UMEM Educational Pearls

Category: Pharmacology & Therapeutics

Title: A "Stick-y" Situation: Treatment of Epinephrine Autoinjector-Induced Digital Ischemia

Keywords: epinephrine, anaphylaxis, allergy, digital ischemia, phentolamine, nitroglycerin ointment, terbutaline (PubMed Search)

Posted: 10/12/2023 by Alicia Pycraft
Click here to contact Alicia Pycraft

Background: It is estimated that nearly 6% of U.S. adults and children report having a food allergy.1,2 Epinephrine autoinjectors are used to provide life-saving pre-hospital treatment for patients experiencing anaphylaxis in the community, but can have serious consequences if administered incorrectly. Accidental finger-stick injuries with epinephrine auto-injector can result in significant pain and ischemia due to vasoconstriction and decreased blood flow to the digit. Treatments for digital epinephrine injection include supportive care, topical vasodilators, and injectable vasodilators.3

Supportive care3,4:

  • Warm compresses are preferred to increase local blood flow and enhance removal of the drug. Cold compresses may result in worsening ischemia. 
  • Apply for 15 minutes every 6 hours
 
Topical nitroglycerin3-6:
  • Increases production of nitric oxide which relaxes smooth muscles and causes vasodilation
  • Literature shows variable symptomatic improvement for adults and neonates, but safe use as an adjunct to injectable vasodilators or as monotherapy.
  • Apply a 1-inch strip of nitroglycerin 2% ointment over the affected area and repeat every 8 hours until symptoms resolve
  • Patients should be monitored for hypotension after application, as topical nitroglycerin is systemically absorbed.
 
Phentolamine4, 7-9:
  • Alpha-1 adrenergic antagonist that competitively blocks alpha-adrenergic receptors to produce brief antagonism of circulating epinephrine and norepinephrine. Phentolamine also promotes vasodilation and increases capillary blood flow. 
  • Evidence for use after accidental injection of epinephrine autoinjector is mostly described in case reports, but one study showed that phentolamine was more effective at vasodilation than either nitroglycerin or sodium nitroprusside for treatment of digital norepinephrine injection. In another study of epinephrine-injected patients, subjects reported normal fingertip sensation in an average of 120 minutes after injection of phentolamine compared to 549 minutes after injection of saline. It took an average of 85 minutes for the epinephrine-injected digits to return to normal color after phentolamine injection compared to an average of 320 minutes after injection with saline.
  • Preparation/application: Dilute 5 mg of phentolamine in 10 mL of 0.9% sodium chloride. Inject small amounts subcutaneously into the affected area.
 
Terbutaline6,10:
  • Beta-2 adrenergic agonist that causes vasodilation and attenuates the effect of alpha adrenoreceptor-mediated vasoconstriction.
  • Evidence shows that terbutaline has resulted in immediate and complete resolution of symptoms following accidental digital epinephrine injections if administered within 2 hours of the incident and it may be considered if phentolamine is not available.
  • Preparation/application: Dilute 1 mg of terbutaline with 1 mL of 0.9% sodium chloride and inject subcutaneously into the affected area.
  • May cause elevations in heart rate and blood pressure, as well as ECG changes. Terbutaline should be used cautiously in patients with cardiovascular disease.
 
Bottom line: Most cases of epinephrine autoinjector-induced digital ischemia can be conservatively managed with warm compresses and topical nitroglycerin, but phentolamine should be considered for patients with refractory pain or tissue ischemia. Terbutaline should be considered in the event of phentolamine shortage.

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Diverticular disease is a common condition, with 60% of individuals over age 80 and 30% of those over age 45 (!) having diverticula. Recent estimates show that 10-25% of this subset with suffer at least one episode of acute diverticulitis in their lifetime. Fortunately, the majority of these cases are uncomplicated. This study provides evidence that outpatient treatment of acute diverticulitis is reasonable. 

Study Design:

The DINAMO study was a multicenter randomized open-label non-inferiority trial evaluating the utility of antitbiotics in uncomplicated diverticulitis. The study included adult patients with uncomplicated diverticulitis without significant comorbities. The diagnosis was based on modified Neff classification with patients with a mNeff of 0 being included. Eligible patients were randomized to one of two treatment groups:

1) 600 mg ibuprofen q 8 h alternating with 1000 mg of acetaminophen q 8 h x7 d (Exerimental arm) OR

2) 875/125 mg amoxicillin/clavulanate q 8 h x 7 d in addition to the above (Control arm)

Outcomes of interest and Results: 

Any patients who returned to the hospital underwent repeat CT. Primary of outcome of interest was admission to the hospital on revisit, with secondary outcomes being revisit itself, follow up, pain control, and recovery

There was no statistically significant difference in any of these (for numbers, please refer to article 1 linked below); further, no patients required emergency surgery. 

