LITERATURE REVIEW
| SHOULD THESE ARTICLES CHANGE YOUR PRACTICE?—Edward A. Panacek, MD, Professor of Emergency
Medicine, University of California, Davis, School of Medicine, and UC Davis Health System, Sacramento
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| Magnesium for acute myocardial infarction (AMI): 10 yr ago, every patient presenting with AMI given 2 g intravenous
(IV) magnesium; thought to decrease ventricular dysrhythmias; patients thought to be relatively magnesium deficient,
especially those on diuretics; shown beneficial in animal models and small human studies but not in larger
studies; Magnesium in Coronaries (MAGIC) trial, comparing magnesium to placebo, showed no difference in 30-day
mortality, development of congestive heart failure (CHF), or ventricular dysrhythmias
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| Location of defibrillator paddles: study comparing anterolateral (AL) position to anteroposterior (AP) position; AP
position had more frequent cardioversion, lower average joules required, fewer shocks to convert to normal rhythm,
and 66% more success on crossover (ie, when AL position failed and AP position used; no success going from AP to
AL)
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| Brugada syndrome: originally described as important cause of sudden cardiac death in young Asian men; now seen in
all populations; probably genetic and involves sodium channels; predisposes people to sudden ventricular tachycardia
and ventricular fibrillation; thought to be responsible for 5% to 10% of all sudden deaths in United States (current research
looking at possible role in sudden infant death syndrome [SIDS]); does not respond to pharmacologic therapies;
does respond to placement of automatic implantable cardioverter defibrillator (AICD); electrocardiography
(ECG) changes intermittent; looks like right bundle branch pattern but not quite (ST segments convex upward in V1 ,
V2 ); look carefully at ECG in anyone presenting with syncope, light-headedness, palpitations, or resuscitated from
sudden cardiac death; refer to cardiologist
|
| Pulmonary edema (PE): treat in emergency department (ED) and send patient home on low molecular weight heparin
(LMWH), provided patient reliable for follow-up; 33% of patients with deep vein thrombosis (DVT) had PE; study
shows outcomes with LMWH equivalent to those with unfractionated heparin; in carefully selected patients with PE
who are not hemodynamically unstable and not having dyspnea, trend is to treat these patients as if they have DVT
and send them home
|
| Chronic obstructive pulmonary disease (COPD): steroids are back; study showed patients with COPD severe enough
to require hospital admission had shorter hospital stay, fewer recurrences, and lower relapse rates when put on prednisone,
40 mg/day for 10 days; study confirmed patients on steroid treatment did better on every parameter, and 30-
day relapse rate decreased by almost 50%
|
| Asthma: for patients with mild to moderate asthma, 2.5 mg albuterol every 20 min (standard aggressive dose) equivalent
to giving 7.5 mg once over 1 hr; more efficient way of administering drug and ensures patient gets medication
|
| Noninvasive positive pressure ventilation (NIPPV) for COPD: Cochrane systematic review found NIPPV (eg, bilevel
positive airway pressure [BIPAP]) better in severe COPD exacerbations not requiring immediate intubation; avoiding
intubation in patients not requiring it reduces stay in intensive care unit (ICU), shortens time spent on ventilator, reduces
risk for nosocomial or ventilator-associated pneumonias, and for sepsis in ICU, decreases complications, and
decreases mortality; avoids one intubation for every 5 patients treated; BIPAP standard of care
|
| Etomidate alone: 0.5 mg/kg does not work well for relaxing patients before intubation; muscle relaxant required
|
| Elderly patients with rib fractures: study showed elderly patients with radiographically demonstrated rib fractures
may seem less severely injured, but have much higher mortality, comorbidity, and longer average length of stay, and
should be admitted to ICU; age alone independent severe risk factor after severe rib fractures
|
| Elbow injuries: patients who can fully extend and lock elbow (compared to uninjured side) do not need x-rays (98% sensitive,
69% specific); speaker thinks addition of pronation and supination of elbow would increase specificity to almost
100%
|
| Shoulder dislocation complications: retrospective study; rate of axillary nerve injuries 13%; majority improved after
reduction; check axillary nerve before and after manipulating shoulder to avoid liability; in older patients and those
