UMEM Educational Pearls

Post-Arrest Tidal Volume Setting

  • Most patients with ROSC from out-of-hospital cardiac arrest undergo endotracheal intubation and mechanical ventilation.
  • Optimal management of mechanical ventilation for the post-arrest patient is currently not well defined.
  • A recent retrospective cohort study sought to determine if a lower tidal volume (Vt) was associated with improved neurocognitive outcome at hospital discharge.
  • Of 256 patients included in the study, investigators found:
    • 38% were ventilated with Vt > 8 ml/kg predicted body weight
    • Lower Vt was significantly associated with favorable neurocognitive outcome, decreased duration of mechanical ventilation, and decreased ICU length of stay
  • Take Home Pearl: Pay attention to Vt in the post-arrest patient.

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Question

Elective surgeries with general anesthesia are often cancelled when the child has an upper respiratory tract infection.  What are the adverse events when procedural sedation is used when the child has an upper respiratory tract infection?

Recent and current URIs were associated with an increased frequency of airway adverse events (AAE).  The frequency of AAEs increased from recent URIs, to current URIs with thin secretions to current URIs with thick secretions.   Adverse events not related to the airway were less likely to have a statistically significant difference between the URI and non-URI groups

AAEs for children with no URI was 6.3%.  Children with URI with thick/green secretions had AAEs in 22.2% of cases.  Children with URIs did NOT have a significant increase in the risk of apnea or need for emergent airway intervention.  The rates of AAEs, however, still remains low regardless of URI status.

 

 

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During the past several years, several new classes of diabetic medications were introduced for clinical use, including SGLT2 inhibitors (canagliflozin, dapagliflozin and empagliflozin).

SGLT2 inhibitors prevent reabsorption of glucose in the proximal convoluted tubules in the kidney and does not alter insulin release.

A recent retrospective study (n=88) of 13 poison center data from January 2013 to December 2016 showed

  1. 91% of the patients were asymptomatic.  
  2. 7% developed minor symptoms (tachycardia, nausea/vomiting, abdominal pain, & confusion)
  3. 2% developed moderate symptoms (metabolic acidosis, hypertension [166/101], & hypokalemia)
  4. Hypoglycemia was not reported.

49 patients were evaluated in a health care facility (HCF) with 18 admissions. Referral to HCF was more common in pediatric patients. This was likely due to unfamiliarity with a new mediation and lack of toxicity data.

Other case reports have shown higher incidence of DKA with the therapeutic use of SGLT2 vs. other classes of DM medications.

 

Bottom line:

Limit data is available regarding the toxicologic profile of SGLT2 inhibitors.

Based upon this small retrospective study, hypoglycemia may not occur and majority of the patient experience minimal symptoms.

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Category: Neurology

Title: IV vs. Non-IV Benzodiazepines for Cessation of Seizures

Keywords: seizure, status epilepticus, benzodiazepine, RAMPART, pediatric (PubMed Search)

Posted: 9/13/2017 by WanTsu Wendy Chang, MD (Updated: 9/14/2017)
Click here to contact WanTsu Wendy Chang, MD

Question

IV vs. Non-IV Benzodiazepines for Cessation of Seizures

  • A meta-analysis by Alshehri et al. included 11 studies with a total of 1633 patients, comparing IV vs. non-IV benzodiazepines from any route (buccal, intranasal, intramuscular) for seizure cessation in status epilepticus.
  • They found that non-IV benzodiazepine is more effective than IV benzodiazepine in patients presenting without IV access.
  • The largest and highest quality study included in the meta-analysis was the RAMPART study, which was also the only study to include adults.
  • When considering pediatric studies only, there is no difference between IV vs. non-IV benzodiazepine in seizure cessation for status epilepticus.

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Category: Critical Care

Title: Negative-Pressure Pulmonary Edema

Keywords: respiratory failure, pulmonary edema, airway obstruction (PubMed Search)

Posted: 9/12/2017 by Kami Windsor, MD
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Question

Negative-pressure pulmonary edema (NPPE) is a well-documented entity that occurs after a patient makes strong inspiratory effort against a blocked airway. The negative pressure causes hydrostatic edema that can be life-threatening if not recognized, but if treated quickly and appropriately, usually resolves after 24-48 hours. These patients may have any type of airway obstruction, whether due to edema secondary to infection or allergy, laryngospasm, or traumatic disruption of the airway, such as in attempted hangings.

