antagonists (metoclopramide, prochlorperazine, and chlorpromazine), and ketorolac, which have response rates of up to 70%. However, narcotic analgesics, recommended as rescue drugs, are still widely used, even though their administration may result in significantly longer stays in the emergency department compared with non-narcotic treatments.

Migraine pain persists or recurs within 24 hours of discharge from the emergency department regardless of treatment in over half of patients. Animal studies suggest that migraine pain may be caused by sterile inflammation in the nerves, which is why it was proposed that corticosteroids might reduce inflammation, relieve the pain, and prevent recurrence.

In their meta-analysis, Colman and colleagues included seven randomised controlled trials (n=738) of intravenous dexamethasone (10-24 mg given once) for treatment of acute severe migraine headache and for preventing recurrence. There was no significant difference between dexamethasone and placebo for the immediate relief of acute migraine (weighted mean difference 0.37, 95% confidence interval –0.20 to 0.94). However, when added to standard treatment, intravenous dexamethasone significantly reduced headache within 72 hours (relative risk 0.74, 0.60 to 0.90). Nine patients need to be treated to prevent one recurrent headache, a modest response.

Although side effects were minor and similar between groups, repeated doses in regular attendees to the emergency department may increase the long term risk for osteoporosis or, rarely, aseptic osteonecrosis of the femoral head or knees. Caution should be used when treating people with diabetes, who may have raised blood sugars during the 36-72 hour half life of dexamethasone.

Future research on corticosteroids might clarify the interaction with other drugs used to treat migraine; the optimum dose; whether oral administration is effective; and whether subgroups of people, such as those with prolonged severe headaches, may benefit in particular.

For now, we should try to keep patients out of the emergency department by encouraging them to treat their symptoms early on; making triptans, antiemetics, and rescue drugs more available as appropriate; and prescribing preventive drugs. An oral antagonist of calcitonin gene related protein, which may be available in the next couple of years, might provide better sustained pain-free responses at 24 hours than triptans. However, its use depends on regulatory approval and an acceptable safety profile, and it is unclear how effective it will be in people who do not respond to triptans. Doctors and migraine advocacy groups should lobby for increased government funding for migraine research, which, annually, is only about $13m (£6.5m; 8.2m) in the United States and 6 million in Europe.

Colman article (full-text): http://www.bmj.com/cgi/content/full/336/7657/1359

8. Clot aspiration during PCI saves lives as well as myocardium

Vlaar PJ, et al. Lancet 2008;371:1915–20.

Earlier this year, a team of researchers reported that aspirating clots from blocked coronary arteries improves early myocardial perfusion after a heart attack, compared with conventional percutaneous coronary intervention (PCI) without aspiration. The one year results are now available and show a fall in the risk of cardiac death for patients treated with aspiration (3.6% (19/535) v 6.7% (36/356); P=0.02). Clot aspiration was also associated with fewer deaths from all causes (4.7% (25/535) v 7.6% (41/536); P=0.042) and a lower risk of reinfarction (2.2% (12/535) v 4.3% (23/536); P=0.05).

These results are good news for people having primary PCI after a heart attack, says a linked comment. The follow-up data from this landmark trial provides the first convincing evidence that clot aspiration can save lives as well improve perfusion. Aspiration catheters are cheap and easy to use, and they should soon feature in clinical guidelines. In the meantime, researchers must continue to look for other strategies that might enhance reperfusion after a technically successful PCI. Even after clot aspiration only 56.6% of the patients in this trial had normal ST segments on electrocardiography performed after PCI.

9. CTA in the ED Can Safely and Effectively Screen for Acute Coronary Syndrome

Laurie Barclay, MD. From Heartwire — a professional news service of WebMD

June 3, 2008 — Findings from a new study suggest that computed tomography angiography (CTA) safely and effectively stratifies high- and low-risk patients admitted to the emergency room for chest pain [1]. Investigators screened patients admitted to the emergency room for acute coronary syndrome using high-resolution CTA and showed that negative scans were a quick and accurate way of identifying patients who were safe to be discharged from the hospital.

"If you look at the literature, CTA is a relatively new technology," said lead investigator Dr Anna Marie Chang (University of Pennsylvania, Philadelphia). "Most people aren't using it in the emergency department to make decisions about the patient. Most people using it in this way are still testing it out, trying to see if it's okay, but we're using CTA in the low-risk patient. These are patients who traditionally would come into the emergency department and we'd have to admit them to the hospital or send them to observation unit before they could be sent home. Now we can send them home immediately from the emergency department."