with more direct trauma, be aware of possibility of fracture
|
| Simple minor lacerations of hand: <2 cm; excludes diabetic patients, bite wounds, puncture wounds, and foreign bodies;
study compared closing wound with sutures or bandages; found no difference in cosmetic outcome or infection
rates; less pain and ED time with bandaging
|
| Treatment of uncomplicated subungual hematoma: trephining faster, less expensive, and just as good as removing
nail; no evidence supporting removing nail if no other injury present that requires suturing or repair under nail bed
|
| Tetanus prophylaxis for corneal abrasions: no evidence that patient with corneal abrasion needs tetanus prophylaxis;
study anesthetized dog, abraded its cornea, and poured liquid solution of Clostridium tetani into dog’s eye; dog got no infection;
however, there are cases of tetanus with penetrating injuries to eye
|
| Spinal fractures and pain: in elderly osteoporotic patients with compression fractures of spinal column, calcitonin nasal
spray consistently resulted in greater pain relief and less need for additional analgesics
|
| Low back pain: cyclobenzaprine 5 mg tid works just as well as 10 mg and less sedating; 2.5 mg does not work; onset of
relief after 3 to 4 doses
|
| No IV access: case study of heroin overdose patient with no IV access; gave nebulized naloxone (Narcan) 2 mg in 3 mL
normal saline; patient awoke and improved within 5 min; mental status gently returned to normal (did not become combative);
“it shows that the lung is a wonderful delivery organ”
|
| Analgesics for abdominal pain: 10 randomized studies support giving “reasonable doses of” analgesics before surgical
examination; some studies showed improved diagnostic accuracy (decreases pain and anxiety and enables more accurate
examination); none of these studies showed delay in diagnosis
|
| Hyperemesis gravidarum: no evidence of harm with trimethobenzamide (Tigan), metoclopramide (Reglan), prochlorperazine
(Compazine), promethazine (Phenergan), or ondansetron (Zofran) during pregnancy; does not make much difference
which of these agents used as long as steroids not used
|
| Filling bladder for pelvic ultrasonography: no longer needed, since now using transvaginal probes; stop performing
full-bladder protocol; transabdominal ultrasonography with empty bladder plus transvaginal just as accurate as full-
bladder protocol
|
| Modafinil (Provigil): used in Europe for years; approved by Food and Drug Administration (FDA) for narcolepsy; off-
label use for sleep apnea and depression; being used by military pilots, air traffic controllers, some attending physicians
on night shift; unknown how it works; does not change heart rate or seem to be stimulant drug per se; works
well for aging shift workers
|
| EMERGENCY MEDICINE CARDIOLOGY LITERATURE REVIEW—Amal Mattu, MD, Associate Professor and
Program Director, Emergency Medicine Residency, University of Maryland School of Medicine, Baltimore
|
| How studies selected: reviewed studies published within last ≈1 yr; studies selected if relevant to emergency medicine,
conclusions supported by study, and clinically applicable now or in near future; rejected studies that were pathologic,
theoretic, or severely flawed
|
Acute Coronary Syndromes
| Does sex make difference? women (especially young women) misdiagnosed more often than men and present higher
medicolegal risk; women—tend to present later; less likely to get ECGs and tend to have more subtle abnormalities
on ECG; more likely to have false-negative stress test; more likely to have single-vessel disease (men tend to have
multivessel disease); more likely to have sharp stabbing pain instead of substernal crushing pain, pain that radiates to
right arm, or isolated arm pain instead of chest pain; elderly or diabetic women typically complain of general malaise
and loss of appetite (get ECG early)
|
| External triggers of AMIs: article looked at type of activity patient was doing when MI pain began; most engaged in
physical activity; 21% awakened from sleep; in almost 7% of MIs, pain started during emotional stress; 8% of MIs
occurred while eating; reflux esophagitis most common misdiagnosis on charts of patients with missed MI
|
| Young patients: 1 in 20 patients 24 to 39 yr of age complaining of chest pain had acute coronary syndrome within 30
days; 1 of 50 had adverse event (ie, death, MI, or need for emergent revascularization); young patients have cardiac
disease more often than thought; do not discount risk just because patient young
|
| Diabetes: now considered equivalent to atherosclerotic disease, ie, if patient diabetic, “you can assume they have atherosclerosis”;
