UMEM Educational Pearls - Critical Care

Category: Critical Care

Title: Guidewire length

Keywords: central venous catheter, guidewire (PubMed Search)

Posted: 3/25/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Guidewire length for central venous catheterization

  • 18 cm should be considered the upper limit of guidewire insertion during internal jugular or subclavian central venous catheterization (16cm for right IJ)
  • There is the Peres Nomogram for determining guidewire length, which is based on patient height
  • However, height is less reliable in predicting safe guidewire length

Category: Critical Care

Title: "K-Phos"

Keywords: phosphate, hypotension, hypomagnesemia (PubMed Search)

Posted: 3/18/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Potassium Phosphate ("K-phos")

Over the weekend, I had a patient with Dr. Scott that had a phosphate of 0.8 mmol/L.  Phosphate < 1.0 mmol/L is an indication for IV repletion.  IV repletion involves giving potassium phosphate.  An important clinical question, therefore, is how much potassium does the patient actually get?

  • 1 mmol of IV phosphate delivers 1.46 mEq of potassium
  • Recommended infusion rate is 5 mmol/hr
  • Rapid infusion may lead to severe hypocalcemia, hypotension, acute renal failure, hypomagnesemia, and hypernatremia

Category: Critical Care

Title: Coagulopathy and Trauma

Keywords: fresh frozen plasma, coagulopathy, PRBC (PubMed Search)

Posted: 3/11/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Coagulopathy and Trauma

  • When resuscitating a trauma patient recall that the "lethal triad" consists of acidosis, hypothermia, and coagulopathy
  • Coagulopathy is induced by the combination of direct loss of clotting factors, consumption in clot formation, dilutional due to crystalloid administration, acidosis, and hypothermia
  • When giving PRBCs in trauma resuscitation, don't forget to give FFP
  • The ratio to remember is 1U of FFP for every 2U PRBCs

Category: Critical Care

Title: Aspiration pneumonitis

Keywords: aspiration pneumonitis (PubMed Search)

Posted: 3/4/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Aspiration Pneumonitis

  • Aspiration pneumonitis is an acute lung injury resulting from the aspiration of gastric contents
  • It is an inflammatory condition rather than infectious
  • Despite the inflammation, corticosteroids have been shown to have no effect on mortality
  • Aspiration pneumonitis is self limited
  • Antibiotics are generally held for 24 to 48 hours
  • When to consider empiric broad spectrum antibiotics in the ED:  Gastric contents are sterile in most patients.  Patients who may have colonization/contamination of gastric contents are more likely to progress from pneumonitis to pneumonia.  Consider empiric antibiotics for aspiration pneumonitis in the patient with SBO, gastroparesis, those receiving enteral feeds through a G- or J-tube, and those on chronic PPI's/antacids.

Category: Critical Care

Title: D-Dimer in the critically ill

Keywords: d-dimer (PubMed Search)

Posted: 2/26/2008 by Mike Winters, MD (Updated: 10/22/2019)
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D-Dimer in the Critically Ill

  • Diagnosis of VTE in the critically ill can be challenging and these patients are at high risk for the disease
  • Only 3.6% - 16% of critically ill patients have a negative d-dimer, regardless of the presence or absence of VTE
  • Even in patients with low pretest probability, d-dimer in the critically ill is of limited utility

Crowther MA, et al. Neither baseline tests of molecular hypercoagulability nor D-dimer levels predict deep venous thrombosis in critically ill medical-surgical patients. Intensive Care Med 2005;31(1):48-55.


Category: Critical Care

Title: Central Venous Pressure

Keywords: central venous pressure (PubMed Search)

Posted: 2/19/2008 by Mike Winters, MD (Updated: 10/22/2019)
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  • The use of central venous pressure as a monitor of volume status remains very controversial in the critical care literature
  • Remember that CVP can be affected by many conditions
  • Important conditions that affect the accuracy of CVP include: 
    • right ventricular disease
    • tricuspid valve disease
    • pericardial disease
    • changes in intrathoracic pressure (PEEP, positive pressure ventilation) 
    • arrhythmias
    • reference level of the transducer

Category: Critical Care

Title: Spontaneous pneumomediastinum

Keywords: spontaneous pneumomediastinum (PubMed Search)

Posted: 2/12/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Spontaneous Pneumomediastinum