The results of the study were presented here at the Society of Academic Emergency Medicine (SAEM) 2008 Annual Meeting.

Cutting costs by sending low-risk patients home

Speaking with heartwire, Chang said that approximately 5% to 15% of individuals admitted to the hospital for chest pain have an acute coronary syndrome, but more than half of these patients are admitted to the hospital for observation and further testing. While previous studies have traditionally compared CTA with other ACS screening protocols to determine how well it stacked up against these traditional tests, Chang and colleagues wanted to determine whether CTA could be used clinically to quickly and accurately determine whether patients could be discharged.

Investigators evaluated 568 patients with chest pain admitted to the Hospital of the University of Pennsylvania for acute coronary syndromes. Of these patients, 285 received CTA immediately in the emergency department and 283 received coronary CTA after a brief observation period. Overall, 84% of patients were discharged home following coronary CTA.

Investigators report that negative scans were accurate and allowed investigators to safely discharge patients from the hospital. Thirty days after discharge, none of 285 patients who received a coronary CTA immediately in the emergency department and were discharged died from cardiac causes, had an MI [myocardial infarction], or returned to the hospital for revascularization.

In terms of cost, Chang and colleagues report that CTA is more cost-effective than traditional methods of identifying at-risk patients [2]. In another study of 643 patients, also presented at the SAEM meeting, investigators compared the costs of receiving CTA in the emergency room with the costs associated with CTA following time in an observation unit, as well as with the costs of stress tests and telemetry monitoring following hospital admission.

The cost of screening with immediate CTA in the emergency room was $1240, while the cost of stress testing, measuring serial biomarkers, and monitoring in the observation unit was more than $4000 per patient. The cost of usual care, defined as admission with serial biomarkers and hospital-directed evaluation, was $2913. Among these low-risk patients without ACS, immediate CTA helped discharge patients faster, with these patients discharged an average of eight hours following admission. Those who were screened with stress testing and received telemetry monitoring were kept, on average, 24 hours.

"Not only is it a safe test, but it's less expensive," said Chang. "Patients are getting out of the emergency department much faster, which is important because of issues related to overcrowding. If a patient can leave the department in eight hours rather than 20 hours or more while waiting for a bed, this can free up more time for us to see other patients."

Chang told heartwire that if a hospital has the technology and the hospital administration is supportive of CTA in the emergency department, with radiologists trained in cardiac imaging to read the CTA scan, the test can routinely be used in clinical practice.

She noted there is currently a debate about reimbursement, with the Center for Medicare & Medicaid Services voting in November 2007 to not reimburse CTA use in the emergency room, although this decision was overturned. As previously reported by heartwire, all 50 individual US states already provide Medicare coverage for patients undergoing cardiac CTA under local coverage determinations, but the overturned federal policy decision would have limited Medicare coverage of a diagnostic CT to just two indications and only in cases where the patient was enrolled in a clinical trial of cardiac CT.

Sources

1. Chang AM et al. Coronary computerized tomography for rapid discharge of low-risk patients with potential acute coronary syndromes, Society of Academic Emergency Medicine 2008 Annual Meeting; May 29-June 1, 2008; Washington, DC.

2. Chang AM et al. Actual financial comparison of four strategies to evaluate patients with potential acute coronary syndromes. Society of Academic Emergency Medicine 2008 Annual Meeting; May 29-June 1, 2008; Washington, DC.

10. New Practice Parameter for Benign Paroxysmal Positional Vertigo

May 30, 2008 — The American Academy of Neurology's Quality Standards Subcommittee has released a new practice parameter to guide the treatment of benign paroxysmal positional vertigo (BPPV).

After their evidence-based review, the authors give a level-A recommendation to the use of the canalith-repositioning procedure (CRP), concluding that it is safe and highly effective to treat patients of all ages with posterior BPPV, which makes up about 90% of cases.

The procedure is "not difficult to do, it doesn't require any special equipment, and it has a high effectiveness rate and essentially no complications," corresponding author Terry Fife, MD, from the Barrow Neurological Institute and University of Arizona College of Medicine, in Phoenix, told Medscape Neurology & Neurosurgery.

"I think the idea now is to try to get the word out to primary-care physicians who see people in their offices and emergency departments, so that people don't end up getting brain scans or admissions for this simple-to-treat condition," he said.

