UMEM Educational Pearls - By Mike Winters

Monitoring Hyperosmolar Therapy

  • Hyperosmolar therapy (mannitol or hypertonic saline) is commonly used in the treatment of neurocritical care paitents with elevated ICP.
  • When administering mannitol, guidelines recommend monitoring serum sodium and serum osmolarity.  Though targets remain controversial, most strive for a serum sodium of 150-160 mEq/L and a serum osmolarity between 300 - 320 mOsm/L.
  • Unfortunately, serum osmolarity is a poor method to monitor mannitol therapy.
  • Instead of serum osmolarity, follow the osmolar gap.  It is more representative of serum mannitol levels and clearance.  If the osmolar gap falls to normal, the patient has cleared mannitol and may be redosed if clinically indicated. 

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Neuromuscular Blocking Agents in the Critically Ill

  • NMBAs are used in critically ill patients for RSI, patient-ventilator asynchrony, reducing intra-abdominal pressure, reducing intracranial pressure, and preventing shivering during therapeutic hypothermia.
  • There are a number of alterations in critical illness that affect the action of NMBAs
    • Electrolyte abnormalities
      • Hypercalcemia: decreases duration of blockade
      • Hypermagnesemia: prolongs duration of blockade
    • Acidosis: can enhance effect of nondepolarizing agents
    • Hepatic dysfunction: prolongs effects of vecuronium and rocuronium
  • In addition, there are a number of medications that may interact with NMBAs
    • Increased resistance: phenytoin and carbamazepine
    • Prolongs effect: clindamycin and vancomycin
  • Key complications of NMBAs in the critically ill include:
    • ICU-aquired weakness (controversial)
    • DVT: NMBAs are one of the strongest predictors for ICU-related DVT
    • Corneal abrasions: prevalence up to 60%

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Massive Transfusion Pearls

  • As discussed in previous pearls, massive transfusion (MT) is defined as the transfusion of at least 10 U of packed red blood cells (PRBCs) within 24 hours.
  • While the optimal ratio of PRBCs, FFP, and platelets is not known, most use a 1:1:1 ratio.
  • Though scoring systems have been published to identify patients who may benefit from MT (ABC, TASH, McLaughlin), they have not been shown to be superior to clinical judgment.
  • A few pearls when implementing massive transfusion for the patient with traumatic shock:
    • Monitor temperature and aggressively treat hypothermia.
    • Monitor fibrinogen levels and replace with cryoprecipitate if needed.
    • Monitor calcium and potassium.  MT can induce hypocalcemia and hyperkalemia.

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Hormonal Dysfunction in Neurologic Injury

  • In the critically ill patient with neurologic injury (SAH, TBI), the initial treatment focus is to maintain adequate cerebral perfusion pressure, control intracranial pressure, and limit secondary injury.
  • Once stabilized, however, it is important to consider endocrine dysfunction in the brain injured patient.
  • Endocrine dysfunction is common in neurologic injury and may lead to increased morbidity and mortality.  In fact, over half of SAH patients develop acute dysfunction of the HPA, resulting in low growth hormone, ACTH, and TSH. 
  • In addition to hormonal dysfunction, sodium abnormalities (i.e. hyponatremia) are present in up to 80% of critically ill SAH patients.
  • Consider hormonal replacement therapy (or hypertonic saline in cases of severe hyponatremia) for patients with evidence of endocrine dysfunction.  For some, this therapy can be life-saving.

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Title: Extubating in the ED

Category: Critical Care

Posted: 3/19/2013 by Mike Winters, MBA, MD (Updated: 12/12/2024)
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Extubating in the ED

  • With the increasing LOS for many of our intubated critically ill ED patients, it is possible that select patients may be ready for extubation while still in the ED.
  • Patients who remain intubated unnecessarily are at increased risk for pneumonia, increased hospital LOS, and increased mortality.
  • To be considered for extubation, patients should meet the following criteria:
    • The condition that resulted in intubation is improved or resolved
    • Hemodynamically stable (off pressors)
    • PaO2/FiO2 > 200 with PEEP < 5 cm H2O
  • If these criteria are met, perform a spontaenous breathing trial (SBT).
    • Discontinue sedation
    • Adjust the ventilator to minimal settings: pressure support or CPAP (5 cm H2O) or use a T-piece.
    • Perform the trial for at least 30 minutes.
    • If the patient develops a RR > 35 bpm, SpO2 < 90%, HR > 140 bpm, SBP > 180 mm Hg or < 90 mm Hg, or increased anxiety, the SBT ends and the patient should remain intubated.
  • Before removing the endotracheal tube, be sure to assess mentation, the quantity of secretions, and strength of cough.

