UMEM Educational Pearls

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

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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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.

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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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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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)

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

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

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

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

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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Seizures in the Critically Ill

• Seizures are a common complication in medical and surgical patients commonly arising from coexisting conditions associated with critical illness
• Most seizures in the critically ill are generalized convulsions rather than focal
• The majority of seizures occur in patients without a pre-existing history of seizure disorder
• Common causes of seizures in the critically ill include sepsis, cardiovascular disease, metabolic abnormalities, medications, and drug intoxication/withdrawal
• Metabolic abnormalities account for 30 -35% of causes
• The most common metabolic abnormalities include hyponatremia, hypocalcemia, hypophosphatemia, uremia, and hypoglycemia
• Be sure to check these labs in ICU patients with a seizure

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Auto-PEEP in the non-COPD patient

• In previous pearls we have discussed the concept of auto-peep in patients with expiratory flow limitation (asthma and COPD)
• Unexpected auto-peep can also occur in up to 35% of patients without asthma or COPD
• In these patients, auto-PEEP typically occurs with high minute ventilations (> 20 L/min) with shortened exhalation times or if exhalation is blocked (blocked ETT, exhalation valve, or PEEP valve)
• Recall that auto-PEEP increases the work of breathing, worsens gas exchange, and can cause hemodynamic compromise 
• Treatment of auto-PEEP can be as follows:
  • Change ventilator settings
    • increase expiratory time
    • decrease respiratory rate
    • decrease tidal volume
  • Reduce ventilatory demand
    • reduce anxiety, pain, fever with sedatives
  • Reduce flow resistance
    • large-bore ETT
    • frequent suctioning
  • Apply external PEEP

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Ventilator Therapy for ED Patients with ARDS

• As we manage critically ill patients for longer periods of time, it is likely that many of us will manage patients who develop ARDS
• Current mortality for patients with ARDS ranges from 30-40%
• ED treatment for patients with ARDS includes treating the inciting event, supportive critical care, and ventilator management
• Current ventilator management in patients with ARDS includes:
  • avoiding alveolar overdistention (tidal volumes of 6 ml/kg)
  • maintaining F_iO₂ < 60% (mitigates oxygen toxicitty)
  • PEEP to prevent alveolar derecruitment (levels of 10-15 cm H₂O)
  • permissive hypercapnea

 Influenza and the Critically Ill

• It is that time of year again to be vigilant for cases of influenza
• Influenza is not benign and causes > 40,000 deaths per year and is the 7th leading cause of death in the US
• In the critically ill, the most severe disease occurs in patients > 65 and those with underlying cardiopulmonary disease
• Critically ill patients with influenza can present with fever, cough, bilateral interstitial infiltrates, hypoxemia, and leukopenia
• Other serious complications include myocarditis, encephalitis, and Reye syndrome
• Amantadine and rimantadine should no longer be used, as the resistance has risen to > 90% in some populations
• Oseltamivir (PO) and zanamivir (powder/inhalation) are the approved neuraminidase inhibitors; both decrease the severity and duration of illness; should be given as early as possible, preferably within 36 hours

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Can You Rely on Your Clinical Impression to Exclude SBP?

• SBP is an important can't miss diagnosis, as the mortality rate even for treated patients is approximately 20%
• The incidence of SBP ranges from 2.5% (clinic setting) to 12% of all patients admitted with decompensated cirrhosis
• SBP is diagnosed by a neutrophil count > 250 or a positive ascitic fluid culture obtained via paracentesis

• Can our clinical impression exclude SBP without performing a paracentesis? Unfortunately, the answer is NO.
• Sensitivity of physician clinical impression is just about 75%, with a specificity of 34%
• Fever is uncommon in patients with SBP (sensitivity as low as 17%)
• Take Home Point: only a diagnostic paracentesis can reliably exclude SBP in patients admitted for decompensated cirrhosis

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Tension gastrothorax?

• Tension gastrothorax is a life threatening condition characterized by herniation of the stomach through a defect in the diaphragm with compression of the mediastinal contents
• Although many cases occur in pediatric patients (secondary to congenital defects), adults with a history of diaphragmatic injury are at risk (also patients with a type III or IV hiatal hernia)
• The clinical presentation is the same as a tension pneumothorax - hypotension, tachycardia, hypoxia, JVD, and decreased breath sounds
• CXR appearance can be very similar to tension pneumothorax, however, the treatment is substantially different
• Needle decompression and tube thoracostomy are contraindicated, as this may cause visceral perforation
• The treatment of choice is NGT (or OGT) decompression followed by surgical repair

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Subcutaneous Insulin in the Critically Ill

• Although intensive insulin therapy in the critically ill remains controversial and a matter of much debate, hyperglycemia is common in the critically ill ED patient
• Hyperglycemia is associated with worse outcomes in this patient population
• When treating hyperglycemia in the critically ill ED patient, use caution with subcutaneous insulin
• Absoprtion of insulin administered subcutaneously is slow, erratic, and highly variable often due to poor perfusion, hypotension, and/or vasopressor therapy
• In these patients, IV insulin is a better route of administration and leads to more reliable control of hyperglycemia
• Recall that the onset of action of insulin given IV is 10 - 30 minutes, with a duration of action of about 1 hour

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AIDS: coming to a critically ill patient in your ED

• Acute intestinal distress syndrome (AIDS) is a recently coined term used in the continuum of intraabdominal hypertension (IAH) to abdominal compartment syndrome (ACS)
• In previous pearls we have discussed the importance of IAH in the critically ill and how to measure intraabdominal pressure (IAP)
• Recall that IAH is defined as a sustained elevation of IAP > 12 mmHg
• The focus of attention is shifting to "secondary ACS" - it is highly prevalent in the critically ill and is independently associated with increased mortality
• Sepsis is a cause of secondary ACS and is the most likely condition we will encounter in our critically ill patient population
• Current recommendations suggest that IAP be measured daily in patients at risk for IAH (i.e. the septic ED patient)

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Health care-associated pneumonia

• Health care-associated pneumonia (HCAP) is a distinct entity
• HCAP includes any patient with pneumonia and 1 or more of the following:
  • hospitalization for 2 or more days in an acute care facility within the preceeding 90 days
  • nursing home patients
  • patients of long-term care facilities
  • patients who attend a hospital or hemodialysis clinic
  • patients who received IV antibiotics, chemotherapy, or wound care within 30 days of infection
• Data indicate that the mortality for HCAP is higher than CAP
• The most common organisms in HCAP include S.aureus, P.aeruginosa, Klebsiella species, Haemophilus species, and Escherichia species
• An initial recommended antibiotic regimen includes a combination of an antipseudomonal cephalosporin plus a fluoroquinolone plus an agent active against MRSA

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