Converging Evidence

BPPV is characterized by brief recurrent episodes of vertigo triggered by changes in head position with respect to gravity, the authors write. The problem usually arises from abnormal stimulation of the cupula by otoliths, or crystals of calcium carbonate, that are present in 1 of the 3 semicircular canals: the posterior, horizontal, and anterior. The most common form, posterior semicircular canal BPPV, is caused by otoliths from the macula of the utricle falling into the posterior canal; these ectopic otoliths, called canaliths, move within the canal in response to gravity when the head is moved, resulting in a burst of vertigo and nystagmus.

A number of repositioning procedures have been developed to help move these canaliths into the vestibule, where they can be absorbed, but they lack standardization, the authors note. The current practice parameter is an evidence-based review of the literature on these maneuvers, which also looked at other questions such as the necessity of postmaneuver restrictions and patient self-administered exercises.

Their major conclusions include:

For posterior semicircular canal BPPV, they give a level-A recommendation that CRP should be offered as a safe and effective therapy to patients of all ages. The Semont maneuver is possibly effective, they note, but receives only a level-C recommendation because it is based on only 1 class 2 study. "There is insufficient evidence to establish the relative efficacy of the Semont maneuver to CRP," the authors write.

For horizontal canal BPPV, they conclude that, based on class 4 studies, variations of the Lempert supine roll maneuver, the Gufoni method, or forced prolonged positioning seem "moderately effective" for this type of BPPV. "The bottom line is that the jury is still out on the best treatment for that particular variation," Dr. Fife noted.

For anterior canal BPPV, 2 uncontrolled class 4 studies report high response rates to maneuvers, the authors note. However, Dr. Fife points out that this type of BPPV is uncommon and, unlike particular the posterior canal BPPV, often resolves on its own.
The document also touches on drug and surgical treatments. They conclude that there is no evidence that any drug treatment is useful, and surgical treatments, while possibly effective in some retrospective, class 4 studies, are rarely required with the efficacy of CRP, Dr. Fife noted.

For future research, they recommend that more class 1 studies be undertaken to clarify the best treatments for horizontal canal BPPV.

"One of the things we hope for this is that physicians who are motivated will go through and learn how to do these treatments and offer them to their patients," Dr. Fife concluded. "There's no reason you couldn't treat the patient and have them walk out of the room free of vertigo and on their way, instead of giving them a sheet of exercises to muddle through on their own, doing some sort of scan, or referring them to some other person for evaluation and referral."

Dr. Fife reports he has received research support from GlaxoSmithKline and estimates that 6% of his time is spent on canalith-repositioning procedures. Disclosures for the coauthors appear in the paper.

Neurol. 2008;70:2067-2074. Full-text: http://www.neurology.org/cgi/content/full/70/22/2067

11. Etomidate: Safe for Septic Patients? Pro and Con

Ann Emerg Med Editor's note: Because it exhibits many favorable characteristics, including rapid onset, minimal respiratory depression, and preservation of hemodynamic stability, etomidate has frequently been used as an induction agent for endotracheal intubation of septic patients. This practice has recently been questioned in light of studies demonstrating that even a single dose of etomidate may interfere with cortisol production and produce relative adrenal insufficiency in critically ill patients. In this installment of Clinical Controversies, pro and con advocates present opposing perspectives and discuss the available evidence and arguments that must be considered in deciding to embrace or abandon the use of etomidate as an induction agent for endotracheal intubation of septic patients.

Yes, it’s safe

Walls RM, Murphy MF. Clinical Controversies: Etomidate as an Induction Agent for Endotracheal Intubation in Patients With Sepsis: Continue to Use Etomidate for Intubation of Patients With Septic Shock. Ann Emerg Med. 2008;52:13-14.

Their conclustion: ‘According to the supporting evidence, including that cited above, calls for a ban on etomidate for intubation in sepsis are not justified. Finfer states, “Perhaps the greatest service we can do our patients is to conduct the large, high-quality trials needed to base our clinical practice on truly robust evidence.” Etomidate opponents should advocate such a properly designed, randomized trial, lest they cause further harm by forcing those of us charged with resuscitation of these vulnerable patients to use agents much more likely to disturb their fragile hemodynamic balance, with potentially fatal consequences.’

Subscribers: Full-text: http://www.annemergmed.com/article/S0196-0644(08)00488-5/fulltext

No, it’s not safe.

Sacchetti A. Etomidate: Not Worth the Risk in Septic Patients. Ann Emerg Med. 2008;52:14-16.

