UMEM Educational Pearls

Intubation considerations

• Use large ET tube (at least 8.0 if possible): minimizes airway resistance, facilitates aggressive pulmonary toilet and bronchoscopy if needed
• Consider using ketamine as induction agent as it has bronchodilator properties and can maintain blood pressure
• Appropriate choices for initial sedation includes propofol, fentanyl, and ketamine

Vent management strategies

• No overall outcome differences between volume vs pressure control modes. Volume control has been recommended as initial mode due to familiarity and ensures your set tidal volume will be delivered.
• Goal is to minimize autoPEEP, which occurs from incomplete exhalation prior to initiation of next inhaled breath. This can be achieved by adjusting a few vent settings: decreasing RR, decreasing I:E ratio, decreasing inspiratory time, or increasing inspiratory flow rate. Allow for permissive hypercapnia, pH >7.2 has been advocated though precise target is unknown.
• If patient becomes hemodynamically unstable, consider first disconnecting the ventilator from the ET tube and manually decompress the chest to facilitate exhalation.
• Peak inspiratory pressures are expected to be high in the acute severe asthmatic. More important is to keep plateau pressures <30 cm H₂O to prevent lung injury.
• Don't forget to continue asthma-directed therapy. Administer albuterol via in-line nebulization unit of the vent.

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Exertional Heat Stroke at the Boston Marathon

Study goal: To assess for possible associations between exertional heat stroke (EHS) and sex, age, prior performance and environmental conditions

Data sourced from 2015-2019 Boston Marathon races.

Why Boston:  The Boston marathon is one of the only marathons that require qualifying times for entry for a majority of runners which yields a high proportion of faster than average runners. The race is frequently characterized by extreme weather conditions, including warm and humid days.

Results: 136,161 race starters. Incidence of EHS was 3.7 cases per 10,000 starters.

                Note: Twin Cities Marathon found 3 cases per 10,000 runners.

Mean age of runners was 43.3. Female 45%, male 55%.

Significant associations between sex and age, sex and start wave and age group and start wave.

Sex not associated with increased EHS incidence.

Age < 30 and assignment to the first 2 waves (faster runners) was significantly associated with increased EHS.

All cases of EHS occurred with average wet bulb globe temperatures (WBGT) were 17° – 20° C.

Linear correlation between EHS and incidence in addition to increases in WBGT from start to peak.

72.5% of cases were race finishers. Non finishers presented after mile 18.

Almost 30% developed post treatment hypothermia.

Almost 2/3rds were discharged directly, the remainder required hospital transport.

Authors estimate needing at least 4 ice water immersion tubs per 10,000 runners with potential of needing 8-10 if race day is humid.

Conclusions: Overall, EHS represented a small percentage of medical encounters but required significant resources.

Younger and faster runners are at high risk of EHS.

Greater increases in heat stress from start to peak worsens risk.

Definitions: WGBT - The Wet Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: ambient temperature, relative humidity, wind speed, sun angle and cloud cover (solar radiation). This differs from the heat index, which takes into consideration temperature and humidity and is calculated for shady areas. 

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Management of Intermediate-High Risk PE Patients

• Though there are varying definitions, intermediate-high risk patients with a PE are generally defined as those who are hemodynamically stable, have radiographic or laboratory evidence of right heart strain, and an elevated PE risk score.
• A few key management pearls include:
  • Be judicious with IVFs to avoid worsening septal shift and fruther decreases in LV cardiac output.
  • Consider dobutamine for severe RV dysfunction.
  • Administer norepinephrine, if needed, to achieve a MAP of 65 mm Hg.
  • Avoid initiation of positive pressure ventilation, if possible. 
  • If intubation is needed for clinical deterioriation avoid propofol for RSI.  Propofol has been associated with increased mortality in this patient population.

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• Watch out for Streptococcus pneumoniae sepsis! Patients can look well for several hours, then suddenly decline, leading to shock or death.
• Note that nearly half of patients with HgSS will have diminished spleen function by 1 year of age
• Start antibiotics early, even if patients are immunized or are taking prophylactic penicillin
• Antibiotic recommendations: long-acting cephalosporin +/- Vancomycin 
• Order CBC, reticulocyte count, blood culture, CXR, and other testing as needed based on presentation
• Admit patients with high fever, toxic appearance, infiltrate on CXR, hypoxia, tachypnea not explained by fever, poor intake/dehydration, severely abnormal CBC, history of S. pneumoniae sepsis, pain crisis + fever

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Background: Interest in moving to balanced fluid administration has grown after publication of the SPLIT trial and SALT-ED/SMART trials, which showed respectively evidence of benefit to balanced crystalloid over normal saline on mortality and major adverse kidney events at 30 days.

