Question

Gallstones account for 35-40% of cases of pancreatitis and the risk increases with diminishing stone size. Bile reflux into the pancreatic duct can form stones there, beyond where they can be visualized by ultrasound. Biliary colic may precede the pancreatitis, but not necessarily. The pain typically reaches maximum intensity quickly but can remain for days.

Alanine aminotransferase (ALT) > 3x normal is highly suggestive of biliary pancreatitis.

Abdominal ultrasound is not sensitive to common bile duct stones but may find dilation.

In the absence of cholangitis, endoscopic ultrasound or MRCP are sensitive tests and permit intervention. Patients who recover are much more likely to develop cholangitis, therefore cholecystectomy is indicated in patients after they recover from gallstone pancreatitis.

Bottom Line: a patient presenting with days of abdominal pain but an absence of gallstones or cholangitis may still suffer from gallstone pancreatitis which requires further intervention, including cholecystectomy.

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Mechanical Ventilation in the Obese Critically Ill

• Rates of obesity have steadily risen over the past three decades.  In fact, the prevalance of obesity in the ICU is now estimated at 20%.
• Obesity affects numerous organ systems and impacts the resuscitation and management of these patients.
• The pulmonary systems undergoes several changes that include decreased lung compliance, decreased chest wall compliance, increased O2 consumption, increased CO2 production, and increased work of breathing.
• When initiating mechanical ventilation in the obese patient without ARDS, consider the following initial settings:
  • Tidal volume 6 ml/kg ideal body weight
  • PEEP of 10-12 cm H2O
  • RR to achieve a PaCO2 35-45 mmHg
  • FiO2 to maintain SpO2 92-95%
  • Driving pressure < 15 cm H2O

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Background:  Previous systematic reviews^1,2,3 have indicated that the absence of cardiac activity on point-of-care ultrasound (POCUS) during cardiac arrest confers a low likelihood of return of spontaneous circulation (ROSC), but included heterogenous populations (both traumatic and atraumatic cardiac arrest, shockable and nonshockable rhythms).

The SHoC investigators⁴ are the first to publish their review of nontraumatic cardiac arrests with nonshockable rhythms, evaluating POCUS as predictor of ROSC, survival to admission (SHA), and survival to discharge (SHD) in cardiac arrests occurring out-of-hospital or in the ED.

• 10 studies, 1485 patients
• Compared to absence of cardiac activity, presence of cardiac activity = higher odds, increased incidence of ROSC, SHA, and SHD
• Pooled sensitivity for ROSC, SHA, SHD relatively low (60%, 75%, 69%, respectively)
  • On subgroup analysis, sensitivity higher in PEA group (77%) than asystole group (25%)

Bottom Line:  In nontraumatic cardiac arrest with non-shockable rhythms, the absence of cardiac activity on POCUS may not, on its own, be as strong an indicator of poor outcome as previously thought.

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The Lung Transplant Patient in Your ED

• Infections are the most common reason for ICU admission in lung transplant patients.
• Not surprisingly, healthcare-aquired pneumonia is the most common infection seen in lung transplant recipients.
• In contrast to non-transplant patients, gram-negative bacteria (i.e., Pseudomonas aeruginosa) are the most common pathogens.
• Be sure to include antimicrobial coverage for Pseudomonas in your lung transplant patients presenting to the ED with pneumonia.

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When managing transplant patients it is important to keep in mind the anatomic and physiologic changes that occur with the complete extraction of one person's body part to replace another's. 

For cardiac transplant patients with symptomatic bradycardia:

• Remember that due to lack of autonomic/vagal innervation, resting HR should be around 90 bpm.
• HR will not respond to atropine. Use direct sympathomimetics like epinephrine instead.
• If medication is unsuccessful, proceed to transcutaneous or transvenous pacing.