His Conclusion: ‘Etomidate's use could be justified if no acceptable alternatives existed. However, emergency physicians have multiple options for sedation during intubation, and limiting rapid sequence intubation choices to a single agent should be no more acceptable than restricting physicians to a single antiarrhythmic or antibiotic. In normotensive patients, drugs such as propofol, methohexital, thiopental, and even midazolam are realistic sedative/induction agents. In the more common hypotensive septic patient, ketamine may be the most appropriate rapid sequence intubation agent. In addition to providing hemodynamic stability during the intubation procedure, there is a growing body of experimental evidence suggesting that ketamine exerts a protective anti-inflammatory effect against the sepsis process itself.

‘Future evidence-based studies may ultimately prove that etomidate is a safe agent in septic patients requiring endotracheal intubation. However, given the information currently available, it is difficult to justify the use of this agent in any critically ill patients whose long-term survival is directly linked to the performance of their adrenal glands.’

Subscribers: Full-text: http://www.annemergmed.com/article/S0196-0644(08)00004-8/fulltext

12. The Maple Leaf Model: What Canada Can Tell American Emergency Physicians About Practice With Universal Coverage

Cearnal L. Ann Emerg Med. 2008;52:19-21.

With political momentum seeming to build toward some sort of system that will extend health coverage to everyone, doctors in the US might be expected to be curious about how it might affect them. Though what form such “reform” might take is anyone's guess, emergency physicians in the US have a universal coverage model close by that might offer some comparisons and contrasts.

Everyone in Canada is covered by health insurance, paid for by the government, or more properly, the federal, provincial and territorial governments jointly. But what effect does the system of reimbursement have on clinical practices, diagnostics, pay, work frustrations and other areas?

The answer—based on interviews with several prominent doctors familiar with emergency medicine on both sides of the border—seems to be: not so much. In Canada, it all depends on where you work; but the same is true across the US. The payment mechanism is different, but the pay for emergency physicians seems to be similar. In Canada, most doctors submit bills for services to an insurance payer, and the bill is usually paid without much of the hassle seen in the US. But in some provinces, such as Ontario, they are salaried, at a rate that has to be periodically negotiated with the provincial government…

Full-text (free): http://www.annemergmed.com/article/S0196-0644(08)00847-0/fulltext

13. Independent Evaluation of an Out-of-hospital Termination of Resuscitation (TOR) Clinical Decision Rule

Richman PB, Acad Emerg Med. 2008;15:517-521.

Objectives: Recently, investigators described a clinical decision rule for termination of resuscitation (TOR) designed to help determine whether to terminate emergency medical services (EMS) resuscitative efforts for out-of-hospital cardiac arrests (OOHCA). The authors sought to evaluate the hypothesis that TOR would predict no survival for patients in an independent cohort of patients with OOHCA.

Methods: This was a retrospective cohort analysis conducted in the state of Arizona. Consecutive, adult, OOHCA were prospectively evaluated from October 2004 through October 2006. A statewide OOHCA database utilizing Utstein-style reporting from 30 different EMS systems was used. Data were abstracted from EMS first care reports and hospital discharge records. The TOR guidelines predict that no survival to hospital discharge will occur if 1) an OOHCA victim does not have return of spontaneous circulation (ROSC), 2) no shocks are administered, and 3) the arrest is not witnessed by EMS personnel. Data were entered into a structured database. Continuous data are presented as means (±standard deviations [SD]) and categorical data as frequency of occurrence, and 95% confidence intervals (CIs) were calculated as appropriate. The primary outcome measure was to determine if any cohort member who met TOR criteria survived to hospital discharge.

Results: There were 2,239 eligible patients; the study group included 2,180 (97.4%) patients for whom the data were complete; mean age was 64 (±11) years, and 35% were female. The majority of patients in the study group met at least one or more of the TOR criteria. A total of 2,047 (93.8%) patients suffered from cardiac arrest that was unwitnessed by EMS; 1,653 (75.8%) had an unwitnessed arrest and no ROSC. With respect to TOR, 1,160 of 2,180 (53.2%) patients met all three criteria; only one (0.09%; 95% CI = 0% to 0.5%) survived to hospital discharge.

Conclusions: The authors evaluated TOR guidelines in an independent, statewide OOHCA database. The results are consistent with the findings of the TOR investigation and suggest that this algorithm is a promising tool for TOR decision-making in the field.

