UMEM Educational Pearls

• It is traditionally taught that in hypotensive patients the presence of a carotid pulse corresponds to a SBP of 60-70 mmHg, a femoral pulse with a SBP of 70-80 mmHg, and a radial pulse with an SBP of at least 80 mmHg
• These physical exam estimates of BP have been shown to poorly correlate with the patient's actual BP
• Similarly, non-invasive measurements of BP (automated cuff) in patients with hypotension may either overestimate or underestimate SBP by as much as 20 mmHg
• Since physical exam estimates and non-invasive measurements are inaccurate in low-flow states, utilize invasive arterial monitoring
• Radial and femoral artery sites have been found to produce results that are clinically interchangeable

Splenic Artery Aneurysm

• According to autopsy studies, splanchnic artery aneurysms (spleen, celiac, etc.) may be more frequent than AAA
• Most asymptomatic and detected incidentally on CT
• Splenic artery aneurysms most common splanchnic aneurysm
• With increased use of abdominal CT, emergency physicians will be seeing this diagnosis more often

Who cares, you ask?

• Splanchnic artery aneurysms are at risk for rupture
• This type of vascular abnormality will be discovered more often because of increased CT use
• Aneurysms > 2cm indication for repair
• Consider consultation and /or expeditious followup if this is encountered
• May be treated with catheter embolization or surgery

Although CHF is usually associated with low cardiac output, "high output failure" can occur as well. In this condition, cardiac output is normal or even high but not high enough to meet markedly elevated metabolic demands of the heart in certain conditions. Those conditions include: severe anemia, thyrotoxicosis, lartge arteriovenous sunts, Beriberi, and Paget disease of the bone.

What should I do about this finding on the MRI I ordered

Now tha ta lot of EDs are getting MRIs on a more urgent basis, we will need to know what to do with the resutls.  However, the natural history of findings on MRI has not been well studied, so what should we do with that small meningioma you find.  Well some researchers in the Netherlands have attempted to address your question. In a population-based study [Rotterdam Study] , 2000 adults aged 45 or older underwent a brain MRI.

Some of the common findngs were:

• Asymptomatic brain infarcts were observed in 7%.
• Aneurysms and benign tumors (mostly meningiomas) were each found in nearly 2%.
• The two most urgent findings were a chronic subdural hematoma and a 12-mm aneurysm. Both required surgey.
• Only two out of the 2000 (0.001%) people had symptoms related to their MRI findings (hearing loss in both).
• The prevalence of asymptomatic brain infarcts and meningiomas increased with age, as did the volume of white-matter lesions, whereas aneurysms showed no age-related increase in prevalence.

Most of the study patients were white and middle class so these results may not be generalized to the general public.  I am sure more studies are in the works, but for now don't be two suprised if you find an asympomatic infarct or meningioma.

Vernooji MW, Ikram MA, Tanghe HL. Incidental Findings on Brain MRI in the General Population. NEJM. 2007;357(18):1821-1828.

Children s/p Heart Transplantation – Rejection

• Children need heart transplantation for complex congenital heart defects (hypoplastic left heart syndrome is most common) or dilated cardiomyopathies.

• Signs of Acute rejection
  • Chest Pain is uncommon
  • Common presentions: fever, myalgias, and vomiting.
    • ECG may show a decreased R wave amplitude and an increased QRS duration.
  • Labs are most often NOT diagnostic in acute rejection.
    • Troponin and CK levels may or may not be elevated.
    • Elevated LFTs are concerning for right heart failure.
  • Echo – Diastolic dysfunction is the earliest change seen in acute rejection
• Signs of Chronic Rejection
  • Clinical symptoms often related to the accelerated atherosclerosis
  • “Silent” ischemia or infarction – decreased exercise tolerance or malaise
  • Syncope

Woods, WA. Care of the Acutely Ill Pediatric Heart Transplant Recipient. Pediatric Emergency Care. 23(10):721-724, October 2007.

Carbamazepine

• Anticonvulsant that can be monitored (you can draw a level)
• Toxicity resembles a TCA with seizures and cardiac conduction delays
• > 40 mcg/mL assoc with coma, seizures, respiratory failure and cardiac toxicity
• Treat widened QRS comples with sodium bicarbonate
• Adsorbs very well to activated charcoal, multi-dose may be required

• Xanthochromia is the result of metabolized hemoglobin in cerebrospinal fluid (CSF), which suggests intracranial bleed.
• It helps differentiate traumatic lumbar puncture results from true intracranial bleeding.
• It causes the CSF to have a yellowish color which can be detected with the naked eye or analyzed with a machine (done visually at UMMS).
• It typically takes at least 6 hours for xanthochromia to manifest itself. 

