Lit Bits: December 6, 2007

From the recent medical literature...

1. Statewide System for Coronary Reperfusion May Improve MI Care

NEW YORK (Reuters Health) Nov 27 - A statewide system that promotes expeditious coronary reperfusion may improve the quality of care for ST-segment elevation myocardial infarction (STEMI), according to a report in the Journal of the American Medical Association for November 28.

Whether this translates into improved clinical outcomes, however, is unclear.

The system focuses on improving treatment in four areas: emergency medical systems, emergency department, catheterization laboratory, and interhospital transfer. Under the system, hospitals with percutaneous coronary intervention (PCI) facilities will agree to provide single-call catheterization laboratory activation by emergency personnel, accept patients even if no beds exist, and improve STEMI care for the whole region regardless of hospital affiliation.

In the current study, Dr. Christopher B. Granger, from Duke Clinical Research Institute, Durham, North Carolina, and colleagues examined the outcomes of 579 STEMI patients who were treated before and 585 treated after the statewide coronary reperfusion system was implemented. The outcomes of 925 STEMI patients treated at non-PCI hospitals were also evaluated.

Implementation of the statewide program was associated with significant improvements in reperfusion times. For instance, the program significantly reduced the time from the initial emergency medical response to receipt of fibrinolytic therapy or PCI. Moreover, it appeared to hasten the transfer of patients from non-PCI to PCI hospitals.

Nonreperfusion rates fell from 23% to 11% in the PCI hospitals, while no change occurred in non-PCI hospitals. Despite these apparent improvements, implementation of the statewide program did not significantly reduce the occurrence of death, cardiac arrest, or cardiogenic shock.

"Further research is needed to ensure that this and other programs that demonstrate improvement in application of reperfusion therapies lead to reduced mortality and morbidity from acute myocardial infarction," the researchers conclude.

JAMA 2007;298:2371-2379. Full-text (Free): http://jama.ama-assn.org/cgi/content/full/298.20.joc70124

2. Risks for MI, Stroke Elevated in the Month After Respiratory Infection

Risks for myocardial infarction and stroke are elevated in the month after respiratory infection, according to a case-control analysis in the European Heart Journal.

Using a large general practice database, U.K. researchers identified some 11,200 adults with first MIs and 9200 with first strokes, as well as matching controls, over a 10-year period. They also gathered data on respiratory infection diagnoses in the year before MI or stroke.

Overall, risks for MI and stroke were significantly increased within the month after respiratory infection. In adjusted analyses, the risk for either endpoint was approximately doubled within 1 week after infection, with risk being highest in the first 3 days (odds ratios: 3.8 for MI, 4.1 for stroke).

Given the findings, the authors conclude: "The benefits of reducing respiratory infection either through immunisation or treating or preventing infection may be substantial."

European Heart Journal article (Free): http://eurheartj.oxfordjournals.org/cgi/content/full/ehm516v1

3. ACEP survey suggests rise in ED crowding

Modern Physician (10/10, Zigmond) reports, "In a survey of nearly 1,500 practicing emergency physicians," which was conducted last month at the American College of Emergency Physicians' (ACEP) conference in Seattle, "more than 80 percent said crowded conditions in their emergency departments had increased either slightly (40.2 percent) or significantly (42.4 percent) in the past year." Over two-thirds (67 percent) of the survey's respondents "cited 'not enough staffing and/or resources' as their leading concern about patient care." The respondents were also concerned about "decreased throughput in the emergency department because of boarding patients (65.4 percent) and long wait times (65.3 percent)." Almost half (47 percent) of the physicians "said they had experienced a patient suffering as a result of crowded emergency rooms." Furthermore, 200 respondents said that "at some point" they "had experienced a patient death" due to crowded emergency department conditions.

The NBC Nightly News (10/9, story 8, 2:20, Curry) also covered the story, and interviewed Dr. Linda Lawrence, ACEP president, who said, "We knew patients were suffering. We watch it each and every day as they've lost their privacy and dignity lying in our hallways." HealthDay (10/10) reprises the story in its Health Highlights section.

