UMEM Educational Pearls - By Mike Winters

Ventilation in the Brain-injured Patient

  • As we have discussed in previous pearls, the ARDSnet trial forms the basis for ventilatory management in the ICU.  A primary component to current ventilatory management is the focus on maintaining lower and safer distending pressures through the use of lower tidal volumes.
  • Similar to last week's pearl on the obstetric patient, these ventilatory settings may not be applicable to all patients.
  • Recall that the use lower tidal volumes results in lower minute ventilation.  This leads to the accumulation of CO2, termed permissive hypercapnia.  In general, we tolerate higher levels of CO2 in favor of lower plateau pressures.
  • For the brain-injured patient, however, increases in CO2 may increase intracranial pressure (ICP) causing adverse effects.
  • Current recommendations for mechanical ventilation in the brain-injured patient include maintaining a PaCO2 between 35 - 40 mm Hg.  Thus, you need to be more vigilant at following PaCO2 in this patient population.

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Mechanical Ventilation of the Obstetric Patient

  • In previous pearls, we have discussed ventilatory settings to avoid excessive volumes and limit plateau pressures to < 30 cm H2O
  • Importantly, these settings have not be extensively evaluated in pregnant patients
  • Some important pearls when ventilating the pregnant patient:
    • Avoid hyperventilation, as this adversely affects uterine blood flow
    • Optimize oxygenation to ensure adequate fetal oxygen delivery (us 100% FiO2)
    • In the presence of adequate oxygenation, PaCOs values <= 60 mm Hg do not appear to be detrimental to the fetus

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Category: Critical Care

Title: CIRCI

Posted: 3/24/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Critical Illness-Related Corticosteroid Insufficiency (CIRCI)

  • CIRCI is defined as inadequate corticosteroid activity for the severity of illness of a patient
  • CIRCI arises due to steroid tissue resistance and inadequate circulating levels of free cortisol
  • Hypotension refractory to fluids and requirement of vasopressors is the primary manifestation of CIRCI
  • In contrast to chronic adrenal insufficiency, hyponatremia and hyperkalemia are uncommon
  • Consider CIRCI in all critically ill patients requiring vasopressor support

So, which critically ill patients do you treat with steroids?  Current literature suggests the indications for steroid treatment include vasopressor dependent septic shock and persistent ARDS despite supportive therapy and lung protective ventilation.  A patient who requires only an hour or two of a vasopressor while being fluid resuscitated is unlikely to benefit.  An accepted dosing schedule is hydrocortisone 50 mg IV every 6 hours.

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Category: Critical Care

Title: Aneurysmal SAH

Posted: 3/17/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Early Critical Care Management of Aneurysmal SAH

  • 30,000 patients per year have an SAH
  • Early ED management certainly should focus on airway assessment, emergent CT scanning, continuous caridac monitoring, and serial neurologic exams
  • A few other pearls regarding management:
    • Volume management - maintain euvolemia with an isotonic crystalloid fluid
    • Anticonvulsants - routine use is associated with cognitive impairment and is not recommended
    • Steroids - once used to reduce meningeal irritation, however, there is no convincing evidence of a beneficial effect.  As such, corticosteroids are no longer recommended.
    • Rebleeding - risk of rebleeding is highest in first 24 hours after initial SAH.  Definitive prevention is done by repair via surgery or endovascular coiling.  A large, prospective study found outcome was better with endovascular coiling.

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Category: Critical Care

Title: NMBs in intubated patients

Posted: 3/3/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Neuromuscular Blocking Agent (NMBA)

  • NMBAs are used to facilitate intubation when performing RSI
  • Importantly, NMBAs have no analgesic or amnestic effects
  • Indiscriminate and repeated dosing of NMBA can lead to prolonged recovery and critical illness polyneuromyopathy, a devastating complication of critical illness that prolongs ventilation, ICU/hospital length of stay, and increases mortality
  • Take Home Point: provide adequate amounts of sedation and analgesia to your intubated ED patients rather then reflexively giving repeated doses of NMBA


