UMEM Educational Pearls

Nitroprusside-Friend or Foe?

Nitroprusside is a direct venous and arteriolar vasodilator and is very effective at lowering blood pressure. It has been used for the treatment of hypertensive emergencies for many years and most of are comfortable with using it.

The problems with the drug:

• May cause precipitous drops in BP and lead to overshoot of BP target goals
• The drug is inactivated by light so the infusion bag and tubing must be protected  from light
• Frequently causes nausea, vomiting, and muscle twitching
• Most importantly, cyanide (CN) is released from nitroprusside in a dose-dependent fashion and may cause clinical toxicity
• Good alternatives exist: Fenoldopam as an example. Just as effective and without any of these side effects.

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Patients with catastrophic cardiovascular conditions often manifest with JVD + hypotension. The DDx for this combination is therefore critical to know:

1. large LV MI
2. right ventricular MI
3. cardiac tamponade
4. tension PTX
5. massive PE
6. acute mitral regurgitation
7. acute aortic regurgitation

You can make a diagnosis clinically among these 7 entities by:

1. Listening to the lungs
2. Listening for murmurs
3. Getting an ECG.

Of course if you have bedside U/S, it becomes even easier. ECG is almost always diagnostic with either the large LV MI or RV MI. Wet lungs found in large LV MI, acute MR, and acute AR. Murmur found in MR (systolic) and AR (diastolic).

Hamate Fractures:

• Typically the result of a direct blow, and the hook of the hamate is commonly fractured in batters or golfers.
• Like the scaphoid, the hook is at risk for avascular necrosis and non-union of the hook.
• Fractures of the body are more common than fracture of the hook of the hamate
• On exam you will typically find:
  • Increased pain with axial loading of ring (4th) and little finger (5th) metacarpals
  • Most patients complain of pain and tenderness on ulnar side of palm or on the dorsoulnar aspect of the wrist.
  • Pain also aggravated by grasping items.
• Diagnosis
  • Fracture often missed on routine AP & lateral films
  • Most fractures can be diagnosed by plain films if you as for the "Carpal tunnel view"
  • CT scan can also be used to see the fracture
• Treatment
  • Good Immobilization will often prevent avascular necrosis and allow early healing
    • Volar splint or short arm cast are usually adequate.
  • Excision of the hook of the hamate provides similar results as an ORIF in those that have non-union or displaced fractures.
  • Refer to orthopedics

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Serotonin is a neurotransmitter that has central and peripheral effects. It regulates the secretion of ADH from the hypothalamus and also controls the chemoreceptive trigger zone (CTZ) which induces emesis. Here are a list of medications categorized by the way they affect serotonin. Remember, any combination of these agonists could precipitate serotonin syndrome:

Enhance 5-HT synthesis: L-tryptophan

Direct HT agonists: Ergots, metoclopramide, sumatriptan, buspirone

Increase 5-HT release: amphetamines, cocaine, dextromethorphan, MDMA, L-dopa

Inhibit 5-HT breakdown: MAOIs, Linezolid

Inhibit 5-HT re-uptake: SSRIs (paxil), amphetamines, carbamazapine, tramadol, TCAs, citalopram, trazodone, lamotrigine, meperidine

 

• The first part of the NIH Stroke Scale assesses level of consciousness in 3 parts, 1A, 1B, and 1C.

• Part 1B assesses orientation by having the patient tell the examiner (1) their age and (2) the month.

• Part 1B is scored in the following manner:

          -- Answers both questions correctly = 0

          -- Answers one of the two questions correctly = 1

          -- Answers neither question correctly = 2

• If patient is unable to speak due to being intubated, having orotracheal trauma, dysarthria, a language barrier, or any other reason other than truly being aphasic, a score of 1 should be assigned.

Parainfluenza viruses (types 1, 2, 3) account for more than 65% of all cases. The different serotypes have seasonal patterns, with type 1 and 2 occuring in the autumn and being the most common pathogens associated with croup while type 3 is more frequent in the spring and summer and is associated with pneumonia and bronchiolitis.

