Topics in this EM Quick Hits podcast

Megan Landes on providing HIV PEP and PrEP in the ED (1:05 )

Justin Morgenstern and George Kovacs on evidence for pre-oxygenation with NIPPV before intubation in RSI (19:05 )

Brit Long on recognition and management of blast crisis in the ED (41:31 )

Leah Flanagan and Liam Loughrey on the rise of nitrous oxide toxicity (50:40 )

Andrew Petrosoniak on the role of vasopressors in the hemorrhaging trauma patient (59:55 )



Podcast production, editing and sound design by Anton Helman

Podcast content, written summary & blog post by Brandon Ng and Brit Long, edited by Anton Helman, July, 2024

Cite this podcast as: Helman, A. Morgenstern J. Landes, M. Kovacs, G. Long, B. Flanagan L. Loughrey, L. Petrosoniak, A. EM Quick Hits 58 - HIV PEP and PrEP, PREOXY Trial, Blast Crisis, Nitrous Oxide Poisoning, Vasopressors in Trauma. Emergency Medicine Cases. July, 2024. https://emergencymedicinecases.com/em-quick-hits-month-year/. Accessed October 1, 2024.

HIV Post-exposure prophylaxis (PEP) and pre-exposure prophylaxis (PrEP)

This is part 2 of our 2-part EM Quick Hits series on HIV. We suggest reviewing part 1 if you haven't already - Part 1 of this 2-part EM Quick Hits series on HIV



* PEP is an effective method for reducing the risk of transmission for persons who have been exposed to HIV. It needs to be given less than 72 hours from initial exposure to be maximally effective and is prescribed as a 28-day course of Anti-retroviral therapy (ART).

* PEP reduces the relative risk of a single exposure event to HIV by 80% (reduces risk of percutaneous exposure and mucocutaneous exposure to HIV positive blood to 0.3% and 0.09%, respectively).

* Note that every risk of exposure to HIV is relatively low, and PEP reduces that to an even more minuscule risk.



HIV post-exposure risk stratification and indications for post-exposure prophylaxis (PEP)?

1.Determine the source risk for transmissible HIV, which can be categorized into substantial, low but nonzero, and negligible/none:

Source: Canadian guideline on HIV pre-exposure prophylaxis and nonoccupational postexposure prophylaxis by Tan et al. EMAJ 2017



* Concomitant STIs increase the risk of transmitting HIV through methods such as breaking down mucosal barriers and increasing inflammatory states.



2.Determine the type of transmission:

Source: Canadian guideline on HIV pre-exposure prophylaxis and nonoccupational postexposure prophylaxis by Tan et al. EMAJ 2017



* There is no good data on the risk of HIV transmission via mucocutaneous splash. Refer to your local occupational health policies.



Who should we advise to start PEP?



* Consider PEP if the source risk is in the substantial category and the type of exposure is high/moderate risk.

* PEP is not recommended if the source’s risk is negligible/none and the exposure type is low risk.



Indications for pre-exposure prophylaxis for HIV (PrEP)?



* PrEP is ARTs (e.g. Truvada®) on an ongoing basis due to expecting repeated high-risk exposures to HIV.

* There is a relative risk reduction of 44% and a NNT of <15.

* People who should consider taking PrEP include: sexually active adults who have ongoing exposure (e.g. ongoing condomless sex with known HIV exposure), patients with recent STI, and those presenting to ED for recurrent PEP.

* There are also current studies and ongoing evidence for adding doxycycline t...