UMEM Educational Pearls

Chronic kidney disease is a risk factor for accelerated atherogenesis. It is also a poor prognostic factor for patients with ACS or after MI. Elevated serum creatinine has been found to be an independent predictor of death after ACS and also a predictor of recurrent cardiovascular events. Cardiovascular death is 10-30 times higher in dialysis patients with ACS than in the general population.

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Treatment of Wernicke's Encephalopathy

Traditionally the treatment dose of thiamine in those that we suspect to have Wernicke's Encephalopathy is 100mg per day.  The problem is that this does was arbiarily picked by two physicians, Victor and Adams, in the 1950's.  They thought that 100mg a day would be a large dose. They also made their recommendation without fully understanding the pharmacokinetics of thiamine which has a half life of 96 minutes or less.  Compound this with case reports of individuals dying of Wernike's Encephalopathy despite being given 100mg of Thiamine daily.

Several authors are now advocating that patients with Wernicke's Encephalopathy be treated with 500mg of IV thiamine daily, but with the short half life some are advocating that the thiamine be given 2 to 3 times a day.  There are no good studies to refute or support the claims that higher doses are needed, but there are well documented cases of treatment failures at the lower dose.

PEARLs: 

• Consider high dose thiamine 500mg IV in patients that you are treating with Wernike's encephalopathy. 
• The 100mg dose is still appropriate for those that are just being suppliemented and in who Wernicke's encephalopathy is a consideation but not high up on the differential.

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Pediatric vascular access can be a challenge especially in a critically ill child.  When placing central lines finding information on what size catheter to use and the depth of insertion can be hard to locate so here are some starters :

Age (yrs)     IJ       SC     Femoral

  0-0.5         3F       3F          3F

  0.5-2         3F       3F         3-4F

  3-6             4F      4F          4-5F

  7-12          4-5F   4-5F      5-8F

Use a single, double, or triple lumen.  (General rule more lumens the better.)

Right IJ and Right SC Depth of insertion:

If Height < 100cm    then   Initial Catheter Depth (cm) = Ht (cm)/10 -1 cm

If Height > 100 cm   then   Initial Catheter Depth (cm) = Ht (cm)/10 -2 cm

These formulas will place 98% of catheters above R atrium.

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• Seizures occur in 5-7% of patients within the first 24 hours of stroke.
• Although seizure prophylaxis is not indicated, prevention of subsequent seizures with standard antiepileptic treatment is recommended.

Acinetobacter in the Critically Ill

• As all of us know, there has been an alarming increase in the incidence of acinetobacter infections
• At present, infections mostly occur in ICU/critically ill patients
• Important risk factors for colonization and infection include mechanical ventilation, recent surgery, tracheostomy, residents of long-term care facilities, central venous catheterization, and enteral feedings
• The most frequent clinical manifestations are ventilator associated pneumonia and bacteremia
• Susceptible strains can be treated with a broad-spectrum cephalosporin, carbapenem, or B-lactam-B-lactamase used alone or in combination with an aminoglycoside
• For resistant strains, the most active agent in vitro are the polymyxins
• The most common adverse effect of the polymyxins is nephrotoxicity (up to 36%)
• Tigecycline has been used but resistance rates are rapidly increasing

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What study should we be getting to evaluate for DVT in patients with suspected VTE (venous thromboembolic disease)?

Ultrasound of the legs seems to be equivalent to CT Venography (CTV). 

Drawbacks of CT Venography (CT scanning into the abdomen/pelvis/legs after pulmonary CTPA):

• Radiation (TONS of radiation!)
• Cost
• Never been proven superior to non-invasive ultrasound

Despite the fact that leg ultrasound obviously doesn't evaluate for deep pelvis clots and intraabdominal clots (IVC, etc), outcome studies and other studies in recent years show ultrasound is just as good as  CTV. 

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  Lisfranc Fracture:

Typically consists of a fracture of the base of the second metatarsal and dislocation, though it can also be associated with fractures of a cuboid.  Common current  mechanism is when a person steps into a hole and twists the foot.Originally described when a horseman would fall of their horse with their foot still trapped in a stirrup.

Diagnosis should be considered if patient has difficult weight bearing with pain on palpation over the 2^nd and 3^rd metacarpal head with an appropriate mechanism.

Pearls:

• Fracture findings on plain films may be subtle.
• Can obtain weight bearing AP views of the foot to demonstrate dislocation/fracture.
• If still suspicious consider a CT scan of the foot.