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Ventilator-associated Pneumonia

  • Ventilator-associated pneumonia (VAP) is a well known complication of mechanical ventilation (MV) and is associated with increased duration of MV, hospital length of stay, and cost.
  • VAP is commonly associated with multi-drug resistant organisms, including Pseudomonas, Acinetobacter, Klebsiella, and Enterobacteriaceae.
  • Given the significant impact upon morbidity, a number of organizations have recommended "bundles" of care for the prevention of VAP.
  • Important measures for the prevention of VAP include:
    • Strict hand hygiene
    • Head of bed elevation to 30-45 degrees
    • Closed endotracheal suctioning
    • Maintaining endotracheal tube cuff pressure > 20 cm H2O
    • Oral chlorhexidine rinses
    • Orogastric tube placement

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Managing Traumatic Hemorrhagic Shock

  • When managing the critically ill patient with traumatic hemorrhagic shock, the primary objectives are to stop bleeding, maintain tissue perfusion and oxygen delivery, and limit organ dysfunction.
  • Pearls to consider when resuscitating these patients include:
    • In the patient without brain injury, target an SBP of 80 - 100 mm Hg until major bleeding has been controlled.
    • Limit aggressive fluid resuscitation
    • Avoid delays in blood and blood component transfusion.  Transfuse early. Though the optimal ratio remains controversial, most transfuse PRBCs and FFP in a 1:1 ratio.
    • Consider point-of-care testing, such as thromboelastography (TEG), to assess the degree of coagulopathy and guide transfusion strategies.
    • Consider the use of tranexamic acid

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Needle Decompression - Are we Teaching the Right Location?

  • Tension pneumothorax frequently results in circulatory collapse and may lead to cardiopulmonary arrest.
  • In the event that tube thoracostomy cannot be immediately performed, traditional teaching is to perform needle decompression in the second intercostal space, mid-clavicular line using a 5-cm angiocath needle.
  • Recent literature, however, has challenged the traditional location for needle decompression.  In fact, researchers found:
    • Needles placed in the second intercostal space often failed to enter the chest cavity and relieve tension physiology.
    • Needles placed in the fifth intercostal space in the anterior axillary line were more likely to enter the chest cavity with a lower failure rate.
  • Take Home Point: It may be time to reconsider the optimal position for needle decompression of tension pneumothorax.

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Postintubation Hypotension

  • It is clear that preintubation hypotension is associated with increased mortality in critically ill patients who require mechanical ventilation.
  • Unfortunatley, the literature is less clear on the frequency and impact of hypotension that develops after intubation.
  • Two recent publications in the Journal of Intensive Care provide valuable information on postintubation hypotension.  Some highlights of the studies include:
    • Retrospective cohorts of over 300 patients who developed postintubation hypotension, defined as a SBP < 90 mm Hg within 60 min of intubation.
    • Postintubation hypotension occurred in almost 25% of patients.
    • Median time to hypotension was 11 minutes.
    • Patients with postintubation hypotension had a higher inhospital mortality (33% vs. 23%).
    • A preintubation Shock Index > 0.8 was the strongest predictor of cardiovascular collapse after intubation.
  • Take Home Point: Postintubation hypotension occurs frequently and may be associated with worse outcomes.

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The Crashing Cardiac Transplant Patient

  • Approximately 2000 patients receive a cardiac transplant each year in the United States.
  • With improvements in surgical techniques, immunosuppression, and management of complications, graft half-life is now approximately 13 years; thereby increasing the likelihood that a cardiac transplant patient will show up in your ED. 
  • In the crashing cardiac transplant patient, think of the following causes for acute decompensation:
    • Acute rejection
    • Primary graft failure
    • RV failure
    • Sepsis
  • For patients with primary graft failure initiate inotropic support with dobutamine, epinephrine, milrinone, or isoproteronol.  Those failing standard inotropes will likely require mechanical circulatory support (VAD) or ECMO.
  • Patients with acute RV failure will often require the combination of a pulmonary vasodilator (inhaled NO, prostaglandins) and inotropic agent. In addition, it is critical to avoid hypercapnia and hypoxia.  