Implications:

There is a low likelihood ot treatment failure when antibiotics are avoided in acute uncomplicated diverticulitis. This study finds this treatment regimen ot be noninferior to antibiotic treatment in terms of hospital admission, revisit rates, and recovery.  Consider this treatment regimen in eligible patients. 

 

 

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Category: Trauma

Title: Large bore vs small bore chest tube for traumatic hemothorax

Keywords: Chest tube henothorax (PubMed Search)

Posted: 10/8/2023 by Robert Flint, MD (Updated: 3/19/2024)
Click here to contact Robert Flint, MD

This article reminds us that using a small bore chest tube to drain traumatic hemothorax is supported by small studies and the Easterm Society for the Surgery in Trauma. 

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Category: Administration

Title: A Unique Look at the Impact of Boarding

Keywords: Boarding, Mortality, Crowding (PubMed Search)

Posted: 9/22/2023 by Brent King, MD (Emailed: 10/7/2023) (Updated: 2/3/2024)
Click here to contact Brent King, MD

Takeaway Points - A 10 percent reduction in ED volume reduces an ED patient's chance of dying by 24% at 30 days and by 17% at six months

The author of this study conducted a unique natural experiment. They identified cases in which a new emergency department opened near one or more existing departments. Then, they confirmed that the opening of the new department was the only substantial change that occurred (e.g. the staff in the existing EDs were unchanged, the types of complaints were unchanged etc.). The author then determined the impact of the new ED on the existing ED's patient volume and compared death records from the existing EDs before and after the new ED opened.

Simply offloading 10 percent of patients from the existing ED to the new ED, significantly reduced the 30 day and six month risk of death for the existing ED's patients. 

The Bottom Line: Many studies have attempted to determine the impact of boarding and to tie boarding to morbitiy and mortality. This author's unique approach to the problem serves to reinforce the need for comprehensive solutions to the problem of patient boarding. Even a modest reduction in emergency department volume has a measureable impact on patient outcomes

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- Magnets move through the GI tract at different rates and become lodged in adjacent loops of intestine. Adjacent bowel segments can stick together when the magnets attract each other through the bowel walls which can cause obstruction, perforation, fistula formation, and necrotic bowel.

- Obtain xray to identify ingested metallic object(s)

- Any object lodged in the esophagus should be emergently removed by a pediatric gastroenterologist.

- Once an object is past the stomach and beyond the reach of endoscopy, affected patients need to be watched carefully for signs of obstruction or peritonitis, either occurrence requiring the prompt consultation of a pediatric surgeon.

- Enhancement of magnet movement through the GI  tract may be aided by a laxative such as polyethylene glycol, but there is no clear data that this approach speeds the passage of the magnet. There is no clear guidance on how frequently to obtain abdominal radiographs to determine movement or passage of ingested magnets.

- More frequently lodge in esophagus due to seize and cause electric urn on contact

- Complications include perforation or fistula formation

- Honey or liquid ulcer medication carafate can slow extent of esophageal injury

- Current recommendations from National Button Battery Hotline: caregiver to give 2 teaspoons of honey every 10 minutes while en route to hospital

- Causes caustic contact to vocal cords, which leads to acute laryngospasm 

- Airway compromise, if to occur, occurs rapidly. If after brief obs period, it does not appear, it is very unlikely to be a late occurance. 

- Corrosive on GI tract. pH of detergents range from 7-9. 

- Any child with difficulty swallowing, drooling, stridor, and recurrent vomiting should have GI consulted for endoscopy

Tiki Torch Oil

- Tiki torch oil looks like apple juice (the container looks similar too)

- Lamp oil ingestion (hydrocarbons) can cause excessive drowsiness, lung injury, difficulty breathing

- Preventing accidental tiki torch oil ingestion: NEVER use torch fuels near area where food or drinks are served, keep out of reach and out of sight of young children, and only buy bottle of torch fuels with child-resistant cap and make sure to replace cap securely after every single use

Hydrogen Peroxide

- 35% hydrogen peroxide has become more popular as food-grade or nutraceutical product (food additive purportedly used for medicinal purposes)

- When hydrogen peroxide reacts with HCl in the stomach, it liberates large volumes of oxygen causing immediate frothy emesis and systemic absorption of oxygen. Gastric oxygen, once absorbed, passes through the portal vein to liver causing gas embolisms in liver

- Preferred evaluation of kids with known ingestion and acute vomiting should image by noncontrast limited upper abdominal CT (to reduce radiation exposure) to assess bubble burden. 

