UMEM Educational Pearls

Thrombolytic Therapy for Pulmonary Embolism

Indications for administration of fibrinolytic therapy for acute PE:

• Cardiac arrest presumed to be secondary to PE-tPA 50 mg bolus, may be repeated once.
• Massive PE (hemodynamic instability)-arbitrarily defined by BP < 90 mm Hg systolic. Give 10 mg tPA bolus followed by 90 mg over 2 hours. Make sure heparin off during this time frame. tPA is the only FDA approved drug for this but some are starting to use Tenecteplase (single 0.5 mg/kg bolus).
• Submassive PE (normal hemodynamics and evidence of RV strain). This tends to be the most controversial group, although many authorities are now advocating its use. Strongly suspect strain if the Troponin/BNP are elevated and get an ECHO if they are. Most studies that advocate for lytics in this group show significant improvement in PA pressures, RV wall dilatation, etc. What is currently missing is outcome data...i.e. how short of breath and disabled are people with submassive PE at 6, 9, and 12 months? Bottom line, enough evidence exists to support giving to stable patients with RV strain as long as they are carefully screened.
• There is NO evidence that lytics are useful in stable patients without RV strain.
• The administration of thrombolytic therapy for acute PE is within the scope of practice of emergency medicine.

 

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Most clinicians maintain ventilation with 100% oxygen for cardiac arrest patients with return of spontaneous circulation (ROSC). However, there is increasing literature demonstrating that "hyperoxia in the early stages of reperfusion harms postischemic neurons by causing excessive oxidative stress," and this may result in worse neurological outcomes. It is recommended to avoid unnecessary arterial hyperoxia and simply focus on maintaining oxygen saturations in the 94-96% range during the initial post-cardiac arrest period. [Reference: Neumar RW, Nolan J. Post-cardiac arrest syndrome and management. In The Textbook of Emergency Cardiovascular Care and CPR. Lippincott Williams & Wilkins, Philadelphia 2009.]

Conjunctivitis:

Patient presenting to the Emergency Department complaining of "Pink Eye" is very common but how can you be sure that they do not have a bacterial conjunctivitis and absolutely need antibiotics or are they just suffering from a viral or allergic conjunctivitis.

• Bacterial conjunctivitis will typically have  a mucopurulent discharge and the patients will complain that their lids are matted shut in the morning. Though this can occur in allergic or viral conjunctivitis, those with bacterial conjunctivitis typically have a wet, sticky mucopurulent material matted to their lids where viral/allergic conjunctivitis typically have crusting on their lids and lashes due to dried tears and serous secretions.  Bacterial conjunctiviits is also an uncommon condition due to the defense systems of the eye. So most patients can be treated with support care (ie: Warm Compresses).
• Allergic conjunctivitis should affect both eyes.  It would be odd for only one eye to be allergic, so if only one eye is infected that diagnosis is most likely viral or bacterial conjunctivitis.
• When treating allergic conjunctivitis go with the drops.  Several studies have now shown that topical therapy is better than systemic (ie: benadryl, zyrtec, allegra, or claritin) in the resolution of symptoms.

• Burn injuries are common in children and are the 3rd leading cause of unintentional injuries in children age 0 to 18 yrs, only behind MVCs and drowning.
• Burns greater than 20% TBSA require agressive fluid resuscitation. Lactated Ringer's is the most commonly used fluid. 
• Parkland Burn Formula:  LR over 24 hours = 4mlxkgx %BSA burned. 1st half over 1st 8 hours, 2nd half over subsequent 16 hours.  Add maintenance fluids to this amount for patients < 30 kg.
• Urine output is the best way to assess adequate fluid resuscitation.  Place a foley and goal output is 1-2 ml/kg/hr in children.  (0.5 to 1 ml/kg/hr in adults)
• Oligoanalgesia is very common in pediatric patients.  Use morphine 0.1 mg/kg IV/IM or Oxycodone 0.1 mg/kg po.
• 6% of burned children < 12 years old are victims of abuse.  So keep a high index of suspicion in children with burns. 

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A few previous pearls have touched on identifying drugs that cause QT prolongation.  In our patient population, methadone is one of the more common causes of drug-induced prolonged QT syndrome.  Of 692 physicians surveyed (35% family practitioners, 25% internests, 22% psychiatrists, and 8% self-identified addiction specialists) only 41% were aware of methadone's QT-prolonging properties and just 24% were aware of methadone's association with torsade de pointes.

 

Now that you know, what do you do when a patient on methadone presents with a QTC of 580 msec and intermittent runs of vtach and torsade de pointes?