Abid Mogannam & Brian Potts MD, MBA, Managing Editors, CAL/AAEM News Service. University of California, Irvine

4. Diclofenac or Spinal Manipulative Therapy Not Helpful for Acute Low Back Pain

Laurie Barclay, MD. November 13, 2007 — Patients with acute low back pain receiving recommended first-line care did not recover more quickly with the addition of diclofenac or spinal manipulative therapy, according to the results of a randomized controlled trial in the November 8 issue of The Lancet.

"Present treatment guidelines for acute low back pain recommend that general practitioners should give advice (remain active, avoid bed rest, and reassurance of favourable prognosis) and paracetamol [a.k.a. acetaminophen] as the first line of care," write Mark J. Hancock, MAppSc, from the University of Sydney in Australia, and colleagues. "Non-steroidal anti-inflammatory drugs (NSAIDs) and spinal manipulative therapy are recommended as second-line management options for patients who have slow recovery. We do not know whether NSAIDs or spinal manipulative therapy, or both, in addition to advice and paracetamol as initial treatment results in quicker recovery for such patients."

In this community-based study, 240 patients with acute low back pain who had been given advice and paracetamol by their general practitioner were randomized to receive diclofenac 50 mg twice daily and placebo manipulative therapy (n = 60), spinal manipulative therapy and placebo drug (n = 60), diclofenac 50 mg twice daily and spinal manipulative therapy (n = 60), or double placebo (n = 60). The main endpoint was days to recovery from pain, evaluated with survival curves in an intent-to-treat analysis.

Compared with placebo drug or placebo manipulative therapy, neither diclofenac nor spinal manipulative therapy significantly decreased the number of days until recovery (diclofenac hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.84 - 1.42; P = .516; spinal manipulative therapy HR, 1.01; 95% CI, 0.77 - 1.31; P = .955). By 12 weeks after randomization, 237 (99%) patients had either recovered or were censored. Secondary analyses showed no significant effects on pain, disability, or global perceived effect at 1, 2, 4, or 12 weeks, when diclofenac or spinal manipulative therapy, or both, was added to baseline care.

Possible adverse reactions occurred in 22 patients; these included gastrointestinal tract disturbances, dizziness, and heart palpitations. Half of these patients were in the active diclofenac group, and the other half were taking placebo. One patient taking active diclofenac stopped treatment because of a suspected hypersensitivity reaction.

"Neither diclofenac nor spinal manipulative therapy gave clinically useful effects on the primary outcome of time to recovery," the study authors write. "We can reasonably assume that when quality baseline care is provided, previously effective treatments might no longer provide additional benefit." Limitations of the study include cointerventions during the study period in 28 patients and imperfect compliance rates.

"These results are important because both diclofenac and spinal manipulative therapy have potential risks and additional cost for patients," the study authors conclude. "If patients have high rates of recovery with baseline care and no clinically worthwhile benefit from the addition of diclofenac or spinal manipulative therapy, then GPs [general practitioners] can manage patients confidently without exposing them to increased risks and costs associated with NSAIDs or spinal manipulative therapy."

Lancet. 2007;370:1638-1643.

5. Predicting Adverse Outcomes in Syncope

Grossman SA, et al. J Emerg Med. 2007;33:233-239.

Syncope is a common presentation to the Emergency Department (ED); however, appropriate management and indications for hospitalization remain an ongoing challenge. The objective of this study was to determine if a predefined decision rule could accurately identify patients with syncope likely to have an adverse outcome or critical intervention.

A prospective, observational, cohort study was conducted of consecutive ED patients aged 18 years or older presenting with syncope. A clinical decision rule was developed a priori to identify patients at risk if they met any of the following 8 criteria: 1) Signs and symptoms of acute coronary syndrome; 2) Signs of conduction disease; 3) Worrisome cardiac history; 4) Valvular heart disease by history or physical examination; 5) Family history of sudden death; 6) Persistent abnormal vital signs in the ED; 7) Volume depletion; 8) Primary central nervous system event. The primary outcome was either a critical intervention or an adverse outcome within 30 days.