- There is no consensus on what is considered a significant air embolism burden that would require hyperbaric treatment

A single tablet of buprenorphine, or a single dissolvable gel strip of its formulation as Suboxone has been lethal to children.

Prescribing intranasal naloxone spray to the family of patients on buprenorphine (and methadone as well) is potentially lifesaving to the patient, should they take too much, but also for children in their homes who may accidentally eat a single tablet or chew on what appears to be a “gummy” product, a dissolvable formulation of Suboxone.

Pediatricians doing anticipatory safety guidance to parents at the 9-month-old to 1-year-old health supervision visit should ask about opiates and medication-assisted therapy present in the home or used by caregivers (especially grandparents) and should offer to write a prescription for naloxone nasal spray 

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Category: EMS

Title: EMS Overdose Response: Better with Bupe ?

Keywords: Emergency medical services, harm reduction, buprenorphine, overdose (PubMed Search)

Posted: 10/5/2023 by Ben Lawner, DO
Click here to contact Ben Lawner, DO

BACKGROUND:
Emergency Medical Services (EMS) systems, especially those within urban jurisdictions, struggle to effectively meet the needs of patients experiencing complications of substance use. The exceedingly high burden of disease, coupled with potentially life-threatening sequelae of substance use stresses EMS systems beyond capacity. The current paradigm of naloxone administration and subsequent refusal of care places patients at an increased risk of death and other complications such as aspiration. EMS agencies, in collaboration with area hospitals, public health experts, and addiction medicine specialists are devising novel mitigation strategies to reduce morbidity and mortality. “Leave behind” naloxone, peer outreach, and 911 diversion programs are part of a more over-arching strategy that links patients to longer term, definitive health care resources within the community. EMS-administered buprenorphine has emerged as a novel treatment modality for prehospital patients. This study examined outcomes of patients who were a) experiencing symptoms of opiate withdrawal and b) given buprenorphine by a credentialed EMS paramedic. Patients included in the buprenorphine cohort scored >5 on the clinical opiate withdrawal scale (COWS), regained “full decisional capacity” after being resuscitated from an overdose, and were > 18 years of age. The study excluded pregnant patients and those who took methadone within 48 hours prior to an EMS encounter. After consultation with an EMS physician, patients received 16 mg of sublingual buprenorphine. Paramedics could administer ondansetron and an additional 8 mg of buprenorphine for continued symptoms. Finally, the study cohort was matched to a similar group of patients who were treated by “non buprenorphine equipped” ambulance. Outcomes of interest included: rates of repeat overdose, likelihood of transport, and follow up with addiction medicine/substance use resources. The study was conducted in an urban EMS system with robust EMS physician oversight and advanced life support transport units.


RESULTS:
Patients receiving buprenorphine did not experience a reduction in repeat overdose. However, they were less likely to be transported. The buprenorphine cohort, predictably, was much more likely to be enrolled in a substance use treatment program within 30 days of the initial encounter. Paramedics spent more time on scene with the buprenorphine cohort.  Though far from a conclusive study, the manuscript adds to a growing body of literature that attests to the feasibility of paramedic administered buprenorphine.

BOTTOM LINE:
Though far from a conclusive study, buprenorphine administration by EMS paramedics is feasible. The increased linkage to care and decreased rates of transport will hopefully motivate EMS systems to consider novel strategies for harm reduction. The study authors opine that buprenorphine may “be a promising…link to long term recovery.”

