UMEM Educational Pearls

Auto-PEEP in the non-COPD patient

• In previous pearls we have discussed the concept of auto-peep in patients with expiratory flow limitation (asthma and COPD)
• Unexpected auto-peep can also occur in up to 35% of patients without asthma or COPD
• In these patients, auto-PEEP typically occurs with high minute ventilations (> 20 L/min) with shortened exhalation times or if exhalation is blocked (blocked ETT, exhalation valve, or PEEP valve)
• Recall that auto-PEEP increases the work of breathing, worsens gas exchange, and can cause hemodynamic compromise 
• Treatment of auto-PEEP can be as follows:
  • Change ventilator settings
    • increase expiratory time
    • decrease respiratory rate
    • decrease tidal volume
  • Reduce ventilatory demand
    • reduce anxiety, pain, fever with sedatives
  • Reduce flow resistance
    • large-bore ETT
    • frequent suctioning
  • Apply external PEEP

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The classic risk factors for coronary artery disease (e.g. hypertension, diabetes, smoking, etc.) are helpful at predicting the long-term risk of CAD, but they have limited utility at predicting whether a patient with acute symptoms is having an acute coronary syndrome or not. In one recent study of > 800 patients with suspected cardiac chest pain, 12% of patients with NO cardiac risk factors ruled-in for acute MI.

Never rule out ACS in a patient purely based on the absence of traditional cardiac risk factors!

[Body R, McDowell G, Carley S, et al. Do risk factors for chronic coronary heart disease help diagnose acute myocardial infarction in the Emergency Department? Resuscitation 2008;79:41-45.]

High altitude illnesses is typically called Acute mountain sickness (AMS) and is associated with two major complications high altitude pulmonary edema (HAPE) and high altitude cerebral edema (HACE).

Symptoms associated with AMS are headache, fatigue, nausea and vomiting, anorexia and insomia. Cough, Cyanosis, hypoxia, and dyspnea are associated with HAPE.  HACE is associated with progressive neurologic symptoms and can lead to ataxia and coma.

Factors that increase your risk for altitude illnesses are:

• Rate of ascent
• Elevation obtained
• Exertion on arrival to elevation
• Duration at that altitude
• Recent URI
• Previous symptoms of AMS

How do we know if we really need to put all those red eyes sent in from daycare centers and schools on antibiotics? The following study shows us why.

Bacterial Conjunctivitis in Children

• Prospective study in a children’s hospital ED
• Conjunctival swabs for culture were obtained from patients aged 1 mo - 18 yrs presenting with red or pink eye and/or the diagnosis of conjunctivitis
• 111 patients enrolled over one year
• Mean age of 33.2 mos, 55% male
• 87 patients (78%) had positive bacterial cultures
  • Nontypeable H influenzae = 82%
  • S pneumoniae = 16%
  • Staphylococcus aureus = 2.2%
• The combination of a history of gluey or sticky eyelids and the physical finding of mucoid or purulent discharge had a post-test probability of 96% that the infection was bacterial.(So when both these are present you definitely should treat)
• And since the majority of these children (78%) had positive cultures even if they only had a pink eye it is reasonable to use empirical ophthalmic antibiotic therapy in children who present with the complaint of a pink eye.

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Methylenedioxymethamphetamine (MDMA) or "Ecstasy"

A designer club drug that has been classified as a "hallucinogenic" amphetamine though it does not cause visual hallucinations like are reported with LSD. It has many of the sympathomimetic effects like other amphetamines but its main mechanism of action which both causes the euphoria and toxicity is serotonin agonism. Since Anti-diuretic hormone is released by the hypothalamus under the direct regulation of serotonin, there is a transient but dangerous episode of Syndrome of Inappropriate ADH (SIADH). Combined with the club culture and fear of dehydration while taking MDMA, patients ingest MDMA concomitantly with free water through the night further exacerbating the hyponatremia. The time sequence of events for these patient is (women appear genetically predisposed to this phenomena):

