UMEM Educational Pearls

Breath analyzers are commonly used by law enforcment officers to test for alcohol intoxication. Breath analyzer uses ethanol partition ratio between blood:breath of 1:2100 = 1 gm of ethanol in 2100 mL of breath/air.

Mouth wash products are frequently used for oral hygiene, and at times, to "mask" odor of substances. These products are readily available in any grocery stores or pharmacy and contain upto 26.9% ethanol (e.g. Listerine) (18.9% - Scope; 14.0% - Cepacol).  

Recently, a small study using healthy volunteers (n=11) was published to investigate the impact of limited ethanol exposure (mouth wash and ethanol vapor) on the breath-alcohol concentration (BrAC).

Method

1. Ethanol vapor exposure (856 mg/m3) for 15 minute. 
2. Oral rinse (for 30 sec) using mouth wash containing 22% ethanol, 1 hour after the ethanol vapor exposure
3. Blood and breath samples were collected before, between and after exposure.

Results

Blood: No or very low levels of ethanol (0.002 mg/g) were detected in blood at all collection time for both exposures.

BrAC - first collection -- seconds after exposure

• Ethanol vapor: 0.14 mg/L (0.014 mg/dL)
• Mouth wash: 4.4 mg/L (0.44 mg/dL)

Mean time to negative BrAC level (Swedish statutory limit of 0.1 mg/L = 0.01 mg/dL in air) (FYI: US limit = 80 mg/dL)

• Ethanol vapor: 0.5 min (0.06 - 0.7 min)
• Mouth wash: 11 min (6 - 15 min) 

Conclusion

• Ethanol vapor did not affect the BrAC
• Mouth wash use can transiently increase BrAC; however, their use does not sufficiently increase the BrAC to result in "false positive" based upon US limit.

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It's important to remember the differential for the patient with Ventricular Assist Device (VAD) difficulties, as these patients are likely to show up in your ED. 

1) Assess the patient as you usually would (signs of life, mental status, breathing, arrhythmias on monitor, etc). Listen for a hum over the chest.  Don't expect to feel a pulse.

2) Look at the VAD including controller, driveline, and power source for alarms, disconnections, signs of infection, and other obvious issues.

3) Look at the power (displayed flow), pulsatility index, and pump speed on the controller to help determine the cause of the issue (see attached chart).  Once you have a suspected etiology, typical management of these issues is usually similar to non-VAD patients (i.e. gentle IVF for hypovolemia, vasodilators if low flow is due to afterload/hypertension, defibrillation/CPR for arresting pts, etc).

Don't forget to call your VAD coordinator when able.  Consider a-line placement for precise evaluation of blood pressure (focus on MAP).

Bottom Line: Consider obstruction/thrombosis, bleeding, infection, hypovolemia, afterload/hypertension, arrhythmia, worsening LV function, and suction events when troubleshooting VADs.  The power, pulsatility index, and pump speed help differentiate these conditions.

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Attachments

• 1909092328_VAD_Differential.jpg (134 Kb)

Droperidol is a butyrophenone with primary action as a dopamine D2 receptor antagonist.  Historically, it has been used to treat a variety of conditions from nausea and headaches to acute agitation.  In 2001, the FDA issued a black box warning for risk of cardiac arrhythmias. Following this warning, droperidol was on national shortage for several years, further limiting its use.

Several months ago, droperidol returned to the US market and is available at some institutions. Below is a refresher on dosing and monitoring.  Similar to haloperidol, droperidol can cause extrapyramidal symptoms. Consider pre-treatment with diphenhydramine.

Dosing Recommendations:

Nausea and vomitting: 1.25 mg IV

Headache: 2.5 mg IV, 5 mg IM

Acute agitation: 5mg IM/IV

QTc prolongation is still a concern, especially at higher doses. If using doses > 2.5mg, or using repeated doses, obtain an ECG to ensure safe use of this medication. If the QTc is greater than 440 msec for males or 450 msec for females, droperidol is not recommended.  There is little data regarding the risk with lower doses. Utilize clinical judgement and assess patient risk factors.

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Numerous different household products can potentially be misused/abused. One such product is whipped cream charger/propellant that contains nitrous oxide.

