What caustic exposure from the pictured item can lead to ocular injury?
- Acetic Acid
- Hydrofluoric Acid
- Potassium Hydroxide
- Sodium Hydroxide
[Image from Istockphoto]
Reveal the Answer
4. Sodium Hydroxide (Lye)
While automobile airbags are an important life-saving device, sodium hydroxide powder and aerosol released by their inflation can cause significant ocular injury for which prompt ocular irrigation is indicated [1,2].
Why in the world is lye used in airbags? [1,2]
- To create rapid airbag inflation, sodium azide is ignited producing hydrocarbon gas.
- This reaction releases powdered sodium hydroxide, sodium bicarbonate, and fine metallic oxides.
- Upon impact, sodium hydroxide may escape through the fabric resulting in ocular exposure.
What is caustic ocular exposure? [3-5]
- Both acid and alkali substances can cause corrosive ocular injury
- Alkali substances, such as lye, are more harmful than acidic substances partly due to rapid tissue penetration.
- Alkali solutions saponify the cell membranes and penetrate the corneal stroma causing tissue damage.
- The damaged tissue secretes proteolytic enzymes, further worsening the injury.
- Other caustic alkali agents include ammonia, potassium hydroxide, magnesium hydroxide, and calcium oxide.
- Caustic eye injury symptoms include irritation, pain, redness, and visual disturbance.
How do I treat caustic ocular exposure? [3-6]
- Whether acidic or alkaline, treatment is the same.
- Prompt irrigation is of paramount importance and should not be delayed to perform a thorough ophthalmologic examination
- Remove contaminated clothing.
- To facilitate irrigation, proparacaine HCL 0.5% or tetracaine HCl 0.5% solution may be used to anesthetize the eye.
- You can measure an initial pH a minimum of 5 minutes after initiation of irrigation.
- Consider anxiolytics or analgesics if systemic symptoms or other sites of injury are a barrier to prompt irrigation.
What is the best way to irrigate the eye? [5-7]
- Begin by anesthetizing the eye with proparacaine or tetracaine.
- While a sterile solution such as normal saline or lactated ringers is preferred, tap water can be used as well.
- Avoid neutralizing solutions as this can worsen damage.
- A Morgan™ lens, if available, or a nasal cannula can be used to irrigate the eye(s).
- If you utilize the nasal cannula method, you may connect it directly to the IV tubing and the bag of irrigation fluid.
- If a Morgan lens is used, start the flow of irrigation solution before the lens is placed on the eye to avoid a suction contact injury to the cornea.
- Irrigation should be continued for a minimum of 30 minutes using 1-3 L of fluid or continued until a physiological pH is reached at 7.0.
What should I do after irrigation is completed? [2,4,5,8]
- Assess visual acuity.
- Perform a detailed examination of the limbus, cornea, and iris. Chemical ocular injury is classified by ophthalmologists based on limbal ischemia via the Roper-Hall classification or the Dua classification [4,8].
- Evaluate intraocular pressure.
- If greater than mild injury is suspected, ophthalmologic consultation is warranted.
- In patients who are discharged, discuss treatment and follow up with ophthalmology.
Bedside Pearls
- Suspect caustic eye injury in patients with eye pain after airbag deployment
- Do not delay irrigation if caustic eye injury is suspected.
- Perform irrigation until pH is physiologic.
- Perform a thorough eye examination after the irrigation is complete.
- Consult with ophthalmology
The American College of Medical Toxicology hosts this Toxicology Visual Pearls series. The post was peer reviewed on behalf of ACMT by Drs. Louise Kao, Kristine Naňagas, and Andrew Stolbach.
Read More in the Series
References
- Richards A. Beware traumatic conjunctivitis: airbags can cause severe alkali eye injuries. Clinical & Experimental Ophthalmology. 2016;44(8):732-734. PMID: 27083383
- Barnes SS, Wong W Jr, Affeldt JC. A case of severe airbag related ocular alkali injury. Hawaii J Med Public Health. 2012;71(8):229-231. PMID: 22900239
- Chemical (Alkali and Acid) Injury of the Conjunctiva and Cornea – EyeWiki. eyewiki.aao.org. Accessed May 3, 2024.
- Hemmati H, Colby K. Treating Acute Chemical Injuries of the Cornea. American Academy of Ophthalmology. Published October 1, 2012. Accessed May 3, 2024.
- Olson E and Murphy C. ToxCard: Caustic Eye Injuries – emDOCs.net – Emergency Medicine Education (2020) Accessed May 3, 2024.
- Ikeda N, Hayasaka S, Hayasaka Y, Watanabe K. Alkali burns of the eye: effect of immediate copious irrigation with tap water on their severity. Ophthalmologica. 2006;220(4):225-228. PMID: 16785752
- Lin M. Trick of the trade: Eye irrigation setup. ALiEM. Published April 7, 2010. Accessed May 3, 2024.
- Kam KW, Patel CN, Nikpoor N, Yu M, Basu S. Limbal ischemia: Reliability of clinical assessment and implications in the management of ocular burns. Indian J Ophthalmol. 2019;67(1):32-36. PMID: 30574887
Author information
Hannah Corral, MD
Emergency Medicine Resident
Carolinas Medical Center, Charlotte, NC
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The post ACMT Toxicology Visual Pearls: Lye to the Eye appeared first on ALiEM.