UMEM Educational Pearls - By Mike Winters

Title: Sedation and Analgesia in Acute Neurologic Disease

Category: Critical Care

Posted: 1/11/2011 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Dexmedetomidine for Sedation in Acute Neurologic Disease

Critically Ill patients with acute neurologic disease are managed daily in the ED.
Due to the need for frequent neurologic assessments, these patients can be challenging should they require sedation.
Dexmedetomidine, a selective alpha-2 adrenergic receptor agonist, has emerged as an alternative to traditional sedatives (i.e. opioids and benzodiazepines).
Dexmedetomidine provides sedation and anxiolysis, while producing little effect on level of arousal and cognitive function. In essence, it reduces discomfort while permitting the patient to arouse for a neurologic examination.

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Title: Pharmacotherapy in the Critically Ill Obese Patient

Category: Critical Care

Posted: 12/28/2010 by Mike Winters, MBA, MD
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Vancomycin Dosing in the Critically Ill Obese Patient

Obesity related changes to drug metabolism and distribution can significantly impact the critically ill obese patient.
Many meds can either be underdosed or overdosed depending on which body weight (ideal vs. actual) is used.
With the increased incidence of MRSA infections, vancomycin is often included in the initial antibiotic selection for most critically ill ED patients.
Importantly, vancomycin is one of the most studied antibiotics in obese patients.
Recent guidelines recommend that an initial vancomycin dose of 25-30 mg/kg actual body weight be considered for any critically ill patient, with subsequent dosing dependent upon renal function and trough levels.

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Title: Antibiotic Timing

Category: Critical Care

Posted: 12/15/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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The Importance of Antibiotic Timing for Sepsis and Septic Shock

Septic shock is perhaps the most common critical illness that emergency physicians manage.
In several studies, delays in initiating antibiotics for patients with septic shock were the strongest predictor of mortality.
Broad spectrum antibiotics should be administered ASAP (preferably within 60 minutes) to patients with septic shock.
Selection of antibiotics should be based on the presumed source, the antibiogram at your institution, and the patient's risk factors for resistant organisms.

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Title: Patient Positioning in the Critically Ill Obese Patient

Category: Critical Care

Posted: 11/30/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Beware Trendelenburg Positioning in the Critically Ill Obese Patient

When inserting a central venous catheter (CVC) into the internal jugular or subclavian vein, clinicians often place patients in the Trendelenburg position to increase the size of the vein.
When possible, avoid Trendelenburg position for CVC placement in the morbidly obese patient.
These patients can quickly deteriorate in this position due to reduced lung volumes, increased right heart pressures, decreased cardiopulmonary reserve, and the effects in intra-abdominal pressure.

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Title: Obesity and Mechanical Ventilation

Category: Critical Care

Posted: 11/16/2010 by Mike Winters, MBA, MD
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Positioning for Ventilated, Critically Ill Obese Patients

Up to one-quarter of patients in the ICU are obese, as defined by a BMI > 35 kg/m²
Obesity can significantly alter pulmonary physiology causing
- reduced lung volumes
- decreased compliance
- abnormal ventilation to perfusion relationships
- respiratory muscle inefficiency
For intubated obese patients, body position can affect ventilatory management
In the supine position, obese patients can have collapse of lung segments along with increased impedance of the diaphragm
Elevating the head of the bed to 30-45 degrees in intubated obese patients has been shown to improve tidal volumes and lower respiratory rates.

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Title: Ventilation in the Post-Cardiac Arrest Patient

Category: Critical Care

Posted: 11/2/2010 by Mike Winters, MBA, MD
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Ventilation Pearls in the Post-Cardiac Arrest Patient

Some ventilation pearls from the recently released 2010 AHA guidelines include:
- Set the tidal volume to 6-8 ml/kg ideal body weight
- Titrate minute ventilation to achieve a P_aCO₂ between 40-45 mm Hg or P_ETCO₂ between 35-40 mm Hg
- Reduce the F_iO₂ to maintain S_pO₂ > 94%

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Title: Ketamine for RSI in Unstable ED Patients

Category: Critical Care

Posted: 10/19/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Ketamine for RSI in Hemodynamically Unstable ED Patients

Recall that ketamine acts as a sympathomimetic resulting in increases in heart rate, blood pressure, and ultimately cardiac output.
Because of its rapid transport across the blood-brain barrier, its sympathomimetic effects, and lack of significant adverse effects, ketamine is recommended by many organizations as a first line agent for RSI in unstable patients.
Important contraindications to ketamine include an acute coronary syndrome, aortic dissection, and acute heart failure.
Take Home Point: Consider using ketamine the next time you need to intubate a hypotensive, critically ill ED patient.