Among 362 patients enrolled with syncope, 293 (81%) patients completed their 30-day follow-up. Of these, 201 (69%) were admitted. There were 68 patients (23%) who had either a critical intervention or adverse outcome. The rule identified 66/68 patients who met the outcome for a sensitivity of 97% (95% confidence interval 93–100%) and specificity of 62% (56–69%). This pathway may be useful in identifying patients with syncope who are likely to have adverse outcome or critical interventions. Implementation and multicenter validation is needed before widespread application.

6. Patent Foramen Ovale Linked to Cryptogenic Stroke in Old and Young

Patent foramen ovale (PFO) is associated with cryptogenic stroke in both older and younger patients, reports the New England Journal of Medicine.

Some 500 adults admitted with stroke underwent routine diagnostic testing (CT and/or MRI, carotid ultrasound, transthoracic echocardiography, and EKG). A known cause was identified in 55% of cases, while the rest were classified as cryptogenic strokes. All patients then had transesophageal echocardiography to determine the presence of PFO.

PFO was significantly more common in patients with cryptogenic stroke than in those with stroke of known cause, both in patients aged 55 or older (44% vs. 14%) and younger patients (28% vs. 12%). Associations between PFO and stroke were particularly strong among patients who also had atrial septal aneurysm.

The authors say their findings indicate that PFO plus atrial septal aneurysm is a "high-risk characteristic," although they note the lack of guidelines for therapy in affected patients.

NEJM abstract: http://content.nejm.org/cgi/content/short/357/22/2262

7. The increasing use of chest CT for trauma: is it being overutilized?

Plurad D, et al. J Trauma 2007;62:631-5.

OBJECTIVE: Chest computerized tomography (CCT) has gained popularity in trauma evaluation, but it is expensive, increases exposure to radiation, and leads to findings of debatable clinical significance. The objective of this study was to determine the change in usage of CCT over time and the number of injuries missed on plain chest radiograph (CXR) with normal findings that required therapy.

METHODS: Data on all patients evaluated with a screening CXR during a 7-year period were extracted from a Level I center trauma registry. The incidence of CCT utilization during the duration of the study was identified. Patients who had CCT done after the initial CXR were analyzed separately for the presence of occult injuries. The association of these findings with demographic and injury data were examined.

RESULTS: There were 2,326 CCT performed, and 1,873 (80.5%) of them were after negative CXRs. The percentage of patients studied with CCT increased incrementally from 2.7% to 28.7% for blunt and from 0.4% to 2.9% for penetrating injury. The identification of occult pneumothorax, hemothorax, rib fractures, and lung contusions significantly increased during the study period with the increased frequency of CCT use. There were 102 occult pneumothoraces and/or hemothoraces identified, but only 12 patients underwent tube thoracostomy during the 7-year period. There were 43 patients with blunt aortic injury (BAI) and 6 (13.9%) of these patients had normal CXR findings. There was no trend in increased BAI diagnosed during the study period, although the utilization of CCT was increased.

CONCLUSIONS: There has been a 10-fold increase in use of CCT for trauma evaluation. Although occult findings increased, the number of patients who needed treatment was small. The excess utilization of CCT after negative CXR needs continued refinement to identify the small number of potentially lethal injuries while reducing the number of trivial findings.

8. ED US in the Diagnosis of DVT

Crisp JG, et al. J Emerg Med. 2007;33: 328

Background: Portable vascular ultrasound machines are already used in many hospitals for vascular access, are less expensive than conventional machines, and have never been studied for the detection of deep vein thrombosis (DVT). Compression ultrasound(CUS) of the lower extremity is a rapid method of detecting DVT, yet few studies have directly compared this technique to formal doppler ultrasound by the Department of Radiology (DOR).