Infections are rarely associated with high fever and usually last 4 to 5 days. There are no distinctive laboratory abnormalities, and diagnosis is generally made clinically.  Chest and neck xray may demonstrate a “steeple sign” from narrowing of the subglottic region.  Viral cultures and immunofluorescent rapid antigen identification can be obtained from respiratory secretions.  Specific antiviral therapy is not available. Aerosolized epinephrine can be given to severely affected, hospitalized patients to decrease airway obstruction.  Parental (>0.3mg/kg) and oral ((0.15mg/kg) dexamethasone have been demonstrated to lessen the severity and duration of symptoms and hospitalization in patients with moderate to severe croup.  
 

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Critical Illness-Related Corticosteroid Insufficiency (CIRCI)

• CIRCI is defined as inadequate corticosteroid activity for the severity of illness of a patient
• CIRCI arises due to steroid tissue resistance and inadequate circulating levels of free cortisol
• Hypotension refractory to fluids and requirement of vasopressors is the primary manifestation of CIRCI
• In contrast to chronic adrenal insufficiency, hyponatremia and hyperkalemia are uncommon
• Consider CIRCI in all critically ill patients requiring vasopressor support

So, which critically ill patients do you treat with steroids?  Current literature suggests the indications for steroid treatment include vasopressor dependent septic shock and persistent ARDS despite supportive therapy and lung protective ventilation.  A patient who requires only an hour or two of a vasopressor while being fluid resuscitated is unlikely to benefit.  An accepted dosing schedule is hydrocortisone 50 mg IV every 6 hours.

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Documentation of the Chest Pain Patient

Chest pain is a high risk entity in emergency medicine. And since many patients we see with chest pain are eventually discharged, we should consider what our charts should look like should we discharge a patient who has a missed life-threatening diagnosis. In other words, what would an attorney look for?

Considerations for the chart:

• Consider documenting some type of medical decision making in the chart. What were you thinking? Why didn't you think the patient needed cardiac enzymes, a CT, or admission? The chart should support your decision to send the patient home.
• Document a thorough history...enough said
• Document risk factors for the deadliy causes of chest pain (ACS, PE, dissection, etc.). This is frequently missing on charts.
• Consider documenting important, pertinent negative "chest pain physical exam findings," such as a normal leg exam (frequently missing on missed PE charts), no murmurs, equal pulses. Comments like this in the chart prove that you were thinking about a differential diagnosis. A question to ask yourself is, "Does my physical exam look like I was searching for the bad players of chest pain?"

Traditional teaching for patients with hypotension in the setting of MI and heart failure (i.e. not just RV MI) is to give dobutamine as a first-line agent when the SBP is 80-100, and to use dopamine when the SBP is 70-80s [note that this recommendation is NOT based on good evidence, but primarily on consensus opinion]. The problem with using these medications, especially at higher doses (e.g >10-15 mcg/kg/min) is that they result in excessive alpha-1 adrenergic stimulation that can produce end-organ ischemia.

However, there is some evidence that rather than using high dosages of dobutamine or dopamine, "the deliberate combination of dopamine and dobutamine at a dose of 7.5 mcg/kg/min each was shown to improve hemodynamics and limit important side effects compared with [high dosages of] either agent [alone]."

[Overgaard CB, Dzavik V. Inotropes and vasopressors: review of physiology and clinical use in cardiovascular disease. Circulation 2008;118:1047-1056.]

