UMEM Educational Pearls - By Mike Winters

Acute Kidney Injury and Tumor Lysis Syndrome

  • Tumor lysis syndrome (TLS) is characterized by hyperkalemia, hyperphosphatemia, hypocalcemia, and hyperuricemia.
  • Acute kidney injury in TLS increases patient mortality and can be caused by an obstructive uropathy from calcium phosphate crystalluria or uric acid crystal precipitation.
  • Fluid resuscitation remains the primary treatment for TLS.
  • Urine alkalinization, however, is no longer recommended, as it can result in calcium phosphate crystal precipitation. 
  • Recombinant urate oxidase rapidly decreases uric acid levels and should be given to patients at high-risk for TLS and those with pre-existing kidney disease and high uric acid levels.

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Category: Critical Care

Title: Anion Gap in DKA

Posted: 6/13/2012 by Mike Winters, MD (Updated: 3/28/2024)
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Use the Measured Sodium Concentration!

  • During a recent shift, a question arose regarding whether to use the measured or corrected sodium to calculate the anion gap in a critically ill patient with DKA.
  • Recall that the anion gap provides an estimation of unmeasured anions - in this case acetoacetate and beta-hydroxybutyrate.
  • Glucose is electrically neutral and therefore does not affect the anion gap.
  • When calculating the anion gap in a patient with DKA, use the actual (measured) serum Na, rather than the corrected value.

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Category: Critical Care

Title: Severe UGIB

Posted: 5/29/2012 by Mike Winters, MD (Updated: 3/28/2024)
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Severe UGIB

  • Differentiating between upper and lower GIB can be challenging. 
  • A recent review evaluated the accuracy of historical features, symptoms, signs, and lab values in distinguishing between UGIB and LGIB. 
  • Features with the highest likelihood for identifying UGIB included:
    • Melenic stool on exam (LR 25)
    • A prior history of UGIB (LR 6.2)
    • Serum urea:creatinine ratio > 30 (LR 7.5)
  • Features that increased the likelihood of severe UGIB (defined as requiring blood transfusion, need for urgent endoscopy, surgery, or interventional radiology) included:
    • Heart rate > 100 bpm (LR 4.9)
    • Hemoglobin < 8 g/dL (LR 6.2)
    • History of cirrhosis or cancer (LR 3.7)
  • For patients with an UGIB, the Blatchford Score can be used to determine the need for urgent intervention.  Those with a Blatchford Score of 0 have a low likelihood for severe UGIB and may not need emergent intervention.

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Balloon Tamponade for Variceal Bleeding

  • Despite advances in pharmacology and endoscopy, placement of a balloon tamponade device is occasionally required to stabilize a patient with acute variceal bleeding.
  • Currently, there are 3 devices available: the Linton-Nachlas (gastric balloon only), the Blakemore (gastric and esophageal balloons), and the Minnesota (gastric and esophageal balloons) tubes.
  • The tube should initially be passed at least to the 50-cm mark and preferably to the maximum depth allowed by the length of the tube.
  • Once the gastric balloon is inflated and correct position confirmed, traction must be applied to keep the gastric balloon engaged in the cardia and fundus of the stomach.
  • An overhead pulley system is the preferred method to deliver traction.  If you don't have weights for the pulley system, a 1-liter bag of crystalloid provides the desired 1.0 kg of traction.


Category: Critical Care

Title: SBP, HRS, and Albumin

Keywords: spontaenous bacterial peritonitis, hepatorenal syndrome, albumin (PubMed Search)

Posted: 5/1/2012 by Mike Winters, MD (Updated: 3/28/2024)
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SBP, HRS, and Albumin

  • Spontaneous bacterial peritonitis (SBP) is the most common infection in patients with end-stage liver disease (ESLD).
  • In critically ill patients, SBP can precipitate type 1 hepatorenal syndrome (HRS), which, if not treated, carries a mortality > 90%.
  • Infusion of albumin at 1.5 g/kg at the time of SBP diagnosis (and a second dose of 1 g/kg on day 3) has been shown to significantly decrease the incidence of type 1 HRS and decrease mortality.
  • In your next critically ill patient wth ESLD, strongly consider giving albumin at the time of SBP diagnosis.