Objective: To measure the accuracy of CUS with a portable vascular ultrasound machine for the detection of lower extremity DVT.

Methods: This was an observational, prospective trial in which emergency department (ED) physicians performed portable vascular compression ultrasound (PV-CUS) with the Bard Site-Rite IV ultrasound on patients suspected of having a lower extremity DVT. All ED physicians had a 15-minute training session before enrolling patients. PV-CUS evaluation involved identification of the femoral and popliteal vessels with subsequent compression of the femoral and popliteal veins. The study was considered positive for DVT if either vein was not compressible or a thrombus was visualized. PV-CUS occurred before doppler ultrasound by the DOR, and was compared to the board-certified radiologist reading of the DOR ultrasound. Results: A total of 146 patients, enrolled by 44 physicians, had bedside PV-CUS in the ED followed by DOR evaluation. Mean exam per physician was 3.3 (range 1-28). There were 31 DVTs seen on DOR evaluation: all correctly identified by PV-CUS. One patient with a negative DOR ultrasound had decreased compression of the popliteal vein in the ED, giving a single false positive result. The 115 patients without DVTs all had negative PV-CUS. The sensitivity and specificity of PV-CUS for DVT were 100% (CI 86.2-100%) and 99.1% (CI 94.5-99.9%), respectively.

Conclusion: Portable vascular compression ultrasound can accurately detect DVT of the lower extremities. This approach is less expensive than conventional US, is widely available, and may improve patient care and efficiency in the ED.

9. Antibiotic, Nasal Steroid Not Effective for Treating Acute Sinusitis

Amoxicillin or budesonide, either alone or in combination, doesn't improve symptoms of acute sinusitis, according to a randomized, double-blind trial in JAMA.

The study included some 200 patients over age 15, from 58 family practices in the U.K., who met clinical criteria for acute sinusitis (at least two of the following: unilateral or bilateral purulent nasal discharge, unilateral pain, and intranasal pus). The patients were assigned to receive the antibiotic amoxicillin, the topical nasal steroid budesonide, both, or placebos. Patients with recurrent sinusitis were excluded.

The proportion of patients with symptoms lasting 10 days or more did not differ among the four groups. Overall, 40% of patients were cured at 1 week, with no differences among groups.

An editorialist notes that certain subgroups of patients may benefit from antibiotics or topical steroids, but until such subgroups are identified, "cautious use of antibiotics in the general practice setting for patients with sinusitis is warranted."

JAMA article (Free): http://jama.ama-assn.org/cgi/content/full/298/21/2487

10. Patient sex and quality of ED care for patients with AMI

Vinson DR, et al. Amer J Emerg Med. 2007;25:996-1003.

Objective
The aim of the study was to assess the quality of care between male and female emergency department (ED) patients with acute myocardial infarction (AMI).

Methods
A 2-year retrospective cohort study of 2215 patients with AMI presenting immediately to 5 EDs from July 1, 2000, through June 30, 2002 was conducted. Data on patient characteristics, clinical presentation, and ED processes of care were obtained from chart and electrocardiogram reviews. Multivariable regression models were used to assess the independent association between sex and the ED administration of aspirin, β-blockers, and reperfusion therapy to eligible patients with AMI.

Results
There were 849 women and 1366 men in the study. Female patients were older than male patients (74.3 years for women vs 66.8 years for men, P less than .001). Among ideal patients, women were less likely than men to receive aspirin (76.3% of women vs 81.3% of men, P less than .01), β-blockers (51.7% of women vs 61.4% of men, P less than .01), and reperfusion therapy (64.0% of women vs 72.8% of men, P less than .05). However, after adjustment for age, there was no longer a significant relationship between sex and the use of aspirin (odds ratio [OR], 0.99; 95% confidence interval [CI], 0.95-1.03), β-blockers (OR, 0.94; 95% CI, 0.82-1.04), or reperfusion therapy (OR, 1.01; 95% CI, 0.89-1.09). In models adjusting for additional demographic, clinical, and hospital characteristics, there remained no association between sex and the processes of care.