  • Spontaneous pneumomediastinum is largely a benign disease typically seen in young males ages 18-21 years
  • It is typically caused by activities that increase alveolar pressure such as coughing, sneezing, vomiting, inhalational drug use, and Valsalva maneuver
  • The most common symptoms include chest pain and dyspnea; chest pain is usually centrally located, may radiate to the neck, and may be worse with inspiration
  • CT scan is the "gold standard"; CXR is a good place to start but it is normal in up to 30% of cases
  • The vast majority of patients do not require admission or supplemental O2
  • Advise patients to avoid strenuous activity until after symptom resolution (typically takes about 2 weeks)
  • Any patient with a fever, elevated WBC count, hemodynamic instability, severe dysphagia or odynophagia should first be evaluated for infectious mediastinitis or esophageal perforation (spont. pneumomediastinum is a diagnosis of exclusion in these patients)

Category: Critical Care

Title: Complications of Radial Artery Catheters

Keywords: radial arterial line (PubMed Search)

Posted: 1/29/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Invasive Arterial Pressure Monitoring - Complications

In critically ill patients with hemodynamic instability we often place arterial catheters to continuously monitor mean arterial pressure.  Since we frequently use the radial artery for cannulation, it is important to know the complications associated with these catheters.  Scheer et al performed, perhaps, the largest review of complications of peripheral arterial catheters.  The results:

  • Radial arterial catheters
    • 19,617 cannulations reviewed
    • temporary occlusions - 19.7%
    • hematoma - 14.4%
    • serious ischemic damage - 0.09%
    • pseudoaneurysm - 0.09%
    • sepsis - 0.13%

Pearl: Although permanent ischemic damage is rare, when placing a radial artery catheter use the non-dominant hand.

Scheer BV, Perel A, Pfeiffer UJ. Clinical review: Complications and risk factors of peripheral arterial catheters used for haemodynamic monitoring in anaesthesia and intensive care medicine. Crit Care 2002;6:198-204.


Category: Critical Care

Title: Pulse Oximetry

Keywords: pulse oximetry (PubMed Search)

Posted: 1/22/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Pitfalls in pulse oximetry in the critically ill

  • Pulse oximeters are calibrated by manufacturers using data collected from healthy volunteers
  • In general, pulse oximeters are accurate  within +/- 2% for sats > 70%
  • In the critically ill, however, the accuracy of pulse oximetry diminishes when sats drop below 90%
  • Also, there may be a significant lag time between a hypoxic event and the actual display of the event - most commonly seen in low flow states, hypotension, mild hypothermia, and when using vasoactive medications
  • Prolonged lag times are more common with finger probes
  • Pitfall - pulse oximetry does not provide any assessment regarding ventilation (PaCO2) or acid-base status (pH) - it is simply an estimate of arterial oxgyen saturation
  • Pearl: anemia does not affect the accuracy of pulse oximetry

Category: Critical Care

Title: Mean arterial pressure

Keywords: mean arterial pressure (PubMed Search)

Posted: 1/15/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Mean Arterial Pressure

  • Arterial pressure is the input pressure for organ perfusion
  • Mean arterial pressure (MAP) is the best physiologic estimate of perfusion pressure
  • MAP is less subject to measurement variability than SBP and DBP
  • MAP remains relatively constant when measured at different sites throughout the arterial circuit
  • MAP of 60 mmHg is considered the autoregulatory threshold below which perfusion becomes compromised
  • Goal: maintain MAP > 65 mmHg
  • There is no proven value to achieving a MAP higher that 65 mmHg.  In fact, there is some literature to support that if you try and drive the MAP higher, patients do worse

Category: Critical Care

Title: Pulmonary Hypertension Pearls

Keywords: pulmonary hypertension, hypotension, calcium channel blockers (PubMed Search)

Posted: 1/8/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Pulmonary Hypertension Pearls

We are beginning to see more and more patients with pulmonary hypertension (PAH),  many of whom are on continuous IV infusions of new medications.  With that in mind, here are a few pearls:

  • The most common causes of rapid deterioration in patients with PAH are: catheter occlusion/pump malfunction, pneumonia, indwelling catheter infection, RV ischemia, PE, and GI bleeding
  • Hypotension is usually due to worsening RV failure and less likely to hypovolemia
  • If a catheter occlusion or pump failure is found, the drug should be restarted as soon as possible through an alternative access (including peripheral)
  • Calcium channel blockers, a prior treatment for PAH, are no longer indicated and should not be given