Acute toxicity produce dose dependent response

• Euphoria 
• Anxiolysis
• Sedation
• Unconsciousness
• Asphyxiation

Chronic toxicity causes myeloneuropathy (demyelination of the dorsal and lateral columns of the spinal cord) due to vitamin B12 deficiency

• Extremity paresthesias
• Ataxia
• Peripheral sensory neuropathy (loss of vibration sense and proprioception)
• Weakness 
• Hematologic effects: leukopenia, thrombocytopenia, megaloblastic anemia

Management

• Cessation of nitrous oxide use
• Vitamin B12 (cyanocobalamin) repletion (IM)

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One third of your critically ill patients will have atrial fibrillation. 

More than one third of those patients will develop immediate hypotension because of it.

More than one in ten will develop ischemia or heart failure because of it.

This is what you should know for your next shift:

#1 Don't wait to use electricity. If your patient is hypotensive or ischemic because of atrial fibrillation, you do not need to wait for anticoagulation before you cardiovert.

#2 Electricity buys you time to load meds. Fewer than half of patients you cardiovert will be in sinus rhythm an hour later and fewer than a quarter at the end of a day.

#3 There is no perfect rate control agent. Beta blockers have a lower mortality in A-fib from sepsis. Esmolol has the benefit of being short-acting if you cause hypotension. Diltiazem has better sustained control than amiodarone or digoxin. 

#4 There is no perfect rhythm control agent. Magnesium is first-line in guidelines. Amiodarone can be used even when there is coronary artery or structural heart disease.

#5 Anticoagulation is controversial. In sepsis, anticoagulation does not reduce the rate of in-hospital stroke, but does increase the risk of bleeding. Use with caution if cardioversion isn't planned.

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There is no standardized national reporting of dog bites in the US. Based on the reported figures, it is estimated that 2% of Americans are bitten annually, and children are affected disproportionately. With kids, it's usually the family dog, and occurs at home.

To avoid infection, usually from Pasturella species, many of us were taught never to primarily repair dog bites by suturing, and to always prescribe prophylactic antibiotic coverage with amoxicillin-clavulanate. However, the literature recommends otherwise in certain cases.

Bite wounds to the face and hands should have special considerations.  In general, face wounds heal with lower rates of infection, but provide the greatest concern for cosmetic appearance.  Hand wounds have notoriously higher rates of infection.  

The latest recommendations for dog bites are as follows:

1. All dog bites should be copiously irrigated under high pressure.

2. Dog bites to the face should be primarily repaired when <8 hours old, as infection rates are not significantly different and cosmesis is greatly improved. 

3. Injuries to the hands should be left open, unless function is in jeopardy or there are neurovascular concerns.

4.  Prophylactic antibiotics do not always have to be prescribed, especially in low risk patients.  Examples of high risk patients include, but are not limited to: primarily repaired bites, injuries in the hand, >8 hours old, deep or macerated or multiple bites, and the immunocompromised.

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• Elevated BP is common with acute ICH and is associated with hematoma expansion and worse outcome.
• Early BP lowering in ICH appear to be safe, though did not improve outcomes in the two largest trials INTERACT2 and ATACH-II.
• A preplanned pooled analysis of 3829 patients from these 2 trials found:
  • Every 10 mmHg reduction in SBP was associated with a 10% increase in odds of better functional recovery.
  • Reduced variability of SBP was associated with improved outcomes.
• The association between BP variability and outcomes in ICH has been observed in several other recent studies.

Bottom Line: Reduced SBP variability is associated with improved outcomes in ICH.

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Critical Care Management of AIS

• In addition to reperfusion therapy, the critical care management of patients with an acute ischemic stroke also includes airway and ventilation management, hemodynamic management, glucose control, anticoagulation management, and surgery in select cases.
• Consider the following management pearls:
  • Mechanical ventilation
    • Target SpO2 > 94% (avoid supplemental oxygen for non-hypoxemic patients)
    • Target normocarbia (PaCO2 35-45 mmHg)
  • Hemodynamics
    • Target euvolemia with isotonic saline
    • Target BP < 185/110 mmHg for 24 hrs after tPA
    • Target BP < 220/120 mmHg if tPA ineligible
    • Target SBP < 160 mmHg after endovascular therapy
  • Glucose
    • Target serum glucose 140-180 mg/dL

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Tarsometatarsal fracture-dislocation

The Lisfranc ligament is critical for stabilization of the midfoot arch and the 2^nd MT

Injuries can range from mild (sprains) to severe (gross dislocation)