Population/Intervention: The BaSICs trial is an RCT in 75 ICUs in Brazil, testing P-Lyte versus NS (with each arm getting two different infusion rates that were analyzed as a separate trial) for volume administration per protocol.

--10,520 ICU patients requiring fluid expansion, expected ICU stay >1 day, and 1 additional risk factor for AKI (age>65, hypotension, sepsis, MV, NIV, oliguria, elevated creatinine, cirrhosis, or acute liver failure).

--Exclusions: severe dysnatremia, expected RRT within 6 hours, expected death.

--Average age was 61, with a SOFA score of 4, and 48% on were elective surgical admissions.

Outcome:

--No difference in 90 days mortality (P-Lyte 26.4% v NS 27.2, aHR p=0.47), AKI or RRT out to 7-days, or in duration of MV, ICU LOS or hospital LOS

--Median study fluid by day 3 was 2.9L in each group

--Higher neurological SOFA score observed in P-Lyte group

--Higher mortality seen with P-Lyte in TBI subgroup (P-Lyte 31.3% vs NS 21.1%, p=0.02)

Discussion:

--Adds contrasting negative data to previous large positive RCTs showing benefit of balanaced fluids

--Expect further reanalysis/metanalysis of BSS versus NS trials

--Signal for harm in TBI pts with P-Lyte correlates with SMART point estimates that were not significant

--Compared to SMART trial population BaSICs had: 2x higher mortality, more planned surgery, received about 1L more study fluid in the first 3ds

Takeaway:

--Balanced crystalloid versus normal saline debate will continue considering this large negative trial

--Signal for possible harm in TBI population with balanced crystalloids compared to normal saline

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Study Question:  A recent study investigated whether a history of concussion caused greater disturbances in cerebral blood flow and cerebral white matter after subsequent concussions.

Background:  Researchers used changes in blood flow in the cingulate cortex and white matter microstructure in the corpus callosum as evidence of underlying brain injury.

Population:  228 athletes with an average age of 20.  Divided into 2 groups, recent and non-recent concussion.

61 athletes had a recent (uncomplicated) concussion and 167 did not. Within the first group, 36 had a history of concussion. Within the second group, 73 had a history of concussion.

Note: researchers used “self-reported” history of concussion in study.

Intervention: Researchers took up to 5 MRI scans of each recently concussed athlete. This encompassed the acute phase of injury (1 to 7 days post-injury), the subacute phase (8 to 14 days), medical clearance to return to sport, one month post return and one year post return.

The sport concussion assessment tool (SCAT) was also used to evaluate effects of history of concussion on symptoms, cognition and balance.

Results:  One year after a recent concussion, those athletes with a history of concussion had sharper declines in blood flow within one area of the cingulate cortex compared to those without a history of prior concussions.

Athletes with a history of concussion had an average cerebral blood flow of 40 mL per minute, per 100 grams of brain tissue.

Athletes without a history of concussion had an average cerebral blood flow of 53 mL per minute, per 100g of brain tissue.

In the weeks following concussion, those athletes with a prior history of concussion had microstructural changes in the corpus callosum.

 Effects were seen in the absence of differences in SCAT domains or time to return to sport.

Conclusion:  Athletes with a history of concussion experience identifiable injury to their brains as evidenced by changes in blow flow and white matter microstructure.  Athletes “cleared” for return to play following concussion may be at greater risk of subtle patterns of brain injury versus their peers.

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Background: SOFA score has been used as a predictor for poor outcomes in patients with sepsis.  However, the original SOFA score utilizes PaO2/FiO2 ratio to calculate the SOFA’s respiratory component.  When there are no ABG, thus no PaO2, we have to convert patients’ spO2 to PaO2, and the amount of oxygen support to FiO2 (for example, 2 liters of oxygen via nasal cannula = 0.27).  This is cumbersome.

Objective: This study assessed whether spO2 can be used instead of PaO2/FiO2 ratio for SOFA’s respiratory score.