71% of diabetics with acute coronary syndromes have elevated biomarkers; diabetics less likely to have ST
elevation on ECG, more likely to develop CHF, pulmonary edema, or renal failure in hospital, and more likely to die
in hospital (7.3% vs 4.0%); 6-mo mortality in diabetic patients with negative cardiac markers same as 6-mo mortality
in nondiabetic patients with positive cardiac markers; treat diabetic patients more aggressively
|
| HIV infection: now considered independent risk factor for development of atherosclerosis; most popular proposed
mechanism is that HIV causes endothelial injury, which sets in motion process of inflammation (big risk factor for
development of coronary thrombosis); risk even greater if patient taking protease inhibitors (shown to induce insulin
resistance and dyslipidemia); HIV patients have MIs >10 yr earlier than non-HIV patients
|
| Systemic lupus erythematosus (SLE): independent risk factor for acute coronary syndromes in women; young lupus patients
9 to 10 times more likely to have early MI; women <45 yr of age have 50 times higher risk for premature atherosclerosis;
lupus patients tend to have MI 20 yr earlier than age-matched nonlupus counterparts; add 20 yr to their age
“because that’s what their coronaries look like”; lupus thought to abolish protective effect of menses; lupus patients have
higher incidence of endothelial dysfunction (significant marker of early atherosclerosis) and at higher risk for carotid
disease as well
|
| American College of Cardiology/American Heart Association (ACC/AHA) guidelines for management of patients
with ST segment elevation MI: <30 min from patient contact with health care system to initiation of lytic therapy, <90
min to balloon inflation (patient should arrive at catheter laboratory by 60 min); <50% of EDs meet these goals; should
give lytics if patient must be transferred or if delay with cardiologist; 12-lead ECG should be shown to experienced emergency
physician within 10 min; oral and IV β-blockers should be given early in ED unless contraindication (eg, bradycardia)
present (to reduce mortality by reducing incidence of cardiac arrest due to ventricular fibrillation); patients going for
percutaneous coronary interventions (PCIs), coronary artery bypass grafts (CABGs) or getting thrombolytics should be
given unfractionated heparin (maximum bolus 4000 U, maximum infusion 1000 U; lower than previous guidelines);
LMWH acceptable if patient <75 yr of age and has good renal function; clopidogrel (Plavix) indicated if patient has aspirin
allergy; withhold clopidogrel for 5 to 7 days if CABG planned (decision made and clopidogrel administered by cardiologist
in catheterization laboratory); glycoprotein IIb/IIIa inhibitors now considered reasonable before PCI, even in ST
elevation MI (start as early as possible; best evidence for abciximab [ReoPro]); start abciximab for ST elevation MI before
patient sent to catheterization laboratory; ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs) should be
avoided (block antiplatelet effect and can cause myocardial scar thinning and infarct expansion); if patient has persistent
pain, give morphine or fentanyl; trend toward early PCI for high-risk patients (ie, positive troponin, ST depression, recurrent
or intractable ischemic pain, previous CABG or recent PCI, or ischemia with decompensated CHF or ventricular dysrhythmias)
|
Resuscitation
| Hyperventilation during cardiac arrest: resuscitation guidelines recommend 12 breaths/min; studies show average bag-
valve-mask rate 55 breaths/min; hyperventilation increases intrathoracic pressure and decreases preload, which decreases
cardiac output, coronary perfusion, and cerebral blood flow; animal studies showed decreased survival rates in
animals that were hyperventilated; during code, check every 5 to 10 min to ensure patient being bagged at correct rate
|
| Chest compression rates during cardiopulmonary resuscitation (CPR): recommended rate 100/min; study found
<70/min in 25%, <80/min in >33%; when rates averaged 95/min, return to spontaneous circulation in 75% of cases vs
42% in patients receiving <40/min
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Educational Objectives
| The goal of this program is to educate the listener about recent scientific literature related to emergency medicine. After hearing
and assimilating this program, the clinician will be better able to:
|
 | Review the current evidence regarding the efficacy of magnesium in the management of acute myocardial infarction (AMI).
|
| Describe the most effective placement of defibrillator paddles.