Category: Critical Care

Title: The Crashing Vented Patient

Posted: 2/24/2009 by Mike Winters, MD (Updated: 3/29/2024)
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The Crashing Intubated ED Patient

  • For intubated ED patients who develop respiratory distress and are hemodynamically unstable, perform the following:
    • Immediately disconnect from the ventilator
    • Manually ventilate with 100% FiO2
    • Exclude tension pneumothorax (decompress)
    • Exclude auto-PEEP (allow for lung deflation)
    • Check ET tube for kinks, twisting, or obstruction
    • Check for air leak (check pilot balloon and listen for air coming from mouth/nose during manual ventilation)
    • Check the ventilator circuit


Category: Critical Care

Title: Sepsis in Pregnancy

Posted: 2/17/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Sepsis in Pregnancy

  • Sepsis in the setting of pregnancy is primarily the result of pelvic infections such as chorioamnionitis, endometritis, septic abortion, or urinary tract infection
  • In these patients, aerobic gram-negative rods (E. coli, Enterococci, Beta-hemolytic strep) are the principal etiologic agents
  • An empiric broad spectrum antibiotic regimen is ampicillin, gentamicin, and clindamycin (or metronidazole)

 

 

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Category: Critical Care

Title: Preventing VAP

Keywords: ventilator associated pneumonia, head of bed (PubMed Search)

Posted: 2/10/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Ventilator Associated Pneumonia (VAP)

  • VAP is the leading cause of death among hospital acquired infections
  • VAP causes prolongation of mechanical ventilation, ICU/hospital length of stay, and adds about $40,000 to the patient's admission
  • As we care for more and more intubated patients for longer and longer periods of time, it is crucial to know some simple preventative measures we can do in the ED to reduce morbidity and mortality
  • In the absence of contraindications, elevate the head of the bed to 30-45 degrees for intubated patients
  • This is a simple, no cost intervention that has been shown to decrease the incidence of VAP


Category: Critical Care

Title: Sedation and Analgesia in Mechanical Ventilation

Keywords: sedation, analgesia, mechanical ventilation (PubMed Search)

Posted: 2/3/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Sedation and Analgesia in Mechanical Ventilation

  • Mechanically ventilated patients routinely experience pain and anxiety from the presence of an endotracheal tube, ventilator strategies, placement of invasive catheters, surgical procedures, and even nursing procedures such as suctioning and repositioning.
  • Recent literature highlights that many of our vented patients received inadequate amounts of analgesia and anxiolysis
  • When giving anxiolytics and analgesics, focus first on analgesics
  • Patients given analgesics first, followed by anxiolytics, consistently achieve goals with less amounts of supplemental medications needed.


Category: Critical Care

Title: Sepsis and Pneumonia

Keywords: pneumonia, sepsis, severe sepsis, septic shock, mrsa, vancomycin (PubMed Search)

Posted: 1/28/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Pneumonia and Sepsis

  • As we have discussed, one of the most important components in the ED management of sepsis is the administration of early and appropriate broad-spectrum antibiotics
  • Pneumonia remains one of the most common causes of sepsis in the US and worldwide
  • Given the steady rise in incidence of MRSA, remember to add vancomycin to your empiric treatment of patients with pneumonia and severe sepsis or septic shock


Category: Critical Care

Title: Anaphylaxis

Keywords: anaphylaxis, urticaria, angioedema, shock (PubMed Search)

Posted: 1/20/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Clinical Manifestations of Anaphylaxis

  • Importantly, manifestations of anaphylaxis occur along a continuum and are dependent upon the type, route, and quantity of antigen exposure.
  • Cutaneous (90%), respiratory (40-70%), cardiovascular (30-35%), gastrointestinal (40%), neurologic (10%), ocular, and genitourinary symptoms can all be seen.
  • Include anaphylaxis in the differential of any patient with undifferentiated shock, as 10% will not manifest the cutaneous symptoms of urticaria and/or angioedema.

