UMEM Educational Pearls - By Mike Winters

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: 9/27/2022)
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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: 9/27/2022)
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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: 9/27/2022)
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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: 9/27/2022)
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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: 9/27/2022)
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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: 9/27/2022)
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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: 9/27/2022)
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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: 9/27/2022)
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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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Spontaneous Bacterial Peritonitis

  • Critically ill patients with end-stage liver disease (ESLD) may be some of the sickest patients you'll ever manage.
  • Recall that patients with ESLD have higher rates of infection and worse outcomes.
  • Always consider spontaneous bacterial peritonitis (SBP) in the sick patient with ESLD.  In fact, SBP is the most common infection in ESLD patients.
  • Physician impression alone has been repeatedly shown to be inaccurate in ruling out SBP.
  • In the critically ill patient with ESLD and ascites, tap the belly!

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Category: Critical Care

Title: Fungal Sepsis

Posted: 9/6/2011 by Mike Winters, MD (Updated: 9/27/2022)
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Fungal Sepsis in the Critically Ill

  • In recent years, the incidence of invasive fungal infections has risen dramatically.
  • Candida species (C. albicans, C. glabrata, C. parapsilosis, C tropicalis, C. krusei) account for the majority of invasive infections in the critically ill patient.
  • Key risk factors for invasive candidal infections include:
    • Exposure to broad spectrum antibiotics
    • Cancer chemotherapy
    • Indwelling catheters
    • TPN administration
    • Neutropenia
    • Hemodialysis
  • Given the significant mortality of invasive fungal infections, early and appropriate antifungal therapy is paramount.
  • First-line empiric antifungal therapy recommendations from the Infectious Disease Society of America include caspofungin, micafungin, or fluconazoleAmphotericin B is now reserved for patients who are either intolerant or not responding to the echinocandins (caspofungin, micafungin).

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Re-expansion Pulmonary Edema After Chest Tube Placement

  • Tube thoracostomy is a common procedure in the emergency department.
  • For patients who develop respiratory distress after chest tube placement, think about re-expansion pulmonary edema.
  • While a rare occurrence, re-expansion pulmonary edema is reported to have a mortality rate of up to 20%.
  • The mechanism by which edema forms remains controversial, but is thought to be due to increased alveolar-capillary membrane permeability in the expanding lung.
  • Treatment is supportive with supplemental oxygen and diuretics.  Some patients may require mechanical ventilation depending on the degree of distress and hypoxia.

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When may an ED thoracotomy be futile?

  • Performing an ED thoracotomy is incredibly stressful and a resource-intense procedure.
  • While we've all learned that stab wounds to a ventricle have the highest survival rate, what about indicators that an ED thoracotomy may be futile?
  • A recent study of 18 trauma centers across the US found that ED thoracotomy was unlikely to yield productive survival in the following:
    • Blunt trauma patients that require > 10 min of prehospital CPR without response
    • Penetrating trauma patients that require > 15 min of prehospital CPR without response
    • Patients presenting in asystole without evidence of pericardial tamponade on bedside ultrasound.

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Blood Pressure in the Critically Ill Obese Patient

  • Recall that incorrectly sized cuffs can significantly overestimate blood pressure, especially in obese patients.
  • In fact, some studies show that false BP readings can occur in up to 75% of obese patients.
  • By relying solely on noninvasive BP measurements, many of your critically ill obese patients may actually be hypotensive and under perfused.
  • When you've got a sick obese patient, strongly consider early placement of an arterial line to assess and monitor blood pressure.

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Hemodynamic Optimization in the Post-Arrest Patient

  • Hemodynamic instability is common in the post-cardiac arrest patient.
  • While the optimal targets remain unclear, hemodynamic stabilization often consists of intravenous fluids, vasopressors, and in rare cases mechanical support, such as an intra-aortic balloon pump or left-ventricular assist device.
  • Based on recent literature, current recommendations for mean arterial pressure (MAP) in the post-arrest patient range from 65-100 mm Hg.
  • Depending upon the baseline blood pressure and degree of myocardial stunning, many post-arrest patients will need a higher MAP (80-100 mm Hg) in order to maintain critical perfusion pressure to vital organs such as the brain.

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Category: Critical Care

Title: Hepato-Renal Syndrome

Posted: 6/28/2011 by Mike Winters, MD (Updated: 9/27/2022)
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Hepato-Renal Syndrome

  • Hepato-renal syndrome (HRS) is the development of acute kidney injury (AKI) in patients with advanced cirrhosis.
  • HRS is traditionally divided into two types based upon how quickly AKI develops:
    • Type I: a rapid decline in function in less than 2 weeks
    • Type II: a slow decline in function over weeks to months
  • Type I is more likely to be seen in the ED and is often due to a precipitating event such as:
    • GI bleed
    • Spontaneous bacterial peritonitis (SBP)
    • Hypovolemia from aggressive diuresis
  • In ED patients with advanced cirrhosis and new, or worsening, AKI think about HRS. 
  • If suspected, look for precipitants (i.e. SBP), restore volume with IVFs, avoid nephrotoxins (IV contrast), and administer vasopressor therapy when indicated.

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AKI in the Critically Ill Cancer Patient

  • Acute kidney injury (AKI) is common in the critically ill cancer patient and associated with worse outcomes.
  • The incidence seems to be higher in patients with hematologic malignancies.
  • Despite many different etiologies for AKI in cancer patients (tumor lysis syndrome, hypercalcemia, chemotherapeutic drugs, etc) the most common cause is sepsis, accounting for 58-65% of causes.
  • Given the emphasis on early antibiotic administration in sepsis, be sure to double check the potential for nephrotoxicity of antibiotics for this patient population.  When possible, avoid nephrotoxic meds, such as aminoglycosides, that can worsen AKI.

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Cardiovascular Complication of ESLD

  • Patients with end-stage liver disease (ESLD) can develop a number of complications that lead to, or complicate, critical illness.
  • Regarding the cardiovascular system, ESLD patients can develop:
    • Hyperdynamic vasodilated cardiovasculature: low baseline blood pressure and high cardiac output
    • "Cirrhotic cardiomyopathy": impaired systolic response to stress or altered diastolic relaxation
    • Autonomic dysfunction: reduced responsiveness to vasoconstrictors
  • ESLD patients also tend to have a normal or near-normal lactate at baseline, despite lactate being cleared more slowly.
  • When managing the critically ill patient with ESLD, look for signs of heart failure, expect an abnormal response to vasopressors, think about steroids for persistent shock, and don't ascribe an elevated lactate simply to impaired hepatic clearance.

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Category: Critical Care

Title: Acute Liver Failure

Posted: 5/17/2011 by Mike Winters, MD (Updated: 9/27/2022)
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Acute Liver Failure (ALF)

  • ALF is defined as sudden and severe liver failure in a patient without preexisting liver disease.
  • The clinical presentation can include altered mental status, coagulopathy, MODS, & cerebral edema.
  • In the US, the most common cause of ALF is drug-induced (e.g. acetaminophen).
  • Important components of the ED management of patients with ALF include:
    • Monitoring and correcting hypoglycemia (may need infusion of D20)
    • Monitoring and maintaining a normal sodium concentration
    • Volume resuscitation with isotonic crystalloids or colloids
    • Prophylactic administration of broad spectrum antibiotics (given high incidence of sepsis)
    • Consideration for continuous veno-venous hemodiafiltration (CVVHD) for severe elevations in ammonia and acidosis (even if renal function is normal)
    • Transfer to center capable of liver transplantation

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