UMEM Educational Pearls

Passive Leg Raising (PLR)

• We have discussed that static measures of volume (CVP, PA wedge pressures) are not reliable markers of fluid responsiveness
• PLR has recently gained interest as a simple and transient way to assess fluid responsiveness in the critically ill
• Patients are placed in the horizontal position (not Trendelenburg) and the legs are raised to 45 degrees
• A hemodynamic response should be seen in 30 - 90 seconds
• Patients who have improvement in hemodynamics with PLR are said to be fluid responsive (i.e on the ascending portion of their Starling Curve) and require additional volume resuscitation

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 Thrombolytic Therapy for PE

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Just a reminder...an initially normal or non-specific ECG can certainly occur in patients that are actively having chest pain from acute MI. A 2001 study published in JAMA nicely pointed this out:

7.9% of patients having an acute MI had an initial normal ECG.
35.1% of patients having an acute MI had non-specific abnormalities on ECG.
57% of patients having an acute MI had diagnostic changes on ECG.

The greater the abnormality on the ECG, the worse the prognosis, but note that even when the ECG was normal, the in-hospital mortality in acute MI patients was 5.7%.

Although serial ECGs won't detect 100% of acute MIs, the diagnostic yield does certainly increase, and so whenever a patient has a concerning presentation, especially in the presence of on-going pain, make sure to get repeat ECGs!

[ref: Welch RD, et al, JAMA 2001]

Now that we have entered the session of cookouts, picnics, and family get togethers I thought I would review some of the more common causes of food poisoning and the typical foods that they are found in.

Remember to save childrens lives be aggressive with septic shock treatment early!

Do NOT allow long delays at IV attempts before moving to central lines or IOs.

        Goal in the first 0 to 15 minutes from presentation:

• Recognize decreased perfusion and mental status, maintain airway, and obtain access.
• Push 20 ml/kg of Isotonic bolus (up to and over 60 ml/kg) and reassess shock after each.*
• Correct Hypoglycemia and hypocalcemia if present. 

When community ED physicians successfully achieved shock reversal (defined by return of normal systolic blood pressure and capillary refill time) in the first 75 min from arrival there was an associated 96% survival and a > 9-fold increased odds of survival.  Each additional hour of persistent shock was associated with >2-fold increased odds of mortality.

*To push this amount of fluid in an infant or young child it may be easier to use 60 ml syringes for boluses rather than pumps

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Trandermal Delivery Systems

• Uses a gradient (high concentration drug in patch) and a matrix to facilitate transdermal absorption
• Patch often contains up to 100x the amount of drug that is on the label (ex: fentanyl 100mcg/hr actually = 10 MILLIGRAMS of fentanyl in patch)
• When prescribing the following will increase absorption: sweating, heat, swallowing the patch, trying to eat the gel in the patch
• Fentanyl and clonidine are the two most lethal patches on the market in regards to toxicity.
• Rarely needed in the ED, shouldn't be prescribed except in rare instances

• One large study showed that cerebrovascular diseases represented the most common etiology of secondary epilepsy.
• Animal studies have shown most antiepileptic drugs to be neuroprotectants.
• Animal studies have also shown, however, that phenytoin, benzodiazepines, and phenobarbital may impair post-stroke motor recovery.
• Carbamazepine (Tegretol) has not been found to demonstrate any significant hinderance of  post-stroke recovery.
• From an anicdotal clinical perspective, levetiracetam (Keppra) is often used to treat post-stroke seizure.

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Submitted on behalf of Dr. Winters:

Sepsis, Fluids, and ESRD
-ESRD patients are at increased risk of sepsis and bacteremia secondary to
indwelling devices
-Many of are hesitant to aggresively fluid resuscitate patients with ESRD
-Several studies have concluded that volume resuscitation should proceed the
same as patients without ESRD, even if that means more patients are eventually
intubated.

Reference:
Otero RM, et al. Chest 2006;130:1579-95.
 