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Cuff Pressures and the Prevention of VAP

  • As highlighted in a recent pearl, ventilator-associated pneumonia (VAP) is the second most common nosocomial infection in the US and is associated with increases in ICU length of stay and mortality.
  • With increasing ED lengths of stay for many critically ill patients receiving mechanical ventilation, measures to prevent VAP should be initiated in the ED.
  • In addition to elevating the head of the bed to 30-45 degrees, another low cost intervention is the measurement of endotracheal tube cuff pressures.
  • Cuff pressures below 20 cm H2O increase the risk of VAP.
  • Measure cuff pressure within 4 hours of inflation and maintain between 20-30 cm H2O.

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Transferring Multidrug-Resistant Organisms

  • Hospital-associated infections are a major cause of morbidity and mortality, especially among the critically ill.
  • Worldwide, the emergence of multidrug-resistant (MDR) bacteria has caused significant problems.
  • A recent study from the University of Maryland examined the impact of environmental contamination on the rate of transfer of MDR bacteria to healthcare workers clothing.
  • Two important findings from this study of ICU patients were:
    • Up to 8% of healthcare workers entered a patient's room with MDR bacteria on their hands
    • Almost 5% of healthcare workers had MDR bacteria (most notably Acinetobacter) on their hands upon exiting the room despite using gloves and a gown
  • Take Home Point: Be sure to use hand hygiene upon entering and exiting a patient's room who is colonized with MDR bacteria!

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Category: Critical Care

Title: HFOV in ARDS

Posted: 3/20/2012 by Mike Winters, MD (Updated: 3/28/2024)
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High-Frequency Oscillatory Ventilation for ARDS?

  • High-frequency oscillatory ventilation (HFOV) is increasingly utilized for adult patients with ARDS who remain hypoxemic despite optimal settings of conventional mechanical ventilation (CMV).
  • HFOV maintains a constant mean airway pressure and delivers very small tidal volumes (1-3 ml/kg) at very high respiratory rates (frequency range up to 10 Hz).
  • Potential advantages to HFOV over CMV include greater alveolar recruitment, prevention of atelectrauma, and limiting excess alveolar distension (i.e. volutrauma).
  • Studies on HFOV in adults are not as numerous as those in neonates.  As a result, optimal timing for initiation of HFOV is unclear.
  • Nevertheless, some recommend considering HFOV for patients who persistently need an FiO2 > 60% with at least 10 cm H2O of PEEP on CMV.
  • Due to the ventilator settings, patients receiving HFOV often require significant sedation and often neuromuscular blockade.  

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Category: Critical Care

Title: Reducing VAP

Posted: 3/6/2012 by Mike Winters, MD (Updated: 3/28/2024)
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Preventing VAP in the Intubated ED Patient

  • Ventilator-associated pneumonia (VAP) occurs in 9-27% of patients receiving mechanical ventilation (MV).
  • VAP increases the duration of MV and increases the ICU length of stay.
  • VAP is primarily caused by aspiration of oropharyngeal secretions either during intubation or while receiving MV.
  • While there are many interventions that may potentially reduce the incidence of VAP (aspiration of subglottic secretions, selective digestive decontamination, monitoring endotracheal cuff pressure), a simple, no cost intervention is patient positioning.
  • Placing intubated patients in the semirecumbent position is associated with a lower risk of VAP.