Conclusion
Women with AMI treated in the ED have a lower likelihood of receiving aspirin, β-blocker, and reperfusion therapy. However, this association appears to be explained by the age difference between men and women with AMI. Although there are no apparent sex disparities in care, ED AMI management remains suboptimal for both sexes.

11. Survival Outcomes with the Introduction of Intravenous Epinephrine in the Management of Out-of-Hospital Cardiac Arrest

Ong MEH, et al. Ann Emerg Med 2007;50:635-642.
Editor’s Summary: There are few human data supporting the current use of intravenous epinephrine for patients with out-of-hospital cardiac arrest. Does the introduction of a single dose of 1 mg intravenous epinephrine improve outcomes from out-of-hospital cardiac arrest in a system that previously did not use this drug? Only 44% of eligible subjects received epinephrine in this 1,296-patient before-after trial in Singapore. No benefit in initial survival or other common short-term resuscitation metrics occurred. Given the study’s limitations, the role of epinephrine remains unclear. This study highlights the difficulties in establishing the value of standard EMS resuscitative care.

Abstract: http://www.annemergmed.com/article/PIIS0196064407003897/abstract

12. FDA Ponders Psychiatric Warning for Common Flu Drugs

An FDA staff report recommends adding label warnings about possible neuropsychiatric side effects in individuals taking the influenza drugs oseltamivir (Tamiflu) and zanamivir (Relenza).

The report was prepared for a meeting of the Pediatric Advisory Committee to take place this week. The FDA found 596 cases of neuropsychiatric events associated with oseltamivir and 115 with zanamivir. The cases, mostly in people age 21 or younger and mostly from Japan, included delirium, hallucinations, and impulsive behavior, including a desire to jump. Five fatalities were associated with oseltamivir use while none were associated with zanamvir.

The agency cautioned it could not rule out the possibility that the behavior was due to the illness rather than the treatment. However, the reports "raise the question" of whether the events result from the neuraminidase inhibitor class. It said "it seems prudent" for both drugs to carry label warnings of hallucinations, delirium, and abnormal behavior.

Glaxo and Roche, which make the two drugs, said label updates are unnecessary, because the events could have resulted from flu symptoms.

FDA staff report (Free PDF): http://www.fda.gov/ohrms/dockets/ac/07/briefing/2007-4325b_02_04_Tamiflu%20Adverse%20Event%20Review%202007.pdf

13. Pet-Related Infections: A Review

A review on pet-related infections, including prevention and treatment, appears in the November issue of American Family Physician.

The article includes:
· a helpful table outlining the various types of infections, with specific information about signs and symptoms, diagnostic tests, and primary treatment;
· CDC recommendations on safe pet handling, including guidelines for high-risk individuals (pregnant women, young children, older adults, and immunocompromised patients);
· a list of resources for more information on pet-related infections.

American Family Physician article (Free): http://www.aafp.org/afp/20071101/1314.html

14. Cricoid Pressure in ED Rapid Sequence Tracheal Intubations: A Risk-Benefit Analysis (Review Article)

Ellis DY, et al. Ann Emerg Med 2007;50: 653-665.

Summary: Cricoid pressure is considered an integral part of patient safety in rapid sequence tracheal intubation and emergency airway management. Cricoid pressure is applied to prevent the regurgitation of gastric contents into the pharynx and subsequent aspiration into the pulmonary tree. We analyze the published evidence supporting cricoid pressure, along with potential problems, including increased difficulty with tracheal intubation and ventilation.

Conclusions: Cricoid pressure entered medical practice on a limited evidence base but with common sense supporting its use. Given that the risks of cricoid pressure worsening laryngeal view and reducing airway patency have been well described, we recommend that the removal of cricoid pressure be an immediate consideration if there is any difficulty either intubating or ventilating the ED patient.