Management: 

1.     Alleviate or bypass the airway obstruction.

·      Usually via intubation; may require a surgical airway

·      If obstruction in an intubated patient is due to biting on tube or dyssynchrony, add bite-block (if not already in place), sedation, and even paralysis if needed.

2.     Provide positive pressure ventilation and oxygen supplementation.

3.     Use low tidal volume ventilation.

4.     In severe hypoxemia without shock, add a diuretic agent and consider additional measures such as proning and even ECMO if the hypoxemia is refractory to standard therapy.  

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Category: Orthopedics

Title: Viscosupplementation

Keywords: Knee OA, injection (PubMed Search)

Posted: 9/9/2017 by Brian Corwell, MD (Updated: 7/16/2024)
Click here to contact Brian Corwell, MD

 

Viscosupplementation

Hyaluronic acid (HA) is a high-molecular weight polysaccharide

A major component of synovial fluid and of cartilage

Major role of HA is as a lubricant, shock absorption, antinociceptive effect

               Used in veterinary medicine for decades

Multiple brands exist with differences based on the molecular weight and how they are produced

Use supported by the Cochrane database (2007, 2014) for knee OA

Post injection strength gains are due to pain relief

May have a role for those who cannot receive steroid injections

Inject in similar manner to intra articular steroids

Caution in those with known allergy to poultry /eggs

Risks: Local reaction (likely from preservative), injection site pain, infection, bleeding.



Category: Toxicology

Title: X-rays in poisoning diagnosis?

Keywords: Radiographs, poisoning (PubMed Search)

Posted: 9/7/2017 by Kathy Prybys, MD (Emailed: 9/8/2017) (Updated: 9/8/2017)
Click here to contact Kathy Prybys, MD

Question

Radiographs studies can be valuable in poisoning diagnosis, management, and prognosis.  Radiographic imaging should be utilized for the following toxins:

Heavy metals 
  • Iron (gastrointestinal)
  • Mercury (gastrointestinal, intravenous or subcutaneous)
  • Lead (bullets intraarticular, gastrointestinal foreign bodies, lead lines)
  • Zinc phosphide (gastrointestinal)

Container toxins - Body packers

  • Drug packets and vials

Sustained Released preparations

  • Potassium Chloride
Button Batteries and Coins

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There have been reports of “intoxication” or adverse effects among first responders and law enforcement due to exposure to a “powder” suspected to be fentanyl or its analog.

 

This has led to a significant concern among first responders and law enforcement when investigating or handling “powder” at the scene of overdose or drug enforcement related raids. (http://www.foxnews.com/health/2017/08/15/police-department-gets-hazmat-like-protective-gear-for-overdose-calls.html)

 

American College of Medical Toxicology and American Association of Clinical Toxicology recently published a position statement to help clarify the potential health risk associated with exposure to fentanyl and its analogs.

 

  1. Opioid toxicity is unlikely from incidental dermal exposure.
  2. Nitrile gloves provide sufficient protection against dermal exposure.
  3. N95 respirator provide sufficient protection against aerosolize fentanyl/opioids.
  4. Naloxone should be administered for patients with objective signs of opioid toxicity - hypoventilation and CNS depression – not for vague or subjective symptoms.


Category: International EM

Title: Top Natural Disasters By Death Toll

Keywords: Floods, earthquakes, hurricanes, natural disasters (PubMed Search)

Posted: 9/6/2017 by Jon Mark Hirshon, PhD, MPH, MD (Updated: 7/16/2024)
Click here to contact Jon Mark Hirshon, PhD, MPH, MD

With the recent destruction by Hurricane Harvey and the impending impact of Hurricane Irma, it is important to recognize the historical death toll from natural disasters. While the list can vary, here is a top ten list from the library of the National Oceanic and Atmospheric Administration:

Rank

Event

Location

Date

Death Toll (Estimate)

1

1931 Yellow River flood

Yellow River, China

Summer 1931

850,000-4,000,000

2

1887 Yellow River flood

Yellow River, China

September-October 1887

900,000-2,000,000

3

1970 Bhola cyclone

Ganges Delta, East Pakistan

November 13, 1970

500,000- 1,000,000

4

1201 Earthquake

Eastern Mediterranean

1201

1,000,000

5

1938 Yellow River flood

Yellow River, China

June 9th, 1938

500,000 - 900,000

6

Shaanxi Earthquake

Shaanxi Province, China

January 23, 1556

830,000

7

2004 Indian Ocean earthquake/tsunami

Indian Ocean

December 26, 2004

225,000-275,000

8

1881 Haiphong Cyclone

Haiphong, Vietnam

1881

300,000

9

1642 Kaifeng Flood

Kaifeng, Henan Province, China

1642

300,000

10

Tangshan Earthquake

Tangshan, China

July 28, 1976

242,000*

* Official Government figure. Estimated death toll as high as 655,000.