Lunate Dislocation and perilunate dislocation are broken down into 4 stages that relates to the progressive disruption of the carpal ligaments due to hyperextension and ulnar deviation of the wrist:

• Stage 1: Scapholunate Dislocation
  • Has the characteristic sign of widening of the scapholunate joint on the PA view known as the Terry Thomas Sign as it resembles the gap between his teeth
  • Gap between scaphoid and lunate should be less than 2 mm
• Stage II: Perilunate dislocation
  • Best seen on lateral view of the wrist
  • Associated with scaphoid fractures
  • Lunate stays in its normal position with the capitate dislocation posterior when you use the distal radius as your reference point
• Stage III: Perilunate dislocation
  • Also includes dislocation or fracture of the triguetrum
  • Triquetrial and scaphoid malrotation
  • In lateral view, all other carpal bones are dislocated posterior with respect to lunate
• Stage IV:  Lunate dislocation
  • On PA view you will see a triangular view of the lunate on the PA view that looks like a "piece of pie". 
  • On the lateral view of the wrist the lunate will look like a tea cup tipped in the volar direction AKA the "spilled teacup sign"
  • Associated with a scaphoid fracture
     

For a good indepth review of lunate and perilunate injuries please read the article by Andy Perron with this attached link.... doi:10.1053/ajem.2001.21306   

If you are interested in seeing some xray examples please visit LearningRadiology.com

 

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Goldfrank's sniffing bar: no this is not a pub where toxicologist's hang out but rather a bar that assists with teaching the recognition of odors related to toxicology. Certain drugs and compounds have a distinct aroma.

The following is a list odors, see if you can name a medication or compound that has that odor - scroll down further to see the corresponding answers (if you really got all 5 email me and convince me):

1) Bitter Almond

2) Rotten Eggs

3) Wintergreen

4) Garlic

5) Sweet, Fruity (acetone)

 

Answers:

1) Cyanide; 2) N-acetylcysteine or Hydrogen Sulfide; 3) Methylsalicylate (like bengay); 4) Arsenic, organophosphate insecticides; 5) Chloroform, chloral hydrate

• A patient's blood pressure should be maintained at less than 185/110 prior to receiving thrombolytics for stroke.

• The following medications should be used to address blood pressure control in these patients:

               Labetalol 10 to 20 mg IV over 1 to 2 minutes, may repeat x 1  

               OR

               Nitropaste 1 to 2 inches

               OR

               Nicardipine infusion at 5 mg per hour, titrate by 0.25 mg/hr at 5 to 10 minute intervals up to a maximum

               dose of of 15 mg/hr.  Once desired blood pressure is achieved, titrate down in increments of 3 mg/hr. 

          

Early Critical Care Management of Aneurysmal SAH

• 30,000 patients per year have an SAH
• Early ED management certainly should focus on airway assessment, emergent CT scanning, continuous caridac monitoring, and serial neurologic exams
• A few other pearls regarding management:
  • Volume management - maintain euvolemia with an isotonic crystalloid fluid
  • Anticonvulsants - routine use is associated with cognitive impairment and is not recommended
  • Steroids - once used to reduce meningeal irritation, however, there is no convincing evidence of a beneficial effect.  As such, corticosteroids are no longer recommended.
  • Rebleeding - risk of rebleeding is highest in first 24 hours after initial SAH.  Definitive prevention is done by repair via surgery or endovascular coiling.  A large, prospective study found outcome was better with endovascular coiling.

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Keys to a Successful Intubation

• Use both hands-bimanual laryngoscopy should be a routine part of ED intubations.
• Don't forget that you CAN let up cricoid pressure-this can actually obscure your view and make your job more difficult.
• For obese patients, make sure you elevate them. You want their ear level with their sternal notch. This might require A LOT of pillows or towels.
• Use a "straight-to-cuff" technique for stylet shaping. This is accomplished by making the stylet straight down to the cuff and then making a 15-20 degree bend at the cuff.