Clinical Presentation of AAA

Everyone is familiar with the "classic," textbook, presentation of AAA:

• Abdominal pain
• Pulsatile mass
• Hypotension

This presentation, however, is not all that common. Many patients simply present with unexplained abdominal and/or flank pain.

Consider the diagnosis in anyone with risk factors (i.e. older folks, family history, etc) who presents with abdominal and/or flank pain. In most cases, CT scanning of this group of patients is the way to go.

And, one last pearl: put the US probe on early. May make a huge difference in time to diagnosis.

Be afraid, be very afraid.

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"Ketofol" (Ketamine plus propofol)

• Given for conscious sedation, for all age groups
• Takes advantage of properties of both agents
• Ketamine generally produces hypertension, does NOT produce respiratory depression, has an emergence phenomena, and has analgesic properties
• Propofol causes hypotension and respiratory depression, has NO analgesic properties, and may blunt both nausea and emergence phenomena seen with ketamine
• Given as a 1:1 ratio of ketamine and propofol, both 10 mg/ml
• Dose is usually 1-3 ml aliquots; median dose in a recent study was 0.75 mg/kg
• Median recovery 15 minutes (5-45 minutes; 80% recovered in less than 20 minutes)

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Chronic kidney disease is a risk factor for accelerated atherogenesis. It is also a poor prognostic factor for patients with ACS or after MI. Elevated serum creatinine has been found to be an independent predictor of death after ACS and also a predictor of recurrent cardiovascular events. Cardiovascular death is 10-30 times higher in dialysis patients with ACS than in the general population.

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Treatment of Wernicke's Encephalopathy

Traditionally the treatment dose of thiamine in those that we suspect to have Wernicke's Encephalopathy is 100mg per day.  The problem is that this does was arbiarily picked by two physicians, Victor and Adams, in the 1950's.  They thought that 100mg a day would be a large dose. They also made their recommendation without fully understanding the pharmacokinetics of thiamine which has a half life of 96 minutes or less.  Compound this with case reports of individuals dying of Wernike's Encephalopathy despite being given 100mg of Thiamine daily.

Several authors are now advocating that patients with Wernicke's Encephalopathy be treated with 500mg of IV thiamine daily, but with the short half life some are advocating that the thiamine be given 2 to 3 times a day.  There are no good studies to refute or support the claims that higher doses are needed, but there are well documented cases of treatment failures at the lower dose.

PEARLs: 

• Consider high dose thiamine 500mg IV in patients that you are treating with Wernike's encephalopathy. 
• The 100mg dose is still appropriate for those that are just being suppliemented and in who Wernicke's encephalopathy is a consideation but not high up on the differential.

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Pediatric vascular access can be a challenge especially in a critically ill child.  When placing central lines finding information on what size catheter to use and the depth of insertion can be hard to locate so here are some starters :

Age (yrs)     IJ       SC     Femoral

  0-0.5         3F       3F          3F

  0.5-2         3F       3F         3-4F

  3-6             4F      4F          4-5F

  7-12          4-5F   4-5F      5-8F

Use a single, double, or triple lumen.  (General rule more lumens the better.)

Right IJ and Right SC Depth of insertion:

If Height < 100cm    then   Initial Catheter Depth (cm) = Ht (cm)/10 -1 cm

If Height > 100 cm   then   Initial Catheter Depth (cm) = Ht (cm)/10 -2 cm

These formulas will place 98% of catheters above R atrium.

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• Seizures occur in 5-7% of patients within the first 24 hours of stroke.
• Although seizure prophylaxis is not indicated, prevention of subsequent seizures with standard antiepileptic treatment is recommended.