14. The Role of Oral Ondansetron in Children With Vomiting as a Result of Acute Gastritis/Gastroenteritis Who Have Failed Oral Rehydration Therapy: A RCT

Roslund G, et al. Ann Emerg Med. 2008;52:22-29.e6

Study objective
We hypothesize that ondansetron will facilitate oral rehydration therapy in children with acute gastritis or acute gastroenteritis and mild to moderate dehydration who fail initial oral rehydration therapy. We hypothesize that subjects receiving ondansetron will tolerate oral rehydration and that a lower proportion will require intravenous hydration than subjects receiving placebo, with a clinically important difference of at least 30% when comparing 2 groups of patients presenting to the ED with acute gastritis/acute gastroenteritis. Secondarily, we hypothesize that subjects receiving ondansetron will have a lower proportion requiring admission, fewer episodes of vomiting and diarrhea, and fewer revisits.

Methods
This double-blind, placebo-controlled, prospective, randomized trial enrolled a convenience sample of subjects 1 to 10 years old, with acute gastritis or acute gastroenteritis, who failed oral rehydration therapy in the emergency department (ED). Subjects received a weight-based dose of ondansetron (0.15 mg/kg of the orally dissolving tablet) or placebo, and oral rehydration therapy was reattempted 30 minutes later. If a subject vomited or refused to drink, he or she was considered a failed oral rehydration therapy and received acute gastroenteritis. If a subject tolerated adequate oral rehydration therapy, he or she was discharged. Parents completed symptom diaries and were contacted by telephone for follow-up. We used the Chi-squared test to compare the proportions of subjects requiring acute gastroenteritis in each group.

Results
We enrolled 106 subjects: 51 received ondansetron and 55 received placebo. Eleven of 51 (21.6%; 95% confidence interval [CI] 11.3% to 35.3%) of subjects who received ondansetron required intravenous hydration and 30 of 55 (54.5%; 95% CI 40.6% to 68%) of placebo subjects required intravenous hydration (p less than 0.001) for a difference of 32.9% (95% CI 14.54% to 48.37%). Admission rates were 5.9% (3/51) with ondansetron and 12.7% (7/55) with placebo.

Conclusion
In subjects with acute gastritis/acute gastroenteritis and mild to moderate dehydration who failed initial oral rehydration therapy, the proportion of children who received intravenous hydration was smaller in the ondansetron group than in the placebo group.

Full-text (free): http://www.annemergmed.com/article/PIIS0196064407015466/fulltext

15. Career Satisfaction in Emergency Medicine: The ABEM Longitudinal Study of Emergency Physicians

Cydulka RK, et al. Ann Emerg Med. 2008;51:714-721.

Study objective
The primary objective of this study is to measure career satisfaction among emergency physicians participating in the 1994, 1999, and 2004 American Board of Emergency Medicine Longitudinal Study of Emergency Physicians. The secondary objectives are to determine factors associated with high and low career satisfaction and burnout.

Methods
This was a secondary analysis of a cohort database created with stratified, random sampling of 1,008 emergency physicians collected in 1994, 1999, and 2004. The survey consisted of 25 questions on professional interests, attitudes, and goals; 17 questions on training, certification, and licensing; 36 questions on professional experience; 4 questions on well-being and leisure activities; and 8 questions about demographics. Data were analyzed with a descriptive statistics and panel series regression modeling (Stata/SE 9.2 for Windows). Questions relating to satisfaction were scored with a 5-point Likert-like scale, with 1=not satisfied and 5=very satisfied. Questions relating to stress and burnout were scored with a 5-point Likert-like scale, with 1=not a problem and 5=serious problem. During analysis, answers to the questions “Overall, how satisfied are you with your career in emergency medicine?” “How much of a problem is stress in your day-to-day work for pay?” “How much of a problem is burnout in your day-to-day work for pay?” were further dichotomized to high levels (4, 5) and low levels (1, 2).

Results
Response rates from the original cohort were 94% (945) in 1994, 82% (823) in 1999, and 76% (771) in 2004. In 2004, 65.2% of emergency physicians reported high career satisfaction (4, 5), whereas 12.7% of emergency physicians reported low career satisfaction (1, 2). The majority of respondents (77.4% in 1994, 80.6% in 1999, 77.4% in 2004) stated that emergency medicine has met or exceeded their career expectations. Despite overall high levels of career satisfaction, one-third of respondents (33.4% in 1994, 31.3% in 1999, 31% in 2004) reported that burnout was a significant problem.

Conclusion
Overall, more than half of emergency physicians reported high levels of career satisfaction. Although career satisfaction has remained high among emergency physicians, concern about burnout is substantial.