For cardiac transplant patients with tachyarrythmias:

• They are particularly sensitive to adenosine; for SVT start with 1 to 3mg adenosine push (3mg is usually effective) to avoid sustained bradycardia or asystole.
• Digoxin is not effective as an antiarrhythmic.
• Diltiazem can decrease the metabolism of calcineurin inhibitor immunosuppressive agents (such as cyclosporine and tacrolimus), so while it can be used there may need to be dose adjustments to these medications. 

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Hyponatremia in the Brain Injured Patient

• Hyponatremia is the most common electrolyte disorder in neurocritical care and is associated with increased ICP.
• The two most common causes of hyponatremia in this patient population are cerebral salt wasting syndrome and SIADH.
• Symptomatic hyponatremia should be treated with hypertonic saline:
  • 30-45 ml of 10% NaCl or
  • 100-150 ml of 3% NaCl
• In order to prevent osmotic demyelination syndrome (ODM), sodium should not be corrected by more than 10 mmol/L/day.
• The risk of ODM is low when acute hyponatremia develops in less than 48 hours.

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The PROTRACH study recently compared preoxygenation with standard bag valve mask (BVM) at 15 lpm to preoxygenation + apneic oxygenation with high flow nasal cannula 60 lpm/100% FiO2 in patients undergoing rapid sequence intubation.

• There was no significant difference in the primary outcome of median lowest SpO2 during intubation. 
• There were more intubation complications in the BVM group compared to the HFNC group:
  • Severe complications: SpO2 <80%, severe hypotension (SBP < 80mmHg or vasopressor initiation/increase by 30%), and cardiac arrest (6% HFNC vs 16% BVM, RR 0.38, 95% CI 0.15-0.95, p=0.03). 
  • Moderate complications: aspiration, cardiac arrhythmia, agitation, and esophageal intubation (0% HFNC vs 7% BVM, p= 0.01). 
• There was no difference in ventilator days, ICU length of stay, or mortality.

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A True Tracheostomy Emergency

• Patients with a tracheostomy often present to the ED for evaluation of a potential complication.
• Consider a tracheoarterial fistula in any patient with a tracheostomy who presents with brisk bleeding.
• Most occur within 3 to 4 weeks following tracheostomy placement, and the most common location is the innominate artery.
• Up to 50% of patients will present with a sentinel bleed - an episode of brisk bleeding that has usually stopped at the time of presentation.
• For patients who present with active hemorrhage, overinflate the tracheostomy cuff in an attempt to tamponade the bleeding.
• If that does not stop the bleeding, remove the tracheostomy and compress the artery against the poterior sternum with your finger.

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Despite ongoing research and efforts to improve our care of patients with ARDS, it remains an entity with high morbidity and mortality. Early recognition of the disease process and appropriate management by emergency physicians can have profound effects on the patient's course, especially in centers where ICU boarding continues to be an issue.

Recognition of ARDS (Berlin criteria)

• Acute in onset
• Bilateral infiltrates on chest imaging not due to cardiac failure/volume overload
• PaO2 : FiO2 < 300 despite PEEP of at least 5cmH2O 
• This is the standard ED patient who gets intubated with multifocal pneumonia and has continued hypoxemia

*An ABG should be obtained in the ED if physicians are unable to wean down FiO2 from high settings, if oxygenation by pulse ox is marginal, or if the patient is in a shock state.

Tenets of ARDS Management:

• Low tidal volume ventilation (6-8ml/kg ideal body weight*)
• Maintain plateau pressures (Pplat) < 30 cmH2O
• Driving pressure (Pplat – PEEP) < 15 cmH2O
• Goal PaO2 > 55-60 
• Permissive hypercapnia to pH >7.2

*IBW Males = 50 + 2.3 x [Height (in) - 60]   /  IBW Females = 45.5 + 2.3 x [Height (in) - 60]

Strategies for Refractory Hypoxemia in the ED:  You can't prone the patient, but what else can you do? 

