Emergency Medical Minute

Contributor: Travis Barlock, MD
Educational Pearls:
 
Endocannabinoid System: THC binds CB1 and CB2 receptors in neurons and immune cells
Δ9-Tetrahydrocannabinol (THC) is the main psychoactive compound in cannabis

CB1 and CB2 receptors typically bind endogenously-produced 2-arachidonoylglycerol (2-AG) and anandamide (AEA) to regulate pain, stress, and inflammation

THC similarly binds CB1 and CB2, leading to the cannabinoid high: euphoria, paranoia, anxiety, analgesia, anti-inflammation, and appetite, among a variety of others

Ingestion via edibles, vice inhalation via smoking, leads to chemical modification of Δ9-THC to 11-hydroxy-Δ9-THC, which more easily crosses the blood-brain barrier and binds CB1 with higher affinity, leading to increased psychoactivity

 
Cannabinoid Hyperemesis Syndrome (CHS): Chronic THC use leading to the classic presentation of persistent nausea and intense, frequent vomiting
Chronic activation of CB1 receptors in brain builds a tolerance and dependence on THC, in addition to chronic activation of the capsaicin and vanilloid receptor TRPV1, which binds capsaicin or is activated by heat

Treatment by warm showers works due to TRPV1 activation by heat

Treated with benzodiazepines, fluids, and gastro-intestinal or central nervous system agents according to patient presentation

 
Over 200 synthetic cannabinoids have been created (K2, spice, black mamba, mojo, etc), which are more dangerous and can lead to a variety of etiologies
 
Acetaminophen binds CB1 receptors to reduce inflammatory pain
 
References
Loganathan P, Gajendran M, Goyal H. A Comprehensive Review and Update on Cannabis Hyperemesis Syndrome. Pharmaceuticals (Basel). 2024;17(11):1549. Published 2024 Nov 18. doi:10.3390/ph17111549 

Wall ME, Sadler BM, Brine D, Taylor H, Perez-Reyes M. Metabolism, disposition, and kinetics of delta-9-tetrahydrocannabinol in men and women. Clin Pharmacol Ther. 1983 Sep;34(3):352-63. doi: 10.1038/clpt.1983.179. PMID: 6309462. 

Mills B, Yepes A, Nugent K. Synthetic Cannabinoids. Am J Med Sci. 2015 Jul;350(1):59-62. doi: 10.1097/MAJ.0000000000000466. PMID: 26132518.

Klinger-Gratz PP, Ralvenius WT, Neumann E, et al. Acetaminophen Relieves Inflammatory Pain through CB1 Cannabinoid Receptors in the Rostral Ventromedial Medulla. J Neurosci. 2018;38(2):322-334. doi:10.1523/JNEUROSCI.1945-17.2017

 
Summarized by Sam Pahl | Edited by Sam Pahl & Ahmed Abdel-Hafiz, NREMT-P
 
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Contributor: Aaron Lessen, MD
Educational Pearls:
There has long been many questions about which IV fluid is best for ED resuscitation

Multiple adult studies have shown no clear benefit of balanced fluid vs normal saline

A large pediatric randomized clinical trial published in April compared balanced fluid vs normal saline in children with septic shock 

The study included about 9,000 patients from 47 emergency departments in five countries

Patients with septic shock were randomized to receive either balanced fluid or normal saline

The primary outcome was adverse kidney event (death, dialysis, or persistent kidney dysfunction) at 30 days or hospital discharge

Results showed no difference in any safety outcomes and no adverse events occurred

The key takeaway is that early fluid resuscitation matters more than which crystalloid you choose

 
References
Balamuth F, Weiss SL, Long E, et al. Balanced Fluid or 0.9% Saline in Children Treated for Septic Shock. New England Journal of Medicine. Published online April 23, 2026. doi:https://doi.org/10.1056/nejmoa2601969

 
Summarized by Meg Joyce, MS3 | Edited by Meg Joyce & Ahmed Abdel-Hafiz, NREMT-P

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Carepoint Journal Club is a quarterly series with discussions about a medical topic, brought to you by Carepoint's Emergency Physicians.

Contributor: Taylor Lynch, MD
Educational Pearls: 
 
Conduction abnormalities are a common and clinically significant complication in patients who undergo transcatheter aortic valve replacement (TAVR)
 
Clinical Features
The most common abnormalities include high grade AV block and new onset LBBB 

Due to the close proximity of the aortic annulus to the AV node and His-Purkinje system

More common in males, the elderly, and those with pre-existing conduction disease (RBBB or LBBB)

Sinus pauses and sinus arrest are a rare post-TAVR rhythm disturbances

Temporary failure of sinus node firing with absent P waves, followed by return of sinus rhythm

Sinus Pauses: Typically last Sinus Arrest: Typically last > 3 seconds

Not due to direct mechanical injury from the valve, but may occur in patients as a result of pre-existing disease or other external factors:

Medications

Beta blockers, calcium channel blockers, digoxin

Pre-existing damage to the SA node

Fibrosis from a previous MI

 
Treatment
If the patient is asymptomatic, provide ongoing surveillance

If the patient is symptomatic, treatment should be aimed at the underlying cause:

For medication-induced abnormalities, stop the offending medication

For acute, unstable bradycardia:

Medications: Atropine, Dopamine Infusion, Epinephrine Infusion

If cardiology is not immediately available, initiate transcutaneous pacing or insert a temporary transvenous pacemaker

Definitive treatment: Pacemaker

~10–15% of patients may develop a bradyarrhythmia post TAVR, with ~8-15% later requiring a pacemaker

 
Due to the risk of conduction abnormalities post TAVR, many patients are discharged with ambulatory rhythm monitoring such as a ZioPatch or Holter monitor, and may present to the emergency department for evaluation of rhythm disturbances.
 
