UMEM Educational Pearls

The Cuff Leak Test

• As many of us have undoubtedly experienced, we are now extubating patients in the ED due to prolonged lengths of stay
• Critical to extubation is determining whether laryngeal edema may be present
• Laryngeal edema, resulting in airway obstruction, is one of the most common causes of respiratory distress following extubation
• Although shown to have moderate accuracy, many use the 'cuff leak test' to determine the iikelihood of laryngeal edema
• In most studies, performance of the cuff leak test is as follows:
  • take the average of 6 serial measurements of expired tidal volume with the ETT cuff inflated
  • take the average of 6 serial measurements of expired tidal volume with the ETT cuff deflated
  • a difference of < 110 ml between averages strongly suggests the presence of laryngeal edema
• Take Home Point: patients with a cuff leak test < 110 ml are likely to have laryngeal edema and are at high risk of airway obstruction post-extubation.  It is best not to extubate these patients in the ED.

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Hypertensive Encephalopathy

Hypertensive encephalopathy (HE) is one of the true hypertensive emergencies. Although usually seen with diastolic BPs greater than 120 mm Hg, it can occur in patients with lower numbers. And the diagnosis can be really tricky to make. Sometimes the diagnosis isn't clear until symptoms resolve from BP reduction .

The presentation is variable and includes:

• Seizures
• Altered mental status
• Coma
• Vomiting

The goal of treatment is to reduce the BP NO MORE THAN 25% (of the MAP) within the first few hours. In addition, drugs like Hydralazine (which may lead to a precipitous decline in BP) and Clonidine (which can alter mental status) should be avoided.

Medications to consider for treating HE include intravenous drips-Fenoldopam, Nicardipine, Labetalol. Drugs like Nipride are probably best avoided since cyanide toxicity may alter a patient's mental status further.

• CNSD, also known as toddler's diarrhea
• the most common cause of chronic diarrhea in childhood
• possibly a variant of irritable bowel syndrome, family history of IBS is common
• children are 6-58 months of age, most commonly 11-24 months old)
• otherwise in good health with normal weight gain, without signs of malabsorption syndrome or enteric infection
• morning stool is the most formed, with the stools becoming progressively looser through the day that are malodorous with food particles
• most often due to dietary factors causing altered gastrointestinal motility such as reduced fat intake or excessive fluid intake, especially sucrose-containing fruit juices
• treatment is based on modification of the contributing dietary factors

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Blast Injuries:

In honor of the 4th of July holiday, here is a quick pearl about blast injuries.

• Blast injuries due to fireworks most often affect the hands. 
• Other than the obvious superficial wounds that are seen on exam, the EP should be aware of significant cavitation and destruction of muscles that can occur in the forearm, thenar and hypothenar muscle groups which may be distal from the gross wound seen. 
• The energy from the blast is often transmitted through the carpal tunnel leading to an acute carpal tunnel syndrome from contusion of the median nerve.
• Patients should also be monitored for compartment syndrome.
• These patients can have significant injruies that are not immediately apparent. Consider observing these patients for awhile, or have them seen by hand surgery in case complications develop later on.

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The followings is a list of unique clinical findings related to a certain sedative-hypnotic overdose:

1) Hypothermia:Barbiturates, bromides, ethchlorvynol (others but these more pronounced)

2) Unique odors: chloral hydrate, ethchlorvynol (which is Placidyl)

3) Bradycardia: GHB (again others but pronounced in this OD)

4) Tachydysrhythmias: chloral hydrate

5) Muscular twitching: GHB, methaqualone, etomidate

6) Discolored urine: propofol (green/pink)

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• Xanthochromia is the yellowish discoloration of the supernatant from centrifuged cerebrospinal fluid (CSF).

• Xanthochromia is an abnormal finding and results from the lysis of red blood cells.

• Xanthochromia is present is CSF in > 90% of patients within 12 hours of subarachnoid hemorrhage (SAH) onset.

Coagulopathy from Acute Liver Failure

• ALF is defined as
  • absence of chronic liver disease
  • acute elevation in AST/ALT accompanied by INR > 1.5
  • any degree of mental status change (encephalopathy)
  • illness less than 26 weeks duration
• The most common cause is acetaminophen toxicity
• Regarding the coagulopathy that develops with ALF:
  • FFP transfusion is not encouraged, as the volume may exacerbate cerebral edema and it has been shown to be ineffective for improving INR elevations
  • The prophylactic transfusion of platelets for extreme thrombocytopenia is also not recommended for similar reasons

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Todays pearl pertains to a great new blog put together by Dr. Michelle Lin, entitled "Academic Life in Emergency Medicine." The blog is superb and is a great resource for anyone interested in academic EM.

Today's posting is about teaching when time is limited and Michelle discusses a really good article written by Irby, et al. This article addresses a topic that is very pertinent to us in the ED, how to teach when it is busy. Isn't it always busy?

Tips from the article:

1. Identify the learner needs (can't be successful without this important step)
2. Teach rapidly (great tips for how to do this in the ED)
3. Provide feedback (students are starving for this)

Want more??? Gotta check out the article....

Here is the link to the site:

http://AcademicLifeinEM.blogspot.com/ 

Enjoy!