 

 

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Category: Geriatrics

Title: Falls in the Elderly (Submitted by Amal Mattu, MD)

Keywords: arrhythmia, syncope, fall (PubMed Search)

Posted: 9/4/2017 by Danya Khoujah, MBBS (Updated: 7/16/2024)
Click here to contact Danya Khoujah, MBBS

20% of unexplained falls in the elderly can be attributed to an arrhythmia.

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Category: Pharmacology & Therapeutics

Title: Alpha-Blockers for the Management of Ureteral Stones

Keywords: Ureteral stones, Alpha-blockers (PubMed Search)

Posted: 9/2/2017 by Wesley Oliver (Updated: 7/16/2024)
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Question

Alpha-blockers (tamsulosin, alfuzosin, doxazosin, and terazosin) are antagonists of alpha1A-adrenoreceptors, which results in the relaxation of ureteral smooth muscle.    Current evidence suggests alpha-blockers may be useful when ureteral stones are 5-10 mm; however, there is no evidence to support the use of alpha-blockers with stones <5 mm.  Patients with ureteral stones >10 mm were excluded from studies utilizing these medications.

The size of most ureteral stones will be unknown due to the lack of need for imaging able to measure stone size. Given that the median ureteral stone size is <5 mm, most patients will not benefit from the use of an alpha-blocker.

Also, keep in mind that the data for adverse events with alpha-blockers used for ureteral stones is limited and that these medications have a risk of hypotension.

 

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Category: Pediatrics

Title: VTE in Pediatrics

Keywords: VTE, Thrombophilia, Enoxaparin, Children, Thromboembolism (PubMed Search)

Posted: 9/1/2017 by Megan Cobb, MD
Click here to contact Megan Cobb, MD

Background:

There is an increased incidence of venous thromboembolic events (VTE) in pediatrics due to improved diagnosis and survival of children with VTE.

The mortality rate is estimated at 2%.

The most common etiologies vary by age - Central venous catheters in neonates and infants, and inherited thrombophilia in children and adolescents.

Learning Points:

  1. With neonates and infants, carefully assess medical history from neonatal period. Umbilical lines? PICC? Broviac? History of these is likely to be the cause.

  2. In children and adolescents, unprovoked VTE is most likely due to inherited thrombophilia, and can be DVT, PE, Portal venous thrombus, etc.

    1. Antithrombin deficiency: The first discovered inherited thrombophilia. The result is a lack of inhibition of coagulation factors – IIa, IXa, Xa, XIIa.

    2. Protein C or/and S deficiency: The result is lack of inhibition of activated Factor V.

    3. Factor V Leiden: Most common inherited thrombophilic defect. Resultant activated Factor V is resistant to normal Protein C and S activity.

    4. Prothrombin Mutation: Second most common inherited thrombophilia. The result is increased levels of prothrombin, which increases the half-life of factor Va.

  3. Initial treatment of clinically significant VTE can start with enoxaparin (1-1.5 mg/kg q12-24h, while checking Anti-Xa levels 4 hours after administration for therapeutic dosing.)

 

Pearl: Testing for thrombophilia is not always appropriate when diagnosing pediatric patients with their first VTE, but in children and adolescents with first diagnosed, unprovoked VTE, it is worthwhile to send off the initial hypercoaguability work up as this can affect the duration of treatment and need for testing or evaluation. Enoxaparin is a recommended medication to start therapeutic treatment of VTE, even in pediatric patients.

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Category: Toxicology

Title: Deadly in a drop!

