Contributor: Travis Barlock, MD

Educational Pearls:

What is pulmonary edema?

• Pulmonary edema is the accumulation of fluid initially in the interstitium of the lungs, that when severe enough can also accumulate in the alveolar air sacs. It develops when the rate of fluid filtration through the pulmonary vasculature out-paces the lymphatics ability to drain the fluid.

There are 2 theories for what causes pulmonary edema in the setting of naloxone administration: catecholamine surge vs negative pressure/barotrauma

• Catecholamine Surge : Naloxone administration precipitates an acute opioid withdrawal in which epinephrine and norepinephrine surge causing marked vasoconstriction on both the heart and the lungs

• Negative Pressure/Barotrauma: This mechanism is not directly naloxone related but may be confounded by opioid effects. High dose synthetic opioids can induce sustained laryngospasm that is not mu-opioid mediated (thus not easily reversed by naloxone). With rapid awakening, respiratory muscles induce a negative pressure in the thoracic cavity against a closed glottis. This results in an alveolar barotrauma and a transudative pulmonary edema.

What is the treatment for pulmonary edema secondary to opioid overdose reversal?

• Positive pressure ventilation is the mainstay treatment (CPAP/BiPAP) with oxygen supplementation.

• Importantly, diuretics are not recommended. The patient is not fluid overloaded like in the case of other pulmonary edemas, and diuresing the patient can worsen kidney injury which is already at an increased risk in opioid overdoses (rhabdomyolysis in particular).

References:

1. Saari TI, Strang J, Dale O. Clinical Pharmacokinetics and Pharmacodynamics of Naloxone. Clin Pharmacokinet. 2024;63(4):397-422. doi:10.1007/s40262-024-01355-6

2. DailyMed - NALOXONE HYDROCHLORIDE injection, solution. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=201fdedf-1736-4e52-9d7d-de14292547fd

3. Boyer EW. Management of Opioid Analgesic Overdose. New England Journal of Medicine. 2012;367(2):146-155. doi:10.1056/NEJMra1202561

4. Dezfulian C, Orkin AM, Maron BA, et al. Opioid-Associated Out-of-Hospital Cardiac Arrest: Distinctive Clinical Features and Implications for Health Care and Public Responses: A Scientific Statement From the American Heart Association. Circulation. 2021;143(16):e836-e870. doi:10.1161/CIR.0000000000000958

5. Kienbaum P, Thurauf N, Michel M, Scherbaum N, Gastpar M, Peters J. Profound Increase in Epinephrine Concentration in Plasma and Cardiovascular Stimulation after [micro sign]-Opioid Receptor Blockade in Opioid-addicted Patients during Barbiturate-induced Anesthesia for Acute Detoxification Anesthesiology. 1998;88(5):1154-1161. doi:10.1097/00000542-199805000-00004

Summarized by Dan Orbidan, OMS3 | Edited by Dan Orbidan & Ahmed Abdel-Hafiz, NREMT-P

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Contributor: Alec Coston, MD

Educational Pearls:

Benign Paroxysmal Positional Vertigo (BPPV)

• Common inner ear condition that can cause dizziness

• Diagnosis of BPPV can help to avoid admissions and extra imaging

• Three categories: positional, horizontal, and anterior

• • Positional is the most common

  • • Dizziness is not a positive indicator, a torsional nystagmus must be induced

    • Dix's hallpike maneuver is done to diagnose and an epley maneuver is then used for treatment

  • Horizontal

  • • Usually determined to be the case if the vertigo seems positional and the dix hallpike does not work. A supine roll test would then be done to help diagnose.

    • Instead of a rotational nystagmus, a unilateral horizontal nystagmus is expected. The two patterns are termed geotropic and apogeotropic.

    • Geotropic means the fast phase beats toward the ground, and is treated by a barbeque roll maneuver. Apogeotropic means the fast phase beats toward the ceiling, and is treated by Gufoni maneuver.

  • Anterior is more rare

  • • Most cases require neuro consults

    • Determined by attempting to induce a down-beating nystagmus, which is a higher risk nystagmus.

    • Treatment is tilting their head back up in a similar way

    • Inducing the nystagmus is not sided and is more central

References

1. You, P., Instrum, R. and Parnes, L. (2019), Benign paroxysmal positional vertigo. Laryngoscope Investigative Otolaryngology, 4: 116-123. https://doi.org/10.1002/lio2.230

2. Ling X, Zhao D-H, Shen B, Si L-H, Li K-Z, Hong Y, Li Z-Y and Yang X (2020) Clinical Characteristics of Patients With Benign Paroxysmal Positional Vertigo Diagnosed Based on the Diagnostic Criteria of the Bárány Society. Front. Neurol. 11:602. doi: 10.3389/fneur.2020.00602

3. Rah YC. Advances in Benign Paroxysmal Positional Vertigo: Updated Insights on Diagnostic Pitfalls and Management. J Audiol Otol. 2026 Jan;30(1):1-12. doi: 10.7874/jao.2025.00717.

Summarized by Aaryn David | Edited by Aaryn David & Ahmed Abdel-Hafiz, NREMT-P

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Contributor: Aaron Lessen, MD

Educational Pearls:

Blunt cerebrovascular injury (BCVI)

• BCVI is a traumatic injury to the carotid or vertebral arteries

• • Patients may initially have no neurologic symptoms

  • In some cases, a thrombus can form at the site of the injury and later cause ischemic stroke, sometimes hours after the original trauma

• CT angiography (CTA) of the neck is a useful screening tool for BCVI

• • HIstorically, CTA was reserved for patients with high-risk mechanisms or neurologic symptoms

  • CTA screening has expanded as understanding of BCVIs and their prevention progresses

• The Denver criteria were developed to identify patients with increased risk for BCVI

• • High-risk findings include cervical spine injuries and severe facial or skull-base fractures

  • Screening practices still vary between trauma centers, though expansion of proactive CTA is an increasingly common practice

References

1. Kim DY, et al. Evaluation and management of blunt cerebrovascular injury: A practice management guideline from the Eastern Association for the Surgery of Trauma. J Trauma Acute Care Surg. 2020.

2. Biffl WL, et al. Screening for and treatment of blunt cerebrovascular injuries: Western Trauma Association critical decisions algorithm. J Trauma. 2009.

3. Brommeland T, et al. Best practice guidelines for blunt cerebrovascular injury. Scand J Trauma Resusc Emerg Med. 2018.

4. Harper PR, et al. Routine CTA screening identifies blunt cerebrovascular injuries missed by clinical risk factors. Trauma Surg Acute Care Open. 2022.

Summarized by Sam Pahl | Edited by Sam Pahl & Ahmed Abdel-Hafiz, NREMT-P

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