Category: Critical Care

Title: Adrenal Insufficiency in the Critically Ill

Keywords: adrenal insufficiency, hypotension, glucocorticoids, hydrocortisone (PubMed Search)

Posted: 1/1/2008 by Mike Winters, MD (Updated: 10/22/2019)
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Adrenal Insufficiency in the Critically Ill

  • Adrenal insufficiency (AI) is estimated to occur in up to 30% of critically ill patients
  • The most common causes of AI in the critically ill are SIRS and sepsis
  • In most cases of critically ill patients, AI is functional (i.e relative) - the adrenal response is insufficient to respond to the degree of stress
  • Diagnostic clues include hyponatremia, hyperkalemia, hypoglycemia (rare), and hemodynamic instability despite IVFs and vasopressors
  • Although still controversial, most feel that AI is present in critically ill patients with either a basal cortisol < 15 mcg/dl, an increase in < 9 mcg/dl after ACTH stimulation, or a random cortisol < 25 mcg/dl
  • IV hydrocortisone, methylprednisolone, and dexamethasone are the 3 glucocorticoids most commonly administered
  • Hydrocortisone is usually the preferred agent because it is the synthetic equivalent of cortisol (and has both glucocorticoid and mineralocorticoid activity)

Category: Critical Care

Title: Critical Care Monitoring - End-Tidal CO2

Keywords: end-tidal CO2, capnography, status asthmaticus, increased intracranial pressure (PubMed Search)

Posted: 12/18/2007 by Mike Winters, MD (Updated: 10/22/2019)
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Critical Care Monitoring - End-Tidal CO2

  • End-tidal CO2 (ETCO2) monitoring is used to verify ETT placement, monitor procedural sedation, traumatic brain injury, and to estimate prognosis during cardiopulmonary resuscitation
  • ETCO2 concentration typically underestimates PaCO2 by 4-5 mmHg in healthy non-intubated patients
  • This relationship is less reliable in critically ill patients secondary to shunt, altered alveolar dead space, and inadequate ventilation
  • While a low ETCO2 value is less useful in the critically ill, a high value almost always correlates with an equal or higher PaCO2 value
  • This can be useful when monitoring conditions such as status asthmaticus, CHF, or increased ICPs in which a high ETCO2 may signal the need for additional aggressive treatment

Category: Critical Care

Title: Unilateral pulmonary edema

Keywords: pulmonary edema, aortic dissection, heroin (PubMed Search)

Posted: 12/11/2007 by Mike Winters, MD (Updated: 10/22/2019)
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Unilateral Pulmonary Edema

  • unilateral pulmonary edema is a well recognized and well documented entity
  • although there are several causes, the most likely scenarios for EPs are severe mitral valve insufficiency, aortic dissection (with compression of the pulmonary artery), airway obstruction, and heroin use
  • even though radiology will read the xray as likely pneumonia, if the story/exam fit with edema then treat as such

Category: Critical Care

Title: Massive hemoptysis

Keywords: massive hemoptysis (PubMed Search)

Posted: 12/4/2007 by Mike Winters, MD (Updated: 10/22/2019)
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Massive hemoptysis

  • Massive hemoptysis is defined by most as the expectoration of > 600 ml in 24 hrs
  • Chronic lung inflammatory disease and bronchogenic CA are the most common causes in the US
  • TB remains the most common cause worldwide
  • The bronchial artery causes approximately 90% of cases
  • Get a STAT portable and place the patient in the lateral decubitus position toward the affected side (this is theorectical and has not been proven)
  • Options for bleeding control can include endobronchial tamponade methods(pulmonary), bronchial artery embolization (interventional radiology), and emergent surgical resection (surgery)
  • Bronchial artery embolization is now the most successful non-surgical treatment of massive hemoptysis

Category: Critical Care

Title: Acute Liver Failure

Posted: 11/27/2007 by Mike Winters, MD (Updated: 10/22/2019)
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Acute Liver Failure

  • Acute liver failure (ALF) is defined as the onset of encephalopathy and coagulopathy within 26 weeks of jaundice in a patient without prior history of liver disease
  • ALF has an extremely high mortality
  • The most common cause of ALF include Tylenol, HSV, autoimmune hepatitis, HBV, and acute fatty liver of pregnancy/HELLP
  • Complications EPs are likely to see/manage include hepatic encephalopathy, infection, circulatory dysfunction, bleeding, and seizures
  • Fungal infections may be present in one-third of patients with ALF (Candida)
  • Non-convulsive seizure activity occurs in a high proportion of patients with ALF and encephalopathy - consider EEG for severly encephalopathic patients and those with a sudden deterioration in neuro status

Stravitz RT, et al. Intensive care of patients with acute liver failure. Crit Care Med 2007;35:2498-2508.