Keywords: Botulinum, Dimethylmercury, VX, Tetrodotoxin (PubMed Search)

Posted: 8/17/2017 by Kathy Prybys, MD (Emailed: 8/31/2017) (Updated: 8/31/2017)
Click here to contact Kathy Prybys, MD

Botulinum
  • Most poisonous substance known to man
  • LD50 oral dose 1 mcg/kg
  • Heat labile single polypeptide chain undergoes proteolytic clevage irreverisibly binds  and blocks cholinergic transmission causing a deadly neuroparalytic syndrome
  • Rx: Botulin antitoxin (equine derived against Clostriduim botulinum A,B,E)
Dimethylmercury (CH3)2 Hg
  • Highly toxic, restricted availability is rapidly absorbed and metabolized to methylmercury crosses CNS
  • LD50 of 50 mcg/kg means a dose as little as 0.1ml can result in severe poisoning
  • Death of Darmouth inorganic chemist Karen Wetterhahn who spilled a few drops on back of her latex gloved hand, quickly permeated, and absorbed causing severe neurotoxocity and death 10 months later
  • Rx: Chelation

VX ("venomous agent X") 

  • Organophosphate nerve agent has been used as chemical weapon
  • Colorless, odorless, low volatility, and high lipophilicity
  • LD50 of 0.04mg/kg (10 mg). Death can occur within 15 minutes after absorption
  • Blocks acetylcholinesterase enzyme causing excess accumulation of acetylcholine at the neurojunction and cholinergic poisoning
  • Rx: Decontamination, Atropine, 2-PAM
Tetrodotoxin
  • 100 fresh and salt water varieties (pufferlike fish/blue ringed octopus, frogs)
  • Heat stable, water soluble found in fish skin, liver, ovaries,intestine, and muscle
  • 25 mg (0.000881 oz) expected to be lethal to a 75 kg person
  • Neurotoxicity by inhibition of Na-K pump and blockade neuromuscular transmission
  • Rx: Supportive measures

LD50 expresses the dose at which 50% of exposed population will die as a result of exposure.

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Background: Sedation and analgesia are key components for mechanically ventilated patients. While significant data exists regarding how to manage sedation and analgesia in the ICU setting, very little data exists on management in the ED.

Data: A prospective, single-center, observational study of mechanically-ventilated adult patients used linear regression to identify ED sedation practices and outcomes, with a focus on sedation characteristics using the Richmond Agitation-Sedation Scale (RASS).

Findings:

  • 15% of intubated patients had no sedation or analgesia ordered
  • 64% of intubated patients were documented as deeply-sedated (RASS -3 to -5)
  • Deep sedation was not only associated with more ventilator days, but also increased mortality, with an adjusted OR of 0.77 (95% CI 0.54-0.94) favoring patients with lighter sedation.


Bottom line:  Avoid early deep sedation in your intubated patients as this may be directly associated with increased mortality. Instead, a goal RASS of 0 to -2 should be appropriate for most non-paralyzed, mechanically-ventilated ED patients, extrapoloating from ICU guidelines.

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Category: Orthopedics

Title: Concussion outcome predictors

Keywords: Concussion recovery (PubMed Search)

Posted: 8/26/2017 by Brian Corwell, MD (Updated: 7/16/2024)
Click here to contact Brian Corwell, MD

There is tremendous interest in identifying factors that may influence outcome from sports related concussion.

The strongest predictor of slower recovery is the severity of symptoms in the 1-2 days post injury

     -Fewer Sx's in this time period predict a quicker recovery

Pre injury history of mental health problems, depression or migraine headaches predict a longer recovery course

Teenagers might be more vulnerable to having persistent symptoms with greater risk for girls than boys

Having a prior concussion is a risk for having a future concussion

The large majority of injured athletes recover from a clinical perspective within the first month of injury many within the first 10 days

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Category: Pediatrics

Title: What about Anaphylaxis in kids? (submitted by Yitschok Applebaum, MD)

Keywords: allergic reaction, anaphylaxis, auto-injector, epi-pen (PubMed Search)

Posted: 1/27/2017 by Mimi Lu, MD (Emailed: 8/25/2017) (Updated: 8/25/2017)
Click here to contact Mimi Lu, MD

What if you were out in public and a 1 year old child (est 10 kg) suddenly develops anaphylaxis but you only have an epinephrine auto-injector with the “adult” dose of 0.3 mg.  Is it safe to give?

Anaphylaxis is a life threatening emergency with mortality of up to 2% [1]. Early recognition is imperative and administration of timely Epinephrine is the single most important intervention [2]. While providers may be hesitant to administer epinephrine in older patients due to fear of precipitating adverse cardiovascular events, they may also hesitate in younger patients due to fear of overdose. 