16. CLEAR Result: Low-Dose tPA Safe, Effective in Treating Intraventricular Hemorrhage

May 15, 2008 (Nice, France) — Treatment of intraventricular hemorrhage (IVH) with catheter-based clot lysis using low-dose tissue plasminogen activator (tPA) is safe and dramatically reduces death and disability in individuals with this usually lethal condition.

Here at the 17th European Stroke Conference, investigators presented the final results of the Clot Lysis: Evaluating Accelerated Resolution of Intraventricular Hemorrhage (CLEAR-IVF) trial, showing that administration of 1-mg tPA every 8 hours to a maximum of 4 days reduced expected mortality by approximately 70% and resulted in a dramatic improvement in functional outcomes.

"At 30 days, the mortality rate in study subjects was 15%. Typically, the expected 30-day mortality in such patients is about 80% to 85%," study investigator Daniel F. Hanley, MD, told Medscape Neurology & Neurosurgery.

However, he added, the "real news" is that fact that over 30, 90, and 180 days, more than 40% of patients recovered to the point that they were able to live independently, a result that Dr. Hanley described as "phenomenal."

"With this type of devastating disease, there is always the consideration that even if you can save lives, are patients paying a price in terms of their quality of life? In this study, 40% of our subjects recovered to the point of living independently, and 10% were completely normal with no deficits. The most recent patient I saw has now returned to work," he said.

Counterintuitive Treatment?

According to Dr. Hanley, while the idea of using thrombolysis to treat hemorrhagic stroke may seem "counterintuitive," he pointed out that over the past 15 years there has been a large number of published case series suggesting the use of tPA for IVH is feasible and likely safe.

However, dose effect and dose safety remained unclear as well as the treatment's potential impact on outcome. Dr. Hanley said the CLEAR-IVH trial is the first multicenter, international prospective assessment of this treatment.

Building on previous research showing that low-dose tPA did not increase bleeding risk and that the treatment is more effective if the catheter used to deliver the drug is placed closer to the clot, the researchers embarked on the current phase 2 study to determine the safest and most effective regimen.

Developed by Dr. Hanley and colleagues, the procedure clears trapped blood by bathing — and dissolving — the clot directly in tPA in a system that is closed for 1 hour to allow the drug to interact with the clot. The system is then opened up to facilitate drainage of lysed clot materials.

The study included 52 patients from 20 centers in the United States, Canada, the United Kingdom, and Germany. All subjects had a confirmed diagnosis of IVH via CT scan with third or fourth ventricle obstruction.

Six-Hour Stability Period Crucial

A second CT scan was performed 6 hours after catheter placement to ensure that there was no ongoing bleeding before administration of the drug.

"This six-hour stability period is necessary to make sure there is no bleeding. After dose, I believe this is the single most important component in determining the safe use of this drug in this [clinical] situation," said Dr. Hanley.

Subjects received 1 of 3 regimens — 0.3 mg of the drug every 12 hours, 1 mg of the drug every 12 hours, or 1 mg of the drug every 8 hours.

Patients were monitored with daily CT scans, and the investigators found that clots dissolved on average within 3 to 4 days. Study subjects who received the 1-mg dose every 8 hours experienced dissolution of their clots an average of 1 day earlier than their counterparts on the other 2 regimens.

The investigators found symptomatic bleeding occurred at a rate of about 6% — a rate that was the same as that found in the placebo group in the investigators' prior trial. "There was no enhanced bleeding as a result of the procedure," said Dr. Hanley. Other complications included a 2% rate of bacterial ventriculitis.

Worldwide Applicability

Because the procedure is relatively simple, uses currently available technology, and requires no special training, the CLEAR-IVH approach could easily be applied worldwide, said Dr. Hanley.

"It requires a CT scan, a neurosurgeon to place a catheter, and a proper understanding of how to use a lower-dose thrombolytic. There's no particular special training required, although there are nuances in the daily reading of the CT scans," he said.

Despite these encouraging findings, Dr. Hanley said it is not yet clear whether this should be employed as a standard treatment for IVH, which affects about 50,000 Americans every year.

To answer this question, the investigators are planning a definitive, multicenter, randomized phase 3 trial that will include 500 patients and is expected to launch at the end of 2008 or early 2009.

"Our group is fully committed to testing the novel ideal that IVH clot-size reduction with thrombolysis decreases mortality and increases good outcome," said Dr. Hanley.

The study was supported by Johns Hopkins University, the FDA Office of Orphan Products Development, and Genentech.

17th European Stroke Conference. Presented May 14, 2008.

