UMEM Educational Pearls

The RV is a low-pressure chamber that doesn’t tolerate acute increases in pulmonary pressures (e.g., ARDS, pulmonary embolism, etc.); acute increases can lead to RV dysfunction / failure

Managing RV dysfunction requires a three-pronged approach:

• Optimize preload – give small fluid boluses (e.g., 250cc) but not too much, because too much can worsen RV function. Use ultrasound to determine volume status
• Optimize RV function – Consider starting inotropes (e.g., dobutamine) for better RV contractility and concurrently start pulmonary vasodilators (e.g., inhaled nitric oxide); also minimize hypoxemia and hypercarbia
• Prevent systemic hypotension – hypotension reduces coronary perfusion that leads to RV ischemia and dysfunction; use norepinephrine to keep blood pressure >65
• Bottom-line: Don't under-estimate the importance of the RV when resuscitating your patients 

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Question

You find this interesting view while scanning a patient. Which view is this and why should you care about it? 

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Sodium Supplementation and Exercise-Associated Hyponatremia (EAH) during Prolonged Exercise (ultramarathon running)

Weight loss of around 4% body weight (relative to pre race weight) can be anticipated to maintain euhydration in such a prolonged event

Those who become symptomatic with EAH have either gained weight or lost less that 3-4% body weight

Overhydration rather than inadequate supplemental sodium intake is a greater contributor to the development of EAH

There is a suggested link between EAH and rhabdomyolysis. The mechanism remains unknown and it is unclear which condition may augment the other. Further research is needed.

Take home: Avoid overhydration during prolonged exercise to prevent EAH.

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The answer may be no, as long as you have a serum HCO3. In this retrospective study, linear regression was used to to assess serum HCO3 as a predictor of venous pH. Logistic regression was also used to evaluate serum HCO3 as a predictor of DKA. Using a HCO3 cutoff of <18 mmol/L had a sensitivity of 91.8% and specificity of 91.7% for detecting a pH <7.3. A HCO3 < 8 had a sensitivity of 95.2 % and specificity of 96.7 % for detecting a pH <7.1.

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Introduction: As discussed in previous Pearls, Middle East respiratory syndrome coronavirus (MERS-CoV) is a recently emerged respiratory viral infection that is caused by a single stranded, positive-sense RNA novel coronavirus.

Updates:

As of August 12^th, 2015, WHO has received reports of:

• 1413 laboratory confirmed cases
• 502 deaths

The current reported case fatality rate is approximately 36%

Recent outbreaks have included

• Wide spread dissemination in Korea, which impacted multiple hospitals and near-by countries
• A very recent outbreak at King Abdulaziz Medical City in Riyadh, Saudi Arabia which has closed an emergency ward for two weeks. Of the approximately 46 people currently reported infected, at least 15 were medical personnel.

Bottom Line:

MERS-CoV is significantly contagious respiratory virus with high lethality.  It is spread primarily as an airborne virus, though the CDC currently recommends both standard contact and airborne precautions. There is currently no vaccine and only supportive treatment is advised.

Don’t be a vector or have your emergency department be a nidus of infection! Take appropriate precautions, including:

• Minimize chances of exposure when patients arrive
  • Have them wear a face mask if they have respiratory symptoms
  • During triage and throughout the visit, have patients adhere to respiratory hygiene and cough etiquette, hand hygiene
• Adhere to standard contact and airborne precautions
• Use caution when performing aerosol-generating procedures

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People who hide illicit drugs can be classified in to three different types.

1.     Body stuffers – people who ingest drugs that are poorly wrapped to “eliminate” evidence from police – e.g. street dealers.

2.     Body packers – people who ingest large amounts of “well” packed drug packets to transport drugs (usually internationally) – aka “mule.”

3.     Body pushers – people hiding drugs in rectum or vagina.

Body stuffers are more frequently encountered in local ED compared to body packers. Stuffers can become symptomatic as the ingested drugs (cocaine, heroin, amphetamines) are often poorly wrapped (e.g. in plastic bag/wrap, cellophane paper, aluminium oil, etc.).