Full-text (subscription required): http://www.annemergmed.com/article/PIIS0196064407006038/fulltext

15. Intravenous Magnesium Safe Adjunctive Treatment for Atrial Fibrillation

By Will Boggs, MD. NEW YORK (Reuters Health) Nov 23 - Intravenous magnesium may be safely used as an adjunct to digoxin in patients with acute onset atrial fibrillation (AF), according to a report in the November issue of Heart.

"Magnesium is a relatively safe drug to use to control rapid ventricular response in acute onset AF and should be considered as an adjunct to other antiarrhythmics (e.g., amiodarone or digoxin) in patients with AF and in rapid ventricular response," Dr. Kwok M. Ho from Royal Perth Hospital, Western Australia, told Reuters Health. "Nevertheless, its effect on achieving rhythm control is not as great, especially in patients with a normal serum magnesium concentration."

Dr. Ho and colleagues performed a meta-analysis of 10 randomized controlled trials to investigate the safety and efficacy of intravenous magnesium in the setting of acute onset AF.

The addition of intravenous magnesium to digoxin or ibutilide did not improve the rate of converting AF to sinus rhythm, the authors report, and by itself it was no better than calcium antagonists or amiodarone in achieving sinus rhythm.

"While previous meta-analysis has shown that magnesium is effective in preventing the occurrence of atrial fibrillation after cardiac surgery," the authors conclude, "our study shows that adding intravenous magnesium to either digoxin or ibutilide is not effective in achieving sinus rhythm once AF has occurred."

When added to digoxin, however, intravenous magnesium increased the proportion of patients achieving a ventricular response rate below 100 beats/minute. Nevertheless, intravenous magnesium was less effective than intravenous verapamil in controlling the ventricular response rate. However, intravenous magnesium was less likely than other agents to induce bradycardia or atrioventricular block and hypotension, the researchers note.

Transient minor symptoms of flushing, tingling, and dizziness followed intravenous magnesium administration in about 17% of patients, the investigators say.

"I will certainly use intravenous magnesium when the serum magnesium concentration is low and also when the ventricular response rate of the AF is fast despite digoxin or amiodarone," Dr. Ho said.

Heart 2007;93:1433-1440.

16. The Success of Vaccine Programs in the U.S.

Roush SR, et al. JAMA. 2007;298:2155-2163.

Context: National vaccine recommendations in the United States target an increasing number of vaccine-preventable diseases for reduction, elimination, or eradication.

Objective: To compare morbidity and mortality before and after widespread implementation of national vaccine recommendations for 13 vaccine-preventable diseases for which recommendations were in place prior to 2005.

Design, Setting, and Participants: For the United States, prevaccine baselines were assessed based on representative historical data from primary sources and were compared to the most recent morbidity (2006) and mortality (2004) data for diphtheria, pertussis, tetanus, poliomyelitis, measles, mumps, rubella (including congenital rubella syndrome), invasive Haemophilus influenzae type b (Hib), acute hepatitis B, hepatitis A, varicella, Streptococcus pneumoniae, and smallpox.

Main Outcome Measures: Number of cases, deaths, and hospitalizations for 13 vaccine-preventable diseases. Estimates of the percent reductions from baseline to recent were made without adjustment for factors that could affect vaccine-preventable disease morbidity, mortality, or reporting.

Results: A greater than 92% decline in cases and a 99% or greater decline in deaths due to diseases prevented by vaccines recommended before 1980 were shown for diphtheria, mumps, pertussis, and tetanus. Endemic transmission of poliovirus and measles and rubella viruses has been eliminated in the United States; smallpox has been eradicated worldwide. Declines were 80% or greater for cases and deaths of most vaccine-preventable diseases targeted since 1980 including hepatitis A, acute hepatitis B, Hib, and varicella. Declines in cases and deaths of invasive S pneumoniae were 34% and 25%, respectively.