1. Escalate PEEP in stepwise fashion

• ex: 2cmH20 every 10 minutes
• can use ARDSnet PEEP/FiO2 table as guide

2. Recruitment maneuvers

• "20 of PEEP for 20 seconds" or "30 for 30"
• if patient is "PEEP responsive," leave PEEP on a higher setting than when you started (ex: 10 instead of 5, 16 instead of 10)
• Risk of barotrauma with higher PEEPs and hypotension in underresuscitated or hemodynamically unstable patients due to decreased venous return

3. Appropriate sedation and neuromuscular blockade

• promotes patient synchrony with lung protective settings
• can result in improved oxygenation by itself

4. Inhaled pulmonary vasodilators (inhaled prostaglandins, nitric oxide) if known or suspected right heart failure or pulmonary hypertension

Bottom Line: Emergency physicians are the first line of defense against ARDS. Early recognition of the disease process and appropriate management is important to improve outcomes AND to help ICU physicians triage which patients need to be emergently proned or even who should potentially be referred for ECMO. 

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Does This Patient Have Pericardial Tamponade?

• Echocardiography is critical for the identification of a pericardial effusion and rapid diagnosis of pericardial tamponade.
• Common echocardiography findings that suggest tamponade include diastolic right ventricular collapse, systolic right atrial collapse, a plethoric IVC with minimal respiratory variation, and potentially exaggerated respiratory cycle changes in mitral and triscupid inflow velocities.
• Of these, systolic right atrial collapse is the earliest echocardiographic sign of tamponade, with a sensitivity ranging from 50% to 100%.
• Of the 4 standard echo views, systolic right atrial collapse can best be viewed in the apical 4-chamber and subxiphoid views.

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Neutropenic enterocolitis can occur in immunosuppressed patients, classically those being treated for malignancy (hematologic much more commonly than solid tumor). When involving the cecum specifically, it is known as "typhlitis."

It should be considered in any febrile neutropenic patients with abdominal pain or other symptoms of GI discomfort (diarrhea, vomiting, lower GI bleeding), and can be confirmed with CT imaging.

A recent study found that invasive fungal disease, most often candidemia, occurred in 20% of febrile neutropenic patients with CT-confirmed enteritis, a rate that increased to 30% if the patient was in septic shock.

Take Home: 

1. Have a lower threshold for abdominal CT imaging in your patients with febrile neutropenia and abdominal pain/GI symptoms, especially if they are critically ill.

2. Consider addition of IV antifungal therapy if they are hemodynamically unstable with enterocolitis on CT.

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Management of Acute Variceal Bleeding

• Patients with an acute UGIB secondary to esophageal or gastric varices frequently present in extremis.
• The initial resuscitation of patients with a variceal bleed should focus on the administration of antibiotics, packed red blood cells (PRBC), vasoactive agents, and emergent endoscopy.
• Antibiotics have been shown to reduce recurrent bleeding and mortality. A third-generation cephalosporin (e.g., ceftriaxone) is commonly recommended as the initial antibiotic of choice.
• Utilize a restrictive PRBC transfusion strategy to target a Hb between 7 to 8 g/dL.
• Vasoactive agents (e.g., octreotide) reduce portal pressure through splanchnic vasoconstriction and have been shown to reduce acute bleeding and the need for transfusion.

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Question

Historically, there has been very limited data regarding the epidemiology of OHCA in pregnant females. Two recently-published studies tried to shed some light on the issue.

Both Maurin et al.¹ and Lipowicz et al.² looked at all-cause out-of-hospital maternal cardiac arrest (MCA) data in terms of numbers and management, in Paris and Toronto respectively, from 2009/2010 to 2014. Collectively, they found: 

• MCA was relatively rare: 0.8 MCA per 1000 OHCA (Maurin) and 1.71 MCA per 100,000 pregnant females (Lipowicz)
• Low incidence of bystander CPR in witnessed MCA (33% and 0%)
• Adherence to PMCS guidelines was poor 
• Maternal survival was lower than what has been previously quoted for in-hospital CA: 12.5 and 16.7% compared to 40-50%^3,4

A few reminders from the 2015 AHA guidelines for the management of cardiac arrest in pregnancy: 

• Hand location for chest compressions should be in the center of the chest as for nonpregnant patients (previous recommendations had been to shift upward to accommodate for the gravid uterus but there is no data to support this).