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Ice-Cold Crystalloid for Therapeutic Hypothermia

  • Therapeutic hypothermia (TH) is a critical component in the care of patients with ROSC from out-of-hospital cardiac arrest.
  • Despite recent guidelines, initiation of TH in the ED for appropriate patients remains less than optimal.
  • Reported barriers to the induction of TH in the ED include lack of familiarity, lack of collaboration with the ICU, access to special equipment, and the logistics of cooling.
  • A recent analysis of studies on the use of ice-cold crystalloids (ICC) found that an infusion of 40 C fluid is a safe, effective, inexpensive, and readily available method for inducing TH.
  • Importantly, no study reported any significant hemodynamic complication (i.e. CHF) from the use of ICC.
  • Lastly, once the target temperature has been reached, ICC alone cannot maintain TH.  Additional methods, such as surface cooling blankets or ice packs, should be used.

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ECMO for ARDS and Refractory Hypoxemia

  • Extracorporeal membrane oxygenation (ECMO), or extracorporeal life support (ECLS), is increasingly being used for a variety of cardiac and pulmonary conditions.
  • Venovenous ECMO (VVE) should be considered in the treatment of patients with profound gas-exchange abnormalities that are refractory to accepted standards in ventilator management.
  • Although indications vary slightly by institution, general indications for VVE include:
    • Severe hypoxemia: PaO2/FiO2 < 80 despite high levels of PEEP for at least 6 hours
    • Uncompensated hypercapnia with pH < 7.15
    • Excessively high plateau pressures (> 45 cm H20)

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Category: Critical Care

Title: SAH and Pulmonary Edema

Posted: 1/24/2012 by Mike Winters, MD (Updated: 3/28/2024)
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SAH and Pulmonary Edema - Think Twice About Diuresis!

  • Delayed cerebral ischemia (DCI) is the most common cause of secondary neurologic injury in patients with aneurysmal subarachnoid hemorrhage (SAH).
  • Intravascular volume depletion is one of several factors thought to cause, or worsen, DCI.
  • Pulmonary edema frequently occurs in patients with SAH.
  • A recent study in patients with SAH and pulmonary edema demonstrated that many were not volume overloaded.  In fact, many were intravascularly volume depleted.
  • Think twice about aggressive diuresis in patients with SAH and pulmonary edema, as this may exacerbate volume depletion and may worsen DCI.

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Category: Critical Care

Title: Hypertonic Saline

Posted: 1/10/2012 by Mike Winters, MD (Updated: 3/28/2024)
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Hypertonic Saline for Intracranial Hypertension

  • Mannitol is commonly used to treat acute increases in intracranial pressure in patients with TBI, ICH, tumor, and CVA.
  • While there is currently no conclusive evidence of superiority, a growing body of literature suggests hypertonic saline (HTS) may be more favorable than mannitol for acute increases in ICP.
  • HTS is believed to work by:
    • osmotic effect
    • increasing cardiac output and MAP, thereby increasing cerebral oxygen delivery
    • improving microcirculatory flow
    • anti-inflammatory effects
  • When administering HTS, concentrations ranging from 1.5% - 23.4% can be used, titrating to a serum Na concentration of 145-155 and a serum osm > 350 mOsm/L.

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Category: Critical Care

Title: ABG vs. VBG

Posted: 12/27/2011 by Mike Winters, MD (Updated: 3/28/2024)
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VBG to Assess Respiratory Function?

  • Arterial blood gas (ABG) analysis is often used in to evaluate pulmonary function in critically ill ED patients.
  • In recent years, venous blood gas (VBG) analysis has replaced ABG analysis for assessing acid-base status (pH, HCO3-) in conditions such as DKA.
  • Some key points about the VBG for assessing pulmonary function:
    • VBG does not replace an ABG in determining the exact PaO2
    • The agreement between the VBG and ABG PCO2 is often poor and unpredictable
    • There is emerging literature on the use of VBG PCO2 as a screen for hypercarbia but more data is needed
  • Bottom line: With the possible exception of screening for hypercarbia, VBG has limited utility in the assessment of pulmonary function.

