Archive | July, 2012

Acute Aortic Dissection: quick review

20 Jul
Epidemiology
Higher incidence in men (65%) and with increasing age
Mortality for proximal dissections of 26% (surgical treatment) vs. 58% (nonsurgical)
Mortality for distal dissections of 10.7% (medical treatment) vs. 31% (surgical)
Pathophysiology
Repetitive stresses on the layers of aortic wall (intima, media, adventitia) include prolonged hypertension, weak connective tissues (e.g. Ehlers-Danlos), bicuspid aortic valve
-Stressors plus age can lead to pulsatile blood tearing through the intima into the media
Classification
-Stanford:
  • type A (ascending aorta proximal to brachiocephalic artery)
  • type B (descending aorta distal to subclavian artery)
-DeBakey:
  • type I (ascending aorta extends to arch and beyond),
  • type II (confined to ascending aorta),
  • type III (originates and extends in descending aorta)
Presentation
-more often in older men BUT women present more atypically (e.g. mental status changes or CHF)
Classic presentation of tearing sudden chest pain, pulse deficit and/or BP differential, and widened mediastinum on CXR occurs in less than 30%
-In up to 12% thoracic aortic dissections may be painless
-May also present with STEMI (beware, thrombolytics contraindicated in these cases), syncope, stroke, mesenteric ischemia
Work-up
ECG usually normal or non-specific (e.g. LVH)
CXR most common findings = widened mediastinum and abnormal aortic contour
TEE, CT, MRI all have similar sensitivities
-TEE may be better for unstable patient but cannot visualize entire aorta (e.g. branches of arch and distal ascending)
-CT requires transfer to radiology and exposure to contrast/radiation
Management
-In ED includes pain control, BP and HR control
Target SBP 100-120 mmHg and HR < 60 bpm
-First choice = IV beta-blockers (e.g. esmolol, labetalol)
-Vasodilators (e.g. nitroglycerin) alone can cause reflex tachycardia leading to increased shear forces, so usually used as adjunct if SBP still uncontrolled after beta blocker
Type A dissection: emergent surgery
Type B dissection: less clear optimal treatment BUT medical management can reduce mortality to 10%
Surgery for type B indicated if ongoing pain, refractory HTN, leaking/rupture, occlusion of major arterial trunks, local aneurysms
-Long-term beta blockers for all
 
Submitted by F. DiFranco.

Reference(s): Upadhye S & Schiff K. Acute aortic dissection in the emergency department: diagnostic challenges and evidence-based management. Emergency Medicine Clinics of North America. 30 (2012), 307-327.; picture: Fig 1 from same article.

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Noninvasive positive pressure ventilation in acute COPD exacerbation

19 Jul

Cochrane review

•Reviewed 14 RCT’s involving adult patients with COPD exacerbation that compared usual medical care (UMC) alone to UMC plus NPPV

•UMC included any of the following: O2, bronchodilators, steroids, theophylline, antibiotics, diuretics, heparin

•NPPV duration varied among studies

NPPV compared to UMC alone showed:

  • decreased need for intubation,
  • improvement in pH,
  • reduced treatment failure, complications and length of hospital stay

•There was significant reduction in risk of mortality with NPPV of 48% compared to UMC

Mortality NNT of 10 (For every 10 patients treated with NPPV, avoid 1 death)

Intubation NNT of 4 (For every 4 patients treated with NPPV, avoid 1 intubation)

Bottom line: Try NPPV early in the course of respiratory failure due to COPD before severe acidosis to reduce the risk of endotracheal intubation, treatment failure and mortality

Submitted by F. DiFranco.

Reference(s): Ram FSF, Picot J, Lightowler J, Wedzicha JA. Non-invasive positive pressure ventilation for treatment of respiratory failure due to exacerbations of chronic obstructive pulmonary disease (Review). Cochrane Library. July 2009.; picture

Loperamide for acute diarrhea in children

18 Jul

QUICK HITS:

Loperamide has been generally discouraged for acute diarrhea in children

•However, there is evidence that its use is safe and effective in children with acute diarrhea

•One study found that it is well tolerated and significantly shortens duration of diarrhea and severity of symptoms in children from age 2-11

•A systematic review concluded that loperamide may be a useful adjunct for acute diarrhea in children > 3 yo with minimal dehydration

Do NOT use loperamide for infants, malnourished, very dehydrated, systemically ill or if they have bloody diarrhea as adverse events outweigh benefits00

Submitted by F. DiFranco.

Reference(s): Kaplan MA, et al. A multicenter randomized controlled trial of a liquid loperamide product versus placebo in the treatment of acute diarrhea in children. Clinical Pediatrics. 38(10):579-591, October 1999.; Li ST, Grossman DC, Cummings P. Loperamide therapy for acute diarrhea in children: systematic review and meta-analysis. PLoS Med. 4(3):e98, March 2007.; picture

blunt abdominal injury

17 Jul

RAGING HYPOTHETICAL:

•Your patient is a 25 yo female s/p low mechanism MVA complaining of some mild LUQ abdominal pain. She has no rebound TTP, no guarding, no rebound. UA is negative. FAST exam is negative. What now?