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Bottom line: As part of a systematic protocol, peripheral pressors administered through a peripheral line greater 22Ga or larger reduced the number of days of central venous catheter (CVC) use in a MICU population at an academic medical center. 35 (5.5%) patients had an extravasation event all with “minimal” tissue injury complications. None required surgery. 51.6% of patients did not require a CVC as a result of the protocol

 

Details

  • Six hundred thirty-five patients received peripherally administered norepinephrine.
  • The median number of CVC days avoided per patient was 1 [IQR 0, 2] days
  • 311 patients (51.6%) never required CVC insertion.
  • Extravasation of norepinephrine occurred in 35 patients (75.8 events/1,000 d of PIVC infusion [95% CI, 52.8-105.4 events/1,000 d of PIVC infusion]).
  • Most extravasations caused no or minimal tissue injury.
  • No patient required surgical intervention.

 

Notes on protocol

PIV were placed and confirmed with US, were between wrist and AC fossa with q2h patency checks. Max allowable dose of NE 15 mcg/min with requirement that patients be able to report pain at site. Initially, max infusion time was set at 48h but was eventually liberalized to indefinite use. 

 

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Category: Trauma

Title: Hypertonic Saline or Mannitol for Head Injury?

Keywords: Head injury mannitol saline ICP (PubMed Search)

Posted: 10/1/2023 by Robert Flint, MD (Updated: 3/19/2024)
Click here to contact Robert Flint, MD

"The main findings were the following: (1) there was no evidence of an effect of HTS compared with other agents (mainly mannitol) on long-term neurological outcome in patients with raised ICP; (2) similarly, there was no evidence of a beneficial effect of HTS on all-cause mortality, uncontrolled ICP, length of hospital or ICU stay, and ICP reduction; and (3) HTS may be associated with increased risk of adverse hypernatremia.”

 

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Kids eat everything (except perhaps carefully prepared and balanced meals). While button battery ingestions are feared, there is more to worry about. Magnet ingestions – especially rare earth metal magnet ingestions – can lead to high morbidity and mortality.

When more than one magnet (or a magnet and another metallic object) are ingested, they can become stuck together through walls in the GI tract, creating risk for obstruction, erosion, fistula formation, and perforation. Sharp metallic foreign objects can be particularly dangerous as they can do much damage while being moved around by the magnet.  

If there is concern for magnet ingestion, care should be taken to try to determine the number ingested (if parents have the magnets, you can compare the size of an object on xray to the size of the magnets as it can otherwise sometimes be difficult to differentiate if it is one magnet or more than one stuck together).  

Higher risk features of ingestion include: 

  • Ingestion of a magnet and a sharp metallic object
  • Higher number of magnets ingested
  • A longer interval over which the magnets were ingested
  • Multiple magnets in the esophagus (raises concern for concomitant aspiration)

 

Ingestions should prompt consultation with pediatric GI and surgery when isolated as many will require either endoscopic or surgical removal. This may include need for referral and transfer.  

 

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Category: Administration

Title: Physician Workforce Diversity in EM

Keywords: Workforce, Diversity, Under-represented minorities (PubMed Search)

Posted: 9/27/2023 by Mercedes Torres, MD (Updated: 3/19/2024)
Click here to contact Mercedes Torres, MD

Physician Workforce Diversity in EM

Health inequities along racial, ethnic, and socioeconomic lines are a brutal reality of the current state of health care in the US.  One way to attempt to address these inequities is to make a concerted effort to diversify our physician workforce.  As authors have noted, “Having physicians from diverse backgrounds as colleagues and role models can promote understanding and tolerance in nonminority physicians, ultimately improving medical care for patients who are part of these racial and ethnic groups. Increasing the population of underrepresented minority (URM) physicians in the workforce also directly improves health care for medically underserved populations from all racial and ethnic backgrounds, as studies have shown that physicians from URM backgrounds are more likely to work with these patients.”

Administrators are often tasked with the difficult job of creating a cohesive group of emergency physicians to meet the needs of the community they serve.  Strategies to diversify that workforce would benefit from a multi-level approach, including the following:

  • Focus on the high school and college pipeline to increase the number of URM entering the field of medicine and emergency medicine more specifically.
  • Make a conscious effort to recruit and interview URM candidates for open positions.
  • In meetings, ask specific questions from individuals whose voices are often marginalized.
  • In group settings, pay attention to your physical position; if you are a White male, let your URM colleagues position themselves at the head of the table.

 Small steps can create big changes.

 

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Category: Hematology/Oncology

Title: Approaches to neutropenic fever- what's out there?