• Chest compressions should be performed with the patient supine, using manual lateral uterine displacement for aortocaval decompression. Left lateral tilt position is no longer recommended due to poorer quality of cardiac compressions, the lack of full aortocaval decompression, and further complication of other procedures such as airway management.

• IV or IO access should be obtained above the diaphragm, to ensure no interference to flow to the heart by the gravid uterus.

• Rate and depth of chest compressions, ACLS drugs and doses, and defibrillation all remain the same as in nonpregnant OHCA patients.
  • NB: As opposed to nonpregnant patients periarrest, oxygen saturation in the pregnant female should be maintained at 95% or greater, or PaO2 > 70mmHg, to ensure appropriate oxygen delivery to the fetus. The goal PCO2 is ~28-32 mmHg, to facilitate fetal CO2 removal.⁶  

• If advanced airway is pursued, the most experienced provider should perform intubation due to the higher intrinsic difficulties, more rapid decompensation, and propensity for airway trauma and bleeding in the pregnant female.

• Perimortem c-section should occur within the first 5 minutes of cardiac arrest / arrival to the ED in ongoing arrest. 

Bottom Line: Although maternal cardiac arrest is relatively rare, survival in OHCA is lower than perhaps previously thought. Areas to improve include public education on the importance of bystander CPR in pregnant females, and appropriate physician adherence to PMCS recommendations, with decreased on-scene time by EMS in order to decrease time to PMCS. 

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Respiratory Complications of ICIs

• Acute respiratory failure (ARF) is the leading cause of ICU admission for immunocompromised patients.
• While infectious etiologies remain the most common cause of ARF in these patients, there is an increasing prevalence of non-infectious, treatment-related causes.
• Immune check-point inhibitors (ICIs) are now used with increasing frequency, and can cause severe pulmonary toxicity in approximately 6% of patients.
• Pearls for ICI pulmonary toxicity include:
  • Acute pneumonitis is the most common presentation
  • Median time of onset of approximately 4 months after treatment initiation
  • Symptoms include dry cough, hypoxemia, and infiltrates not c/w CHF, infection, or progression of malignancy
  • Treatment is to DC the ICI and initiate steroids

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--Late awakening (>48h after sedation held) was common (78/402) in patients with cardiac arrest in prospective cohort study

--Poor prognostic signs of discontinuous (10-49% suppression) EEG and absent brain stem reflexes were independently associated with late awakening. Use of midazolam also associated with late awakening

--Late awakeners had good functional outcome when compared to early awakeners

DON'T NEUROPROGNOSTIC EARLY (OR IN ED)!

And traditional poor prognostic signs may not be as poor as previously thought!

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Critically Ill Renal Transplant Patients

• Renal transplant patients are at high risk of critical illness from a variety of etiologies.
• Sepsis is the most common reason for critical illness and ICU admission.  
• Due to their immunosuppression, renal transplant patients are at risk of a multitude of infections.
• Notwithstanding, acute bacterial pyelonephritis of the transplant is the most frequent cuase of sepsis, followed by bacterial pneumonia.
• Be sure to consider these two etiologies when faced with a critically ill, septic renal transplant patient.

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Dyspnea in the Intubated Patient

• Dyspnea may occur in up to 50% of intubated patients and has been associated with prolonged mechanical ventilation.
• A number of assessment tools are available to detect dyspnea in the intubated patient.
• Regardless of the tool used, once dyspnea is diagnosed, consider the following;
  • When possible, reduce nonrespiratory stimuli of the respiratory drive (i.e., fever, acidosis, anemia)
  • Minimize respiratory impedance (i.e., bronchodilators, thoracentesis for pleural effusion)
  • Optimize ventilator settings (i.e., change modes if applicable, increase inspiratory flow, increase PEEP)
  • Pharmacologic treatment (i.e., opioids, benzodiazepines)

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The European Society of Intensive Care Medicine (ESICM) recently released a review with recommendations from an expert panel for the use of IV fluids in the resuscitation of patients with acute circulatory dysfunction, especially in settings where invasive monitoring methods and ultrasound may not be available.