Nishijima et al; “Does this Adult Patient have a Blunt Intra-abdominal Injury” JAMA April 11, 2012 Vol307, No 14

Question: What physical exam findings, lab test, diagnostic tools can accurately identify patients with intrabdominal injury

Methods: MEDLINE Search for blunt intrabdominal injuries from 1950-2012. 35 studies identified

Results: The factors that were associated with the highest intrabdominal injury were:

  • FAST exam with a positive LR 69 (38-101 CI),
  • base deficit -6; LR 18 (11-30),
  • elevated LFTs >130; LR 5.2(3.5-7.9).
  • Seat belt sign, rebound tenderness, hypotension, hematuria were also all statstically significant.
  • Interesting: leukocytosis and elevated lactate levels were not significant.

Teaching Point: FAST exam remains an excellent screening tool for intrabdominal injury when positive. However a negative FAST does not rule out intra-abdominal pathology. Other factors to consider remain LFTs, unexplained acidosis, hematuria, and a surgical abdomen on exam.

Submitted by W. Rushton.

Reference(s): Nishijima et al; “Does this Adult Patient have a Blunt Intra-abdominal Injury” JAMA April 11, 2012 Vol307, No 14; picture

New onset seizures

16 Jul

Level B recommendations for labs:

  • Labs are very low yield in patients who returned to baseline
  • most frequent abnormality = hypoglycemia, hyponatremia
  • Important to identify pregnancy
  • Lumbar puncture if immunocompromised

Level B recommendations for head CT

  • Neuroimaging should be performed when feasible
  • 1996 study recommended head CT in the ED if:
    • acute intracranial process suspected,
    • acute head trauma,
    • h/o malignancy,
    • immunocompromise,
    • fever,
    • persistent HA,
    • new focal neuro exam,
    • focal onset before generalization
  • May defer outpatient neuroimaging if reliable follow-up

Level C recommendations for hospital admission and AED’s (anti-epileptic drugs)

  • If normal neuro exam can discharge with outpatient follow-up
  • If normal neuro exam, no comorbidities, no known structural intracranial disease, no need to start AED’s in ED
  • Patients with structural lesions on head CT or with focal seizures that secondarily generalize have highest risk of recurrence and probably benefit most from starting AED’s but may not change seizure recurrence

Submitted by F. DiFranco.

Reference(s): ACEP Clinical Policy: Critical issues in the evaluation and management of adult patients presenting to the emergency department with seizures. Ann Emerg med. 2004;43:605-625.; picture

Ketamine-propofol for Peds Fracture Reduction

13 Jul

Advantages of combination

  • increased anesthetic synergy leading to decreased doses,
  • decreased dysphoric emergence from ketamine
  • decreased pain of propofol injection

Pilot study of 20 children with forearm fractures needing closed reduction with procedural sedation

  • showed rapid recovery (average 38 min from time of ketamine injection to suitability for discharge)
  • no clinically significant complications when using 0.5 mg/kg of ketamine followed by 1 mg/kg of propofol

BOTTOM LINE:

  • one small study, but one of many out there
  • ketamine-propofol combo worth considering, need less of either to get a desired effect

Submitted by F. DiFranco.

Reference(s): Sharieff, GQ, et al. Ketamine-propofol combination sedation for fracture reduction in the pediatric emergency department. Pediatric Emergency Care. 23(12):881-884, Dec 2007.; picture

Management of Rhabdomyolosis

12 Jul

RAGING HYPOTHETICAL:

–A 90 year old female presents from SNF after being found on the floor overnight for an unknown amount of time. Her GCS is below baseline and is subsequently intubated. Labs are consistent with a gap acidosis and a CK >1000. What now?

KEY POINTS:

•NO RCTS of acute management. All treatment guidelines are based on expert opionion

Complications of acute rhabdo:

Hypovolemia secondary to necrosis of muscle tissue and subsequent vasodilation

Compartment syndrome

Arrhythmias and cardiac arrest

DIC

acute renal failure

Hepatic Dysfunction

Emergency Management:

Aggressive CRYSTALLOID infusion (maintain UOP >150ml/hr)

Check limbs for compartment syndrome

–As an ADJUNCT to crystalloid infusion, consider a 20%mannitol infusion of 0.5gm/kg over 15 mins and a HCO3 gtt. (ALL EXPERT OPINON)

–Agreesive correction of hyperkalemia

Correct hypocalcemia only if symptomatic

Submitted by W. Rushton.

Reference(s): FY Khan. Rhabdomyolysis: A Review of the Litterature The Netherlands Journal of Medicine October 2009, Vol 67, No 9; picture