Settings: 8 hospitals across Sweden and Canada

Patients: Adults with sepsis.  19396 patients were included for the derivation group while there were 10586 patients for the validation cohort.

Study Results:

• When PaO2 was not measured, assigning respiratory SOFA score of 1 for spO2 94% and respiratory SOFA score of 2 for spO2 < 90% had good discriminatory capability.
• The AUROC with SOFA score using spO2 threshold as above was 0.783 (0.767-0.798), which was slightly increased from the model using previous methods to calculate respiratory SOFA scores (0.781 [0.765-0.796]).

Discussion:

• For Emergency Medicine, using a cut-off threshold  for spO2 of 94% (respiratory SOFA of 1) and 90% (respiratory SOFA of 2) can simplify how to calculate the SOFA score.  
• It’s also simpler to do research when we collect SOFA score retrospectively.

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- A higher metabolic rate, reduced capacity for sweating, greater thermolability, and a larger body surface-to-volume ratio make infants and young children more susceptible to hyperthermia.

- Temperatures can rise rapidly within enclosed vehicles, reaching maximum temperatures within 5 minutes. In an open area with an ambient temp of 98 F (36.8 C), interior temperatures reach 124-152 F (51 to 67 C) within 15 minutes of closing the car doors.

- Texas leads the country in the numbers of pediatric heatstroke fatalities due to unattended children left in cars, followed by Florida and California.

- Most heatstroke victims (78.2%) were unknowingly left in vehicles by their caregivers.

- Most organizations interested in child safety issues recommend placing a phone, briefcase, or handbag in the back seat when traveling with a child as one way to prevent heatstroke fatalities.

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There are several clinical scoring systems (SAPS II, SAPS III, SOFA, etc.) to assess the severity and/or risk of mortality in critically ill patients. However, the routinely used physiologic scoring systems are not always suitable for poisoned patient. 

ICU requirement score (IRS) has been recently developed by investigators from Europe and a validation study (retrospective cohort) has been performed.

ICU requirement score (IRS) components (see inserted table)

• Age
• Systolic blood pressure
• Heart rate
• GCS
• Type of intoxication
• Comorbidities (dysrhythmia, cirrhosis, and/or respiratory insufficiency, secondary diagnosis requiring ICU admission)

Retrospective cohort 

• Study duration: Jan 1, 2009 to Dec 31 ,2019
• Positive IRS score: >= 6
• Comparison to SAPS II, SAPS III, SOFA score, and PSS
• End point: need for ICU treatment

Results

N=1503

Area under the curve for IRS ROC: 0.736 (95% CI: 0.702-0.770)

IRS <6

• Negative predictive value: 95% (95% CI: 93-97)
• Positive predictive value: 21% (95% CI: 18-24)
• Sensitivity: 89% (95% CI: 85-93)
• Specificity: 38% (95% CI:36-41)

Conclusion

• IRS of < 6 demonstrated excellent negative predictive value for ICU admission.
• A larger study of ICU requirement score will be needed to further assess its usefulness/limitation prior to clinical use.  

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Attachments

2108191337_Untitled.pdf (252 Kb)

Background:

There are also no clear guidelines regarding how fast fluid boluses should be administered, and there has been debate about whether different infusion rates could lead to different outcomes in patients receiving intravenous fluid (IVF) boluses (i.e. fast infusions may cause more third spacing due to the rapidity of the expansion of the intravascular space compared to fluid administered more slowly). A recent study compared IVF infusion rates in ICU patients.

-- Unblinded, randomized

-- 10,520 patients clinically requiring a fluid challenge, from 75 ICUs in Brazil

-- Infusion rate 333 mL/hr vs 999 mL/hr

   * (Trial also compared plasmalyte vs 0.9% saline, analyzed in separate study)

-- Some notable exclusion criteria: severe hypo/hypernatremia, AKI or expected to need RRT 6 hrs after admission

--Other caveats:

   * Faster infusion rates allowed at physician discretion in patients with active bleeding or severe      hypotension (SBP < 80 or MAP < 50 mmHg); patient was returned to assigned rate after condition resolved

   * Almost 1/2 the patients received at least 1L of IVF in 24 hours prior to enrollment

-- Results: No sig difference in 90-day survival, use of RRT, AKI, mechanical ventilator free days, ICU/hospital mortality/LOS 

Bottom Line: There is not yet compelling evidence that there are differences in patient outcomes in patients receiving fluid boluses given at 333 cc/hr vs. 999 cc/hr.

