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Hydrofluoric Acid

Hydrofluoric Acid. Intensive Review Course in Clinical Toxicology 2007 Rama B. Rao. Hydrofluoric Acid (HF). Household Glass etching Cleaning bricks and porcelain Rust removal Industrial Leather tanning Electroplating Etching microchips. Hydrofluoric Acid. pK a 3.5 Weak Acid

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Hydrofluoric Acid

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  1. Hydrofluoric Acid Intensive Review Course in Clinical Toxicology 2007 Rama B. Rao

  2. Hydrofluoric Acid (HF) • Household • Glass etching • Cleaning bricks and porcelain • Rust removal • Industrial • Leather tanning • Electroplating • Etching microchips

  3. Hydrofluoric Acid • pKa 3.5 • Weak Acid • Permeability coefficient 1.4 x 1024cm/sec • Concentrations of HF • Household (aqueous) 3-40% • Industrial (aqueous) >70% • Anhydrous HF 100%

  4. Pathophysiology • Deep penetration of tissues • Fluoride binding of divalent cations • Calcium • Magnesium • Alters Calcium dependent Potassium channels

  5. Routes of Exposure • Dermal • Inhalational • Oral • Ocular

  6. HF Clinical Presentation: • Local • Systemic

  7. Hypocalcemia Hypomagnesemia Hyperkalemia Prolonged QT Bleeding Prolonged QT Torsades ECG changes Systemic HF

  8. Assessment: Systemic HF • Vital signs • Mental status • ECG • Hyperkalemia • Peaked T waves • Progression to sine waves • QT prolongation • Ventricular dysrhythmias, ectopy

  9. Laboratory Indicators Systemic HF • Acidemia • Prolonged PT (or bleeding) • Electrolytes: iCa2+, Mg2+, K+

  10. Management Systemic HF • Continuous ECG Monitoring • 2+ large bore IVs, foley • Laboratory: • Ca2+, Mg2+ , electrolytes, CBC • Type and Screen • PT/PTT • ABG or VBG

  11. Therapy Systemic HF • Restore electrolyte homeostasis • Decontamination • Enhancement of urinary excretion F- • Treatment of dysrhythmias

  12. Calcium • Cardioprotective, restorative • Dosing: • 1 gm IV over 5 minutes • Titrate to ECG effect • May require grams • Pediatrics: • 20-60 mg/Kg • Monitor concentrations

  13. Calcium Preparations (10%) • Calcium gluconate • 0.465 mEq/mL • Peripheral lines • 60 mg/kg pediatric • Calcium chloride • 1.36 mEq/mL • Central line • 20 mg/kg pediatric

  14. Magnesium sulfate 20% • Adults • 20 ml (4 gm) over 20 minutes* • Cautious/avoid in renal failure • Observe vascular, neurological effects • Pediatrics • 25-50 mg/kg/dose over 20 minutes

  15. NaHCO3 • Urinary alkalinization/Ion trapping F- • 1-2 mEq/kg bolus • Isotonic drip at 1.5 –2 x maintenance • Serum pH 7.5-7.55 • No potassium supplementation without absolute indication

  16. Dysrhythmias • Correct underlying derangements • In refractory cases: • Amiodarone • In vitro • Animal models with HF induced hyperkalemia • Human data lacking

  17. HF Ingestions

  18. HF Ingestions • Readily absorbed • High fatality rate • Assume all ingestions are systemic exposures

  19. HF Ingestions: Clinical Presentation • Vomiting • Dysrhythmias • Rapid deterioration • Caustic injury minor

  20. HF Decontamination • Removal of gastric contents* • Careful NGT suction • Use caution as provider • Delivery cations to GI tract • Calcium carbonate • Magnesium citrate

  21. Inhalational HF • Assume exposure with any dermal exposure to the face • Burning, stridor • Dyspnea • Bronchospasm • Presume associated systemic and ocular toxicity

  22. Inhalational HF • Airway management prn • Screen for systemic, ocular toxicity • Nebulization therapy • 2.5 - 5 % Calcium gluconate • (Dilution of a 10% solution) • Limited data

  23. Ocular HF • Assume in inhalational exposures • Screen for additional facial/systemic exposures • Irrigation 1L LR • Avoid calcium or magnesium application*

  24. Dermal HF • Most common presentation • Evaluate for systemic toxicity if: • Vital sign abnormalities • Facial/neck exposures • Alteration mental status • High concentration solution • Large body surface area • any concentration

  25. Dermal HF • Severe pain with few findings • Onset pain often related to concentration

  26. Dermal HF

  27. Dermal HF • Irrigation with soap and water • Topical calcium • Sterile water soluble lubricant • 3.5 gm CaGluconate powder in 150 mL • 25 mL of 10% CaGluconate in 75 mL • Can consider • calcium carbonate • Calcium chloride • Consider filling glove if hand exposure

  28. Dermal HF • Local intradermal injection calcium • 0.5 mL/cm3 of 5% calcium gluconate • Distal to injury • Limited utility esp in digits

  29. Dermal HF • Intra-arterial Calcium • Hand injuries • Careful placement arterial line on AFFECTED side

  30. Intra-Arterial Calcium • 10 mL of 10% Calcium gluconate in 40 mL D5W or NS • Infuse over 4 hours • Repeat prn Huisman LC, et al. Lancet. 2001;358:1510.

  31. Dermal HF • Digital blocks useful • Single digit/tip • Delayed presentations • No systemic toxicity • “Bier” blocks • 25 mL of 2.5% CaGlu • Limited utility: tourniquet

  32. HF Summary • Rapid screening for systemic toxicity • Intravascular Calcium administration: • Gluconate unless central venous line • Adjunctive pain control

  33. Acknowledgements • Lewis Nelson • Susi Vassallo • NYCPCC

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