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Category: Critical Care

Title: Sepsis and Mechanical Ventilation

Keywords: sepsis, mechanical ventilation, oxygen delivery (PubMed Search)

Posted: 1/13/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Sepsis and Mechanical Ventilation

  • Essential components of the ED management of sepsis include early identification, antibiotics ASAP, fluid resuscitation, and maintaining adequate perfusion pressure.
  • If patients continue to have evidence of shock (i.e. high lactate) despite adequate fluids and/or pressors, strongly consider intubation, even in the patient without acute respiratory decompensation.
  • The respiratory muscles are avid consumers of oxygen and can use up to 50% of circulating O2.
  • Intubation and paralysis not only increase available O2 to vital organs, it can also augment cardiac output for patients with persistent septic shock.


Category: Critical Care

Title: Fluids and ICH

Keywords: intracerebral hemorrhage, normal saline, hypertonic saline (PubMed Search)

Posted: 1/7/2009 by Mike Winters, MD (Updated: 3/29/2024)
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Intracerebral hemorrhage and fluid management

  • Isotonic fluids (0.9% saline) are the standard IV fluid for patients with ICH
  • The goal for fluid management is to maintain euvolemia with a urine output > 0.5 cc/kg
  • Importantly, 0.45% saline and dextrose containing IVFs should be avoided, as they can exacerbate cerebral edema and increase ICP
  • Hypertonic saline has become a popular aternative to normal saline in patients with significant perihematomal edema and mass effect
  • Goals when using hypertonic saline are to maintain serum osmolality between 300 - 320 mOsm/L and serum sodium between 150 - 155 mEq/L

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Category: Critical Care

Title: Blood Pressure and ICH

Keywords: blood pressure, intracerebral hemorrhage (PubMed Search)

Posted: 12/31/2008 by Mike Winters, MD (Updated: 3/29/2024)
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Blood Pressure Control in ICH

  • Aggressive BP reduction after ICH is currently the focus of an ongoing NINDS study (ATACH Study)
  • Current literature recommends that extreme levels of BP after ICH be treated to reduce hematoma expansion
  • Mean arterial pressures (MAP) > 130 mmHg should be treated with continous IV medications
  • Current recommended medications include labetalol, esmolol, nicardipine, and fenoldopam
  • Nitroprusside is avoided by many given its tendency to increase ICP
  • Oral and sub-lingual medications are not indicated for immediate and precise BP control

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Category: Critical Care

Title: Hemofiltration

Keywords: renal replacement therapy, hemofiltration (PubMed Search)

Posted: 12/23/2008 by Mike Winters, MD (Updated: 3/29/2024)
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Hemofiltration

  • Renal replacement therapy (RRT) involves the use of semipermeable membranes to remove fluid and toxic substances from the bloodstream
  • The basic methods of RRT are hemodialysis (HD) and hemofiltration (HF)
  • There have been a few cases in our ED in which our Renal consultants have used HF
  • Hemofiltration can remove large volumes of fluid (up to 3 Liters per hour)
  • Major advantages to HF: less likely to produce hypotension than HD, can remove larger molecules than HD
  • Disadvantages to HF: must be done continuously to provide effective dialysis, requires anticoagulation to maintain circuit patency, not well suited for hypotensive patients (requires a hydrostatic pressure gradient for solute clearance)


Category: Critical Care

Title: Catheter Positioning

Keywords: central venous catheter (PubMed Search)

Posted: 12/16/2008 by Mike Winters, MD (Updated: 3/29/2024)
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Catheter Positioning

  • Central venous catheters (CVC) inserted from the left side must make an acute angle downward when the enter the SVC from the innominate vein
  • CVCs that do no make this turn can end up with the tip pointing directly at the lateral wall of the SVC
  • CVCs in this position can cause perforation of the SVC
  • If the catheter tip is pointing at the SVC, then advance the catheter further down


Category: Critical Care

Title: Catheter Occlusion - Correction

Keywords: central venous catheter, tissue plasminogen activator (PubMed Search)

Posted: 12/9/2008 by Mike Winters, MD (Emailed: 12/11/2008) (Updated: 3/29/2024)
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My math may appear incorrect, however, I mistakenly left out that the protocol may be repeated once thereby giving up to a total of 4 mg of tPA.