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VV-ECMO for Refractory Hypoxemia

  • In the absence of significant cardiac disease, patients with refractory hypoxic respiratory failure should be considered for venovenous extracorporeal membrane oxygenation (VV-ECMO).
  • Though indications vary slightly among organizations, the Extracorporeal Life Support Organization states that ECMO is indicated when the PaO2/FiO2 is < 80 mm Hg on FiO2 > 90% or safe plateau pressures (< 30 cm H2O) cannot be maintained.
  • A few pearls when initiating VV-ECMO:
    • Fluids are often needed in the first few hours after initiation of ECMO
    • Reduce tidal volumes to maintain plateau pressures < 25 cm H2O
    • Decrease FiO2 to maintain oxygen saturations > 88%
    • Use a hemoglobin threshold of 7-8 g/dL for blood transfusion

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Ultrasound-Guided Pericardiocentesis

  • Though emergent pericardiocentesis is a relatively rare procedure in the ED, it is a critical intervention in patients with effusion and life-threatening instability/PEA arrest.
  • Ultrasound-guided pericardiocentesis is preferred over the traditional "blind" approach, as it allows the provider to choose an optimal position and is associated with fewer complications.
  • A few pearls when using ultrasound for emergent pericardiocentesis:
    • Consider placing an NGT for abdominal decompression.
    • Don't mistake the epicardial fat pad for an effusion; fat pads don't change size and usually move in concert with the ventricle.
    • The apical 4-chamber view tends to be the most common probe position, as the largest collection of fluid is usually around the apex.
    • If you are unsure about your needle location, inject 5-ml of agitated saline to confirm you are in the pericardial space.

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Title: Management of AKI

Category: Critical Care

Posted: 11/27/2012 by Mike Winters, MBA, MD (Updated: 12/12/2024)
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Managing Critically Ill Patients with AKI

  • Acute kidney injury (AKI) occurs in almost 50% of hospitalized patients and is an independent risk factor for mortality. 
  • Updated guidelines have recently been published on the management of patients with AKI.
  • Pearls for the management of patients with, or at risk of, AKI include:
    • Optimize volume status and perfusion pressure
      • Crystalloids preferred over colloids
      • Consider vasopressors to maintain MAP > 65 mm Hg
    • Avoid nephrotoxic drugs
    • Control co-factors
      • Monitor intra-abdominal pressure
      • Avoid hyperglycemia - target glucose < 150 mg/dL

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Burn Patients and Antibiotic Dosing

  • Burn patients have a number of abnormalities in the early postinjury phase that can significantly impact the efficacy of antimicrobial therapy.  These include hypovolemia, hypoalbuminemia, and increasing GFR.
  • A few pearls when dosing select antibiotics in burn patients:
    • Aminoglycosides: in the absence of renal impairment, consider more frequent dosing to achieve adequate concentrations.
    • Beta-lactams: typical doses often don't reach effective concentrations; increase the dose, frequency of administration, or duration of infusion.
    • Vancomycin: the typical dose of 1 gm is usually ineffective; use a larger loading dose (15-20 mg/kg).
    • Linezolid: standard doses are usually ineffective; use a higher initial dose.

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Title: Serotonin Toxicity

Category: Critical Care

Posted: 10/30/2012 by Mike Winters, MBA, MD (Updated: 12/12/2024)
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Serotonin Toxicity in the Critically Ill

  • Serotonin toxicity (aka serotonin syndrome) can easily be overlooked and misdiagnosed in many of our critically ill patients.
  • Several common ED medications are associated with serotonin toxicity and include tramadol, linezolid, ondansetron, and metoclopramide.
  • Clues to the diagnosis include hyperthermia, increased muscle tone, hyperreflexia, dilated pupils and clonus.  Of these, clonus is the most sensitive and specific sign.
  • A few important treatment pearls:
    • Avoid physical restraints
    • Consider cyproheptadine: only available in PO form; initial dose is 12 mg
    • Avoid dopamine for those that need vasopressors
    • Avoid bromocriptine and dantrolene