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Chronic Exertional Compartment Syndrome (CECS)

Similar pathology to acute compartment syndrome except symptoms are related to activity (frequently running) and abate with rest.

95% involve lower extremity

Inappropriately elevated tissue pressure in one or more lower leg compartments associated with exercise

Anterior compartment most frequently involved

As tissue pressure increases, local perfusion is decreased. This leads to symptoms of pain, pressure, cramping and paresthesias.  

Also commonly associated with team sports such as soccer, lacrosse and field hockey.

More likely in competitive athletes than recreational.

Patient will be symptom free at time of ED evaluation

Make diagnosis of CECS with history

1. Pain must be induced with exercise
2. Usually limited to a single compartment, frequently the anterior
3. Pain occurs at predictable time in exercise and forces athlete to stop running
4. Pain resolves with rest
5. If witnessed, tenderness is present only in the involved compartment and not elsewhere

Diagnosis with compartment pressure measurements done in office with treadmill exercise.

Non operatively, gait retraining programs have been shown to help symptoms. Appropriate if symptoms are mild.

Surgical treatment involves a minimally invasive fasciotomy

Post surgery success rates are between 63-100% with recurrence rates up to 20%

Approximately 15,000 children experience an in hospital cardiac arrest (IHCA) with little improvement in outcomes over the last two decades. During that time, epinephrine has been the constant basis for resuscitation of these patients. Current recommendations by the AHA recommend bolus dosing of epinephrine every 3-5 minutes in a pediatric cardiac arrest. Animal studies suggest that more frequent dosing of epinephrine may be beneficial. 

This was a retrospective study of 125 pediatric IHCAs with 33 receiving “frequent epinephrine” interval (≤2 minutes). Pediatric CPC score 1-2 or no change from baseline was used as primary outcome to reflect favorable neurologic outcome, with frequent dosing associated with better outcome (aOR 2.56, 95%CI 1.07 to 6.14). Change in diastolic blood pressure was greater after the second dose of epinephrine among patients who received frequent epinephrine (median [IQR] 6.3 [4.1, 16.9] vs. 0.13 [-2.3, 1.9] mmHg, p=0.034). 

This study is subject to all sorts of confounding and should be studied more rigorously, but suggests that more frequent dosing for pediatric IHCA may be of benefit.

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• Generally a seasonal illness that circulates in fall/winter (Maryland’s season is October-April)
• Following low incidence since April 2020, there is current ongoing circulation outside of the normal seasonal patterns
• Updated regional trends are available via the National Respiratory and Enteric Virus Surveillance System (https://www.cdc.gov/surveillance/nrevss/rsv/index.html)
• Causes upper respiratory illness characterized by copious nasal secretions which may cause increased work of breathing and necessitate hospitalization
• Severity tends to peak at around day 5 of illness
• In infants younger than 6 months, may also present with poor feeding, lethargy, or apnea
• Risk of apnea is highest in premature infants (post conception age <48 weeks) and infants under 1 month of age
• Routine administration of albuterol has not been shown to have benefit, the most recent AAP guidelines have a recommendation against trial of albuterol (common practices continue to be variable). It should be noted that children with severe disease were excluded from the studies used to make this recommendation.
• Hypertonic saline administration has not shown to be helpful in the ED setting, but may decrease length of stay in patients being admitted
• Consider admission for persistent tachypnea, hypoxia, inability to adequately feed, moderate to severe increased work of breathing at rest, or apnea

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Resuscitative thoracotomy is a dramatic and heroic procedure used in the emergency department in an attempt to resuscitate a patient in arrest due to trauma. There are a few techniques commonly used, but due to the extreme nature of the procedure no prior randomized controlled trials (RCTs) have been done.

The modified clamshell thoracotomy (MCT) is a technique in which the standard left anterolateral thoracotomy (LAT) is extended across the sternum, but does not involve surgical opening of the right chest. The MCT allows for increased visualization of the mediastinum and thoracic cavity structures. 

Sixteen Emergency trained physicians (approximately half attending and half senior residents) from a level 1 trauma center underwent didactic and skill based training on both the MCT and LAT techniques using fresh, human cadavers. Following training they were randomized based on order of intervention, performing both techniques.