Central Venous Catheter Occlusion

  • Many of us care for patients that present with pre-existing CVCs
  • Catheter occlusion is the most common complication associated with CVC
  • Thrombosis is the most common cause of obstruction of CVCs
  • Thrombosis is often be due to insoluble precipitates; meds such as diazepam, digoxin, phenytoin, and TMP-SMX can cause these precipitates
  • Local instillation of a thrombolytic agent (tPA) can be effective in restoring CVC patency
  • One protocol for use of tPA in CVC occlusion is to:
    • reconstitute a 50 mg vial with 50 mL sterile water (1 mg/mL)
    • draw up 2 mL in a 5 cc syringe and inject into the CVC - total tPA dose 2 mg
    • leave in place for approximately 2 hours
    • attempt to flush the CVC with a saline solution
  • If the catheter remains obstructed, a new CVC should be placed at a new site
  • The total drug dose in this regimen (4 mg) is too small to cause systemic thrombolysis


Category: Critical Care

Title: Hemodialysis Catheters

Keywords: hemodialysis catheters (PubMed Search)

Posted: 12/2/2008 by Mike Winters, MD (Updated: 3/29/2024)
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Hemodialysis Catheters

Two weeks ago, we had a PEA arrest of a patient receiving HD.  A significant delay occurred in administering fluids and medications as a result of "no iv access".  Don't forget that in these situations you can use the hemodialysis catheter.

  • Typically these are double-lumen catheters in the IJ or femoral vein; one lumen carries blood to the HD machine and the other returns it to the patient
  • Importantly, each lumen is equivalent in diameter to an introducer catheter (8 French) - permitting rapid flow
  • Fluids and medications can be rapidly given through these catheters in code situations


Category: Critical Care

Title: SRMI ???

Keywords: stress related mucosal injury, histamine antagonists, proton pump inhibitors, sucralfate (PubMed Search)

Posted: 11/25/2008 by Mike Winters, MD (Updated: 3/29/2024)
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Stress Related Mucosal Injury (SRMI)

  • As the length of stay for many of our critically ill patients continues to rise, it is important to think about some preventative therapies
  • SRMI is the term used to describe gastric mucosal erosions that occur in the critically ill
  • SRMI can be demonstrated in 75 - 100% of critically ill patients within 24 hours and can cause clinically apparent bleeding in up to 25%
  • Independent risk factors for SRMI include mechanical ventilation, coagulopathy, and a prior history of gastritis or peptic ulcer disease
  • Additional risk factors in our ED patient population include sepsis, hypotensive states, severe head injury, multisystem trauma, and renal failure
  • Typically an H2 antagonist is provided (i.e. ranitidine or famotidine).  Currently there is no evidence of superiority of PPIs over H2 antagonists in preventing SRMI
  • Pearl:  the best agent to give is probably sucralfate - there is a slightly higher incidence of bleeding compared to ranitidine; however, ranitidine is associated with a much higher incidence of nosocomial pneumonia.  The risk and mortality associated with nosocomial pneumonia in these patients outweighs the minimal risk of major hemorrhage associated with SRMI


Category: Critical Care

Title: Dopamine

Keywords: dopamine, hemodynamic medication, vasopressors (PubMed Search)

Posted: 11/18/2008 by Mike Winters, MD (Updated: 3/29/2024)
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Dopamine in the ED

  • Recall that dopamine is an endogenous catecholamine that is a precursor for norepinephrine synthesis
  • Despite the popularity of norepinephrine, dopamine is still used by many EPs in the setting of septic shock
  • Dopamine produces progressive alpha-receptor stimulation at doses > 10 mcg/kg/min
  • Tachyarrhythmias (namely sinus tachycardia) is the predominant adverse effect
  • When selecting a vasopressor agent, be sure to check the HR.  If the patient is already tachycardic, the addition of dopamine will only worsen the tachycardia
  • Additional important adverse effects are increased intraocular pressure and delayed gastric emptying

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