UMEM Educational Pearls - By Mike Winters

Can NIV be Used in ARDS?

  • Mechanical ventilation can cause lung injury and increase patient morbidity and mortality.
  • Noninvasive ventilation (NIV) is well-known to decrease intubation rates and improve patient outcome in select disease states (i.e., COPD, acute CHF).
  • For patients with acute respiratory distress syndrome (ARDS), NIV may reduce the work of breathing by opening collapsed alveoli, increasing FRC, and improving oxygenation.
  • To date, there are only a few RCTs that have evaluated the use of NIV in ARDS.
  • Unfortunately, these trials have failed to demonstrate improved patient outcome or decreased intubation rates in patients with ARDS.
  • Clinical Bottom Line: Intubate patients with ARDS who are difficult to oxygenate with standard oxygen therapy.

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Cerebral Venous Thrombosis

  • Approximately 25% of patients with cerebral venous thrombosis (CVT) will experience neurologic deterioration.
  • This is most commonly due to an increase in ICP that results in transtentorial herniation.
  • While heparin remains the treatment of choice for CVT, consider the following alternative strategies in the acutely decompensating patient:
    • Endovascular thrombolysis
    • Mechanical thrombectomy
    • Decompressive hemicraniectomy

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Sepsis-3

  • After nearly 2 decades, the definitions for sepsis and septic shock have been updated.
  • Key findings from the Task Force convened by SCCM and ESICM include:
    • Sepsis
      • Definition: life-threatening organ dysfunction due to a dysregulated host response to infection
      • ICU patients: organ dysfunction is defined as an increase of 2 points or more in the Sequential Organ Failure Assessment (SOFA) score
      • ED patients: 2 or more of the following new qSOFA (quickSOFA) score may identify patients with increased mortality
        • SBP less than or equal to 100 mm Hg
        • RR greater than or equal to 22
        • Altered mental status
    • Septic Shock
      • Definition: a subset of patients with sepsis and profound circulatory, cellular, and metabolic abnormalities
      • Clinical Criteria:
        • Persistent hypotension requiring vasopressors to maintain MAP greater than or equal to 65 mm Hg despite adequate volume resuscitation
        • Lactate greater than or equal to 2 mmol/L
    • The term "severe sepsis" is no longer used

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Shock Index

  • The shock index (SI) is calculated as the ratio of heart rate to systolic blood pressure and is often used in the assessment of critically ill patients.
  • A SI > 0.8 has been shown to be an independent predictor of post-intubation hypotension during emergency airway management.
  • Kristensen and colleagues performed a retrospective review in a single-center in Denmark to evaluate the ability of SI to predict 30-day mortality.
  • In over 110,000 patients, they found a weaker association of SI with 30-day mortality in patients > 65 years of age, those taking a beta-blocker or calcium channel blocker, or those with a history of hypertension.
  • Notwithstanding, a SI > 1 was a significant predictor of mortality across all patient populations and should be considered a warning of serious illness.

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Category: Critical Care

Title: Sickle Cell Disease in the ICU

Posted: 12/29/2015 by Mike Winters, MD (Updated: 4/22/2024)
Click here to contact Mike Winters, MD

Acute Chest Syndrome

  • Acute chest syndrome (ACS) accounts for the most common cause of ICU admission and the most common cause of death in sickle cell patients.
  • Important pearls for ACS include:
    • Chlamydophila pneumonia is the most common bacterial cause of ACS in adults, whereas Mycoplasma pneumonia is the most common bacterial cause in children.
    • CXR abnormalities may be absent early in disease.
    • Children are more likely to have middle lobe disease, in contrast to adults who often have lower lobe involvement.
    • Acute RV failure is a well recognized complication of ACS - use ultrasound to evaluate the RV and be careful with fluids.

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Mechanical Ventilation for Septic Patients in Resource-Limited Settings

  • An international team of physicians just published a series of recommendations for ventilatory support of septic patients in resource-limited settings.
  • Pearls from these recommendations include:
    • Elevate the head of the bed to 30o - 45o
    • Consider tidal volumes of 5 - 7 ml/kg PBW in all patients
    • Use minimum levels of PEEP ( 5 cm H2O) in all patients with sepsis and acute respiratory failure (unless the patient has moderate to severe ARDS)
    • Lower FiO2 to target SpO2 > 88% or PaO2 > 60 mm Hg
    • Use lung ultrasound to evaluate pulmonary edema when CXR is not available
    • Consider using SpO2 to FiO2 (S/F) as an alternative to P/F when blood gas analyzers are not available

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Pain Management in the Critically Ill Patient

  • Pain is common, often underappreciated, and routinely undertreated in our critically ill patients.
  • Poorly treated pain has been shown to adversely affect both short- and long-term outcomes.
  • Key pearls when treating pain in the critically ill:
    • Vital signs should not be used in isolation to assess pain
    • Use a validated assessment tool to objectively quantify pain (i.e., Critical Care Pain Observation Tool)
    • An analgosedation strategy (analgesics before sedative medications) has been shown to decrease duration of mechanical ventilation and decrease ICU LOS
    • Opioids have no maximum or ceiling dose. The appropriate dose is that which controls pain with the fewest side effects.