Conclusions: The number of cases of most vaccine-preventable diseases is at an all-time low; hospitalizations and deaths have also shown striking decreases.

17. Detection of Bloodstream Infections in Adults: How Many Blood Cultures Are Needed?

Andrew Lee A, et al. J Clin Microb 2007;47: 3546-3548

Although several reports have shown that two to three 20-ml blood cultures are adequate for the detection of bacteremia and fungemia in adults, a recent study (F. R. Cockerill et al., Clin. Infect. Dis. 38:1724-1730, 2004) found that two blood cultures detected only 80% of bloodstream infections and that three blood cultures detected 96% of episodes.

We reviewed data at two university hospitals to determine whether the recent observations by Cockerill et al. are applicable more widely. We assessed all blood cultures obtained from adult inpatients from 1 January 2004 through 31 December 2005 at Robert Wood Johnson University Hospital and Duke University Medical Center. All instances in which 3 blood cultures per patient were obtained during a 24-h period were included. The medical records of patients who met the inclusion criteria were reviewed retrospectively to determine the clinical significance of the positive blood culture (true infection versus contamination). Data were analyzed to determine the cumulative sensitivity of blood cultures obtained sequentially during the 24-h time period.

Of 629 unimicrobial episodes with 3 blood cultures obtained during the 24-h period, 460 (73.1%) were detected with the first blood culture, 564 (89.7%) were detected with the first two blood cultures, 618 (98.2%) were detected with the first three blood cultures, and 628 (99.8%) were detected with the first four blood cultures.

Of 351 unimicrobial episodes with 4 blood cultures obtained during the 24-h period, 257 (73.2%) were detected with the first blood culture, 308 (93.9%) were detected with the first two blood cultures, 340 (96.9%) were detected with the first three blood cultures, and 350 (99.7%) were detected with the first four blood cultures. Among unimicrobial episodes, Staphylococcus aureus was more likely to be detected with the first blood culture (approximately 90% detected with the first blood culture).

There were 58 polymicrobial episodes in which 3 blood cultures were obtained. Forty-seven (81.0%) were detected with the first blood culture, 54 (93.1%) were detected with the first two blood cultures, and 58 (100%) were detected with the first three blood cultures.

The results of this study indicate that two blood cultures in a 24-h period will detect approximately 90% of bloodstream infections in adults. To achieve a detection rate of greater than 99%, as many as four blood cultures may be needed. The previously held axiom that virtually all bloodstream infections can be detected with two to three blood cultures may no longer be valid but may also depend on the definition of the "first" blood culture obtained

18. Myths and Misconceptions of Wernicke’s Encephalopathy: What Every Emergency Physician Should Know (Review Article)

Donnino MW, et al. Ann Emerg Med. 2007;50:715-721.

Summary: Wernicke’s encephalopathy continues to be an unrecognized and misunderstood disease. The cause of Wernicke’s encephalopathy is thiamine deficiency as a result of any nutritionally deficient state, though many physicians erroneously consider this disease to be confined only to alcoholics. Unfortunately, the syndrome is most often recognized only on autopsy, especially among nonalcoholics. Despite advances in magnetic resonance imaging, Wernicke’s encephalopathy remains primarily a clinical diagnosis. The common clinical findings include mental status changes, ocular dysfunction, and gait ataxia. Treatment mandates timely intravenous thiamine therapy, for which the optimum dosage remains controversial. We trace the history of Wernicke’s encephalopathy from the first description to our current understanding of the disease and include many of the misconceptions, myths, and controversies that surround this disease.

Full-text (subscription required): http://www.annemergmed.com/article/PIIS0196064407002077/fulltext

19. International Agency Plans to Call Night Work a Probable Carcinogen

The International Agency for Research on Cancer plans to categorize overnight shift work as a probable carcinogen, according to the Associated Press.

The AP says the agency will make the change in December, and the American Cancer Society is likely to follow suit. Until now, the ACS has considered the association between cancer and night work to be "uncertain, controversial or unproven."

