• When considering starting a patient on non-invasive ventilation (NIV), ask yourself whether the patient is having a problem of oxygenation (Type I respiratory failure) or a problem of CO2 removal or ventilation (i.e., Type II respiratory failure); don’t forget both types can be present, simultaneously
• Examples of Type I problems are pneumonia and pulmonary edema; examples of Type II problems are COPD, drug overdose, and neuromuscular disease (e.g., myasthenia gravis). Once the underlying problem is identified, selecting the type of NIV is straight-forward. 
• There are only two interventions for type I disorders: 1) increase fio2 and/or 2) increase mean airway pressure (positive end-expiratory pressure; a.k.a. PEEP). There are only two interventions for type II disorders: 1) increase tidal volume and/or 2) increase respiratory rate 
• Continuous positive airway pressure (CPAP) only provides support for type I problems (i.e., can titrate FiO2 and PEEP); CPAP does not provide a tidal volume or a respiratory rate (needed for type II support)
• Bi-level positive airway pressure (BPAP) provides support for type II problems; tidal volume can be titrated by increasing the pressure support and a respiratory rate can be dialed in.

Editors note: The new Back 2 Basic series will review essential critical care concepts on the first Tuesday of each month. Want a specific topic reviewed? Contact us by email or Twitter.

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Question

10 year-old male complains of fever and rash (shown below); no other complaints. He went camping 10-days ago. What’s the diagnosis...and what medication(s) should he receive?

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Role of Magnesium in Cardiovascular Disease

* Magnesium (Mg2+) is an essential element that is obtained via dietary intake of leafy green vegetables, legumes, nuts/seeds, and whole grains; it is relatively deficient in the American diet.

* Mg2+ is critical for the normal physiological functioning of the vascular smooth muscle, endothelial cells, and myocardium. Several epidemiological and clinical studies have linked Mg2+ in the pathogenesis of cardiovascular disorders (CVD).

* Mg2+ is well known for its antiarrhythmic properties via modulation of myocardial excitability and in the pathogenesis and treatment of cardiac arrhythmias (polymorphic ventricular tachycardia/torsades de pointes & digoxin toxicity).

* Mg2+ supplementation has also been shown to cause significant decrease in ventricular ectopic beats and nonsustained ventricular tachycardia in NYHA class II–IV heart failure patients.

* A recent meta-analysis by Qu et al examined the association between dietary Mg2+ intake, serum Mg2+ levels, and the risk of total CVD events; the greatest reduction in CVD events was observed for intake between 150-400 mg/d.

* Given the magnitude of CVD and Mg2+-deficient diet in the US, there is a critical need to further investigate the interrelationship between Mg2+ and CVD events. Additionally increasing Mg2+ intake in the diet to maintain high normal serum Mg2+ level is both physiologic and judicious.

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Clindamycin used to be a first-line agent for many SSTIs, particularly where MRSA was suspected. With growing resistance to staph species, the 2014 IDSA Guidelines recommend clindamycin as an option only in the following situations:

• Nonpurulent SSTI (primarily strep species)
  • Mild - oral clindamycin
  • Moderate - IV clindamcyin
  • Severe, necrotizing infections - adjunctive clindamycin only with suspected or culture-confirmed strep pyogenes
• Purulent SSTI (primarily staph species)
  • Clindamycin only recommended in moderate or severe cases if cultures yield MSSA

* Clindamycin may be used if clindamycin resistance is <10-15% at the institution.

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Question

Background:

• With current medical advances and the adoption of healthier lifestyles, people are living longer.
• 65+ years old is the fastest growing segment of the global population
• In 1994:
  • 65+ accounted for 13% of the population
• By 2030:
  • Developed Countries: 65+ age segment of population will be larger than <65 age in many developed countries
  • Developing Countries: 75% of elderly will be living in lower and middle income countries with less well-developed health care systems

Relevance to the EM Physician:

• Elderly account for 12% to 24% of all ED visits
• Older patients present with a higher level of acuity and generally have more serious medical illness.
  • Arrive more often by ambulance
  • Higher rates of test use and longer ED stays
  • 2.5 to 4.6 times higher risk for hospitalization
  • 5-fold higher admission rate to an ICU
  • More likely to be misdiagnosed
  • More frequently discharged with unrecognized / untreated problems.