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Category: Critical Care

Title: The Crashing Patient with PAH

Posted: 12/13/2011 by Mike Winters, MD (Updated: 3/28/2024)
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The Crashing Patient with PAH

  • In recent weeks, we've highlighted some pearls regarding the management of patients with pulmonary arterial hypertension (PAH).
  • In the crashing patient with PAH, think about the following:
    • Catheter occlusion or malfunction (for those receiving IV prostacyclin analogues)
    • PE (for those inadequately anticoagulated)
    • Pneumonia
    • RV ischemia
    • GI bleeding
    • Ischemic bowel
  • In the patient receiving IV epoprostenol (Flolan) who presents with a catheter occlusion or malfunction, time is of the essence. Restart the medication through a peripheral IV as soon as possible.

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Category: Critical Care

Title:

Posted: 11/29/2011 by Mike Winters, MD (Updated: 3/28/2024)
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Hypotension in the PAH Patient

  • Hypotension in the critically ill patient with pulmonary arterial hypertension (PAH) must be rapidly treated to avoid cardiovascular collapse.
  • Hypotension in the PAH patient is not always due to hypovolemia.  In fact, excessive volume loading may further decrease LV stroke volume.  Consider starting with a fluid bolus of 250 ml of an isotonic crystalloid solution and monitoring response.
  • Patients with severe PAH may present to the ED with a continuous flow pump of a pulmonary vasodilator (epoprostenol, treprostinil).  These medications can also cause hypotension at excessive doses.  Consider decreasing the rate of the infusion by 25% to see if overdosing is the cause.

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Category: Critical Care

Title: Hypertensive Emergencies

Posted: 11/15/2011 by Mike Winters, MD (Updated: 3/28/2024)
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Hypertensive Emergency Pearls

  • Recent literature indicates that many patients with a true hypertensive emergency are mismanaged.
  • Patients with a hypertensive emergency should have an arterial line placed and receive a continuous infusion of a short-acting, titratable medication to reduce blood pressure.  Avoid oral, sublingual, and intermittent IV bolus administration of antihypertensives
  • Recall that most patients with a hypertensive emergency are volume depleted.  Providing IV fluids can help to prevent marked drops blood pressure when you start an IV antihypertensive medication.
  • Avoid diuretics (due to volume depletion) and hydralazineHydralazine can cause precipitous drops in blood pressure and is felt by many to have no role in the treatment of hypertensive emergencies.

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Mechanical Ventilation in Patients with Pulmonary HTN 

  • In the critically ill patient with pulmonary HTN and respiratory failure, improper mechanical ventilator settings can be disastrous.
  • Large lung volumes and high levels of PEEP can result in acute cardiovascular collapse.
  • When setting the ventilator is these patients, select low tidal volumes and relatively low levels of PEEP (3-5 cm H2O).
  • In addition, small studies suggest avoiding permissive hypercapnia, as this may increase pulmonary vascular resistance and mean pulmonary arterial pressure.

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Category: Critical Care

Title: Hyponatremia and SAH

Posted: 10/18/2011 by Mike Winters, MD (Updated: 3/28/2024)
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SAH and Electrolyte Disorders

  • Hyponatremia can be seen in up to 40% of patients with a SAH.
  • Most often, hyponatremia in patients with an SAH is due to SIADH or the cerebral salt wasting syndrome.
  • To date, hyponatremia has not been associated with poor outcome.
  • Treatment should focus on the underlying cause and often includes volume replacement with isotonic crystalloids (0.9% NaCl).

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Category: Critical Care

Title: Fever and ICH

Posted: 10/4/2011 by Mike Winters, MD (Updated: 3/28/2024)
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Fever and ICH

  • Fever is a common event in patients with intracerebral hemorrhage (ICH) and is associated with an increased length of ICU stay, cognitive impairment, and poor outcome.
  • While much of the management (and controversies) of the patient with ICH focuses on blood pressure control and reversal of oral anticoagulants or antiplatelet agents, don't forget about temperature control.
  • Aggressively treat temperatures ≥ 38.3oC in patients with an ICH.
  • Importantly, there is currently insufficient evidence to support a superior method of fever control (antipyretics or surface/intravascular cooling devices).

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