 

The answer is... the exact same thing you would do with any other patient who presents this way, regardless of the cause.

• Give magnesium sulfate 2 gm IV for torsade de pointes
• Check magnesium and potassium levels.  If low (which they often are), replete.
• Monitor continuous EKG.

Buprenorphine, an alternative to methadone, is not associated with prolonged QT syndrome.

 

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• Glasgow Coma Scale (GCS) is a validated score intended to provide a reliable and objective method for recording and communicating a patient's consciousness.
  

• It was originally created to assess head injury patients' neurologic status/deficit.
  

• The scale ranges from 3 (deeply unconscious) to 15 (fully awake).
  

• It tests the following three responses:  (1) eye, (2) verbal, and (3) motor, listed in order of increasing functional significance with regard to status (i.e. optimal eye response assigned lower score (best score = 4), followed by a best score of 5 for verbal response, and optimal motor function being scored at 6.

Intracerebral hemorrhage and fluid management

• Isotonic fluids (0.9% saline) are the standard IV fluid for patients with ICH
• The goal for fluid management is to maintain euvolemia with a urine output > 0.5 cc/kg
• Importantly, 0.45% saline and dextrose containing IVFs should be avoided, as they can exacerbate cerebral edema and increase ICP
• Hypertonic saline has become a popular aternative to normal saline in patients with significant perihematomal edema and mass effect
• Goals when using hypertonic saline are to maintain serum osmolality between 300 - 320 mOsm/L and serum sodium between 150 - 155 mEq/L

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Neurologic Manifestations of Acute Aortic Dissection

A myriad of neurologic presentations of acute aortic dissection have been reported in the literature. Although classic CVA symptoms may occur, nonspecific neurologic symptoms are much more common

These include:

• Classic stroke-like/TIA symptoms
• Encephalopathy (may look like a drug overdose)
• Seizures (ask Mike Abraham about his abdominal pain/seizure case)

Take Home Point:

• Consider the diagnosis of acute aortic dissection in patients with these findings who ALSO HAVE chest, back, or abdominal pain +/- risk factors for the disease (i.e. HTN, family history, Marfans, cocaine, etc.)

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Otitis Externa:

Infections of the external ear canal are common and can typically be treated with topical antibiotic solutions (Cortisporin Otic, Cipro Otic, etc...) or antibiotic solutions mixed with topical steroids (Cortisporin HC Otic, Cipro HC Otic, etc...).  Most patients should not require PO or IV antibiotics.

However, you need to always be on the look out for malginant otitis externa (MOE) which is a more deep seated infeciton extending into the temporal bone and can have a mortality rate as high as 50%.  Patients that are diabetic, immunospressed, or have had radiation therapy to the base of the skull are at increased risk.  Patients with MOE typically have pain out of proportion to clinical findings and granulation tissue may be present in the ear canal.  Suspect this diagnosis in patients that have cellulitis or extreme tenderness over the mastoid process.

If you suspect MOE the patient should be started on antibiotics that cover pseudomonas. Consider obtaining a CT scan with temporal bone cuts and an Otolaryngology consultation.

Next time you have to do a full septic work up on a 2 month old with a fever of 104 F consider giving Ketamine 3mg/kg IM before even starting.  Then you can obtain your cath urine, IV, and LP with a calm pain free patient!!

Ketamine induces a catatonic state that provides sedation, analgesia, and amnesia.  It does not affect pharyngeal-laryngeal reflexes and the patient maintains a patent airway.  This makes it very useful when fasting is not assured.   

Route          Onset          Duration             Dose

  IM            3-5 min         20-30min         3-5 mg/kg

  IV             1 min            5-10 min          1-2 mg/kg

Although we tend to think of ACS with cocaine use, there are many other serious complications, including:

• Agitation, psychosis, and anxiety
• Hyperthermia
• Vascular headache of withdrawal
• Seizures
• Hemorrhagic stroke (many of these patients have an underlying vascular abnormality)
• Ischemic stroke
• Acute Renal Failure
• Crack Lung: acute pulmonary syndrome that occurs after inhaling freebase cocaine presents as fever, dyspnea, hypoxemia, diffuse alveolar infiltrates, and respiratory failure
• Intestinal perforations

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Blood Pressure Control in ICH

• Aggressive BP reduction after ICH is currently the focus of an ongoing NINDS study (ATACH Study)
• Current literature recommends that extreme levels of BP after ICH be treated to reduce hematoma expansion
• Mean arterial pressures (MAP) > 130 mmHg should be treated with continous IV medications
• Current recommended medications include labetalol, esmolol, nicardipine, and fenoldopam
• Nitroprusside is avoided by many given its tendency to increase ICP
• Oral and sub-lingual medications are not indicated for immediate and precise BP control

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This pearl is dedicated to Dr. Michael Rolnick....