17. Strep pneumo Still Top Pathogen in Children with Bacterial Meningitis Presenting to the ED during the Pneumococcal Conjugate Vaccine Era

Nigrovic LE. Et al. Acad Emerg Med. 2008;15:522-528.

Background: The epidemiology of bacterial meningitis in children in the era of widespread heptavalent conjugate pneumococcal vaccination (PCV7) is unknown.

Objectives: The objective was to describe the epidemiology of bacterial meningitis in children presenting to the emergency department (ED) during the era of widespread PCV7 vaccination.

Methods: The authors retrospectively reviewed the medical records of all children aged 1 month to 19 years with bacterial meningitis who presented to the EDs of 20 U.S. pediatric centers (2001–2004). Bacterial meningitis was defined by a positive cerebrospinal fluid (CSF) culture for a bacterial pathogen or CSF pleocytosis (CSF white blood cell [WBC] count ≥10 cells/mm3) in association with either a positive blood culture or a CSF latex agglutination study.

Results: A total of 231 children with bacterial meningitis were identified. The median age was 0.6 years (interquartile range [IQR] = 0.2–4.2). Eight patients (3% of all patients) died. The following bacterial pathogens were identified: Streptococcus pneumoniae (n = 77; 33.3%), Neisseria meningitidis (67; 29.0%), Group B Streptococcus (42; 18.2%), Escherichia coli (17; 7.4%), nontypeable Haemophilus influenzae (10; 4.3%), other Gram-negative bacilli (7; 3.0%), Listeria monocytogenes (5; 2.2%), Group A Streptococcus (5; 2.2%), and Moraxella catarrhalis (1; 0.4%). S. pneumoniae serotypes were determined in 37 of 77 patients; of these, 62% were due to nonvaccine serotypes (including 19A).

Conclusions: Although now a rare infectious disease in United States, bacterial meningitis still causes substantial morbidity in affected children. Despite the introduction of PCV7, S. pneumoniae remains the most common cause of bacterial meningitis in U.S. children, with approximately half of cases due to nonvaccine serotypes.

18. Effect of Ondansetron on the Incidence of Vomiting Associated With Ketamine Sedation in Children: A Double-Blind, Randomized, Placebo-Controlled Trial

Langston WT, et al. Ann Emerg Med. 2008;52:30-34.

Study objective
We investigate the effect of ondansetron on the incidence of vomiting in children who receive intravenous (IV) ketamine for procedural sedation and analgesia in the emergency department (ED).

Methods
In this double-blind, randomized, placebo-controlled trial in a children's hospital ED, patients receiving IV ketamine (1 mg/kg) for ED procedures were randomized to receive either IV ondansetron (0.15 mg/kg; maximum 4 mg) or identical placebo. We recorded whether vomiting occurred in the ED postsedation or up to 12 hours after discharge with telephone follow-up and compared ED length of stay and parental satisfaction.

Results
One hundred twenty-seven children were randomized to placebo and 128 to ondansetron. The groups were similar in age, sex, and fasting duration. ED vomiting was less common with ondansetron: 6 of 128 (4.7%) versus 16 of 127 (12.6%), P=.02, difference 7.9% (95% confidence interval 1.1% to 14.7%), number needed to treat 13. Follow-up was successful in 82.7%, with vomiting in the ED or after discharge less frequent with ondansetron: 10 of 128 (7.8%) versus 24 of 127 (18.9%), P=.01, difference 11.1% (95% confidence interval 2.7% to 19.5%), number needed to treat 9. ED length of stay and parental satisfaction were similar between groups.

Conclusion
IV ondansetron significantly reduces the incidence of vomiting associated with IV ketamine procedural sedation in children.

19. The Utility of Supplemental Oxygen During ED Procedural Sedation With Propofol: A RCT

Kenneth Deitch K, et al. Ann Emerg Med. 2008;52:1-8.

Study objective
We determine whether supplemental oxygen reduces the incidence of hypoxia by 20% compared with breathing room air in adult study patients receiving propofol for emergency department procedural sedation.

Methods
Patients were randomized to receive either supplemental oxygen or compressed air by nasal cannula at 3 L per minute. Physicians were blinded to the gas used and end tidal CO2 (etco2) data. Respiratory depression was defined a priori as oxygen saturation less than or equal to 93%, an etco2 level of greater than or equal to 50 mm Hg, an absolute etco2 change from baseline of greater than or equal to 10 mm Hg, or loss of the etco2 waveform.