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Title: Peak and Plateau Pressures in Intubated ED Patients with Respiratory Distress

Category: Critical Care

Posted: 10/5/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Respiratory Distress in the Ventilated ED Patient

In the ventilated patient with respiratory distress, evaluation of peak and plateau pressures can help to identify the cause.
Isolated increases in peak pressure suggest increased resistance to airflow and should prompt consideration of the following:
- kinked or twisted ET tube
- patient biting ET tube
- obstructed ET tube
- bronchospasm
- lower airway obstruction
Increases in plateau pressure suggest decreased pulmonary compliance and should prompt consideration of the following:
- unilateral intubation
- pneumothorax
- pulmonary edema
- worsening pneumonia
- abdominal HTN/compartment syndrome

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Title: Hemophilia A and Life-threatening bleeding

Category: Critical Care

Posted: 9/21/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Life-threatening Bleeding in Hemophilia A Patients

Although an infrequent occurrence, patients with Hemophilia A can present with life-threatening hemorrhage (e.g. ICH).
Recall that normal clotting factor levels range from 50-150 IU/dL - reported by the lab as 50-150%.
Life-threatening bleeding requires Factor VIII levels between 80-100%. In general, each unit of FVIII/kg raises plasma levels by 2%.
Recombinant Factor VIII products are preferred over plasma derived concentrates or blood products and are dosed as:
- FVIII - 50 IU/kg loading dose followed by infusion of 3 IU/kg/hr
In the event you don't have access to recombinant or plasma derived FVIII concentrates, cryoprecipitate (contains FVIII) can be used.

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Title: Pulmonary Contusion Ventilator Management

Category: Critical Care

Posted: 9/7/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Pulmonary Contusion and Ventilator Management

Pulmonary contusion is the most common injury in blunt thoracic trauma.
Patients with pulmonary contusion often present with hypoxia, hypercarbia and increased work of breathing.
Importantly, patients with pulmonary contusion have a low cardiopulmonary reserve. Maintain a low threshold for initiating mechanical ventilation is these patients.
When starting mechanical ventilation, think about the following:
- Patients are at high risk for developing ARDS
- Most centers use a low tidal volume ventilatory strategy
- Higher levels of PEEP may be necessary to recruit collapsed alveoli
- High frequency oscillatory ventilation (HFOV) and airway pressure release ventilation (APRV) are modes of ventilation that are gaining in popularity for ventilating patients with pulmonary contusions.

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Title: Hemostatic Therapy for ICH

Category: Critical Care

Posted: 8/24/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Hemostatic Therapy for ICH - Updated Guidelines

The AHA/ASA just published updated guidelines for the diagnosis and treatment of acute spontaneous intracerebral hemorrhage (ICH).
Regarding hemostatic therapy, new/revised recommendations from the 2007 AHA/ASA guidelines include:
- Patients with severe thrombocytopenia or factor deficiency should receive platelets or factor replacement
- Patients with ICH due to oral anticoagulants (warfarin) should receive intravenous vitamin-K and vitamin-K dependent factor replacement
  - Prothrombin complex concentrates (PCCs) are being increasingly used and are considered a reasonable alternative to FFP. To date, studies have not shown improved outcome with PCCs.
  - Recombinant factor VIIa (rFVIIa) is not recommended as a sole agent for warfarin-related ICH
- rFVIIa is not recommended in unselected patients
- Usefulness of platelet transfusions for patients using antiplatelet medications is unclear and currently investigational.

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Title: Drug-Induced Hypophosphatemia

Category: Critical Care

Posted: 8/10/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Drug-Induced Hypophosphatemia

Hypophosphatemia is seen in almost 30% of critically ill patients.
As discussed in a prior pearl, hypophosphatemia can result in respiratory failure along with cardiac and neurologic abnormalities.
Although common ED causes of hypophosphatemia include sepsis, hypothermia, and dialysis, don't forget about medications.
Medications that can cause significant hypophosphatemia in the critically ill (along with their mechanism) include:
- Decreased GI intake: antacids, sucralfate
- Transcellular shift: aspirin overdose, albuterol, catecholamines, insulin, and bicarbonate
- Increased urinary excretion: diuretics, acetaminophen overdose, and theophylline overdose

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Title: Hypocapnia and the Injured Brain

Category: Critical Care

Posted: 8/3/2010 by Mike Winters, MBA, MD
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Hypocapnia and Brain Injury

Hypocapnia indirectly reduces cerebral blood volume through reductions in arterial cerebral blood flow.
Despite its continued and frequent use, hypocapnia can actually aggravate cerebral hypoxia through reductions in oxygen supply and increases in cerebral oxygen demand.
In addition to inducing further cerebral injury, hypocapnia can cause deleterious effects on the heart, lung, and GI tract.
To date, there is no evidence that hypocapnia improves outcome in patients with traumatic brain injury or acute stroke.
Induced hypocapnia in critically ill ED patients with acute brain injury should primarily be reserved for those with imminent brain herniation.