Just a few quick pearls about cocaine-chest pain and myocardial infarction:
 

• 0.7%-6% of patients presenting to the ED with chest pain during or immediately after using cocaine will rule in for an MI based on cardiac biomarkers. The 6% figure is the most commonly-quoted number.
• The risk of MI rises as much as 24-fold during the first hour after cocaine use. Although the risk decreases significantly after that, cocaine-related vasoconstriction can still cause acute MI hours or as many as 4 days later.
• Chest pain is not reliably present in patients with cocaine-associated MI, with one study reporting that only 44% of patients with cocaine-associated MI had chest pain (Hollander and Hoffman, J Emerg Med 1992). Dyspnea and diaphoresis are other common symptoms that should prompt concern for acute MI if chest pain is not present.

[McCord J, et al. Management of cocaine-associated chest pain and myocardial infarction. Circulation 2008;117:897-1907.]

Remember in the heat and pressure of a pediatric intubation (if you don't have your Pediatic Qwic Card handy) you can estimate what size blade to use very quickly and successfully by using facial landmarks!!

• Distance from the upper incisor teeth to the angle of the jaw seems to be an excellent clinical landmark for laryngoscope blade length selection for pediatric intubations under 8 years of age 
• Take the blade (excluding the handle insertion block) and place at the upper midline incisor teeth and if the tip is located within 1 cm proximal or distal to the angle of the mandible, oral tracheal intubations are more consistently accomplished on the first attempt!!!     90% on first attempt with correct size blade v. 57% on first attempt if blade too short

And remember to start with a straight blade (Miller, Wisconsin, Guedel, Wis-Hipple etc.) for your patients under 2 years of age because:

• these blades make controlling the tounge and epiglottis easier than curved blades at this age
• and they have a smaller flange profile in the oropharynx so visualization of the vocal cords is clearer

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Fluids in Acute Liver Failure

• Acute liver failure is often complicated by intravascular volume depletion - insensible losses, vomiting, poor oral intake
• Early and adequate fluid resuscitation is mandatory
• AVOID lactated Ringer's solution - exogenous lactate load is poorly tolerated by lack of hepatic function
• AVOID dextrose containing water solutions - will lead to hyponatremia and increase the risk of cerebral edema

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It is well-accepted that good, rapid compressions are one of the best interventions we can employ in managing patients with cardiac arrest. It is imperative that we minimize interruptions. Unfortunately, delivering shocks to a patient is a frequent cause of interruptions in compressions. It now appears that we may not need to discontinue compressions during shocks.

A recent study indicates that if shocks are delivered using the common self-adhesive pregelled pad electrodes and the person performing compressions is wearing gloves, the rescuers do not sense a shock at all. Compressions, therefore, do NOT have to stop during the cardioversion or defibrillation.

Whether this statement is true regarding handheld manual defibrillators also is uncertain.


Lloyd MS, Heeke B, Walter PF. Hands-on defibrillation: An analysis of electrical current flow through rescuers in direct contact with patients during biphasic external defibrillation. Circulation 2008;117:2510-2514.

Kerber RE. "I'm clear, you're clear, everybody's clear:" a tradition no longer necessary for defibrillation? Circulation 2008;117:2435-2436.

I remember being taught as a medical student that clavicle fractures could be treated conservatively.  A direct quote was "if both ends of the clavicle are in the same room it will heal".

Though conservative treatment with a sling for 6 weeks with early pendulum ROM exercises for the shoulder is appropriate for the vast majority of clavicle fractures surgery should be considered for those that have:

1. An open fracture
2. Significant angulation with tenting of the skin
3. Midshaft fractures that have overlap or displacement greater than 1 cm.
4. Displaced fractures of the distal clavicle [high rate of non-union]
5. Surgery can also be beneficial to those that do a lot of lifting or want to return to work as quick as possible.

ALTE and Infections - when to do full septic workups?

Given some recent cases of newborns with ALTEs at UMMS and Wash Co I thought I'd offer the following Pearls:   

• Overall the number of children with bacterial meningitis or bacteremia / sepsis as a cause of the ALTE is very low, much less than 1%
• However there is no data regarding the risk of meningitis in a well-appearing, afebrile infant with an ALTE

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Pool Cleaner Toxicity - Chlorine Gas Exposure 

The "shock" treatment that is utilized in pool cleaner is often contained in a large plastic container and is calcium hypochlorite. Chlorine gas accumulates in the small amount of airspace found in the container. If a future patient opens the container either in an enclosed space or within close proximity of the face that allows for large inhalational exposure.