Injury may be purely ligamentous injuries or a fracture-dislocations

Difficult diagnosis to make

https://www.aafp.org/afp/1998/0701/afp19980701p118-f4.jpg

Mechanisms: MVAs, fall from height or athletic injuries

            Common athletic mechanism: Axial load to a hyperplantar flexed forefoot

https://thumbs.dreamstime.com/z/vector-illustration-healthy-human-foot-foot-lisfranc-injury-weight-bearing-mechanism-injury-100392176.jpg

Injury severity is often underestimated

Severe pain and inability to weight bear

Plantar bruising and bruising throughout midfoot

https://footeducation.com/wp-content/uploads/2019/02/Figure-3-Bruising-from-Lisfranc-Injury-600x781.png

No specific tests as exam is limited due to pain

Midfoot stress tests

-Often positive but unlikely to be allowed by patient due to pain

https://www.youtube.com/watch?v=v8SGVwz2RHs

Midfoot instability test

Grasp metatarsal heads and apply dorsal force to forefoot.

Other hand palpates the TMT joints and feels for dorsal subluxation

• The assessment of peripheral nerves in children with upper limb injuries can be challenging. 
• Neurovascular deficit was not documented in 25% of children presenting with upper extremity injury
• BOAST (British Orthopedic Association Standards for Trauma) guidelines state that each of the Median, Ulnar, Radial, Anterior Interosseous Nerve exams must be individually documented in any supracondylar fracture
• Dawson described an easy way to test and document your exam. Have the child play “Rock, Paper, Scissors, Ok”
  • Rock: tests the Median nerve
  • Paper: tests the Radial nerve
  • Scissors: tests the Ulnar nerve
  • Ok: tests the Anterior Interosseous nerve
• This method increased proper documentation and reduced missed nerve injuries in upper extremity fractures.
• Dr. Sarah Edwards and Dr. Hannah Lock created an easy infographic in the link below and found near 100% increase in NV documentation in their ED. Their poster won the prize for best infographic at the 2018 Emergency Medicine Educators' Conference (EMEC)
• https://www.peminfographics.com/infographics/rock-paper-scissors-ok

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Center for Disease Control and Prevention (CDC) recently issued alerts regarding cases of pulmonary illnesses that may be linked to "vaping" (in 15 states with 149 possible cases). These cases are still under investigation but all cases reported vaping weeks/months prior to hospitalization.

Most cases involve young adults who have been using THC-containing products

Common complaints included

• Gradual onset of shortness of breath, cough, and chest pain
• GI symptoms: nausea, vomiting and diarrhea
• Fever, fatigue

Imaging studies:

• Chest x-ray can show bilateral opacity
• CT lung demonstrates ground-glass opacities with sub-pleural sparing.

Clinical course

• Some cases required mechanical intubation
• Corticosteroid treatment appears to improve clinical course
• Infectious evaluation was negative in almost all cases.
• No clear causative etiology has been identified
• No death has been reported 

What to do:

• Inquire about vaping history when treating patients with suspected cases.
• Providers should contact their local health department, poison center or CDC (VapingAssocIllness@cdc.gov) to report possible case of vaping associated pulmonary injury 

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A new study confirmed the previously-known antibiotics to be associated with Torsades de pointes and QT prolongation (Macrolides, Linezolid, Imipenem and Fluoroquinolones). However, this study found new association between amikacin and Torsades de pointes/QT prolongation.

Methods

The authors queried the United States FDA Adverse Event Reporting System (FAERS) from 01/01/2015 to 12/31/2017 for reports of Torsade de points/QT prolongation (TdP/QT).

Reporting Odd Ratio (ROR) was calculated as the ratio of the odds of reporting TdP/QTP versus all other ADRs for a given drug, compared with these reporting odds for all other drugs present in FAERS

Results

FAERS contained 2,042,801 reports from January 1, 2015 to December 31, 2017. There were 3,960 TdP/QTP reports from the study period (0.19%).

Macrolides               ROR 14 (95% CI 11.8-17.38)

Linezolid                  ROR 12 (95% CI 8.5-18)

Amikacin                 ROR 11.8 (5.57-24.97)

Imipenem-cilastatin ROR 6.6 (3.13-13.9)

Fluoroquinolones   ROR 5.68 (95% CI 4.78-6.76)

Limitations:

These adverse events are voluntary reports

There might be other confounded by concomitant drugs such as ondansetron, azole anti-fungals, antipsychotics.