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Risk of infection from Blood transfusions

• We are already moving to decreasing transfusions in general for most of our hospital patients
• But now there is evidence that more transfusions can lead to an increase in nosocomial infections

JAMA Meta-Analysis

• 18 randomized trials with 7,593 patients
• All tested higher vs lower transfusion thresholds in a variety of inpatient settings
• Hospital-acquired infections were the outcome

What they found

• Absolute risk for nosocomial infection was 17% among patients with a higher hemoglobin target compared to 12% with a lower target
• NNT to avoid an infection was 38 using a restrictive transfusion strategy

Bottom Line

• Potential cost savings to the healthcare industry with less transfusions
• For most patients, a hemoglobin > 7 g/dL is just fine

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Question

49 year-old female on trimethoprim/sulfamethoxazole presents with a rash & lesions on her oral mucus membranes. What's the diagnosis?

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IVUS Plaque Correlation to Cardiovascular Death 

Several non-invasive studies are currently utilized for the identification of coronary artery disease  (i.e. coronary CTA, intravascular ultrasound- IVUS, etc.)

Few studies have quantified which of those with CAD (i.e. coronary plaques) are considered high-risk or unstable plaques

A recent study utilizing IVUS looked at autopsies over a 2 year-period comparing near-infrared detection of high-risk plaques and cardiovascular related deaths

IVUS findings associated with CAD are classified into 3 categories: echo-attenuation, echolucent zone, and spotty calcification

Echo-attenuated plaques, especially superficial echo-attenuation, was found to be a significant and reliable finding suggestive of vulnerable plaques and future cardiovascular death 

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Colchicine tablets and injectable solution is frequently used for the treatment of gout and familial Mediterranean fever.  An overdose is extremely serious, with considerable mortality that is often delayed.  It is considered a cellular poison due to its inhibition of cellular mitosis of dividing cells. 

After an acute overdose, symptoms typically are delayed for 2-12 hours and include nausea, vomiting, abdominal pain, and severe bloody diarrhea.

Chronic poisoning presens with a more insidious onset.

Late complications include bone marrow suppression, particularly leukopenia and thrombocytopenia (4-5 days) and alopecia (2-3 weeks).

Treatment includes aggressive supportive care, monitoring and treatment of fluid and electrolyte disturbances.

The usual cause of death from acute poisoning is due to hemodynamic collapse and cardiac arrhythmias (typically 24-36 hours after ingestion or could be sudden) or from infectious or hemorrhagic complications.

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General Information: Tetanus is caused by the toxin of Clostridium tetani--a gram-positive bacillus found in soil and animal excrement. It is a life-threatening but preventable disease. Cases have declined by > 95% in the past 65 years, but dozens of cases still occur annually in the US and it is still frequently seen in developing countries.

Clinical Presentation:

• Generalized increased rigidity
• Convulsive spasms of skeletal muscles
• Risus sardonicus (severe facial spasms with a “sardonic” smile)
• autonomic instability (fever, sweating, tachycardia, salivation, hyper- or hypo prefusion)
• Lucid mental state

Diagnosis:

Clinical Case Definition: In the absence of a more likely diagnosis, an acute illness with muscle spasms or hypertonia.  There is no diagnostic laboratory test for tetanus.

Treatment:

• Supportive care (including ventilator support as needed)
•  Control symptoms with muscle relaxants and anticonvulsants as needed
• Wound debridement and antibiotics (metronidazole, e.g. 0.5 gm every 6 hours) to decrease C tetani
• Passive immunization with human tetanus immune globulin (TIG) (may shorten course and decrease severity--Dose: TIG 3,000-6,000 units IM)
• Tetanus toxoid vaccine (clinical disease does not produce immunity!)

Bottom Line:

Tetanus is not as rare as we would like to think.  Acute diagnostic acumen and assertive clinical management can help save the life of someone with this potentially deadly disease

University of Maryland Section for Global Emergency Health

Author:  Jon Mark Hirshon, MD, MPH, PhD

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Prophylactic FFP for Procedures?