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Hyperoxia in the Critically Ill

  • Oxygen is liberally administered to many critically ill patients, thereby exposing them to supranormal arterial oxygen levels.
  • Hyperoxia results in the formation of reactive oxygen species, which adversely affect the pulmonary, vascular, cnetral nervous, and immune systems.
  • Though the optimal PaO2 remains unknown, recent evidence indicates that hyperoxia is associated with increased mortality in post-cardiac arrest, CVA, acute coronary syndrome, and traumatic brain injury patients.
  • Take Home Point: Carefully titrate oxygen to the lowest tolerable level to meet the patient's needs.

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Is It Really ARDS?

  • Recent literature suggests that the incidence of ARDS in intubated ED patients may be as high as 10%.
  • The Berlin Definition of ARDS includes the acute onset of bliateral opacities (CXR or chest CT) that is not fully explained by pulmonary edema or fluid overload.
  • Emergency physicians and Intensivists are well versed in lung-protective ventilator settings for patients with ARDS.
  • However, several diseases can appear simliar to ARDS and may require different ventilator strategies and treatments.
  • In the absence of clinical risk factors for ARDS (e.g., sepsis, trauma), consider the following in your differential:
    • Idiopathic pulmonary fibrosis
    • Interstitial pneumonitis
    • Granulomatosis with polyangitis (Wegener's)
    • Diffuse alveolar hemorrhage
    • Goodpasture's syndrome

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Blood Pressure Management in Severe Preeclampsia

  • Severe preeclampsia (preeclampsia + at least one severe complication) accounts for almost 40% of deaths in obstetrical ICU admissions.
  • Systolic arterial hypertension is the most important predictor of morbidity in patients with severe preeclampsia.
  • First-line agents to reduce blood pressure in severe preeclampsia are nicardipine and labetalol.
  • Hydralazine is no longer recommended as first-line therapy.
  • Magnesium is used as an anticonvulsant and should not be considered an antihypertensive.

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Stress-Induced Cardiomyopathy

  • Stress-induced cardiomyopathy (SIC) can be seen in a variety of critical illnesses, especially severe neurologic conditions.
  • SIC is believed to be caused by excess sympathetic stimulation of the myocardium.
  • When managing a patient with SIC, limit further catecholamine exposure by avoiding vasopressors if possible.
  • If the patient requires inotropic support, consider using an agent without catecholamine activity, such as milrinone.

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SIRS and Severe Sepsis Screening

  • Sepsis remains one of the most common critical illnesses managed by emergency medicine and critical care physicians.
  • Many EDs and ICUs have screening protocols for early detection of the patient with sepsis. Most protocols use the systemic inflammatory response syndrome (SIRS) as a central component of early identification.
  • A recent study stresses caution when simply using the SIRS criteria to screen for severe sepsis:
    • Retrospective review of the ANZICS Adult Database
    • Divided patients into SIRS-positive ( 2 SIRS criteria with at least 1 organ failure) and SIRS-negative ( < 2 SIRS criteria with at least 1 organ failure)
    • 109,663 patients
    • 12% of patients diagnosed with severe sepsis or at least 1 organ failure had < 2 SIRS criteria at admission.
    • Mortality for the SIRS-negative cohort remained relatively high at 16.1%
  • Take Home Point
    • Using the SIRS criteria to screen patients for severe sepsis will miss 1 out of every 8 patients with infection and organ dysfunction.

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Mechanical Ventilation in the ED

  • Emergency physicians (EPs) intubate patients on a daily basis.  Due to prolonged lengths of stay for many of these patients, the EP must manage the ventilator during the crucial early hours of critical illness.
  • Despite the marked increase in critically ill patients, emergency medicine residents receive very little training in mechanical ventilation (MV).1
  • In addition, recent literature has demonstrated some common themes regarding MV in the ED.2,3
    • Use of higher than recommended tidal volumes
    • Infrequent use of lung protective ventilation strategies
    • Infrequent monitoring of plateau pressures
  • Take Home Points
    • Pay attention to tidal volume
    • Monitor and maintain plateau pressures < 30 cm H2O

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High-Flow Nasal Cannula for Apneic Oxygenation

  • In recent years, much has been written about the use of apneic oxygenation for patients who require endotracheal intubation (ETI).
  • Critically ill patients often have little cardiopulmonary reserve and can rapidly desaturate during ETI.
  • High-flow nasal cannula (HFNC) devices can deliver heated, humidified O2 up to 60 L/min and can provide a modest amount of positive pressure.
  • A recent study evaluated the use of a HFNC device for apneic oxygenation in ICU patients requiring ETI:
    • Prospective, quasi-experimental, before-after study
    • 101 patients in a single ICU in France
    • Compared NRB + nasal cannula to HFNC for preoxygenation/apneic oxygenation
    • Prevelance of severe hypoxemia (SpO2 < 80%) was significantly lower in the HFNC group
  • Clinical Application: Consider using HFNC for apneic oxygenation in critically ill patients with mild-to-moderate hypoxemia who require ETI.