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Gunshot injuries are a leading cause of morbidity and mortality in the pediatric population.  The Pediatric Trauma Society supports the use of tourniquets in severe extremity trauma.  The Combat Application Tourniquet (CAT) that is commonly used in adults has not been prospectively tested in children.  This study used 60 children ages 6 through 16 years and applied a CAT to the upper arm and thigh while monitoring the peripheral pulse pressure by Doppler.  The CAT was successful in occluding arterial blood flow in all of the upper extremities and in 93% of the lower extremities.

Bottom line: The combat application tourniquet can stop arterial bleeding in the school aged child.

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Direct hepatotoxicity from a drug is predictable and dose-dependent.

Most commonly implicated agents include:

• Acetaminophen
• Niacin
• Aspirin
• Cocaine
• IV Amiodarone
• IV methotrexate
• Cancer chemotherapy

On the contrary, idiosyncratic prescription drug-induce liver injury is rare, unpredictable and not related to dose.

Most commonly implicated agents are:

1. Amoxicillin-clavulanate
2. Isoniazid
3. Nitrofurantoin
4. TMP-SMZ
5. Miocycline
6. Cefazolin
7. Azithromycin

Bottom line:

• Drug-induced liver injury is uncommon and can be a diagnostic challenge.
• Recognition of commonly implicated agents can help recognize/identify drug-induced liver injury. 

The Kidney Transplant Patient in Your ED

• Acute bacterial graft pyelonephritis is the most frequent type of sepis (bacterial pneumonia is the second most common source)
• Obtain renal transplant imaging to evaluate for sources of infection (i.e. urinary tract obstruction, renal abscess, or urine leakage)
• BK polyomavirus may reactivate and lead to nephritis, ureteral stenosis, or hemorrhagic cystitis
• Pneumocystis pneumonia is the most common fungal infection in patients without prophylaxis and after prophylaxis discontinuation (adjunctive steroids for treatment is controversial)
• Vascular access may be challenging. Avoid subclavian lines or femoral venous acess on the side of the graft
• Cardiovascular disease is the leading cause of mortality (accounts for 40-50% of deaths after the first year following renal transplant)

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Plica Syndrome

-A painful impairment of knee function resulting from thickened and inflamed synovial folds

Plicae are embryologic remnant inward folds of the synovial lining present in most knees

Most plica are asymptomatic

A pathological synovial plica can become inelastic, thickened and fibrotic. It may bowstring across the femoral trochlea at 70 to 100 degrees of knee flexion

Can be a cause of anterior knee pain/mechanical Sxs

Medial patellar plica most commonly involved

Hx: Snapping sensation, pain w/ sitting or repetitive activity

Anterior knee pain, clicking, clunking, and a popping sensation on knee loading activity such as squatting/stairs or with prolonged sitting

Many present with history of blunt trauma to the anterior knee

PE: A taut band of tissue that reproduces concordant pain with palpation

Tenderness in the medial parapatellar region

Painful, palpable medial parapatellar cord

-This can be rolled and popped beneath the examiners finger

The knee may be tender to the touch, swollen, and stiff 

Can be difficult to distinguish from other intra-articular conditions such as meniscal tears, articular cartilage injuries, or osteochondral lesions,

The examiner can then palpate for the plica by rolling one finger over the plica fold, which is located around the joint lines in anterior knee compartment

https://www.ortho.com.sg/wp-content/uploads/2018/04/medial-plica-syndrome-31-e1478966479644.jpg

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Managing the intubated patient with exacerbation of severe obstructive lung disease, especially asthma, can be very challenging as it carries higher risks of barotrauma due to higher pulmonary pressures and circulatory collapse due to auto-PEEP and decreased venous return. When measures such as medical therapy and noninvasive positive-pressure ventilation fail to prevent intubation, here are some tips to help:

1. Utilize a volume control ventilation mode to ensure a set tidal volume delivery / minute ventilation, as pressure-targeted modes will be more difficult due to the high pulmonary pressures in acute obstructive lung disease.

2. Set a low RR in order to allow for full exhalation, avoiding air-trapping / breath-stacking and circulatory collapse due to decreased venous return. This may require deep sedation and potentially paralysis.

• Permissive hypercapnea to >7.2 is generally well-tolerated except for pregnant patients, patients with high ICP, or patients with severe pulmonary hypertension

3. Increase your inspiratory flow by shortening your inspiratory time (thereby increasing your time for exhalation.

4. Monitor for auto-PEEP:

• Check your flow curve -- the waveform should return to zero before the start of the next inhalation, otherwise the next breath has been given before the patient has fully exhaled.
• Perform an expiratory hold at the end of exhalation. PEEP greater than set PEEP = auto-PEEP.