Recent retrospective article looked at the utility of 6-hour observation period in the ED as a management strategy for body stuffers. (n=126)

Characteristics

1.     Ingested drugs (self-reported): heroin (48%), cocaine (46%), other drugs [cannabis, MDMA, diazepam, methamphetamine] (16%), unknown (8%)

2.     Time of ingestion to ED presentation

• < 2 hr: 58%
• 2-6 hr: 10%
• > 6 hr: 7%

Clinical findings

76% of the patients experience clinical signs of toxidrome at time of presentation.

Most common findings:

• Hypertension: 30%
• Tachycardia: 20%
• Agitation: 16%

Patients who ingested heroin were more symptomatic vs. cocaine (87% vs. 70%)

Patients were discharged:

• Within 6 hr: 72%
• Between 6 – 12 hr: 10%
• Between 12-24 hr: 10%
• > 24 hr: 8%

Conclusion

• Patients developed new or worsening drug toxicity within 6 hr of presentation
• Majority of patients were discharged within 6 hr.
• Asymptomatic patients at ED presentation should be observed for 6 hr.

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Pressure Regulated Volume Control (PRVC)

Here are some basic pearls about PRVC Ventilation

• Form of Assist Control (AC) ventilation: patient initiated or ventilator intiated
• Constant pressure through inspiration
• Decelerating inspiratory flow pattern
• Ventilator adjusts pressure breath to breath based on patient’s airway resistance and compliance
• Not recommended for asthma or COPD
• Set: RR, tidal volume, upper pressure limit, oxygen level, I:E ratio (can start at 1:2), PEEP

Benefits: minimum PIP, guaranteed tidal volume, patient can trigger more breaths, improved oxygenation, breath by breath changes 

Question

55 year-old male presents with chest pain. Echo is shown below (parasternal long-axis on the left and aortic root / ascending aorta on the right), what's the diagnosis?

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Flumazenil is generally avoided in most adult patients with suspected benzodiazepine overdose due to resedation, seizures/withdrawal, inconsistent reversal of respiratory depression, and the potential for proconvulsant coingestants.

Three relatively recent poison center studies have attempted to demonstrate the safety of flumazenil in this setting. [1-3] In the first study there were 904 adult patients with 13 reported seizures and 1 death. [1] A second study specific to pediatric patients reported 83 patients with no seizures and no deaths. [2] A third study found 80 patients with 1 seizure and 0 deaths. [3]

On the surface, it may appear that flumazenil is safe to give. But, retrospective poison center studies from voluntary reporting cannot be used to prove a drug's safety. The true denominator is unknown. In the pediatric study, we wouldn't expect children to experience withdrawal since they aren't on chronic benzodiazepine therapy. [2] So, it's no surprise there weren't any seizures or deaths.

A recent systematic review and meta-analysis of randomized trials summed it up perfectly: "Flumazenil should not be used routinely, and the harms and benefits should be considered carefully in every patient." [4] Cases in which to consider flumazenil are pediatric patients and reversal of procedural sedation if needed.

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Neuroimaging Tip - Loss of the Insular Ribbon Sign

• Loss of the insular ribbon sign refers to loss of the gray-white differentiation of the insular cortex.
• This is an early sign of middle cerebral artery (MCA) stroke.
• The insular cortex has less collateral blood supply from the anterior cerebral artery (ACA) and posterior cerebral artery (PCA) than other portions of the MCA territory; thus making it more susceptible to ischemia.

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Is It Really ARDS?

• Recent literature suggests that the incidence of ARDS in intubated ED patients may be as high as 10%.
• The Berlin Definition of ARDS includes the acute onset of bliateral opacities (CXR or chest CT) that is not fully explained by pulmonary edema or fluid overload.
• Emergency physicians and Intensivists are well versed in lung-protective ventilator settings for patients with ARDS.
• However, several diseases can appear simliar to ARDS and may require different ventilator strategies and treatments.
• In the absence of clinical risk factors for ARDS (e.g., sepsis, trauma), consider the following in your differential:
  • Idiopathic pulmonary fibrosis
  • Interstitial pneumonitis
  • Granulomatosis with polyangitis (Wegener's)
  • Diffuse alveolar hemorrhage
  • Goodpasture's syndrome

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Question

64 year-old male with no past medical history presents complaining of chronic weight-loss and diffuse chest pain; CXR is shown. What's the diagnosis and what other disease(s) may present similarly?