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Hypertensive Emergency Pearls

  • It is well known that a hypertensive emergency is not defined by an arbitrary blood pressure reading.  Rather, it is characterized by the presence of end-organ dysfunction, often due to a sudden increase in sympathetic activation.
  • When treating patients with a hypertensive emergency, consider the following:
    • Many are hypovolemic due to a pressue-induced natriuresis - give them fluids and avoid diuretics.
    • BP should be reduced in a controlled manner using short-acting titratable intravenous agents. Rapid reductions in BP can lead to organ hypoperfusion.
    • Avoid oral, sublingual, and transdermal medications until end-organ dysfunction has resolved.
    • Clevidipine is the newest agent
      • A third-generation dihydropyridine
      • Relaxes arteriolar smooth muscle
      • Rapid onset (2-4 min) and short acting (5-15 min)
      • Compares favorably with nicardipine in available studies

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"PQRST" - Capnography in Cardiac Arrest

  • Resuscitation of the patient in cardiac arrest can be stressful, chaotic, and variable depending on the setting.
  • Capnography is a valuable tool in the management of patients in cardiac arrest.
  • Heradstveit, et al. published a pneumonic for the use of capnography during cardiac arrest:
    • P - Position of the tube
      • The sensivity and specificity of capnography for endotracheal tube confirmation is superior to auscultation and capnometry.
    • Q - Quality of CPR
      • Early detection of poor-quality compressions.
    • R - ROSC
      • A sudden increase in end-tidal CO2 can indicate ROSC without interrupting CPR for pulse checks.
    • S - Strategy
      • May assist clinicians in determining underlying etiology of cardiac arrest.
    • T - Termination
      • An end-tidal CO2 value < 10 mm Hg after 20 min of resuscitation has been shown to be very accurate in predicting death.

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The Critically Ill Patient with Ebola Virus Disease

  • The current outbreak of Ebola Virus Disease (EVD) is the largest ever recorded and has been declared "a public health emergency of international concern" by the WHO.
  • Pearls regarding critically ill patients within the current EVD outbreak include:
    • Clinical Features
      • Tachycardia, tachypnea, oliguria, and alterations in mental status are common and generally seen about 7-12 days after symptom onset.
      • Shock is often due to profound hypovolemia from GI losses.
      • Hemorrhage is a late finding and most often manifests as lower GIB.
    • Labs
      • Common lab abnormalities include hypokalemia, hypocalcemia, hypoalbuminemia, and lactic acidosis.
    • Treatment
      • The mainstay of treatment is aggressive fluid resuscitation and electrolyte repletion (especially potassium).
      • Blood products can be administered for those with coagulopathy and hemorrhage.
      • Empiric antibiotics and antimalarial medications should be considered while awaiting confirmatory testing for EVD.

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Aminoglycosides in Critically Ill Patients

  • Aminoglycosides remain an important class of antibiotics in critically ill patients, especially those infected with multidrug-resistant organisms (i.e., Klebsiella  and Pseudomonas spp.).
  • Importantly, aminoglycosides are concentration-dependent antibiotics and a greatly affected by the increased volume of distribution and altered elimination commonly seen in the critically ill.
  • As a result, recommended doses are often too low to be effective. 
  • Initial doses of aminoglycosides should, therefore, be higher in critically ill patients.
    • Amikacin: 25-30 mg/kg
    • Gentamicin: 7-9 mg/kg
    • Tobramycin: 7-9 mg/kg
  • Subsequent doses are based on drug level monitoring.

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Hemoglobin Threshold in Septic Shock

  • Numerous trials have demonstrated the benefit of lower hemoglobin thresholds for blood transfusion in critically ill patients.
  • The recently published Transfusion Requirements in Septic Shock (TRISS) trial evaluated the effects on mortality of a lower versus higher hemoglobin threshold in ICU patients with septic shock.
  • The TRISS trial randomized 1005 patients to a lower hemglobin threshold (7 g/dL) or a higher hemoglobin threshold (9 g/dL). 
  • Overall, there was no difference in 90-day mortality between groups.
  • Patients randomized to the lower threshold received significantly fewer units without any increase in ischemic or adverse events.
  • Take Home Point: A hemoglogin threshold of 7 g/dL for blood transfusion appears effective for most patients with septic shock.

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Infectious Risks Associated with TTM

  • Targeted temperature management (TTM) is commonly used in the care of patients resuscitated from cardiac arrest.
  • Despite improving neurologic outcomes, TTM can increase the risk of infection, bleeding, coagulopathy, arrhythmias, and electrolyte derangements.
  • Infectious complications of TTM are associated with increases in ICU length of stay, along with increases in the duration of mechanical ventilation.
  • Pneumonia and bacteremia are the two most common infectious complications of TTM, with S.aureus the most common single pathogen isolated in cases of infection.
  • Since TTM may suppress normal signs of infection, it is important to be vigilant for these two infectious complications.
  • At present, evidence does not support prophylactic antibiotics for all patients receiving TTM.

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