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| Explain the appropriate management of elderly patients with rib fractures.
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| Discuss how women’s presentations for AMI differ from those of men.
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| List the populations that are at particularly high risk for acute coronary syndromes.
|
Discussed on This Program
Abciximab [ReoPro]
Albuterol (salbutamol sulphate in United Kingdom) [many trade names]
Amiodarone HCl [Cordarone, Pacerone]
Aspirin (many trade names and formulations)
Calcitonin-human for injection [Cibacalcin]
Celecoxib [Celebrex]
Clopidogrel bisulfate [Plavix]
Cyclobenzaprine HCl [Flexeril]
Doxycycline (many trade names)
Epinephrine (many trade names)
Etomidate [Amidate]
Fentanyl citrate [Sublimaze]
Hydrocodone bitartrate and acetaminophen [Vicodin, several others]
Ibuprofen (many trade names)
Ibutilide fumarate [Corvert]
Ketorolac tromethamine [Acular, Acular LS, Toradol]
Lidocaine HCl (many trade names)
Low molecular weight heparin (LMWH; dalteparin, enoxaparin, tinzaparin)
Metoclopramide [Reglan, others]
Modafinil [Provigil]
Morphine sulfate (many trade names)
Naloxone HCl [Narcan]
Naproxen [Naprosyn, others]
Ondansetron HCl [Zofran, Zofran ODT]
Prochlorperazine [Compazine, Compro]
Promethazine [Phenergan, Phenadoz]
Rofecoxib [Vioxx] (withdrawn from market 09/30/04)
Trimethobenzamide hydrochloride [Tigan, others]
Vasopressin (8-arginine-vasopressin) [Pitressin]
Trimethoprim-sulfamethoxazole (co-trimoxazole; TMP-SMZ) [Bactrim, others]
Suggested Reading
Aaron SD et al: Outpatient oral prednisone after emergency treatment of chronic obstructive pulmonary disease. N Engl J Med
348:2618, 2003; Batrick N et al: Treatment of uncomplicated subungual haematoma. Emerg Med J 20:65, 2003; Benacerraf BR:
Filling of the bladder for pelvic sonograms: an ancient form of torture. J Ultrasound Med 22:239, 2003; Bergeron E et al: Elderly
trauma patients with rib fractures are at greater risk of death and pneumonia. J Trauma 54:478, 2003; Blau LA et al: Analgesic efficacy
of calcitonin for vertebral fracture pain. Ann Pharmacother 37:564, 2003; Blum A et al: Viral load of the human immunodeficiency
virus could be an independent risk factor for endothelial dysfunction. Clin Cardiol 28:149, 2005; Borenstein DG et al:
Efficacy of a low-dose regimen of cyclobenzaprine hydrochloride in acute skeletal muscle spasm: results of two placebo-controlled trials.
