UMEM Educational Pearls

Extracorporeal Membrane Oxygenation

• In last week's pearl pertaining to critically ill patients with H1N1, I mentioned the use of ECMO as a potentially life-sustaining treatment for refractory respiratory failure.
• Essentially, ECMO removes blood from the patient and circulates it through an artificial lung with a pump.  For patients with respiratory failure, this is usually accomplished via cannulation of the femoral and internal jugular veins.
• General guidelines to consider ECMO in severe, refractory respiratory failure include:
  • P_aO₂ / F_iO₂ ratio < 100 on 100% F_iO₂ or A-a gradient > 600 mm Hg
  • Age < 65 years
  • No known contraindication to anticoagulation
  • Lack of significant co-morbidities (due to prolonged recovery after weaning from ECMO)

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Got some interesting info today on the costs of some commonly used antihypertensive medications. Keep in mind that in patients with severe hypertension, your options of IV drips are limited.

Here is some info from our hospital:

Fenoldopam - $113.28
Nicardipine - $94.67
Esmolol - $82.15
Nitroprusside - $20.86
Labetalol - $14.40
Nitroglycerin - $2.90

Although Fenoldopam (Corlopam), which has been around for years, is more expensive than Nitroprusside, it is just as effective and without the side effects.

A new drug on the market that we don't have yet, Clevidipine, is just as effective as the big guns Nipride and Fenoldopam. Costs at this point are unknown.

More on antihypertensive medications next week....

It's no secret that the elderly are at high risk for adverse drug effects. The average elderly patient takes 5 prescribed medications plus two over-the-counter medications. As many as 5% of admissions in the elderly are attributable to adverse drug effects. 

Anytime you prescribe a new medication to an elderly patient, ALWAYS check for the possibility of drug interactions.

Snuff Box Tenderness:

It has become the standard of care that individuals with snuff box tenderness, or pain with axial loading of the thumb, be placed in a thumb spica splint for 1-2 weeks until follow up x-rays can be done.  This is done to rule out an occult scaphoid fracture.  However, this practice can be hugely inconvenient to the patient and result in some atrophy of their forearm.

An alternative approach is to obtain a CT scan through the wrist to look specifically at the scaphoid bone.  If the CT scan is negative you can send them home with some pain control, RICE (Rest, Ice, Compression, Elevation) treatment and let them use thier thumb.  No splint is needed.  If it is positive then you can splint them and have them follow up with orthopedics or hand surgery.

This is a semi-synthetic opiate with partial agonist activity at the mu receptor. For an example of what a partial agonist is - see attached illustration. It is used in opioid addiction but is not as regulated as methadone clinics. Take a small course and you are licensed to prescribed it.  Primary caregivers are now able to administer buprenorphine to assist addicts though it is not recommended if the patient is requiring more than 40mg of methadone (rules out everyone in Baltimore).

The tablets (Suboxone) also contain naloxone to prevent intravenous injection which would induce withdrawal. Naloxone is not orally bioavailable and thus can be mixed into the pill.

Overdose is treated like any other opioid and naloxone should work.

Buprenorphine can illicit an opioid withdrawal response if the patient is currently on an opioid and then takes buprenorphine. 

Suppose to be safer than methadone - no QT prolongation and less respiratory depression

Attachments

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• Pregnant patients presenting with their first seizure, should essentially be managed in the same way as any other adult patient (i.e. Is the source of the seizure due to a reversible systemic condition, and if not, is the patient at risk for recurrent unprovoked seizures; specialist follow-up arrangement).

• Additional pregnancy-related conditions that can be associated with seizure, such as eclampsia and cerebral venous thrombosis, should be considered.

• While the safety of all anti-epileptic drugs in pregnancy is questionable, the use of valproate (Depakote) should definitely be avoided, given its compelling association with fetal malformations.

Critically Ill Patients with H1N1

• Three recent reports published online in the Journal of the Americal Medical Association (JAMA) detail the potential problems of H1N1 infection in the critically ill.
• The three studies (Mexico, Canada, Australia/New Zealand) seem to have recurring themes:
  • shock and multisystem organ failure were common
  • many were healthy, young adults who developed rapid respiratory failure
  • hypoxemia was prolonged and often refractory to conventional modes of mechanical ventilation
• Newer modes of ventilation and therapies were required to treat refractory hypoxemia.  These included high frequency oscillatory ventilation, prone positioning, neuromuscular blockade, nitric oxide, and extracorporeal membrane oxygenation.
• Take Home Point: Involve your intensivist early in the management of ED patients with respiratory failure and suspected H1N1 infection, as non-conventional methods of ventilation may be needed to treat hypoxemia.