Their thoracotomies were assessed by a board certified surgeon and “success” was determined based on the complete delivery of the heart and cross clamping of the descending aorta. 

Primary outcome: time to successful completion of procedure

Secondary outcomes: successful delivery of the heart from the pericardial sac (as well as time to delivery),  cross clamping of the aorta (and time to clamping),  procedural completion and number of iatrogenic injuries. 

Overall, there was no statistical difference in primary outcome or successful completion between the MCT compared to the LAT (67% vs. 40%). However, 100% of the LAT resulted in some form of iatrogenic injury (rib fractures, lacerations of the diaphragm,/esophagus/heart/lung) compared to 67% of the MCT technique. There was no associated difference in success when previous experience (attending vs. senior resident) were compared. Lastly, MCT was the favored technique of the majority of the study subjects. 

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• Testicular torsion is a straightforward diagnosis ultimately based on lack of blood flow to the affected painful, swollen testicle.
• Testicular torsion is the most common cause of acute unilateral testicular pain in peripubertal boys due to rapid increase in testicle size during puberty.
• Infarction begins as soon as after 2 hours of ischemia.
• There is nearly a 100% salvage rate if blood flow is re-established within 6 hours.
• Intermittent testicular torsion is challenging to diagnosis due to spontaneous resolution of symptoms and return of normal blood flow during ultrasound.
• Beware complaints of repeated episodes of acute unilateral testicular pain and swelling.
• Up to 50% of boys with testicular torsion reported at least one prior similar episode of acute pain and swelling. 
• Ultrasound findings of a whirlpool sign (spiral-like pattern of spermatic cord), boggy spermatic cord, and a psuedomass of the distal spermatic cord are concerning even in the setting of normal blood flow.
• Bottom Line: Peripubertal boys presenting with complaints of acute unilateral testicular pain and swelling should always be referred for urgent follow up even if their symptoms have resolved and when ultrasound may show normal blood flow as intermittent testicular torsion can not be ruled out.

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The much anticipated REMAP-CAP trial was epublished ahead of print July 12th in Intensive Care Medicine.  It was an RCT investigating four antiviral strategies in critically ill adults with COVID-19: lopinavir-ritonavir, hydroxychloroquine, a combination of the two, and no antiviral therapy (control group).  

Despite the hype around protease inhibitors, hydroxychloroquine, and other unproven therapies in COVID (lookin at you next, Ivermectin...), all three strategies had WORSE outcomes than placebo.  They all decreased organ-support-free days (all reaching statistical significance), which was the primary outcome.  They also all led to longer ICU time, longer time to hospital discharge, and reduced 90 day survival.  Not only does this study show no benefit, it shows fairly convincing signs of harm to these therapies.

Bottom Line: Protease inhibitors (e.g. lopinavir-ritonavir) and hydroxychloroquine are unproven therapies for critical COVID-19 infection, and are not recommended.  Providers should focus on interventions with demonstrated benefit, most notably steroids and good supportive/critical care.  

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Low dose ketamine was compared  to morphine for the treatment of patients with long bone fractures

126 patients with upper and lower extremity long bone fractures were divided into two treatment groups

1. IV morphine at a dose of 0.1 mg/kg
2. IV ketamine at a dose of 0.5mg/kg

Pain scores were compared pre and at 10 minutes post treatment

Pain severity significantly decreased in both groups to a similar degree

Increase adverse effects (emergence phenomenon) noted in ketamine group but all effects resolved spontaneously without intervention.

Conclusion:  Analgesic effect of ketamine is similar to morphine in patients with long bone fractures.

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Hemophagocytic Lymphohistiocytosis (HLH)

• HLH is a hematologic disorder that results from overactivation of the immune response (macrophages and cytotoxic T cells).
• HLH is often underrecognized and has a mortality that can be as high as 75%.
• Secondary HLH is most commonly associated with infection (sepsis), malignancy (lymphoma), and autoimmune disorders (SLE, RA).
• Hallmark features of HLH include fever, splenomegaly, hepatomegaly, cytopenias, coagulopathy, elevated ferritin, elevated triglycerides, and decreased fibrinogen levels.
• ED resuscitation of patients with suspected HLH includes Hematology consultation, treatment of the underlying disorder (infection), and potentially corticosteroids and chemotherapeutic agents.

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