References:
Kusumoto FM, Schoenfeld MH, Barrett C, et al. 2018 ACC/AHA/HRS guideline on the evaluation and management of patients with bradycardia and cardiac conduction delay. Heart Rhythm. 2019;16(9):e128-e226.

Lilly, S, Deshmukh, A, Epstein, A. et al. 2020 ACC Expert Consensus Decision Pathway on Management of Conduction Disturbances in Patients Undergoing Transcatheter Aortic Valve Replacement: A Report of the American College of Cardiology Solution Set Oversight Committee. JACC. 2020 Nov, 76 (20) 2391–2411.

https://doi.org/10.1016/j.jacc.2020.08.050
Sammour, Y, Krishnaswamy, A, Kumar, A. et al. Incidence, Predictors, and Implications of Permanent Pacemaker Requirement After Transcatheter Aortic Valve Replacement. J Am Coll Cardiol Intv. 2021 Jan, 14 (2) 115–134.

https://doi.org/10.1016/j.jcin.2020.09.063
Tarakji KG, Patel D, Krishnaswamy A, et al. Bradyarrhythmias detected by extended rhythm recording in patients undergoing transcatheter aortic valve replacement (Brady-TAVR Study). Heart Rhythm. 2022;19(3):381-388.

 
Summarized by Ashley Lyons, OMS3 | Edited by Ashley Lyons & Ahmed Abdel-Hafiz, NREMT-P
 
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Contributor: Alec Coston, MD
Educational Pearls:
What are nasal intubations and when do we use them?
Nasal intubations function similarly to oral intubations with the end goal of passing an endotracheal tube (ETT) through vocal cords and into the trachea to allow for a patent and secure airway, but differ in the main access point for the ETT (nare v.s. mouth).

Nasal Intubations are seldom preferred to oral intubations as they carry risk for inducing bleeding from trauma to the nasal passages. 

Indications for nasal intubations include:

Anatomical abnormalities that may make access through the mouth difficult (i.e. tumors, macroglossia, or rare dental hardware that clenches the jaw shut).

Physiological states such as severe angioedema. 

Nasal intubations are often done with the patient awake and could be advantageous if the patient is presenting in a severely hypoxic state such that prolonged hypoxia in a traditional RSI protocol may be detrimental.

A 2023 retrospective analysis in Germany found that nasal intubations were associated with requiring less sedation than oral intubations and had more spontaneous breathing during hospitalization than oral intubations.

How is a nasal intubation performed?
Consider the use of an anxiolytic medication such as versed to calm the patient down but not fully sedate them.

If there is adequate time without immediate patient compromise, consider glycopyrrolate to reduce airway secretions and dry up the mucous membranes.

Consider the use of Afrin or other local vasoconstrictor in target nare to minimize epistaxis.   

Use 5% lidocaine ointment and lubricate an NPA and place it into the target nare. This will allow for local anesthesia as well as help to open up the nare slightly more. 

Take 5% lidocaine ointment and place it on a tongue depressor and move it around the back of the tongue, allowing it to further anesthetize the oropharynx. 

Remove the NPA and atomize/nebulize 4% lidocaine liquid into the nare and into the oropharynx for further anesthesia. 

Insert the ETT without the bronchoscope through the nare and allow it to pass about 10 cm until visible in the oropharynx. This allows for a "clean" plastic tunnel to pass the bronchoscope through.

Advance both the ETT and bronchoscope, spraying lidocaine through the bronchoscope while advancing to allow for continued numbing. 

Pass the ETT through the cords and inflate. 

At this point, stronger sedation medications such as ketamine and propofol may be considered but the use of a paralytic like succinylcholine and rocuronium may not be needed to allow the patient to maintain their own negative pressure ventilation. 

Which nare is the best to go through?
Most patients will have their right nare be the best (away from the septal deviation) according to a meta-analysis by Tan et al. 

The right nare was generally associated with less epistaxis and lower intubation times. 

However, do not always default to the right nare, and test which nare is more patent by occluding one nare at a time and assessing which one is less resonant  (less resonant = more patent). 

Key Takeaway?
Nasal intubations are rarer than oral intubations and can be more technically difficult, but may offer advantages in patients with difficult oral airways, but should never be first line. 

 
References:
Grensemann J, Gilmour S, Tariparast PA, Petzoldt M, Kluge S. Comparison of nasotracheal versus orotracheal intubation for sedation, assisted spontaneous breathing, mobilization, and outcome in critically ill patients: an exploratory retrospective analysis. Sci Rep. 2023;13:12616. doi:10.1038/s41598-023-39768-1

Tan YL, Wu ZH, Zhao BJ, Ni YH, Dong YC. For nasotracheal intubation, which nostril results in less epistaxis: right or left?: A systematic review and meta-analysis. Eur J Anaesthesiol. 2021;38(11):1180-1186. doi:10.1097/EJA.0000000000001462

Holzapfel L. Nasal vs oral intubation. Minerva Anestesiol. 2003;69(5):348-352.

 
Summarized by Dan Orbidan, OMS2 | Edited by Dan Orbidan & Ahmed Abdel-Hafiz, NREMT-P
 
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