Clin Ther 25:1056, 2003; Bozeman WP et al: Etomidate as a sole agent for endotracheal intubation in the prehospital air medical
setting. Air Med J 21:32, 2002; Culic V et al: Meta-analysis of possible external triggers of acute myocardial infarction. Int J
Cardiol 99:1, 2005; Cydulka RK et al: Comparison of single 7.5-mg dose treatment vs sequential multidose 2.5-mg treatments with
nebulized albuterol in the treatment of acute asthma. Chest 122:1982, 2002; Docherty MA et al: Can elbow extension be used as a
test of clinically significant injury? South Med J 95:539, 2002; Fazel R et al: Prognostic value of elevated biomarkers in diabetic and
non-diabetic patients admitted for acute coronary syndromes. Heart 91:388, 2005; Habib AS et al: Food and drug administration
black box warning on the perioperative use of droperidol: a review of the cases. Anesth Analg 96:1377, 2003; Hsue PY et al: Progression
of atherosclerosis as assessed by carotid intima-media thickness in patients with HIV infection. Circulation 109:1603, 2004;
Kirchhof P et al: Anterior-posterior versus anterior-lateral electrode positions for external cardioversion of atrial fibrillation: a randomised
trial. Lancet 360:1275, 2002; Lightowler JV et al: Non-invasive positive pressure ventilation to treat respiratory failure resulting
from exacerbations of chronic obstructive pulmonary disease: Cochrane systematic review and meta-analysis. BMJ 326:185,
2003; Magee LA et al: Evidence-based view of safety and effectiveness of pharmacologic therapy for nausea and vomiting of pregnancy
(NVP). Am J Obstet Gynecol 186:S256, 2002; Magnesium in Coronaries (MAGIC) Trial Investigators: Early administration
of intravenous magnesium to high-risk patients with acute myocardial infarction in the Magnesium in Coronaries (MAGIC)
Trial: a randomised controlled trial. Lancet 360:1189, 2002; Marsan RJ Jr et al: Evaluation of a clinical decision rule for young
adult patients with chest pain. Acad Emerg Med 12:26, 2005; Mattu A et al: The Brugada syndrome. Am J Emerg Med 21:146,
2003; Merli G et al: Subcutaneous enoxaparin once or twice daily compared with intravenous unfractionated heparin for treatment of
venous thromboembolic disease. Ann Intern Med 134:191, 2001; Montalescot G et al: Early vs late administration of glycoprotein
IIb/IIIa inhibitors in primary percutaneous coronary intervention of acute ST-segment elevation myocardial infarction: a meta-analysis.
JAMA 292:362, 2004; Mukherjee P et al: Tetanus prophylaxis in superficial corneal abrasions. Emerg Med J 20:62, 2003; Mycyk
MB et al: Nebulized naloxone gently and effectively reverses methadone intoxication. J Emerg Med 24:185, 2003; Nissman SA et
al: Critically reappraising the literature-driven practice of analgesia administration for acute abdominal pain in the emergency room
prior to surgical evaluation. Am J Surg 185:291, 2003; Pack AI et al: Modafinil as adjunct therapy for daytime sleepiness in obstructive
sleep apnea. Am J Respir Crit Care Med 164:1675, 2001; Patel H et al: Symptoms in acute coronary syndromes: does sex make
a difference? Am Heart J 148:27, 2004; Perron AD et al: Acute complications associated with shoulder dislocation at an academic
Emergency Department. J Emerg Med 24:141, 2003; Pollack CV Jr et al: 2004 American College of Cardiology/American Heart
Association guidelines for the management of patients with ST-elevation myocardial infarction: implications for emergency department
practice. Ann Emerg Med 45:363, 2005; Quinn J et al: Suturing versus conservative management of lacerations of the hand: randomised
controlled trial. BMJ 325:299, 2002; Thanyasiri P et al: Endothelial dysfunction occurs in peripheral circulation patients
with acute and stable coronary artery disease. Am J Physiol Heart Circ Physiol 289:H513, 2005; Varriale P et al: Acute myocardial
infarction in patients infected with human immunodeficiency virus. Am Heart J 147:55, 2004.
Faculty Disclosure
In adherence to ACCME guidelines, the Audio-Digest Foundation requests all lecturers to disclose any significant financial relationship
with the manufacturer or provider of any commercial product or service discussed. For this issue, the faculty reported
nothing to disclose.
Dr. Panacek was recorded on February 17, 2005, in San Diego at the 11th Annual Scientific Assembly of the American
Academy of Emergency Medicine; Dr. Mattu on April 20, 2005, in Scottsdale, Arizona, at Emergency Medicine 2005: Moving
Forward, sponsored by the Mayo Clinic College of Medicine at Scottsdale. The Audio-Digest Foundation thanks
the speakers and the sponsors for their cooperation in the production of this program.
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