5. Peak inspiratory pressures will be high -- what is more important is the plateau pressure, measured by performing an inspiratory hold at the end of inspiration. Provided your plateau pressure remains <30, you don't need to worry as much about the peak pressure alarms.

6. If your patient acutely decompensates in terms of hemodynamics and oxygenation -- first attempt to decompress their likely auto-PEEPed lungs by popping them off the ventilator and manually press on their chest to assist with exhalation of stacked breaths allowing venous return to the heart.

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The American Diabetes Association requires a plasma glucose concentration greater than 250 mg/dL to diagnose diabetic ketoacidosis (DKA).  However, with the new diabetic agents this is not always the case. With the introduction of SGLT2 inhibitors (canagliflozin [Invokana], dapagliflozin [Farxiga], empagliflozin [Jardiance]) there have been reported cases of DKA and patients being euglycemic. 

Take Home Point

Patients with a low/normal blood glucose can still have DKA.  Especially if they are taking newer medications, such as the SGLT2 inhibitors.

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Hematologic toxicity (coagulopathy/bleeding) can occur with pit viper envenomation. Copperhead is the most commonly implicated pit viper envenomation in the U.S. However, the prevalence of hematologic toxicity from copperhead envenomation is variable, possibly due to regional variation in venom potency and species misidentification. 

An observation study was performing using multi-center (Virginia Commonweath university, University of Virginia Medical Center and Eastern Virginia Medical medical center) electronic hospital/medical records (Jan 1, 2006 to Dec 31, 2016) of suspected copperhead bites. Authors state that copperhead snakes are "nearly exclusively endemic" to the VCU and UVA medical center region.

Results:

388 patients were identified but 244 met inclusion/exclusion criteria.

• Mean age: 34 years
• Male: 59%
• Antivenom administration: 76%
• No bleeding was reported.

Hematologic toxicity: 14%

• Elevated PT: 10.0%
• Elevated PTT: 3.9%
• Thrombocytopenia: 1.2%
• Hypofibrinogenemia: 0.7%

Conclusion

In a small sample of copperhead envenomation in Virginia, “subtle” hematologic abnormalities were observed but clinically significant hematologic toxicity was not observed (i.e. bleeding)

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With increasing critical care boarding and the opioid crisis leading to more intubations for overdose, extubation - which was once a very rare event in the ED - is taking place downstairs more often.  Prolonged mechanical ventilation is associated with a ton of complications, so it's important for the ED physician to be comfortable assessing extubation readiness.  There is no single accepted set of criteria, but most commonly used are some variant of the following:

• Reason for intubation (e.g. overdose, pneumonia, pulmonary edema, AMS, etc) has resolved
• Minimal vent settings - Typically FiO2 < 40%, PEEP <= 5
• Spontaneous breathing present (i.e. pt breathes with reasonable rate on PS, SIMV, VS, PPS, etc) and able to maintain reasonable pH and pCO2 on these settings
• Neuromuscular function adequate - Ask patient to lift head off bed
• Mental status adequate - Ask patient to give thumbs up or squeeze hands
• Secretions tolerable - Ask RN or RT for frequency of suctioning and sputum character.  Think twice about extubation if getting purulent, thick secretions every 15 minutes.
• Clinical course does not require further intubation (i.e. no immediate trips planned to OR, MRI; pt not hemodynamically unstable, etc.)

If the above criteria are met, two additional tests are frequently considered:

• Spontaneous Breathing Trial (SBT) - Typically done by placing pt on PS with low settings (0/0 to 5/5).  Let pt equilibrate (time of SBT is variable) on these settings, then calculate RSBI (RR/Vt). RSBI < 105 is traditionally considered acceptable for extubation.  Remember - lower is better.  Ask RT for this. 
• Cuff Leak Test - becoming less popular, but may consider in patients at risk for laryngeal edema (e.g. prolonged intubation, angioedema, etc). Historically thought to predict airway swelling, but data is mixed.  Ask RT for this.

And don't forget to consider extubating high risk patients directly to BiPAP or HFNC!

Bottom Line: For conditions requiring intubation where significant clinical improvement may be expected while in the ED (e.g. overdose, flash pulmonary edema, etc), be vigilant about, and have a system for, assessing readiness for extubation.

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