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Delirium in the Critically Ill

  • Delirium has been shown to be an independent predictor of mortality and can occur in up to 75% of critically ill patients.
  • Whether preventing or treating delirium in the critically ill patient, consider the following:
    • Minimize the use of anticholinergic medications (i.e. diphenhydramine, chlorpromazine)
    • Ensure pain is adequately controlled (avoid meperidine and tramadol)
    • Be careful with sedative medications; consider bolus dosing and daily interruption of continuous infusions
  • Additional measures to treat delirious patients include reducing sensory deprivation, promoting normal sleep-wake cycles, early physical rehabilitation, and treating psychosis.

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Title: TTP

Category: Critical Care

Posted: 10/2/2012 by Mike Winters, MBA, MD (Updated: 12/12/2024)
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Thrombotic Thrombocytopenic Purpura (TTP)

  • TTP is a true hematologic emergency.  As a result of delays in diagnosis and initiation of treatment, mortality remains around 20%.
  • Often, patients present with nonspecific symptoms that include weakness, anorexia, nausea, vomiting, and diarrhea.
  • Recall that the textbook pentad is rarely present upon presentation.  In fact, renal failure and neurologic deficits are late findings.
  • Plasma exchange remains the treatment of choice for critically ill ED patients with TTP.
  • If plasma exchange is not immediately available, consider FFP (15-30 ml/kg) and methylprednisolone (10 mg/kg).

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The Lung Transplant Patient in Your ED

  • The number of lung transplant recipients is increasing.  With improved immunosuppressant medications, pts are living longer.  In fact, the 5-yr survival rate is now approximately 60%.
  • When evaluating a lung transplant pt who is < 1 yr following transplant, think about acute rejection and infection
  • Acute rejection occurs in up to 40% of pts, can present with cough, SOB, malaise, or hypoxia, and is treated with high-dose corticosteroids.
  • Infection
    • Bacterial infections usually occur in the early stages following transplant, with Pseudomonas the predominant organism
    • CMV is the most common organism affecting up to 33% of pts during the first year after transplant

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Right Heart Failure in the Critically Ill

  • In its most simplistic form, right heart failure (RHF) is due to either to right ventricular contractile dysfunction or elevated right ventricular afterload.
    • Primary causes of RV contractile dysfunction include: coronary ischemia, sepsis, drug toxicity, and acute pulmonary hypertension
    • Primary causes of increased RV afterload include: LV dysfunction, venous thromboembolism, hypoxic pulmonary vasoconstriction, and lung injury
  • Management of the patient with RHF centers on identifying and treating reversible causes, optimizing preload, inotropes, and possible implantation of a right ventricular assist device.
  • Importantly, excessive volume loading can worsen RV contractile function, increase RV dilatation, and impair LV output and systemic perfusion.
  • Consider early use of inotropic agents, such as dobutamine, in critically ill patients with RHF.

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Title: Fluids and AKI

Category: Critical Care

Posted: 8/21/2012 by Mike Winters, MBA, MD (Updated: 12/12/2024)
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AKI and Fluid Balance

  • Up to 70% of critically ill patients develop acute kidney injury (AKI), with 5-6% of ICU patients requiring renal replacement therapy (RRT). 
  • Maintaining adequate renal perfusion is central to the management of AKI in the critically ill patient.  As such, fluids are frequently administered.
  • As we've highlighted in previous pearls, there is mounting evidence to indicate that a positive fluid balance may be detrimental for select critically ill patients.
  • Results from a recent publication suggest a positive fluid balance in patients with AKI may be harmful.
    • Bellomo, et al analyzed data from the RENAL trial to determine the association between daily fluid balance and outcomes.
    • Investigators found a 70% reduction in 90-day mortality for critically ill patients who had a negative mean daily fluid balance compared to those that had a positive balance.
    • A negative fluid balance was also associated with decreased ICU length of stay and the need for RRT.
  • Take Home Point: Once critically ill patients with AKI are resuscitated, maintaining a slightly negative daily fluid balance may be beneficial.

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