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 Permeability coefficient 1.4 x cm/sec Concentrations of HF Household (aqueous) 3-40% Industrial (aqueous) >70% Anhydrous HF 100%

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

Routes of Exposure Dermal Inhalational Oral Ocular

HF Clinical Presentation: Local Systemic

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

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

Laboratory Indicators Systemic HF Acidemia Prolonged PT (or bleeding) Electrolytes:  iCa 2+,  Mg 2+,  K +

Management Systemic HF Continuous ECG Monitoring 2 + large bore IVs, foley Laboratory: Ca 2+, Mg 2+, electrolytes, CBC Type and Screen PT/PTT ABG or VBG

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

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

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

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

NaHCO 3 Urinary alkalinization/Ion trapping F mEq/kg bolus Isotonic drip at 1.5 –2 x maintenance Serum pH No potassium supplementation without absolute indication

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

HF Ingestions

Readily absorbed High fatality rate Assume all ingestions are systemic exposures

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

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

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

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

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

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

Dermal HF Severe pain with few findings Onset pain often related to concentration Concentration of HF (%) Symptoms onset <20May not occur for hours 20-50Within 1-8 hours >50Immediate

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

Dermal HF Local intradermal injection calcium 0.5 mL/cm 3 of 5% calcium gluconate Distal to injury Limited utility esp in digits

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

Intra-Arterial Calcium 10 mL of 10% Calcium gluconate in 40 mL D 5 W or NS Infuse over 4 hours Repeat prn Huisman LC, et al. Lancet. 2001;358:1510.

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

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

Acknowledgements Lewis Nelson Susi Vassallo NYCPCC