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Title: Drug Induced Thrombocytopenia in the Critically Ill

Category: Critical Care

Posted: 7/27/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Drug-Induced Thrombocytopenia

Thrombocytopenia is common in critically ill patients and is associated with increased mortality.
Up to 25% of critically ill patients will develop thrombocytopenia as a result of a medication, termed drug-induced thrombocytopenia (DIT)
Antibiotcs are a common, yet infrequently recognized, cause of DIT.
Antibiotics reported to cause DIT include linezolid, vancomycin, trimethoprim/sulfamethoxazole, and the beta-lactams.
In fact, piperacillin/tazobactam has been associated with DIT more frequently than any other penicillin.

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Title: ICU Acquired Weakness

Category: Critical Care

Posted: 7/19/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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ICU Acquired Weakness

ICU acquired weakness (ICU-aw) is a general term that refers to the weakness that develops in critically ill patients during the course of their illness - especially in patients with sepsis and those receiving mechanical ventilation.
ICU-aw is an very common complication of critical illness that can develop within hours and has been shown to increase the duration of mechanical ventilation and ICU/hospital LOS. Observational studies have also reported an association with mortality.
Risk factors associated with ICU-aw include medications (neuromuscular blocking agents, corticosteroids), hyperglycemia and immobility.
For the critically ill ED patient, current recommendations suggest limiting the administration of neuromuscular blocking agents and corticosteroids, when possible.

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Title: Drug-Drug Interactions in the Critically Ill

Category: Critical Care

Posted: 7/13/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Drug-Drug Interactions in the Critically Ill

Critically Ill ED patients are at risk for drug-drug interactions (DDIs) due to altered organ function, polypharmacy, and altered drug kinetics.
DDIs involving the cytochrome isoenzyme CYP3A4 are of particular importance.
CYP3A4 inhibitors, such as macrolides and azoles (fluconazole, voriconazole), can cause serious DDIs when given concomitantly with meds that are a subtrate for CYP3A4 - midazolam, cyclosporine, tacrolimus, diltiazem, amiodarone.
Pay particular attention to your transplant patients, as administration of an azole can result in significant cyclosporine or tacrolimus toxicity.

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Title: Asthma, Peak Pressures, and the Ventilator

Category: Critical Care

Posted: 7/6/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Asthma, Peak Pressures, and the Ventilator

In previous pearls, we have highlighted ventilator settings for the asthmatic, along with the differences between peak and plateau pressure measurements.
When ventilating the asthmatic, pay attention to the ventilator settings placed by your respiratory therapist.
In general, the respiratory therapist will set the ventilator to stop delivering tidal volumes when the peak pressure exceeds 40-60 cm H₂O.
For asthmatics, this practice can result in very low tidal volumes.
Thus, peak pressure limits must be set higher.
As you know, high peak pressures have not been shown to be injurious, provided that the plateau pressure remains < 30 cm H₂O

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Title: Acidosis and Intubation

Category: Critical Care

Posted: 6/29/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Pre-existing acidosis and mechanical ventilation

Not surprisingly, many critically ill ED patients often develop a metabolic acidosis.
To compensate, patients hyperventilate, thereby producing a respiratory alkalosis.
When these patients require intubation and mechanical ventilation, be sure to provide the same level of respiratory compensation when setting the ventilator.
Failing to provide a rate sufficient to compensate for the pre-intubation acidosis leads to a rapid drop in pH, bradycardia and eventually asystole.
In general, rates can be increased to about 30-35 breaths per minute, after which auto-PEEP becomes problematic.

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Title: Hypotension and MV

Category: Critical Care

Posted: 6/15/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Hypotension after intubation and initiation of mechanical ventilation

Approximately 25-30% of patients develop hypotension after intubation and initiation of mechanical ventilation (MV).
Although the literature is not robust, risk factors for hypotension after initiation of MV include:
- hypotension prior to intubation
- tachycardia prior to intubation
- obesity
- high intrathoracic pressure (COPD)
- excess catecholamine states (ETOH withdrawal, cocaine intoxication) with rapid relaxation during RSI
In addition to administering isotonic intravenous fluids (IVFs) while preparing for intubation, consider having a vasopressor medication, such as phenylephrine, available if IVFs alone prove insufficient at maintaining blood pressure.

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Title: Platelet Transfusions in the Critically Ill

Category: Critical Care

Posted: 6/8/2010 by Mike Winters, MBA, MD (Updated: 11/22/2024)
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Platelet Transfusions in the Critically Ill

Recommendations for the transfusion of platelets in the critically ill patient is primarily extrapolated from the oncology literature; literature that is predominantly observational and expert opinion.
Nevertheless, indications for the transfusion of platelets in a critically ill ED patient include:
- active bleeding with a plt count < 50 x 10⁹/L
- plt count < 10 x 10⁹/L (high risk of spontaneous bleeding)
- prior to an invasive procedure when the plt count is < 50 x 10⁹/L
Importantly, the decision to transfuse platelets should also take into account the clinical setting (ie. a uremic patient with active bleeding)