Category: Critical Care

Title: Antibiotics for Acute Variceal Bleeding

Keywords: esophageal varices, upper gastrointestinal bleeding, antibiotics (PubMed Search)

Posted: 11/20/2007 by Mike Winters, MD (Updated: 10/22/2019)
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A few days ago Dr. Jump and I had a case of an acute variceal hemorrhage.  Dr. Bond already sent out a great pearl earlier in the year highlighting the importance of octreotide in acute variceal bleeding.  In fact, octreotide alone can result in cessation of hemorrhage in up to 80% of patients.  To add onto Dr. Bond's pearl:

  • Don't forget about antibiotics in acute variceal hemorrhage
  • These patients have a relatively high incidence of bacteremia, which leads to worse outcomes
  • Antibiotics have been shown to decrease infection rates and are associated with decreased rebleeding and the need for transfusions
  • A 3rd generation cephalosporin is currently the recommended antibiotic of choice

Category: Critical Care

Title: Acute Chest Syndrome

Keywords: acute chest syndrome, blood transfusion, respiratory failure (PubMed Search)

Posted: 11/13/2007 by Mike Winters, MD (Updated: 10/22/2019)
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  • Acute chest syndrome (ACS) is the leading cause of death in sickle cell patients
  • ACS is defined by the presence of a new infiltrate and one of the following: chest pain, wheezing, fever, tachypnea, or cough
  • Early and aggressive therapy is needed to minimize mortality
  • Up to 50% of patients develop respiratory failure
  • Treatment
    • Broad spectrum antibiotics - including a macrolide
    • Pain control to reduce hypoventilation
    • Early use of blood transfusion to improve O2 carrying capacity
    • Incentive spirometry
    • Bronchodilators if wheezing present
    • Hematology consult

 


Category: Critical Care

Title: Hemodynamic monitoring - arterial pressure monitoring

Keywords: non-invasive arterial monitoring, radial artery (PubMed Search)

Posted: 11/6/2007 by Mike Winters, MD (Updated: 10/22/2019)
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  • It is traditionally taught that in hypotensive patients the presence of a carotid pulse corresponds to a SBP of 60-70 mmHg, a femoral pulse with a SBP of 70-80 mmHg, and a radial pulse with an SBP of at least 80 mmHg
  • These physical exam estimates of BP have been shown to poorly correlate with the patient's actual BP
  • Similarly, non-invasive measurements of BP (automated cuff) in patients with hypotension may either overestimate or underestimate SBP by as much as 20 mmHg
  • Since physical exam estimates and non-invasive measurements are inaccurate in low-flow states, utilize invasive arterial monitoring
  • Radial and femoral artery sites have been found to produce results that are clinically interchangeable

Category: Critical Care

Title: TBI - Critical Care

Keywords: traumatic brain injury, cerebral perfusion pressure, intracranial pressure, hypertonic saline (PubMed Search)

Posted: 10/30/2007 by Mike Winters, MD (Updated: 10/22/2019)
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Critical Care Pearls for Traumatic Brain Injury

  • Avoid hypotension and hypoxia - SBP < 90 and/or PaO2 < 60 are associated with significant increases in morbidity and mortality
  • Hypertonic saline remains controversial - a recent large, controlled trial did not show any early or long-term benefit
  • ICP monitoring routinely recommended in patients with GCS < 8 - they have a 60% chance of increased ICP
  • Maintain ICP < 20 mmHg and CPP > 60
  • Supportive care
    • Elevate the head of bed > 30 degrees, if possible
    • Control fever
    • Provide analgesia and sedation
  • Ventilator management - keep PaCO2 between 30-35 mmHg
  • Surgery - last resort to controlling increased ICP
    • Decompressive craniotomy
    • Decompressive laparotomy