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A lot of what is taught about fracture patterns in abused children has been extrapolated from post-mortem studies which is a different population then what you will see in the Emergency Department. The study referenced did a metanalysis of all the literature in an attempt to determine what fractures suggest abuse and looked at all comers that had fractures.  Some of the patterns they were able to extrapolate are:

 

• Fractures from abuse predominately occurred in infants and toddlers
  • In children less than 12 one study showed that 80% of all fractures from abuse occurred in children less than 18 months old.
  • In children over 5 years old 85% of fractures are not caused by abuse
• In children under 3 years old, skull fractures were by far the most common fracture type in both abused and non-abused children.
  • However, the presense of a skull fracture only has a 1:3 chance of being from abuse.
  • Skull fractures location and type are similar between abuse and non-abuse, though multiple fractures and fractures that cross suture lines are more highly associated with abuse.
• There is a strong relationship between multiple fractures and abuse
  • 74% of abused children had two or more fractures compared to 16% of non-abused
• In the absence of a confirmed traumatic case, rib fractures have the highest probability (71%) of being caused by abuse.
• Humeral fractures have a 1:2 chance of being the result of abuse.
• Femur fracture like skull fractures have a 1:3 chance of being the result of abuse.

 

 

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• For children under 5 years of age the rate of missing an appendicitis remains very high.  (57%-67%)
• The rate of misdiagnosis increases as the age decreases. 
• In cases of missed appendicitis the most common incorrect diagnosis is gastroenteritis.
• Think twice before you label vomiting alone, or diarrhea alone as gastroenteritis.
• If an appendicitis is missed there is an increased risk of perforation, abscess formation, and higher morbidity. 

 

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Add metoclopramide (Reglan) to the laundry list of medications with black box warnings from the FDA. Why was a black box warning added?

• Long-term metoclopramide use has been linked to tardive dyskinesia (involuntary and repetitive body movements) even after the drug is no longer being taken.
• Risk factors: Long-term or high-dose use, elderly, female gender.
• Recommended that metoclopramide treatment not exceed 3 months.

• None really.
• Just be aware of the dopamine antagonist effects (EPS - dystonic reactions) that are possible whenever you order metoclopramide in the acute setting.
• These effects can be treated effectively with an anticholinergic agent, such as diphenhydramine or benztropine.

When performing the NIH Stroke Scale, keep the following conventions in mind:

-- Administer scale items in their exact order.
-- Avoid coaching the patient.
-- Accept the patient's first effort.
-- Be consistent.
-- Score only what the patient actually does.
-- Include all deficits in scoring.

Follow-up for the Hypertensive Patient

We see hypertensive patients every day, every shift. And, we discharge many of them. So, when do you get them follow-up?

The JNC-7 recommends that patients with BPs > 180/110 mm Hg have follow-up within 7 days. Like most of the HTN recommendations in the primary care setting, this recommendation is based on a "smart person" concensus....and no data.

This is a tremendous issue for us in the ED, because we don't want to see a bad outcome in our discharged hypertensive patients.

Some pearls regarding discharging the very hypertensive (but asymtomatic) patient:

• Since there isn't any realy data on follow-up, it would be wise to use caution and have very high BPs checked the next day and to NOT wait a week.
• Discharge instructions should note when/where (if you have to...use the ED as a recheck) the patient is to follow-up
• ALWAYS warn patients about what can/will happen if they don't seek follow-up: MI, stroke, renal failure/need for dialysis, death, and disability and write this in the chart. The last thing you want to hear is that the patient went on to develop renal failure/stroke, etc. and that they claim they were not warned about what could happen.
• When it is possible, contact the patient's doctor to discuss management

Non-invasive ventilation and standard mechanical ventilation can have very deleterious hemodynamic effects on patients with cardiac tamponade because of the drop in preload that results from positive pressure ventilation. The threshold for intubation in these patients should probably be raised. If you are ever caring for a patient with cardiac tamponade that definitely needs to be intubated and ventilated, be prepared for a significant drop in blood pressure and the potential need for pericardiocentesis. Once the patient is intubated, do everything possible to avoid high ventilatory pressures. [Ho AM, Graham CA, Ng CSH, et al. Timing of tracheal intubation in traumatic cardiac tamponade: a word of caution. Resuscitation 2009;80:272-274.]