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Management of Heparin-Induced Thrombocytopenia (HIT)

HIT occurs when antibodies form to a Heparin-Platelet Factor 4 (PF4) complex in patients who have been exposed to Heparin. 

The main clinical manifestation is thrombosis (arterial/venous). Treatment is unique in that only certain medications can be used.

Medical Management options in HIT:

• Direct thrombin inhibitors (DTI). The main ones used in clinical practice include Argatroban and Hirudin. These drugs work by directly binding to thrombin (fibrin bound) and inhibiting it. The drugs are reliable and safe. Hirudin may initiate an allergic reaction in patients who have been exposed and is renally cleared (so shouldn't be used in ESRD or lower GFRs)
• Fondaparinux (Arixtra). Can be given subcutaneously. More expensive. Also approved for once daily treatment of DVT/PE

So, when a patient with a history of HIT shows up in the ED with a DVT/PE or other thrombotic problem, these are your mainstay drugs.

The recent Baltimore City Marathon served as a nice reminder in a few cases that long-distance running and other ultra-endurance events can produce elevations in troponin levels. To review the non-cardiac-disease causes of troponin elevations:

sepsis, PE, COPD, carbon monoxide, intracranial abnormalities (including SAH, stroke, IC hemorrhage, seizures), ESRD, rhabdomyolysis, eclampsia and preeclampsia, extreme endurance exercises, UGI bleeding, LVH, catecholamine toxicity 

Reimburshment Pearls:

Often charts are down coded as it is not clear from the documentation that your medical decision making was complex.

For instance, if your final diagnosis is GERD, and you do not document that you were also concerned about angina or a pneumothorax your level 5 chart could be coded as a level 3, since the final diganosis does not seem that complex.  In order to prevent this document:

• Your differential diagnosis and ideally why you were concerned about them
• Instead of just checking a box stating that you reviewed old records take 5 seconds to summarize their last visit.  (i.e.: Admitted in May for CHF exacarebation, EF 50% by Echo, discharge on lasix).  This helps the coders prove that you looked at the chart and gives you 2 points for medical decision making.
• Document the response or initial lack of response to therapy. (i.e.: Asthmatics might get discharged home and still qualify for critical care time or a level 5 chart if you document how they initially responded to nebulizers and it was the magnesium that finally broke the cycle.)

I realize that when you are busy this might be the last thing on your mind, but the difference between a level III chart and a level V chart is about $100, and the only additional work is the 3 minutes it would take to document what you did for the patient.

More to come...

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While it is often ok to defer removal of pesky nasal foreign bodies until ENT follow up, if the foreign body may be a button battery, emergent identification and removal is indicated.

Damage can occur in 3 hours, and by 24 hours, near complete necrosis of turbinates and ala has been described.

• If the object may be a button battery, consider a plain film - if it doesn't show up, it isn't a battery, and you are in the clear.
• If you can clearly see the button battery, you can try to remove it - consider using a magnet if one is available - more on that in a future pearl.
• Lastly, if you cannot visualize the battery, if there is any evidence of content leakage, or if there is any tissue damage, emergently consult ENT for assistance - this is a surgical emergency.

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A 34 y/o m presents to the ED agitated and combative with the following vitals signs: T 104.6, P 136, BP 198/124. His urine toxicology screen is positive for amphetamines. 

• Controlled animal experience clearly contraindicates the use of phenothiazines (e.g. prochlorperazine, chlorpromazine) and butyrophenones (e.g. haloperidol, droperidol).
• In animal models, these drugs enhance toxicity (seizures) or lethality, or both.
• Additional concerns regarding these drugs include their ability to interfere with heat dissipation, exacerbate tachycardia, prolong the QTc interval, and induce torsades de pointes, or precipitate dystonic reactions.

• Strokes resulting from embolic or thrombic insult to the middle cerebral artery (MCA) are common.

• These patients tend to present with contralateral motor deficit which is most pronounced in the upper extremity (and face), compared to the lower extremity.

• If motor weakness is more pronounced in the lower extremity, consider an anterior cerebral artery (ACA) infarct as the source.