Pericarditis is one of the conditions that is often misdiagnosed as STEMI, resulting in "inappropriate" cath lab interventions. In addition to producing STE, pericarditis also may produce dyspnea, diaphoresis, and elevations in TN levels, all of which will mimic true ACS.

On the other hand, pericarditis does NOT produce STE in up to one-third of cases, so the diagnosis may be missed. Non-STE cases of pericarditis occur more often in women, in patients with pericardial effusions, and in patients without preceding viral syndromes.

[Salisbury AC, et al. Frequency and predictors of urgent coronary angiography in patients with acute pericarditis. Mayo Clin Proc 2009;84:11-15.] 

Metacarpal Fractures and Growth Plates:

The growth plates on metacarpals are on the distal end of the bone, except for the 1st metacarpal which is on the proximal end near the carpal bones.

Don't mistake this for a fracture line, however, make sure you get comparison views if they are tender over the area, as this can help you diagnosis a Salter Harris Type 1 fracture.

Noninvasive ventilation use in children has been shown in some trials to be a useful tool to avoid intubation in children with asthma.

Since children with asthma who are intubated have a much higher risk for complications including pneumotharaces and pneumomediastinum this can be a very useful tool.

Bi-Pap is usually started with typical settings of 10 for IPAP and 5 for EPAP and can be titrated up as tolerated to levels of up to 25/20 cm H2O and can be delivered with a set rate or a back up rate.

Albuterol and nebulized epiephrine may be delivered through newer BiPAP machines.  

Signs that BiPAP is working include decreased Respiratory Rate, decreased retractions and accesory muscle use, improved oxygenation saturation

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A patient presents to the University of MD ED in generalized convulsive status epilepticus. Continuous seizure activity that is not stopped by any dose of benzodiazepine [This is actually a very rare entity]. What is your next move?

- Check your basics: Fingerstick blood glucose (hypoglycemics can cause SE)

- Phenytoin is not going to work fast enough, the clock is ticking and the patient's brain cannot handle continuous status epilepticus, after 45-60min permanent neurologic sequelae or death will occur. If the cause is toxin induced, it just won't work.

- In an area where HIV is endemic, you have to consider Isoniazid - an antituberculous drug - and administer antidotal therapy: empiric dosing of vitamin B6 (pyridoxine) 5g IV. It is the only thing that will work.

- From the ED perspective, you will also be using a barbituate though there is evidence to support the use of propofol (after intubation for both). This will hopefully stop the seizure

- General anesthesia is the last chance if all else fails.

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• Several conditions cause increased intracranial pressure (ICP), requiring lumbar puncture (LP) with opening pressure (OP) measurement for diagnostic and therapeutic management.

• Examples of such include:  pseudotumor cerebri, (cryptococcal) meningitis, intracranial mass, and intracranial hemorrhage.

• In order to ensure an accurate measurement, OP should be assessed while the patient is in the lateral decubitus position with the neck and legs in a neutral position.

• Normal OP ranges from 10 to 100 mm H₂0 in children, 60 to 200 mm H₂0 after age 8, and up to 250 mm H₂0 in the obese.  OP > 250 = intracranial hypertension.

• OP (the meniscus level) can fluctuate by 2 to 5 mm H20 with patient's pulse and by 4 to 10 mm H20 with patient's respirations.

• A patient's symptoms of headache and/or neurologic deficit is often relieved by lowering the ICP through slow removal of CSF during LP.  The pressure level should not be lowered by any more than 50% of the initial OP.

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The Maintenance Phase of Therapeutic Hypothermia

Therapeutic hypothermia (TH) has become standard in the care of patients with return of spontaneous circulation from cardiac arrest.  Although the optimal duration of TH is unknown, current literature supports 12-24 hours of cooling to 32-34^oC.  As many of our critically ill patients remain in the ED for seemingly endless lengths of stay, it is likely that most emergency physicians will be managing patients with TH during the maintenance phase of cooling.  Some pearls regarding the maintenance phase:

• Metabolic and hemodynamic homeostasis is critical
• Target volume-cycled mechanical ventilation to maintain a normal pH
• Maintain a MAP > 65 mm Hg
• Maintain blood glucose between 120 - 160 mg/dL
• Frequently check and aggressively replete potassium, magnesium, and phospate

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Elderly are more likely to have non-diagnostic ECGs. The proportion of patients > 85 years of age with NSTEACS who had non-diagnostic ECGs was 43% vs. 23% for patients < 65 years of age. [Elderly are also more likely to have LBBB as well as prior evidence of MI, either one of which can cause some problems with interpretation of acute cardiac ischemia.] The lack of CP combined with non-diagnostic ECGs probably leads to delays and under-treatment of many of these patients.

[Alexander KP, et al. Acute coronary care in the elderly, part I: Non-ST-segment elevation acute coronary syndromes. Circulation 2007;115:2549-2569.]

• Characterized by proteinuria, hypoalbuminemia, edema, and hypercholesterolemia
• Abnormal Vitals:  tachypnea (due to pulmlonary edema); tachycardia (intravascular depletion); hypertension
• Abnormal PE:  peripheral edema, ascites, S3 on ausculation
• UA demonstrates significant proteinuria.
• TX is uniformly with oral steroids.