• FFP is commonly transfused to correct abnormal coagulation studies prior to performing procedures in nonbleeding critically ill patients.
• Despite common practice, there is little to no supportive evidence to demonstrate a clinical benefit to transfusing FFP in this patient population.
• Muller, et al recently evaluated the use of FFP before invasive procedures in critically ill patients.  Brief highlights include:
  • Prospective, randomized, open-label study at 4 sites in the Netherlands
  • 76 adult ICU patients with INRs between 1.5 and 3.0
  • Procedures: central line placement, thoracentesis, percutaneous tracheostomy
  • Result: no difference in major bleeding events between those who received FFP and those randomized to no FFP
• Take Home Point: In the nonbleeding critically ill patient, routine transfusion of FFP to correct lab abnormalities prior to procedures is not indicated.

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Question

35 year-old female presents with nausea and vomiting 1 week post-op for an abdominal surgery. Abdominal ultrasound is below; what's the diagnosis? 

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Some quick facts about Knee Injuries:

• The most common cause of acute traumatic hemarthrosis of the knee is an anterior cruciate ligament tear.
  • Most patients with an ACL injury will give a history of immediate pain, disability, knee swelling and audible pop.
• The most common ligament injuried in the knee is the medial collateral ligament.
• Patella dislocations
  • Usually lateral dislocations and often spontaneous reduce.
  • Hyperextend the knee to make the reduction easier.
• Dislocation of the knee:
  • Anterior is the most common and usually secondary to hyperextension
  • Popliteal artery injury is commonly seen and must be looked for.  Easy bedside test is Ankle Brachial Index.
  • Normal pulses do NOT exclude a vascular injury.
  • Patients should be monitored for vascular complications and compartment syndrome.
  • Vascular injuries due to knee dislocation are associated with a high rate of amputation, which markedly increases if not repaired within 6-8 hours.

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NAC is an effective antidote against acetaminophen (APAP) toxicity in preventing acute hepatotoxicity. It provides cysteine that is essential for glutathione synthesis and its availability is rate limiting.

Currently, PO and IV formulation is available in the U.S. Regardless of the route, NAC is equally effective in preventing APAP induced acute hepatotoxicity when administered within 8 hours after single acute ingestion. ¹

Adverse effects of NAC

1.     Anaphylactoid reaction

a.     More frequently reported with IV administration and during the first regimen of NAC (150 mg/kg over 60 min) administration. (dose and rate dependent)

b.     Higher risk of anaphylactoid reaction in patients with negative APAP vs. patients with elevated APAP level.²

c.      Management: Benadryl as needed and slow infusion rate.

2.     Hyponatremia in children if inappropriate volume of diluent (D5W) used. Dose calculator: http://acetadote.com/dosecalc.php

3.     Laboratory: increase Prothrombin time (PT).3

4.     Fatality from iatrogenic NAC overdose has been reported.

Advantage of IV NAC

1.     Convenience

2.     100% bioavailability

3.     Shorter hospital length of stay

4.     Minimum GI symptoms (nausea & vomiting) compared to PO route

Indication of IV NAC

1.     Severe hepatotoxicity or fulminant liver failure

2.     APAP poisoning during pregnancy

3.     Unable to tolerate PO intake (nausea, vomiting, altered mental status)

However many clinicians administer IV NAC for their advantages over PO NAC.

 Take home message:

1.     PO and IV NAC are equally effective when administered within 8 hours after single acute ingestion.

2.     Anaphylactoid reaction is frequently encountered AE during the infusion of 1^st NAC regimen and patients with negative/low APAP level may be at higher risk.

3.     No emergent need to start NAC in presumed acetaminophen overdose patients prior to obtaining APAP level.

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Clinical Presentation:

A 35-year-old female presents to your emergency department complaining of fever, malaise, myalgias, headache and an urticarial rash.  Her physical exam reveals a papular rash and hepatosplenomegaly. You also find out that she traveled to Sudan 6 weeks earlier. She stayed mostly in Kharotum, but while there, she swam in the Nile. You send a smear for malaria, which is negative.  What other major parasite should you consider?