• Friday Night: Ingestion of MDMA (even one pill is enough) +/- free water
• Saturday Morning: headache, nausea, vomiting
• Saturday Afternoon: (Realizes its not a hangover) patient becomes confused progressing to unresponsive and eventually seizures
• Saturday Evening: Presents to ED with seizures

Treatment: Fluid restriction - this is the one time that the 1L NS Bolus can kill a patient with cerebral edema. If you must give fluid give 3% NaCl if there is symptomatic hyponatremia. Remember the patient has dropped their sodium in about 24 hours so you can replenish in about the same time quite safely and even faster in severe cases. Treated correctly, patients improve rapidly - within 24-48 hours. Read a great case report in the reference below.

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• It is crucial to be familiar with and use  the NIH Stroke Scale (NIHSS) to objectively describe the extent of a stroke, in a language universal to all physicians, particularly our neurology colleagues.
• This validated tool consists of 15 items and the scale ranges from 0-42.  The higher the number, the worst the stroke.
• The NIHSS does not have to be memorized, but rather accessible for reference when needed.
• Studies have validated an abbreviated, 5-item NIHSS that has the same predictive performance as the 15-item scale.  This scale ranges from 0-16.
• While this abbreviated scale was created primarily for use in the prehospital setting, it can certainly be performed in the ED prior to rushing the patient off the CT for a head scan, in order to provide your neurologist with some objective information in a timely fashion.
• The NIHSS-5 assesses the following functions, in decreasing order of importance in terms of prognosis:

              --  motor function (right leg)

              --  motor function (left leg)

              --  gaze

              --  visual fields

              --  language

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Ventilator Therapy for ED Patients with ARDS

• As we manage critically ill patients for longer periods of time, it is likely that many of us will manage patients who develop ARDS
• Current mortality for patients with ARDS ranges from 30-40%
• ED treatment for patients with ARDS includes treating the inciting event, supportive critical care, and ventilator management
• Current ventilator management in patients with ARDS includes:
  • avoiding alveolar overdistention (tidal volumes of 6 ml/kg)
  • maintaining F_iO₂ < 60% (mitigates oxygen toxicitty)
  • PEEP to prevent alveolar derecruitment (levels of 10-15 cm H₂O)
  • permissive hypercapnea

Reversal of Warfarin

Reversal of Warfarin can be accomplished by administering any of the following:

• Fresh Frozen Plasma (traditional reversal agent)
• Vitamin K (po, sub q, or IV)
• Prothrombin Complex Concentrates (PCC)-not yet available for use in the US (yet)

A few pearls:

• It doesn't take many units of FFP to lower someone's INR
• Don't forget volume considerations if you use FFP
• Vit K is pretty well tolerated but some patients will have an allergic reaction (more common with IV administration)
• These medications in general will be used for life-threatening bleeding (GI, CNS bleeds, retroperitoneal bleeds, etc)
• Prothrombin Complex Concentrates-rich in factors 2,7,9, and 10...perfect drug since Warfarin depletes these factors
• PCC associated with some increased thrombosis

Syncope patients are often misdiagnosed as having a seizure. Some factors favoring true syncope:
1. Preceding nausea or diaphoreses
2. Oriented (not confused) upon waking (no post-ictal period).
3. Age > 45
4. Prolonged sitting or standing before episode
5. History of CHF or CAD

Factors favoring seizures:
1. History of seizure disorder
2. Tongue biting
3. Confusion upon waking
4. Loss of consciousness > 5 min
5. Age < 45
6. Preceding aura
7. Observed unusual posturing, jerking, or head turning during episode

Management of Felons

• An abscess of distal finger that involves the pulp. 
• A difficult infection to treat due to fibrous septa that divide the pulp into multiple small compartments. 
• These septa run from the periosteum to the skin increasing the risk of osteomyelitis
• Patients typically present with a lot of pain, redness, and swelling.
• Typically triggered by a puncture wound (i.e.: splinter)
• Incision and Drainage can result in a:
  
  • anesthetic finger tip
  • unstable finger pad
  • neuroma
• If you are going to drain one it is recommended that you do a volar longitudinal incision down the middle of the finger pad or a high lateral incision. 
• The high lateral incision should be at about 5 mm below the nail plate border. This distance should allow for avoiding the more volar neurovascular structures.