Keywords: Neutropenic Fever, Phamacology, Infectious Disease, Oncology (PubMed Search)

Posted: 9/25/2023 by Sarah Dubbs, MD
Click here to contact Sarah Dubbs, MD

Question

Treatment of neutropenic fever is evolving, especially in the context of multidrug-resistant (MDR) organisms. This article reviews an update on best practices and describes two approaches to antimicrobial therapy- "escalation" and "de-escalation". Escalation begins with a narrow spectrum of antimicrobials and increases based on patient response, suitable for uncomplicated cases. De-escalation starts with broad-spectrum antibiotics and narrows down, recommended for complicated cases. The choice depends on the institution's MDR prevalence. Initial antimicrobials like cefepime or carbapenems are selected based on resistance rates. De-escalation timing varies per guidelines, but clinical trials support its safety and efficacy. Benefits include reducing C. difficile risk, antimicrobial resistance, and complications. Despite these advantages, some centers lack explicit de-escalation guidance, emphasizing the need for clear protocols to optimize patient outcomes by minimizing antibiotic therapy duration.

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Category: Orthopedics

Title: Exercise and asthma, still water and oil?

Keywords: asthma, reactive airway disease, lung function (PubMed Search)

Posted: 9/24/2023 by Brian Corwell, MD (Updated: 3/19/2024)
Click here to contact Brian Corwell, MD

The role of exercise in patients with asthma is complicated.

Asthma symptoms can worsen or be triggered by physical activity. This can lead to avoidance response. Patients with asthma are less physically active than their matched controls.

Recently, however, the role of exercise and physical activity as an adjunct therapy for asthma management has received considerable attention. There is an emerging and promising role of physical activity as a non-pharmacologic treatment for asthma. Exercise reduces inflammatory cytokines and increases anti-inflammatory cytokines thereby reducing chronic airway inflammation.

Physical activity can help improve lung function and boost quality of life. As fitness improves, asthma patients report better sleep, reduced stress, improved weight control, and more days without symptoms.

The Global Initiative for Asthma recommends twice-weekly cardio and strength training. Strength training requires short periods of exertion allowing for periods of rest and recovery. High-intensity interval training (HIIT) is a promising option for people with asthma. These types of workouts allow ventilation to recover intermittently vs conventional cardio exercises.

A 2021 study in adults with mild-to-moderate asthma found that low volume HIIT classes (three 20-minute bouts/week) significantly improved asthma control.  Patients also had improved exertional dyspnea and enjoyment of exercise which will, in turn, increase the odds of further exercise.

A 2022 study compared constant-load exercise versus HIIT in adults with moderate-to-severe asthma. Exercise training lasted 12 weeks (twice/week, 40 minutes/session).  Both groups showed similar improvements in aerobic fitness however the HIIT group reported lower dyspnea and fatigue perception scores and higher physical activity levels.

Conclusion: Patients with asthma should be encouraged to safely incorporate exercise in their daily lives bother for overall health benefits but also as an effective non-pharmacologic asthma treatment.

 

 

 

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Since the switch from fee for service to value based care in the US, there has been a marked push to improve our documentation to expand our MDM and differential considerations.  We are all here becoming adept at the medical documentation (thanks Dr. Adler!), but may not be adequately documenting our patients' social determinants of health using the social Z codes, a subset of ICD-10 coding language

This study wanted to look at the overall prevelance of social Z code utilization.  They used the Nationwide Emergency Department Sample (NEDS), a nationwide database of ED visits, to look at this particular documentation.  They examined 35 million (!) ED visits and found that only 1.2% had any social Z code included in the documentation.  Given how many resources are linked to a verified (eg documented) need, this raises the idea that if Z codes are better documented, this may lead to increased funding for things like food, housing and transportation insecurities.

Limitations- the authors only examined the ED visits for ICD-10 codes, they didn't specifically look at the notes themselves which may have contained SDOH information.  They also found that the social Z codes were more often documented in visits coded for mental health diagnoses, potentially indicating bias.  There is also the concern that patients may not want the social z codes included, given the stigma around things like homelessness.

Overall, social Z code documentation could potentially unlock better resources for our patients by documenting a specific need in a population.  More will come as documentation continues to evolve.

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Category: EMS

Title: What are the barriers for laypeople to be trained in CPR?

Keywords: cardiac arrest, CPR, bystander (PubMed Search)

Posted: 9/20/2023 by Jenny Guyther, MD (Updated: 3/19/2024)
Click here to contact Jenny Guyther, MD

Prior studies have shown that CPR education is associated with a greater willingness to perform CPR.  This was a review of 23 studies to determine factors that enable and hinder a layperson from learning CPR.
 
