Hydrofluoric acid

From WikEM
Revision as of 06:02, 7 May 2017 by Lisayee25 (Talk | contribs) (Clinical Features)

Jump to: navigation, search

Background

  • Used in both commercial and home setting
    • Rust remover (most common home use)
    • Glass etching, chrome and other metal cleaning, petroleum processing
  • Oral ingestion has very high mortality rate

Clinical Features

Hydrofluoric acid burn
  • Skin
  • Ophthalmic
  • Ingestion
  • Inhalation
  • Signs/symptoms of hypocalcemia, hypomagnesemia, and/or hypokalemia
    • Can lead to QTc interval prolongation and cardiac arrhythmias, the primary cause of death in HF burns
  • Onset and severity of symptoms correlated with concentration
    • Dilute solutions (<20%) may have delayed onset up to 24hr post-exposure
    • Moderate solutions (20-50%) develop symptoms within 1-8hr
    • Concentrated solutions (>50%) develop symptoms immediately
      • These patients are at highest risk for systemic toxicity/death
      • Pain immediately (even if wound appears minor) implies severe injury
  • Burn itself is usually relatively minor
  • Toxicity caused by binding of calcium

Differential Diagnosis

Caustic Burns

Evaluation

  • Trend calcium and potassium levels
    • HF acid chelates calcium and poisons the Na+/K+ pump
    • Order serial chemistries, ECGs
    • Expect hypocalcemia and hyperkalemia
  • Obtain other electrolytes including magnesium

Management

  • Remove soiled clothing and irrigate thoroughly

Cutaneous Burns

Minor injuries (<50 cm2 from dilute solutions <20%)

  • Application of gel paste of Ca gluconate or benzalkonium Cl
    • Rub into affected area for 10-15min with pain relief being used as end-point of treatment
    • Calcium gel is commercially available (found in industrial first-aid kits)
    • Calcium gel can be made:
      • Mix calcium gluconate powder 3.5gm with 150mL water-soluble lubricant OR
      • Mix 25mL 10% calcium gluconate solution with 75mL water-soluble lubricant
    • Benzalkonium Cl is commercially available
    • If calcium gluconate is not available calcium chloride can be used

Severe injuries

  • Treat with intradermal injections of 5% calcium gluconate
    • Prepare by diluting conventional 10% Ca gluconate with sterile NS in 1:1 ratio
    • Inject in and around the burned area in amount not to exceed 0.5mL per cm2

Refractory injuries

  • Treat with intra-arterial infusion of calcium gluconate
    • Deliver via arterial line placed proximal to injury in the same limb
    • Infuse 10mL of 10% Ca gluconate dilued in 40mL of NS or D5water over 4 hr

Ocular burns

  • Irrigate with saline for at least 5 min
  • Anesthetic as required
  • If persistent pain administer 1% calcium gluconate to eye
    • Consult ophthalmology due to irritation effect of calcium salts to eye
    • Dilute 10% calcium gluconate with normal saline

Ingestion

  • If <1hr of ingestion place NG tube, suction, gastric lavage
    • Follow lavage by 300mL 10% Ca gluconate down NGT
    • Provide aggressive IV supplementation if ECG signs of hypoCa or hyperK
    • Consider intubation

Inhalation

  • 100% O2 by facemask
  • nebulized 2.5% calcium gluconate
  • Follow ECG, electrolytes, and vitals
  • Low threshold for obs/admission

Hyperkalemia and Hypocalcemia

  • Treat medically as needed

Disposition

  • Consultation with poison center and burn center transfer per Burn center criteria
  • Admission for all patients with arrhythmia on ECG or severe electrolyte disturbance

See Also

References

  • Levine MD, Zane R: Chemical Injuries, in Marx JA, Hockberger RS, Walls RM, et al (eds): Rosen’s Emergency Medicine: Concepts and Clinical Practice, ed 8. St. Louis, Mosby, Inc., 2013, (Ch) 64: pp 818-822.