Several epidemiologic studies, done mostly on nurses and flight crews, have shown a link between night work and cancer of the breast and prostate, the AP notes. Another analysis, prepared by the IARC, will be published in the December issue of Lancet Oncology.

In theory, sleep loss and circadian disruptions resulting from night work could contribute to cancer risk. Being exposed to light at night could disrupt production of melatonin, a hormone that can limit tumor growth.

Associated Press story (Free): http://news.yahoo.com/s/ap/20071129/ap_on_he_me/night_shift_cancer

American Journal of Epidemiology article on rotating shift work and prostate cancer, 2006 (Free): http://aje.oxfordjournals.org/cgi/content/full/164/6/549

20. New Adenovirus Variant Causing Severe Disease

The CDC reports that a new adenovirus variant has caused at least 140 cases of severe respiratory illness in the United States, including 10 deaths.

After the first case in an infant in New York, additional clusters were confirmed in Oregon, Washington, and Texas during March to June 2007. Nearly 40% of the patients were hospitalized, 17% in intensive care. The cases suggest "a new and virulent" variant of adenovirus serotype 14 (Ad14), concludes a report in MMWR.

"What really got people's attention is these are healthy young adults landing in the hospital," the CDC's John Su told the Associated Press.

Several antiviral drugs, including ribavirin, cidofovir, and vidarabine, have been administered for adenoviral infections, but none has shown "definitive efficacy," the CDC says.

The agency encouraged physicians to consult their state health departments with questions about potential Ad14 cases.

MMWR article (Free): http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5645a1.htm

21. Early Oral Feeding in Mild Acute Pancreatitis: Presented at ACG

By Danny Kucharsky. PHILADELPHIA, PA -- October 25, 2007 -- Early feeding in patients with mild acute pancreatitis does not increase the risk of severe disease, according to a study presented here at the annual scientific meeting of the American College of Gastroenterology (ACG).

"It has been a commonly accepted practice that the initial treatment of acute pancreatitis is absence of feeding, to allow the pancreas to rest," said study presenter Nison Badalov, MD, Gastroenterologist, Division of Gastroenterology, Maimonides Medical Center, Brooklyn, New York, United States. "But recent studies have suggested the early feeding of patients in acute pancreatitis is safe and effective."

Among other things, early feeding stimulates bowel function, attenuates the systemic inflammatory response system, prevents bacterial overgrowth and translocation, and promotes the immune response. Dr. Badalov and colleagues therefore conducted their study to evaluate the safety and efficacy of early oral feeding as compared with traditional fasting in patients with mild acute pancreatitis.

The prospective, single-centre study randomised patients into one of three regimens -- standard treatment (fasting); a semi-elemental formula (low-fat diet), as tolerated, started within 12 hours of admission; a regular diet, as desired, started within 12 hours of admission. Patients were followed for pain medication requirements, complications, length of stay, and recurrence of disease.

After randomisation, 22 patients were enrolled in the fasting group, 18 in the low-fat diet, and 22 were enrolled in a regular diet group. The three groups did not differ in terms of age, gender and aetiology of acute pancreatitis. There were no differences in the three groups regarding severe disease, narcotic usage, mortality and recurrence of acute pancreatitis. The study found no significant differences in organ failure or pancreatic necrosis among the three groups. One patient developed multisystem organ failure and subsequently died.

Dr. Badalov concluded, "Patients with mild acute pancreatitis may be fed early in the course of the disease." The study provides further evidence that "placing the pancreas at rest" is not necessary in the management of patients with acute pancreatitis, he said.

Limitations of the study include enrolment, a design that did not include blinding, a lack of study on the placebo effect of eating on patients, and lack of quantification of nutrient intake. Further study with a larger enrolment will be needed to confirm the results, he added.

[Presentation title: Early Oral Feeding in Mild Acute Pancreatitis: A Randomized Prospective Trial. Abstract 10]