Enabling factors included having witnessed someone collapse in the past, awareness of public AEDs, certain occupations and legal requirements for training (i.e. mandatory high school CPR training).
 
Married people were more likely to be trained than those that were not married and people with children younger than 3 years were less likely to take a BLS course.  
 
Barriers that were found to impact people taking CPR classes included lower socioeconomic status and education level, and advanced age and language barriers.  
 
Bottom line: CPR education sessions should target groups with these identified barriers.

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The BRASH syndrome (Bradycardia, Renal failure, AV nodal blockade, Shock, Hyperkalemia) has been increasingly described in the literature in the past 3-5 years.  

The inciting factor is generally considered to be something that prompts acute kidney injury, often hypovolemia of some sort.  Rather than AV nodal blocker overdose or severe hyperkalemia causing conduction problems, the combination of AV nodal blocker use (most often beta-blockers, but can be any type) and hyperkalemia (often only moderate) has a synergistic effect on cardiac conduction with ensuing bradycardia that can devolve into a cycle of worsening renal perfusion and shock.

Treatment is supportive, but most effective when the syndrome is recognized and all parts simultaneously managed.  ED physicians should be familiar with its existence for targeted whole-syndrome stabilization and to avoid diagnostic delay.

  • Shock – If hypovolemic, IV fluid resuscitation. Concomitantly or if still hypotensive, epinephrine infusion is recommended as it provides both chronotropy and inotropy, and also assists with hyperkalemia.
  • Hyperkalemia – usually mild/moderate; IV calcium for any ECG abnormalities, intracellular shifting medications, and kaliuresis (may require high-dose loop diuretics, with IV fluids if needed to maintain volume)
  • Bradycardia – will usually respond to IV calcium and chronotropy (epinephrine, isoproterenol); pacing rarely but sometimes needed
  • Renal failure – IVF and perfusion support as noted above, but patients may require dialysis if renal failure is severe and hyperkalemia is unable to be medically managed

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Point of Care Ultrasound has been shown to change medical management and decrease time to diagnosis. 

However, sometimes on a busy shift we may get an xray or radiological study prior to performing a POCUS exam due to time constraints.

A recent study looked at the time it takes to perform a bedside ultrasound.

The authors measured the duration of time from starting the exam through the ultrasound worklist to the timestamp on the last recorded image. 

They reviewed 2144 studies and found a median time of 6 minutes to perform a study. 

Of course the study is limited by the time it takes to find a machine, make sure it is functioning and other supplies such as gel. 

 

Conclusion: You can take 6 minutes to assist in your patient's clinical care.

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Category: Gastrointestional

Title: Can appendectomy wait until the morning?

Keywords: appendicitis, delayed operating room, appendectomy (PubMed Search)

Posted: 9/17/2023 by Robert Flint, MD (Updated: 3/19/2024)
Click here to contact Robert Flint, MD

This Scandinavian study from the Lancet says yes. They randomized 1800 patients over age 18 to appendectomy either within 8 hours or 24 hours and found no difference in perforation rate or other complications. 

 

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Category: Pediatrics

Title: Spontaneous Pneumomediastinum in Children: What should I do?

Keywords: Spontaneous Pneumomediastinum, asthma, crepitus, esophagram (PubMed Search)

Posted: 9/15/2023 by Jenny Guyther, MD
Click here to contact Jenny Guyther, MD

Spontaneous pneumomediastinum (SPM) is air within the mediastinum in the absence of trauma.  This occurs more often in males and has 2 age peaks: children younger than 6 years as a result of lower respiratory tract infections and adolescents due to asthma exacerbations.  Typical symptoms include chest pain, subcutaneous emphysema and shortness of breath, but can also include neck pain, dysphagia, pneumopericardium, and pneumorrhachis (air in the spinal cord).   SPM has been seen in patients with a history of asthma, current influenza infection and hyperventilation with anxiety, but many have no known precipitating factor. 
The diagnosis of SPM is typically made on CXR.  The literature is mixed on the utility of CT scans, esophagrams, esophagoscopy and bronchoscopy.  This study looked at 179 pediatric patients who were diagnosed with SPM.  No patients were found to have an esophageal injury.  Also, CT scans did not provide additional information or change management based on what was seen on the chest xray.
The author's concluded that CT scans and esophagrams can be avoided unless there is a specific esophageal concern.  Management should be guided based on the patient's symptoms.