Degree of D-Dimer elevation and Mortality Rates

Evidence now exists that links the degree of D-Dimer elevation with mortality rate. The higher the D-Dimer, the higher the PE mortality rate.

Consider this when risk stratifying patients with PE. This adds to our use of biomarkers for risk stratification. Elevation of BNP, D-Dimer, and Troponins have been shown to predict mortality.

Critical Care Pearls for Traumatic Brain Injury

• Avoid hypotension and hypoxia - SBP < 90 and/or PaO2 < 60 are associated with significant increases in morbidity and mortality
• Hypertonic saline remains controversial - a recent large, controlled trial did not show any early or long-term benefit
• ICP monitoring routinely recommended in patients with GCS < 8 - they have a 60% chance of increased ICP
• Maintain ICP < 20 mmHg and CPP > 60
• Supportive care
  • Elevate the head of bed > 30 degrees, if possible
  • Control fever
  • Provide analgesia and sedation
• Ventilator management - keep PaCO2 between 30-35 mmHg
• Surgery - last resort to controlling increased ICP
  • Decompressive craniotomy
  • Decompressive laparotomy

The T-wave in lead V1 is usually inverted or flat. When the T-wave is upright, especially if it is tall (taller than the T-wave in lead V6), be worried about cardiac ischemia...especially if the large upright T-wave is a new finding compared to prior ECGs.

LVH, LBBB, and misplaced precordial leads are the other causes of tall upright T-waves in lead V1. In the absence of any of these three conditions, worry about ischemia.

Marriott described this finding many years ago and refers to it as "loss of precordial T-wave balance."

Seat Belt Sign:

• Patients with a seat belt sign have a high risk of hollow viscus injury
• Often have a negative CT scan
• Admit for serial exams and observation, at an absolute minimum patient should be watched 6 hours.
• Look for associated Lumbar Chance Fractures.

Severe Asthma in Pediatrics (Using “the kitchen sink” when all else fails)

Every effort should be made to avoid intubating an asthmatic pt.  Here are some possible options to consider:

• Atrovent - Multiple doses should be preferred to single doses of anticholinergics. The available evidence only supports their use in school-aged children with severe asthma exacerbation. (reference #1)
• Magnesium - Magnesium sulfate appears to be safe and beneficial in patients who present with severe acute asthma (based on 5 adult and 2 pediatric studies)
• Noninvasive ventilation - The application of NPPV in patients suffering from status asthmaticus, despite some interesting and very promising preliminary results, still remains controversial. (only one trial met criteria.  No pediatric studies)
• Heliox – No good evidence to support its use, but it is relatively safe to use, provided the patient doesn’t need more than 30% FiO2 (70%Helium)
• Ketamine – Cases suggest that for children experiencing severe asthma exacerbations, intravenous ketamine may be an effective temporizing measure to avoid exposing children to the risks associated with mechanical ventilation.
• Singulair - Intravenously administered montelukast, in addition to standard therapy, provided rapid benefits and was well tolerated among patients with acute asthma. (Study population 15yrs – 54yrs).
   

• References:

1. Plotnick LH, Ducharme FM. Combined inhaled anticholinergics and beta2-agonists for initial treatment of acute asthma in children. Cochrane Database of Systematic Reviews 1997, Issue 2. Art. No.: CD000060.
2. Rowe BH, Bretzlaff JA, Bourdon C, Bota GW, Camargo CA Jr. Magnesium sulfate for treating exacerbations of acute asthma in the emergency department. Cochrane Database of Systematic Reviews 1999, Issue 2. Art. No.: CD001490.
3. Ram FSF, Wellington SR, Rowe B, Wedzicha JA. Non-invasive positive pressure ventilation for treatment of respiratory failure due to severe acute exacerbations of asthma. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD004360.
4. Rodrigo, GJ. et al. Use of Helium-Oxygen Mixtures in the Treatment of Acute Asthma. Chest. 2003;123:891-896. 2003
5. T. Kent Denmark, Heather A. Crane, Lance Brown. Ketamine to avoid mechanical ventilation in severe pediatric asthma. Journal of Emergency Medicine. Volume 30, Issue 2. pages 163-166
6. James, JM. et al. A RANDOMIZED, CONTROLLED TRIAL OF INTRAVENOUS MONTELUKAST IN ACUTE ASTHMA. PEDIATRICS Vol. 114 No. 2 August 2004, pp. 547

SSRI Toxicity

Things to watch for in patients that are taking SSRI:

• Therapeutic administration usually safe
• Hyponatremia is a common adverse effect (ADH secretion regulated by serotonin)
• Serotonin Syndrome is a possibilty in combination with other serotnergic drugs
• One SSRI is more problematic than the rest => Citalopram and Escitalopram
  • The only SSRI that can cause QT prolongation (even 24hrs after OD) and can cause seizures
  • This is the only SSRI with significant toxicity and unfortunately is the most commonly Rx by psych

Don't forget to do  thorough assessment of deep tendon reflexes on physical examination when appropriate.  DTR assessment can help localize a lesion and determine a diagnosis (i.e. thyroid disease, Guillain Barre, spinal cord and peripheral nerve lesions).