Diagnosis:

• Schistosomiasis, also know as bilharzia, is a disease caused by parasitic worms.
• While not found in the US, it impacts more than 200 million people globally, and is second only to malaria as a major parasitic infection.

Discussion:

While the acute presentation is generally non-specific, chronic complications may be more serious. Many organ systems can be impacted and symptoms of chronic infection can include liver dysfunction, including portal hypertension and esophageal varacies or hematuria and renal failure.

Treatment:

• Treatment is a one-day course of Praziquantel but must be initiated 6-8 weeks after infection. (It's most effective against the adult worm so timing is key!)

Bottom Line:

Consider a broader differential in travelers. There are many infectious killers that can be easily treated.

University of Maryland Section of Global Emergency Health

Author: Jon Mark Hirshon, MD, MPH, PhD

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Thrombelastography for Management of Non-Traumatic Hemorrhagic Shock

The use of thrombelastography (TEG, ROTEM) has traditionally been utilized and studied in the management of acute coagulopathy of trauma (ACoT) developed by patients in hemorrhagic shock secondary to trauma.

Functional coagulation tests such as the TEG may provide valuable information when resuscitating the hemorrhaging patient, especially if there is any concern for an underlying coagulopathy.  

The following is a TEG recently returned during the resuscitation of a 60 y/o male with a history of HCV cirrhosis presenting with hemorrhagic shock secondary to a massive upper GIB.  The University's Massive Transfusion Protocol was promptly activated and at this point, the patient had received approximately 4 units of PRBCs & FFP along with 1 liter of crystalloid.  His Hgb was 5, PT/PTT/INR were undetectable, and his fibrinogen was 80.

Below is a table that simplifies the treatment, based on the test's abnormalities:

• Prolonged R:  Fresh frozen plasma
• Prolonged K or reduced α angle: Cryoprecipitate
• Low MA: Platelets, desmopressin (DDAVP)
• Elevated LY 30%: Consider antifibrinolytics (aminocaproic acid, TXA)

After reviewing the initial TEG, all perameters were abnormal in addition to the presence of significant fibrinolysis.  The patient was given an additional 4 units of FFP, DDAVP, cryoprecipitate, a unit of platelets, and aminocaproic acid.  The patient still required significant resuscitation, however bleeding had significantly decreased as well has his pressor requirement.  Below is the patient's follow-up TEG 2 hours later.

There is growing enthusiasm for the use of functional coagulopathy testing in the patient with hemorrhagic shock.  Early resuscitation with blood products as your fluid of choice with limited fluid administration while arranging for definitive source control are critical, but also consider early thrombelastography to detect additional causes for uncontrolled hemorrhage.

References

1. Walsh M, Thomas SG, Howard JC, et al. Blood component therapy in trauma guided with the utilization of the perfusionist and thromboelastography. Journal of Extra-Corporeal Technology. 2011 Sep; 43(3):162-7.
2. The Use of TEG & Goal Directed Blood Component Therapy.  MarylandCCProject.org

Follow Me On Twitter: @JohnGreenwoodMD
email: johncgreenwood@gmail.com

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Question

41year-old male without past medical history presents with the image below. What's the diagnosis and what's the most likely causative organism?

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Methadone prolongs the QTc interval. Is the degree of QTC widening correlated to worse outcomes after overdose?

The authors of a new study concluded the triage QTc can predict death, intubation, and respiratory arrest. QTc thresholds of 470, 447.5, and 450 msec had sensitivity (95 % CI) and specificity (95 % CI) of 87.5 (47.3-99.7), 86.8 (74.7-94.5), and 77.3 (62.2-88.5), respectively.

My Thoughts

Respiratory depression is the predominant cause of death in methadone overdoses. QTc interval prolongation may have the potential to help predict outcomes, but the QTc thresholds in this study were really not that prolonged. Patients on chronic methadone without overdose have baseline QTc intervals longer than those in this study after overdose.

Application to Clinical Practice

Many factors contribute to the ultimate disposition of methadone overdose cases. Even if QTc widening is correlated to outcomes, it really won't change our management.

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