Iimmediate administration with any dose available is recommended because:

  • the risks of untreated anaphylaxis are greater than the risk of over-treating with epinephrine.
  • 20% of Anaphylaxis patients require a second dose of Epinephrine [3].
  • The recommended IM dose of 0.01mg /kg was determined arbitrarily.
  • The vast majority of epinephrine overdoses are via IV injection at doses 100 - 1000 fold the recommended  IV dose [4]

Bottom line:

There are no absolute contraindications (including age) for epinephrine in patients with anaphylaxis.  Give the initial dose IM into the anterolateral thigh.

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Category: Toxicology

Title: Idarucizumab for Dabigatran reversal 2.0

Keywords: dabigatran reversal, Idarucizumab (PubMed Search)

Posted: 8/25/2017 by Hong Kim, MD
Click here to contact Hong Kim, MD

Question

Full cohort analysis idarucizumab for dabigatran associated bleeding was recently published in NEJM.

This study evaluated the laboratory correction of elevated ecarin clotting time or diluted thrombin time induced by dabigatran and time to either cessation of bleeding (Group A: patients with GI bleeding, traumatic bleeding, or ICH) or time to surgery (Group B: patients requiring surgical intervention within 8 hours).

Findings

Group A (n=301): Median time to the cessation of bleeding was 2.5 hours in 134 patients.

HOWEVER:

  • Bleeding cessation could not be determined in 67 patients
  • Cessation of bleeding could not be assess in 98 patients with ICH
  • Bleeding stopped spontaneously in 2 patients.

Group B (n=202): Median time to intended surgery after infusion of idarucizumab was 1.6 hours.

  • Normal hemostasis in 184 patients (93.4%), mildly abnormal in 10, and moderately abnormal in 3.
  • Many received PRBC and other blood products during surgery

Laboratory markers:

100% reversal of abnormal ecarin clotting time or diluted thrombin time within 4 hours after the administration

Mortality

  • 5 Day: Group A: 6.3% vs. Group B: 12.6%
  • 30 Day: Group A: 13.5% vs. Group B: 12.6%
  • 90 Day: Group A: 18.8% vs. Group B: 18.9%

 

Conclusion

Authors concluded thate idaurcizumab is an "effective" reversal agent for dabigatran.

Overall, the findings are more promising compared to the interim analysis that was published in 2015.

 

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Rapid detection of bacterial meningitis using point-of-care glucometer

  • CSF:blood glucose ratio is a useful characteristic in differentiating bacterial meningitis from viral meningitis. 
  • Normal CSF glucose is at least 2/3 of serum glucose level.
  • In bacterial meningitis, CSF:blood glucose ratio is usually <0.4
  • Rousseau et al. conducted a study comparing CSF:blood glucose ratio obtained using a bedside glucometer with the laboratory.
  • They found the optimal cutoff of CSF:blood glucose ratio using a bedside glucometer is 0.46 compared to 0.44 using the laboratory.
  • This proof-of-concept study suggests that a point-of-care glucometer can be used for rapid diagnosis of abnormal CSF:blood glucose ratio in the evaluation of meningitis.

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Hyponatremic Encephalopathy

  • Hyponatremic encephalopathy is a true emergency and due to hypoosmolar-induced cerebral edema.
  • In contrast to the asymptomatic patient with hyponatremia, treatment of hyponatremic encephalopathy is determined by symptoms and not the duration of hyponatremia.
  • Clinical manifestations include nausea, vomiting, headache, confusion, seizures, respiratory failure, and coma.
  • Hypertonic saliine is the treatment of choice
    • Administer 2 ml/kg 3% hypertonic saline (100 ml in many cases)
    • This will typically raise serum sodium 2 mEq/L
    • In most cases, a 4-6 mEq/L rise will reverse neurologic symptoms

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Category: Pediatrics

Title: Bacterial Meningitis in Pediatric Complex Febrile Seizures

Keywords: Febrile seizure, meningitis (PubMed Search)

Posted: 8/18/2017 by Jenny Guyther, MD (Updated: 7/16/2024)
Click here to contact Jenny Guyther, MD

Question

Febrile seizures occur in children 6 months through 5 year olds.  A complex febrile seizure occurs when the seizure is focal, prolonged (> 15 min), or occurs more than once in 24 hours.

The prevalence of bacterial meningitis in children with fever and seizure after the H flu and Strep pneumomoniae vaccine was introduced is 0.6% to 0.8%.  The prevalence of bacterial meningitis is 5x higher after a complex than simple seizure.

From the study referenced, those children with complex febrile seizures who had meningitis all had clinical exam findings suggestive of meningitis.  More studies are needed to provide definitive guidelines about when lumbar punctures are needed in these patients.

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