Damage Control Resuscitation

• "Damage control resucitation" is a term that is used to describe the resuscitation strategy of damage control surgical techniques and the tolerance of moderate hypotension, prevention of hypothermia, temporization of acidosis, and the correction of coagulopathy in the severly injured trauma patient.
• In terms of the "lethal triad", it is important to avoid interventions that may cause, or worsen, acidosis.
• A preventable and easily correctable cause of acidosis is hypoventilation.
• In the intubated trauma patient, pay close attention to the minute ventilation to avoid hypoventilation and the accumulation of CO₂.

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The top-normal value for ESR (sed rate) increases with age, such that the top-normal ESR value = (age +10)/2. For example, if you were checking the ESR for evaluation of temporal iritis in an 80yo patient, the top normal value of his ESR is 45.

I am sure everybody has received a patient from a nursing home that had a malfunctioning PEG tube.  Now if they would only crush the tablets before putting them down the tube, or better yet use liquid medications our life would be easier.

But what do you do if it is Friday and the GI lab is not open to Monday.  The answer is that you can remove the PEG and replace it with another PEG tube or even a foley catheter will do for the weekend.  The original PEG tube has a semi-rigid plastic ring (as shown in photo) and does not have a balloon that can be default.  You can pull these out by placing counter traction on the abdominal wall and pulling with steady firm pressure.  This may take a little more force than you are initially comfortable with.

Please see the attached photo of a PEG tube, and remember the other option is to admit these patients for IV fluids until the GI lab opens.

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While breastfeeding is still the preferred source of infant nutrition by the AAP, a little-known fact is that breastfeeding may expose the nursing infant to environmental pollutants to which they might not normally be exposed.  If you have a mother that appears ill due to exposure to any of these agents, don't forget to have the infant examined as well for signs of intoxication.

• Breastmilk can contain approximately 20% of the maternal toxin load, which can produce more severe effects in the infant due to the vastly different dose/weight ratio
• Toxin load is usually due to the lipid solubility of agents
• Formulas are safe due to the nature of their fat sources;  cows usually have a much lower exposure rate to pollutants, and those that are ingested are much more dilute due to the volume of milk produced in comparison to a human female;  also, with non-cows'-milk formulas, the lipid components are usually plant-derived and thus also with a lower risk of exposure
• Common offending agents include:  DDT, PCBs, Dioxin, hexachlorobenzene, Halothane, carbon disulfide, nicotine, lead, methylmercury, Heptachlor, Chlordane, and tetrachloroethylene

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• Should patients continue to seize even after administration of a benzodiazepine (i.e. lorazepam, diazepam) plus phenytoin, additional high-dose phenytoin should first be considered.

• While the standard loading dose for IV phenytoin is 10-20 mg/kg, it is recomended that up to 30 mg/kg of phenytoin be given for refractory status epilepticus prior to using another anti-epileptic, such as phenobarbital, pentobarbital infusion, or propofol infusion.

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Severe mitral regurgitation (MR) after MI, accompanied by cardiogenic shock carries a poor prognosis.

Severe MR in many cases is due to infarction of the posterior papillary muscle, and in these cases the area of infarction tends to be less extensive than in those with MR due to severe left ventricular dysfunction. 

Take Home Pearl:

The presence of pulmonary edema and/or cardiogenic shock in a patient with an inferior STEMI should prompt consideration for acute MR due to papilary muscle rupture. Get an echo as fast as you can to confirm or r/o the diagnosis. Treatment is afterload reduction, inotropic support, and urgent surgical repair. 

Don't forget about pheochromocytoma as a possible cause of severe hypertension...especially in those patients that are recalcitrant to "normal" medications. A few important points:
1. Incidence may be as high as 0.2% of patients with hypertension...sounds very rare, but statistically we'll all see some during our career.
2. Mortality may be as high as 10% if unrecognized; but if recognized and treated, excellent prognosis.
3. Suspect this in patients with intermittent episodes of flushing, palpitations, diaphoresis, headaches, and hypertension.
4. Treatment with beta blockers alone (including labetalol) may induce unopposed alpha-activity and worsen BP.
5. Treat with nitroprusside or phentolamine (an alpha blocker). Phentolamine is 5 mg IV, can be repeated every 5-10min as needed.
6. After phentolamine is given, there may be reflex tachycardia. NOW you can add beta blockers.

The most important thing is to keep the diagnosis in mind. It's out there! But you'll miss 100% of the diagnoses you don't consider.