Results
Of the 110 patients analyzed, 56 received supplemental oxygen and 54 received room air. Ten (18%) patients in the supplemental oxygen group and 15 (28%) patients in the compressed air group experienced hypoxia (P=.3, effect size=10%, 95% confidence interval −24% to 7%). Twenty-seven patients (20 supplemental oxygen; 7 room air) met etco2 criteria for respiratory depression but did not become hypoxic. Physicians identified respiratory depression in 23 of 25 patients who developed hypoxia compared with only 1 of 27 patients who met etco2 criteria for respiratory depression but who did not have hypoxia. One patient in the supplemental oxygen group experienced a transient arrhythmia and had a short apneic episode, both of which resolved spontaneously. The patient was admitted for observation.

Conclusion
Supplemental oxygen (3 L/minute) trended toward reducing hypoxia in adult study patients; however, the 10% difference observed was not statistically significant and was below our a priori 20% threshold. Blinded capnography frequently identified respiratory depression undetected by the treating physicians.

Full-text (free): http://www.annemergmed.com/article/PIIS0196064407018598/fulltext

20. Use of a Standardized Order Set for Achieving Target Temperature in the Implementation of Therapeutic Hypothermia after Cardiac Arrest: A Feasibility Study

Kilgannon JH, et al. Acad Emerg Med. 2008;15:499-505.

Objectives: Induced hypothermia (HT) after cardiac arrest improved outcomes in randomized trials. Current post–cardiac arrest treatment guidelines advocate HT; however, utilization in practice remains low. One reported barrier to adoption is clinician concern over potential technical difficulty of HT. We hypothesized that using a standardized order set, clinicians could achieve HT target temperature in routine practice with equal or better efficiency than that observed in randomized trials.

Methods: After a multidisciplinary HT education program, we implemented a standardized order set for HT induction and maintenance including sedation and paralysis, intravenous cold saline infusion, and an external cooling apparatus, with a target temperature range of 33–34°C. We performed a retrospective analysis of a prospectively compiled and maintained registry of cardiac arrest patients with HT attempted (intent-to-treat) over the first year of implementation. The primary outcome measures were defined a priori by extrapolating treatment arm data from the largest and most efficacious randomized trial: 1) successful achievement of target temperature for more than 85% of patients in the cohort and 2) median time from return of spontaneous circulation (ROSC) to achieving target temperature less than 8 hours.

Results: Clinicians attempted HT on 23 post–cardiac arrest patients (arrest location: 78% out-of-hospital, 22% in-hospital; initial rhythm: 26% ventricular fibrillation/tachycardia, 70% pulseless electrical activity or asystole) and achieved the target temperature in 22/23 (96%) cases. Median time from ROSC to target temperature was 4.4 (interquartile range 2.8–7.2) hours. Complication rates were low.

Conclusions: Using a standardized order set, clinicians can achieve HT target temperature in routine practice.

21. Early Repolarization: Maybe Not So Benign After All

Sudden Cardiac Arrest Associated with Early Repolarization

Haïssaguerre M, et al. N Engl J Med. 2008;358:2016-2023.

Background: Early repolarization is a common electrocardiographic finding that is generally considered to be benign. Its potential to cause cardiac arrhythmias has been hypothesized from experimental studies, but it is not known whether there is a clinical association with sudden cardiac arrest.

Methods: We reviewed data from 206 case subjects at 22 centers who were resuscitated after cardiac arrest due to idiopathic ventricular fibrillation and assessed the prevalence of electrocardiographic early repolarization. The latter was defined as an elevation of the QRS–ST junction of at least 0.1 mV from baseline in the inferior or lateral lead, manifested as QRS slurring or notching. The control group comprised 412 subjects without heart disease who were matched for age, sex, race, and level of physical activity. Follow-up data that included the results of monitoring with an implantable defibrillator were obtained for all case subjects.

Results: Early repolarization was more frequent in case subjects with idiopathic ventricular fibrillation than in control subjects (31% vs. 5%, P less than 0.001). Among case subjects, those with early repolarization were more likely to be male and to have a history of syncope or sudden cardiac arrest during sleep than those without early repolarization. In eight subjects, the origin of ectopy that initiated ventricular arrhythmias was mapped to sites concordant with the localization of repolarization abnormalities. During a mean (±SD) follow-up of 61±50 months, defibrillator monitoring showed a higher incidence of recurrent ventricular fibrillation in case subjects with a repolarization abnormality than in those without such an abnormality (hazard ratio, 2.1; 95% confidence interval, 1.2 to 3.5; P=0.008).

Conclusions: Among patients with a history of idiopathic ventricular fibrillation, there is an increased prevalence of early repolarization.