DTR Assessment Scale:

• 4+ - very brisk, hyperactive with clonus<
• 3+ - brisker than normal
• 2+ - average, normal
• 1+ - somewhat diminished, low normal
• 0 - no response

Major DTR Assessment Locations:

• Triceps (C6, C7)
• Supinator or Brachioradialis (C5, C6)
• Knee (L2, L3, L4)
• Ankle (mainly S1)
• Plantar (L5, S1)

• Binding of vasopressor agents to their receptors is influenced by pH (and temperature and concentration)
• Acidic conditions have been shown to alter receptor numbers on cell surfaces as well as alter binding affinity
• Overall, pH values > 7.15 do not have an appreciable clinical effects on vasopressors
• At pH values < 7.1 reductions in effectiveness become apparent
• Routine administration of bicarbonate remains controversial
• Aggressively search for and treat the underlying cause of the acidosis

Blue Toe Syndrome

This syndrome refers to acute digital ischemia caused by athero-microembolism and is associated with cool, painful, cyanotic toes in the presence of palpable distal pulses.

Presence of this syndrome should prompt the Emergency Physician to search for the proximal source. Failure to identify the source and aggressively treat may lead to limb loss.

Common etiologies include:

• AAA
• Iliac artery aneurysm
• Popliteal artery aneurysm

Recent  studies have identified that a significant cause of morbidity and mortality in women, elderly, and patients with renal failure is the failure to consider renal insufficiency in dosing certain anticoagulants and anti-platelet medications, resulting in bleeding complications. Medications should be based on creatinine clearance, NOT SERUM CREATININE. When the creatinine clearance is < 30 mL/min, the dose of any renally-excreted medications should be decreased.

For example, an 85 yo woman that is 110 lbs and has a serum creatinine of 1.2 (sounds normal!) actually has a creatinine clearance < 30, which means that she has relative renal insufficiency. Her dosages of medications (e.g. enoxaparin) should be adjusted for this.

 Creatinine clearance can easily be calculated via computer programs that you can "google" (e.g. just google "creatinine clearance calculation"). If you enter the patient's gender, age, weight, and serum creatinine, the programs will calculate the value for you.

Placental Abruption

• Leading cause of fetal death (1-80 pregnancy)
• Evaluation
  • Ultrasound has very poor sensitivity
• Can check D-Dimer, Coags, Fibrinogen and Fibrin Split Products
• For a stable patient MRI can make diagnosis.
• Fetal monitoring (minimum four hours) where fetal distress and uterine contractions are seen.
• Risk factors for Placental Abruption
  • Hypertension
  • Pre-eclampsia
  • Diabetes
  • Trauma
  • Smoking
  • Cocaine
  • Advanced maternal age
• Treatment
  • C-Section

Pediatric Septic Shock

• Sepsis is the most common cause of pediatric deaths worldwide.
• Recognition is paramount!  Delayed Dx = Higher Mortality
  • Hypotension is a late finding. 
  • Look for other signs of End Organ Hypoperfusion
    • Prolonged Cap Refill, Change in MS
    • Tachycardia, Tachypnea
    • Elevated Lactate / unexplained metabolic acidosis
• Management strategy is similar to that of adults
  • Get access (Don’t forget your I/O’s if necessary)!
  • Fluid Resuscitation is the most important aspect of the management
    • Get 20-60ml/kg infused within the first 15 minutes
    • Children with septic shock who get >40ml/kg before the first hour have increased survival compared to those who do not.
      • They may require 60-200ml/kg over the first few hours.
  • Get your Abx on board quickly
  • Currently there are Protocols that are based on the Adult Surviving Sepsis Campaign.

Goldstein B, Giroir B, Randolph A. International pediatric sepsis consensus conference: definitions for sepsis and organ dysfunction in pediatrics.  Pediatr Crit Care Med. 2005 Jan;6(1):2-8.

GHB

• Sedating and amnestic, has become notorious in chemical submission (date rape)
• Very fast onset and rapid resolution though respiratory depression can occur 
• Difficult to test for with few labs and quickly eliminated through urine 
• Best chance to catch it is if the patient's first urine void is collected and tested