Points made by the panel include: 

• Circulatory dysfunction should be identified not only by HR and BP, but by other indicators of poor perfusion: altered mentation, decreased urine output, and skin abnormalities (poor skin turgor, mottling, delayed capillary refill)

• The absence of arterial hypotension does not preclude hypovolemia

• The lack of an increase in MAP (especially in patients with decreased vascular tone) does not exclude positive response to IVF

• The purpose of IVF administration is to improve tissue perfusion by increasing cardiac output

• Fluid "loading" as the rapid administration of large volumes of fluid to treat overt hypovolemia, while a fluid "challenge" is a test of fluid responsiveness

• In elderly patients or those with arteriosclerosis or chronic arterial hypertension, a low pulse pressure (e.g. less than 40 mmHg) indicates that stroke volume is low. PP = SBP - DBP

Recommendations from the panel include:

• The early measurement of lactate to incorporate in the assessment of perfusion

• The use of crystalloids as initial resuscitation fluid (unless blood products are indicated)

• When overt hypovolemia is unclear, the use of a fluid challenge of 150-350mL IVF within 15 minutes to help assess fluid responsiveness

• Avoidance of using jugular venous distension alone as a guide for resuscitation

• Avoidance of using acute urine output response alone as a guide for resuscitation, as renal response to fluids can be delayed

• A recommendation against using CVP as a target for resuscitation; if CVP is being measured, a rapid increase with IVF should suggest poor fluid tolerance

• Individualizing fluid resuscitation to the patient's current presentation, underlying comorbidities, and response to fluids

Bottom Line: Utilize all the information you have about your patient to determine whether or not they require IVF, and reevaluate their physical and biochemical (lactate) response to fluids to ensure appropriate IVF administration and avoid volume overload. 

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Noninvasive Ventilation in De-Novo Respiratory Failure

• Noninvasive ventilation (NIV) is a primary therapy for patients with acute hypercapnic respiratory failure, especially those with an acute COPD exacerbation.
• Notwithstanding its benefits in COPD and acute cardiogenic pulmonary edema, NIV should be used cautiously in patients with "de-novo" respiratory failure.
• Many patients with de-novo respiratory failure will meet criteria for ARDS and have a high rate of intubation (30% - 60%).
• The use of NIV with delayed intubation in this patient population has been associated with increased mortality. 

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Hyperoxia has been repeatedly demonstrated to be detrimental in a variety of patients, including those with myocardial infarction, cardiac arrest, stroke, traumatic brain injury, and requiring mechanical ventilation,^1-4 and the data that hyperoxia is harmful continues to mount:

• Systematic review and meta-analysis of 16,000 patients admitted to hospital with sepsis, trauma, MI, stroke, emergency surgery, cardiac arrest: liberal oxygenation strategy (supplemental O2 for average SpO2 96%, range 94-100%) associated with increased in-hospital and 30-day mortality compared to conservative strategy.⁵

• ED patients requiring mechanical ventilation admitted to ICU: hyperoxia defined as PaO@ >120mmHg. Patients with hyperoxia in the ED had higher mortality than not only normoxic but hypoxic patients (30% v 19% v 13% respectively), and longer vent days and ICU/hospital LOS.⁶

• ICU patients, majority respiratory failure, 60% requiring mechanical ventilation; hyperoxia defined as PaO2 >100mmHg. Just ONE episode of hyperoxia an independent risk factor for ICU mortality (OR 3.80, 95% CI 1.08-16.01, p=0.047).⁷

Bottom Line: Avoid hyperoxia in your ED patients, both relatively stable and critically ill. Remove or turn down supplemental O2 added by well-meaning pre-hospital providers and nurses, and wean down ventilator settings (often FiO2). A target SpO2 of >92% (>88% in COPD patients) or PaO2 >55-60 is reasonable in the majority of patients.⁸

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