Acinetobacter in the Critically Ill

• As all of us know, there has been an alarming increase in the incidence of acinetobacter infections
• At present, infections mostly occur in ICU/critically ill patients
• Important risk factors for colonization and infection include mechanical ventilation, recent surgery, tracheostomy, residents of long-term care facilities, central venous catheterization, and enteral feedings
• The most frequent clinical manifestations are ventilator associated pneumonia and bacteremia
• Susceptible strains can be treated with a broad-spectrum cephalosporin, carbapenem, or B-lactam-B-lactamase used alone or in combination with an aminoglycoside
• For resistant strains, the most active agent in vitro are the polymyxins
• The most common adverse effect of the polymyxins is nephrotoxicity (up to 36%)
• Tigecycline has been used but resistance rates are rapidly increasing

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What study should we be getting to evaluate for DVT in patients with suspected VTE (venous thromboembolic disease)?

Ultrasound of the legs seems to be equivalent to CT Venography (CTV). 

Drawbacks of CT Venography (CT scanning into the abdomen/pelvis/legs after pulmonary CTPA):

• Radiation (TONS of radiation!)
• Cost
• Never been proven superior to non-invasive ultrasound

Despite the fact that leg ultrasound obviously doesn't evaluate for deep pelvis clots and intraabdominal clots (IVC, etc), outcome studies and other studies in recent years show ultrasound is just as good as  CTV. 

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  Lisfranc Fracture:

Typically consists of a fracture of the base of the second metatarsal and dislocation, though it can also be associated with fractures of a cuboid.  Common current  mechanism is when a person steps into a hole and twists the foot.Originally described when a horseman would fall of their horse with their foot still trapped in a stirrup.

Diagnosis should be considered if patient has difficult weight bearing with pain on palpation over the 2^nd and 3^rd metacarpal head with an appropriate mechanism.

Pearls:

• Fracture findings on plain films may be subtle.
• Can obtain weight bearing AP views of the foot to demonstrate dislocation/fracture.
• If still suspicious consider a CT scan of the foot.

Just a few quick pearls about cocaine-chest pain and myocardial infarction:
 

• 0.7%-6% of patients presenting to the ED with chest pain during or immediately after using cocaine will rule in for an MI based on cardiac biomarkers. The 6% figure is the most commonly-quoted number.
• The risk of MI rises as much as 24-fold during the first hour after cocaine use. Although the risk decreases significantly after that, cocaine-related vasoconstriction can still cause acute MI hours or as many as 4 days later.
• Chest pain is not reliably present in patients with cocaine-associated MI, with one study reporting that only 44% of patients with cocaine-associated MI had chest pain (Hollander and Hoffman, J Emerg Med 1992). Dyspnea and diaphoresis are other common symptoms that should prompt concern for acute MI if chest pain is not present.

[McCord J, et al. Management of cocaine-associated chest pain and myocardial infarction. Circulation 2008;117:897-1907.]

Remember in the heat and pressure of a pediatric intubation (if you don't have your Pediatic Qwic Card handy) you can estimate what size blade to use very quickly and successfully by using facial landmarks!!

• Distance from the upper incisor teeth to the angle of the jaw seems to be an excellent clinical landmark for laryngoscope blade length selection for pediatric intubations under 8 years of age 
• Take the blade (excluding the handle insertion block) and place at the upper midline incisor teeth and if the tip is located within 1 cm proximal or distal to the angle of the mandible, oral tracheal intubations are more consistently accomplished on the first attempt!!!     90% on first attempt with correct size blade v. 57% on first attempt if blade too short

And remember to start with a straight blade (Miller, Wisconsin, Guedel, Wis-Hipple etc.) for your patients under 2 years of age because:

• these blades make controlling the tounge and epiglottis easier than curved blades at this age
• and they have a smaller flange profile in the oropharynx so visualization of the vocal cords is clearer

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Fluids in Acute Liver Failure

• Acute liver failure is often complicated by intravascular volume depletion - insensible losses, vomiting, poor oral intake
• Early and adequate fluid resuscitation is mandatory
• AVOID lactated Ringer's solution - exogenous lactate load is poorly tolerated by lack of hepatic function
• AVOID dextrose containing water solutions - will lead to hyponatremia and increase the risk of cerebral edema

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