For good photos of the incision technique please visit the reference article listed.

Clark, DC. Common Acute Hand Infections. Am Fam Physician 2003;68:2167-76

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With the cooler weather on us all our favorite viral infections will start to appear.  Included in this is the "slapped - cheek disease" Erythema infectiosum. 

Erythema Infectiosum

• An acute viral illness caused by parvovirus B-19
• Usually is seen in the winter and spring months
• Presents with mild fever, itching, headache, and arthralgias
• Usually have an erythematous, erysipeloid rash on the cheeks (slapped look) and a reticular rash (lace-like) on the arms
• No test are needed
• Management is supportive
• Children with chronic hemolytic anemias can develop an aplastic crisis from this infection

 Olanzapine (Zyprexa)

This is an atypical antipsychotic that gained popularity because it caused less sedation and fewer extrapyramidal effects. However, there are many other adverse effects that need to be emphasized. Some of these may contribute to a patient's condition in the ED:

• Hyperglycemia: has been reported to even cause hyperglycemic hyperosmolar nonketotic coma as well as DKA in patients that were not diabetic prior to initiation of olanzapine.
• Anticholinergic: one of the most anticholinergic antipsychotics, watch for polypharmacy. Perhaps the patients urinary retention and mild confusion is due to the many anticholinergic medications the patient is taking.
• Serotonin Syndrome: again a problem with polypharmacy and in overdose.

• There is mounting evidence in favor of effectively treating migraine headaches with antiemetic dopamine antagonists such as metoclopramide (Reglan) and prochlorperazine (Compazine) as primary parenteral management.

• Diphenhydramine (Benadryl) can be administered simultaneously with such agents to prevent akathisia and dystonic reactions.

• Apart from the prophylactic effects of diphenhydramine, it may also play a synergistic role is actually treating the symptoms.

• A recent study (Friedman, et al) showed no significant difference in the efficacy or adverse events of treating migraine with 20 mg of metoclopramide plus 25 mg of diphenhydramine versus 10 mg of prochlorperazine plus 25 mg of diphenhydramine, although there was an insignificant trend in favor of prochlorperazine lowering the pain score to a greater degree.

• Note that the 20 mg dose of metoclopramide is higher than what is traditionally used in most emergency departments, but escalating the dose of up to 20 mg over a few hours may be more efficacious (the slower the administration and the simultaneous use of diphenhydramine decreases risk of dystonic reactions).

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 Influenza and the Critically Ill

• It is that time of year again to be vigilant for cases of influenza
• Influenza is not benign and causes > 40,000 deaths per year and is the 7th leading cause of death in the US
• In the critically ill, the most severe disease occurs in patients > 65 and those with underlying cardiopulmonary disease
• Critically ill patients with influenza can present with fever, cough, bilateral interstitial infiltrates, hypoxemia, and leukopenia
• Other serious complications include myocarditis, encephalitis, and Reye syndrome
• Amantadine and rimantadine should no longer be used, as the resistance has risen to > 90% in some populations
• Oseltamivir (PO) and zanamivir (powder/inhalation) are the approved neuraminidase inhibitors; both decrease the severity and duration of illness; should be given as early as possible, preferably within 36 hours

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Anticoagulation with Heparin-How to Reverse?

So you just started Heparin on that ACS patient? Just bolused the patient in room 12 with the large PE with a slug of Heparin? The nurse tells you that one of them just vomited blood and the other just had a large bloody bowel movement. What to do, oh, what to do?