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Handcuff Neuropathy

Compression of the superficial radial nerve against the radius.

Tends to occur with prisoners (too tight cuffs or person struggling)

Usually purely sensory lesion

Nerve regeneration can take 8 weeks (about an inch a month)

Document sensory exam to sharps or 2 point sensation.

DDx: De Quervain's, Carpal tunnel, Gamekeeper's thumb,

No need to splint

A recent meta-analysis published in Pediatrics reviews the diagnostic accuracy of lung ultrasound for pneumonia. According to the commentary, pneumonia is the leading cause of illness and death in children worldwide; it accounts for 18% of the total number of deaths in children <5 years, more than TB, AIDS, and malaria combined.

They performed a systematic search on several major databases using a combination of controlled keywords for age <18 years, pneumonia, and ultrasound. Of the initially 1475 identified studies, 8 were ultimately chosen for further evaluation.

Characterizing the meta-analysis:

- Three were conducted in the ED, 2 on the wards, 1 in the PICU and 2 in the NICU.

- Of the 765 children encompassed, the mean age was 5 years and they were 52% boys.

- Five of the 8 studies noted using highly skilled sonographers.

- The studies originated from Italy (5), US (1), China (1) and Egypt (1).

- All studies used CXR +/- clinical criteria as the diagnostic standard; LUS assessment was blinded to associated CXR results in 7 of 8 studies.

Results:

- LUS in the diagnosis of pediatric pneumonia had an overall pooled sensitivity of 96% (95% confidence interval [CI]: 94-97%) and specificity of 93% (95% CI: 90-96%).

- Positive and negative likelihood ratios were 15.3 (95% CI: 6.6-35.3) and 0.06 (95% CI: .03-0.11), respectively. For reference, remember that an LR >1 indicates an increased probability that the target disorder is present and >10 is a large or often conclusive increase in the likelihood of disease. Likewise, an LR <1 indicates a decreased probability that the target disorder is present and <0.1 is large or often conclusive decrease in the likelihood of disease.

- The area under the receiver operating characteristic (ROC) curve was 0.98. The ROC curve represents a measure of the accuracy of a test, >0.9 is considered to be excellent.

- In order to determine whether there are genuine differences underlying the results of the studies (heterogeneity) the I-squared statistic was implemented, with values consistent >0.45, demonstrating significant heterogeneity.

Bottom line: LUS appears to be an accurate test for the diagnosis of pneumonia in children. The limitation of this meta-analysis is mainly in the small number of studies and the significant heterogeneity between them, likely due at least in part to the fact that they used CXR +/- clinical data as the diagnostic standard. Nevertheless, the results provide evidence for the use of LUS as a cost-effective tool that potentially eliminates ionizing-radiation from the work-up of pediatric pneumonia and has application potential in resource-limited settings.

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Poison ivy, oak, and sumac (Toxicodendron sp) causes a highly puritic, allergic contact dermatitits (ACD) that affects between 10 and 50 million in the US every year. It is a significant occupational hazard as well a scourge for outdoor enthusiasts.

Toxicodendron species contain oleoresins, known as Urushiol compound, secreted by all parts of the plant. Contact with the oil usually occurs by brushing against or direct handling of the plant or contaminated items. This toxin triggers a type IV delayed hypersensitivity reaction in approximately 75% of the population. Within 12-24 hours an erythematous, often linear, vesicular rash develops but new lesions can occur up to 2 weeks later.

There is no ideal treatment for ACD induced by Toxicodendron species. Avoidance and barrier protection are the best strategies. Recommended medications include antihistamines, topical preparations, and systemic steroids. However, steroids require a 2-3 week course to prevent recrudescence of the rash and are not without undesirable side affects.

Zanfel, an OTC granular polyethlene paste, removes urushiol by binding with it to create an aggregate cluster that can be washed away with water. It is highly effective, providing rapid relief even as a sole agent but requires multiple initial applications and is expensive. Mean Green hand scrub has similar ingredients and is claimed to bond urushiol also. Excessive scrathing and abrasive scrubs can cause secondary cellulitis requiring antibiotics.