 

Infections That Cause Temperature-PulseDissociation

Certain infections may cause temperature-pulse dissociation (relative bradycardia in association with fever).

Remember that normally there will be an increase in pulse rate by 10 bpm for every 1 degree increase in temperature. So, if a patient has a temperature of 103 F, expect them to be tachycardic.

Any intracellular organism has the potential to cause a relative bradycardia (Faget's sign)

Infections that cause dissociation:

• Salmonella typhi
• C burnetii (agent of Q fever)
• Chlamydia infections
• Dengue fever

Diastolic dysfunction is recognized as a much more common cause of CHF and cardiogenic pulmonary edema than traditionally recognized. Diastolic dysfunction is associated with impaired relaxation, which results in a decrease in LV filling, which results in pulmonary congestion. Common causes of diastolic dysfunction are cardiac ischemia, LVH, and infiltrative diseases.

It is almost impossible to get through a shift these days with out seeing an abscess that is caused by CA-MRSA.  As of the 2007 Antibiotic nomogram (2008 data not yet available) at University of Maryland CA-MRSA was only 70% sensitive to clindamycin, and >98% sensitive to bactrim and > 96% sensitive to doxcycline.  A local community hospital in Baltimore is showing only 55% sensitivity to clindamycin.

As a New Year's resolution to yourself I recommend that you check with your local hospital's Micrology department to see what the sensitivities are to bactrim, clindamycin, doxycycline.  If sensitivities are less than 80% it would generally be recommended that these medications not be used as initial empiric treatment.

For Baltimore bactrim and doxycycline should probably be the preferred treatment options.

Have a Great New Year.

Propofol is an IV hypnotic that is made in a soy-based emulsion containing soybean oil, egg lecithin, and glycerol.  It has a very rapid onset time (10-50 seconds) and a brief duration of action making it ideal for ED sedation.  Children have a more rapid metabolism of propofol than adults.  Propofol has been shown to be safe and effective for Pediatric ED sedation in several studies.  

Pearls on Propofol

• Dosing is 1mg/kg bolus than 0.5 mg/kg IV q 1-2 min until desired sedation occurs
• Due to high lipid concentration can cause pain at injection site in up to 70% of patients.  This can be prevented by applying a rubber tourniquet well above IV site and injecting 0.5 mg/kg of lidocaine 30 seconds before injecting the propofol. 
• Use is contraindicated in those with allergies to Eggs, Soy, or sulfites, or those with mitochondrial disorders
• PRIS (Propofol Infusion Syndrome) was described in 1992 with case reports of children dying due to metabolic acidosis, rhabdomyolysis, and refractory heart failure when receiving high doses (>4mg/kg/h) for >48 hours.  And it is more associated with children < 4 years old. 
• So while safe for pediatric procedural sedation don't use propofol as a drip for intubated children.

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Watch out for tradename and generic name's of medications.

They can get the patient and yourself into trouble:

• coumadin: warfarin, jantoven
• diphenhydramine: unisom, benadryl, tylenol PM

Classic example is my own case: Insert a central line in a patient - subclavian - and shortly after completion am alerted the patient's INR is 25. No adverse outcome but when I reviewed the med list, I did not see coumadin or warfarin and assumed I was in the clear. Patient was on jantoven.

Happy Holidays

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• The most common anatomical locations for ischemic stroke are in the internal capsule and the basal ganglia.
• Look for hypodensity (i.e. darkening which suggests edema) in these parts of the brain on CT when trying to locate areas of stroke.
• Acute stroke typically takes at least 3 hours to manifest in the form of edema on Head CT.  The larger the stroke, the quicker the abnormality is seen.

Hemofiltration

• Renal replacement therapy (RRT) involves the use of semipermeable membranes to remove fluid and toxic substances from the bloodstream
• The basic methods of RRT are hemodialysis (HD) and hemofiltration (HF)
• There have been a few cases in our ED in which our Renal consultants have used HF
• Hemofiltration can remove large volumes of fluid (up to 3 Liters per hour)
• Major advantages to HF: less likely to produce hypotension than HD, can remove larger molecules than HD
• Disadvantages to HF: must be done continuously to provide effective dialysis, requires anticoagulation to maintain circuit patency, not well suited for hypotensive patients (requires a hydrostatic pressure gradient for solute clearance)