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Category: Pharmacology & Therapeutics

Title: DOAC "Loading Dose" = Misnomer

Keywords: DOAC, apixaban, rivaroxaban, loading dose (PubMed Search)

Posted: 9/14/2023 by Wesley Oliver (Updated: 3/19/2024)
Click here to contact Wesley Oliver

DOACs (dabigatran*, apixaban, rivaroxaban) each have different dosing strategies based on indication and patient characteristics. While there is no official term for the doses, the higher initial doses for apixaban (10 mg BID for 7 days) and rivaroxaban (15 mg BID for 21 days) for the treatment of venous thromboembolism (VTE) are commonly referred to as “loading doses.” However, the term “loading dose” is actually a misnomer.

Loading doses are used to reach therapeutic drug levels quicker with medications such as vancomycin and phenytoin/fosphenytoin. However, this is not the purpose of the higher initial doses of apixaban and rivaroxaban. The purpose of the higher doses is to provide increased levels of anticoagulation during the acute phase of VTE when patients are hypercoagulable. For this reason, VTE and heparin-induced thrombocytopenia are the only indications where a higher dose is used initially, all other indications start with the standard dose. The difference in duration of these higher doses between apixaban (7 days) and rivaroxaban (21 days) are due to the durations used in trials by the drug company, versus any pharmacokinetic reasons.

To apply this concept:

Apixaban/Rivaroxaban: For the treatment of VTE, a higher dose is only required for the initial 7- (apixaban) or 21-day period (rivaroxaban). After this period, if there is any interruption in therapy, the standard dose can be restarted because therapeutic levels are rapidly achieved and higher doses are not needed outside of the acute phase.

One caveat to this would be if the patient developed a new VTE while therapy is interrupted, in which case another period of the higher dosing could be considered.

 

*Remember: Dabigatran cannot be used for initial treatment of VTE and must be started only after at least 5 days of a parenteral anticoagulant. (Dabigatran and the parenteral anticoagulant should not be overlapped).

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Category: Critical Care

Title: CPAP vs HFNC for undifferentiated acute respiratory failure

Keywords: NIPPV, CPAP, HFNC, High Flow, Respiratory Failure (PubMed Search)

Posted: 9/12/2023 by Mark Sutherland, MD
Click here to contact Mark Sutherland, MD

When patients fail simple respiratory support therapies like nasal cannula or non-rebreather, it is often a point of debate whether to move next to High Flow Nasal Cannula (HFNC) or Noninvasive Positive Pressure Ventilation (NIPPV).  This study randomized patients in acute respiratory failure (ARF) to CPAP, a form of NIPPV, vs HFNC.  They looked at all comers in ARF, and primary outcome was need for intubation.  Importantly, they excluded asthma/COPD exacerbation, for which BiPAP is typically considered the first line therapy due to improved CO2 clearance.

They found a significantly lower number of patients required intubation in the CPAP (28.9%) group than the HFNC (42.6%) group (p=0.006).  They hypothesized that the enhanced PEEP improved oxygenation (hypoxia being a common trigger for moving to intubation), but as opposed to BiPAP,  the lack of additional driving pressure limited tidal volumes and Patient Self-Inflicted Lung Injury (P-SILI), which is a known mechanism of ARDS and mortality.  They use this argument to explain why trials like FLORALI, pitting HFNC vs BiPAP, tend to not find an advantage for the NIPPV arm.  While this rationale makes sense, it should be noted that the study does not directly investigate if this was the reason for the difference, and for what its worth the inverse argument that using driving pressure to reduce respiratory rate, hypercarbia, and work of breathing (other very common indications for intubation) would also theoretically reduce intubations.  Furthermore, it's not clear why reducing P-SILI, which tends to cause mortality on a much longer duration, would improve the short-term outcome of need for intubation.

 

Bottom Line: This study demonstrated a benefit to CPAP over HFNC in terms of decreasing need for intubation amongst non-asthma/non-COPD patients with acute respiratory failure, and offered a physiologic rationale but one that requires further verification and discussion.  While it may be reasonable to choose CPAP instead of HFNC in marginal patients at risk of intubation (but stable enough to trial noninvasive support first), in my opinion more studies are likely needed before a wholesale change in practice.  The study also does not take into consideration the enhanced comfort and compliance we tend to see with HFNC over NIPPV, which should be considered as well.  

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