• Toxicity looks like CHF with hypoxia, rales and acute lung injury on CxR
• Chlorine gas will bind hydrogen ion in the aveoli forming HCl - hydrochloric acid
• Nebulized NaHCO3 would theoretically neutralize this acid but has not been found to improve clinical outcome though it has been found to improve symptoms.
• Supportive care and observation including CxR  4-6 hours after exposure are necessary since the effects of the chlorine gas may be delayed.

• Respiratory drive can be affected by injury to certain parts of the brain.  This is often seen in patients with traumatic brain injury (TBI).

• In the setting of TBI, recognizing abnormalities in respirations can be helpful in localizing the injury.

• Cheyne-Stokes respiration, in which breathing is rapid for a period and then absent for a period, is associated with injury to the cerebral hemispheres or diencephalon.

• Hyperventilation can occur when the brain stem or tegmentum is injured.

Superior Vana Cava Synrome....when to suspect

Two common causes of SVC syndrome include thrombus (secondary to CV catheters) and lung tumors/lymphoma

Consider this diagnosis in patients with a history of cancer and/or who have a central line in place and the complaint of facial swelling. Patients may not look swollen to you.

In addition, make sure to look at their necks and chest wall-presence of asymmetric, prominent veins should prompt consideration for this diagnosis. 

A useful clinical tool is to look at the patient's driver's license (assuming they have one) and compare to their appearance on presentation.

Workup in most cases will involve a CT of the chest.

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COPD and mechanical ventilation

• In some studies, the failure rate of non-invasive positive pressure ventilation (CPAP, BiPAP) in acute exacerbations of COPD has been as high as 50%
• When setting the ventilator in patients with COPD, keep in mind that the majority have chronic ventilatory failure with a chronic compensatory respiratory acidosis
• Pearl: Look at the serum bicarbonate level obtained from a recent period of stability
• A recent serum bicarbonate level can provide an indirect indication of the patient's baseline P_aCO₂ if you have no prior ABGs
• Rather than target a P_aCO₂ of 40 mm Hg, manipulate the ventilator to target the patient's baseline serum bicarbonate or a pH of 7.35 - 7.38.

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Extensor Tendon Injuries [Mallet Finger]

• Due to jamming the finger or to use a Pittsburgh term "stoving it".
• Can result in a swan neck deformity or permanent flexion of the DIP joint.
• Due to stretching of the extensor tendon,or avulsion of the extensor tendon off the distal phalanx.
• Approximately 50% will develop a complication.
• Conservative treatment is splinting the DIP joint in full extension for 5-6 weeks. 
  • The DIP joint must not be flexed for the full treatment period.
  • If the patient does flex their DIP, the 5-6 week time frame needs to completely restart.
• Due to the high complication rate all of these patients should be referred to a hand specialist early.

According to the most recent (2007 Updated) ACC/AHA Guidelines for management of STEMI, the ECG is one of the most important tools to assess for successful reperfusion after thrombolytics. The treating physician should assess the ECG at 90 minutes after administration of lytics. Failure of the ST elevation to decrease by at least 50% in magnitude in the lead with the greatest initial amount of ST elevation is an indication of failed thrombolysis...regardless of whether or not the patient has persistent symptoms. In fact, the Guidelines specifically state that signs and symptoms are considered unreliable indicators of successful reperfusion.

Patients with ECG evidence of failed thrombolysis at 90 minutes should be referred for emergent PCI ("rescue PCI").

Retropharyngeal Abscess

• Retropharyngeal Abscess is primarily a disease of younger children
• Origin may be medical or traumatic (ie running with popsicle stick in mouth).
• Complications:
  • Airway compromise
  • Sepsis
  • Mediastinal extension or invasion into other local structures
• Presentation:
  • Neck Pain – most common
    • Limitation of neck movement, especially neck extension
    • Torticollis
  • Fever
  • Sore throat
  • Neck mass
  • Respiratory distress, stridor – rarely
• Consider retropharyngeal abscess in pt with fever and limitation of neck mobility even in the absence of respiratory symptoms.
  • Were you considering Meningitis (fever and neck pain) and the LP results are normal? Think of retropharyngeal abscess.
     

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