How to reverse Heparin...use Protamine:

• Protamine is obtained from the sperm of salmon and other species of fish....glad you know that now?
• Given IV, it binds to Heparin (Unfractionated Heparin) and inactivates it
• Administer Protamine (IV) at a dose of 1 mg for every 100 Units of Heparin given within the last four hours. Max dose 50 mg of Protamine. May give more than 50 mg, but use caution as may lead to bleeding
• If the dose of Protamine is exceeded, patients may bleed. Protamine is actually an anticoagulant. 
• Give slowly over 10 minutes as may cause anaphylactoid reaction
• Can use to reverse LMWH as well: 1mg Protamine per 1 mg of LMWH (Lovenox)

Amiodarone-induced hypothyroidism is well-reported and should be considered anytime a patient that chronically takes amiodarone presents with hypothyroid symptoms, including decompensated CHF, decreased mental status, or myxedema coma (e.g. bradycardia, hypotension, hypothermia). 

Other drugs that have been implicated in producing hypothyroidism include lithium, iodine, iodinated contrast, and sulfonamides.

Bisphenol A (BPA) is found in epoxy resins that line common food and beverage materials. There has been concern that this compound, like phthalates, may be causing harm through chronic low exposure. An epidemiologic study was performed and published in JAMA that has raised this question. Amazingly, the study did find that:

• Higher urinary BPA levels correlated with an increase incidence of: NIDDM, CAD and elevated liver enzymes
• Mechanism may be an estrogen effect, disruption of Beta-islet cell function and even obesity promoting effects
• Study was strictly epidemiologic but raises a serious public health concern that you will see in the news more

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-- Tourette Syndrome (TS) is an inherited neurological disorder characterized by repetitive involuntary movements and uncontrollable vocal sounds called tics.
-- Underlying defect is unknown; however, research suggests that it could be caused by abnormalities in serotonin and dopamine activity within the basal ganglia.
-- Associated behavioral problems include OCD, ADHD, anxiety, and depression.
 

Diagnostic criteria:

Can You Rely on Your Clinical Impression to Exclude SBP?

• SBP is an important can't miss diagnosis, as the mortality rate even for treated patients is approximately 20%
• The incidence of SBP ranges from 2.5% (clinic setting) to 12% of all patients admitted with decompensated cirrhosis
• SBP is diagnosed by a neutrophil count > 250 or a positive ascitic fluid culture obtained via paracentesis

• Can our clinical impression exclude SBP without performing a paracentesis? Unfortunately, the answer is NO.
• Sensitivity of physician clinical impression is just about 75%, with a specificity of 34%
• Fever is uncommon in patients with SBP (sensitivity as low as 17%)
• Take Home Point: only a diagnostic paracentesis can reliably exclude SBP in patients admitted for decompensated cirrhosis

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Cerebral Venous Sinus Thrombosis (CVST)

An uncommon but very serious entity that leads to three distinct types of presentations:

• Headache
• Seizures
• Stroke

Caused by thrombosis of one of the intracerebral venous sinuses (most commonly the transverse sinus) The major risk factor is hypercoagulable disease. May be the underlying cause of a majority of cases of idiopathic intracranial hypertension.

When to suspect:

• Headache with negative CT, negative LP, but high opening pressure
• In any patient with new onset idiopathic intracranial hypertension (i.e. pseudotumor cerebri). Can't be formally diagnosed without a negative MRI.
• Stroke syndrome that doesn't quite fit. May see bilateral infarcts in the posterior regions. These are actually venous infarcts secondary to the sinus thrombosis.

Diagnosis:

• Just like a lot of other things in medicine, "If you don't think about it, you can't diagnose it."
• 1 in 3 head CT scans will be normal
• MRI with MRV (venous phase) is the diagnostic standard

Treat:

• Anticoagulation with heparin then warfarin