Introduction

Obtaining quality information about emergency care in low- and middle-income countries (LMIC) is challenging.  Data is sparse and often of low quality and the number of peer reviewed publications is limited.

In order to address this, Obermeyer et. al. just published in the WHO Bulletin a systematic review of emergency care in 59 low- and middle-income countries.  In this article, the authors systematically reviewed 195 reports related to 192 facilities. The search included English or French articles from 1990 found within PubMed, CINAHL and World Health Organization (WHO) databases.

Burden of Emergency Care

Most articles were from emeregncy departments (EDs) in academically-affiliated hospitals in urban areas. Median mortality in the EDs was 1.8% (interquartile range, IQR: 0.2–5.1%), though in sub-Saharan Africa it was 3.4% (IQR: 0.5–6.3%).  The median number of patients seen per year was 30,000 (IQR: 10 296–60 000). The facilities were staffed primarily by physicians-in-training or by physicians whose level of training was unspecified.  There were very few providers specialized in emergency care.

Bottom Line

Based upon available data, there are high patient loads and mortality in LMIC- particularly in sub-Saharan Africa.  This report highlights the importance of emergency care and the opportunity for systematic improvement to reduce mortality in these countries.

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Ever forget all the things that make up MUDPILES in your AG acidosis differential?

Instead, consider the less-complicated mnemonic "KILR"!

K Ketoacidosis (diabetic, alcoholic, starvation)

I Ingestion (salicylate, acetaminophen, methanol, ethylene glycol, CO, CN, iron, INH)

L Lactic acidosis (infection, hemorrhage, hypoperfusion, alcohol, metformin)

R Renal (uremia)

Once you rule out the KLR causes, begin to consider ingestion or a tox source as your source. Remember that many of the listed ingestions can also cause a lactic acidosis.

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How much does the blood glucose concentration increase when dextrose 50% (D50) is administered?

A new study found a median increase of 4 mg/dL (0.2 mmol/L) per gram of D50 administered.

This retrospective study was conducted in critically ill patients who experienced hypoglycemia while receiving an insulin infusion. While it may not directly apply to all Emergency Department patients, an estimation of the expected blood glucose increase from rescue dextrose is helpful. If the blood glucose doesn't respond as anticipated, it can help us troubleshoot possible issues (eg, line access).

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Oral hypoglycemic agents (e.g. sulfonylureas) can cause symptomatic hypoglycemia. Unlike metformin, sulfonylureas stimulate the release of insulin from beta-cells (in pancreas) in response to serum glucose level.

ED management of hypoglycemia involves:

1. Dextrose (D₅₀ 50mL via IV) administration if symptomatic: e.g. altered mental status
2. Feeding: food items that are more substantial than juice: e.g. food tray or sandwich
3. Serial finger stick glucose check

However, for recurrent hypoglycemia (> 3 episodes of hypoglycemia), think about octreotide, rather than starting a dextrose (D₅) infusion.

For example, D₅ infusion at 150 mL/hour has only 7.5 gm of dextrose (calculation: D5% = 5gm/100 mL). One gram of dextrose contains about 4 calories (equivalent to one piece of Skittles) So, with a D₅ infusion at 150 mL/hour, you are giving your patients 8 pieces of Skittles per hour. A bottle of Snapple lemon ice tea (non-diet) has more calories (150 calories in 16 oz. or 473 mL)! 

Octreotide 50 mcg SQ (q6 hour) injection will decrease the insulin release from the beta-cell by blocking the voltage-gated Ca channel on the beta-cell.

All patient who received octreotide in the ED requires admission to the hospital for observation. Patients can be safely discharge from the hospital when finger stick glucose level remains normal for 24 hours after the last dose of octreotide.

Bottom line: In sulfonylrea-induced recurrent hypoglycemia, administer octreotide, rather than continuous infusion of dextrose (D₅) solution.

Every wonder what are the major global killers? Per the World Health Organization, the following were the top 20 causes. 

Not unexpected, diseases primarily of the elderly, such ischemic heart disease, stroke and chronic obstructive pulmonary disease are on the top of the list.  However, there are others, such as road traffic injuries and HIV/AIDS that could impact anyone.

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