Hydrofluoric Acid Intensive Review Course in Clinical Toxicology

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

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

Hydrofluoric Acid n n p. Ka 3. 5 Weak Acid Permeability coefficient Concentrations of HF n n n Household (aqueous) Industrial (aqueous) Anhydrous HF 1. 4 x 1024 3 -40% >70% 100% cm/sec

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

Routes of Exposure n n Dermal Inhalational Oral Ocular

HF Clinical Presentation: n Local n Systemic

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

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

Laboratory Indicators Systemic HF n n n Acidemia Prolonged PT (or bleeding) Electrolytes: i. Ca 2+, Mg 2+, K+

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

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

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

Calcium Preparations (10%) n Calcium gluconate n n 0. 465 m. Eq/m. L Peripheral lines 60 mg/kg pediatric Calcium chloride n n n 1. 36 m. Eq/m. L Central line 20 mg/kg pediatric

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

Na. HCO 3 n n n Urinary alkalinization/Ion trapping F 1 -2 m. Eq/kg bolus Isotonic drip at 1. 5 – 2 x maintenance Serum p. H 7. 5 -7. 55 No potassium supplementation without absolute indication

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

HF Ingestions

HF Ingestions n Readily absorbed n High fatality rate n Assume all ingestions are systemic exposures

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

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

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

Inhalational HF n n n Airway management prn Screen for systemic, ocular toxicity Nebulization therapy n n n 2. 5 - 5 % Calcium gluconate (Dilution of a 10% solution) Limited data

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

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

Dermal HF n n Severe pain with few findings Onset pain often related to concentration Concentration of HF (%) toms onset <20 20 -50 >50 Symp May not occur for 12 -18 hours Within 1 -8 hours Immediate

Dermal HF

Dermal HF n n Irrigation with soap and water Topical calcium n Sterile water soluble lubricant n n n 3. 5 gm Ca. Gluconate powder in 150 m. L 25 m. L of 10% Ca. Gluconate in 75 m. L Can consider n n n calcium carbonate Calcium chloride Consider filling glove if hand exposure

Dermal HF n Local intradermal injection calcium n n n 0. 5 m. L/cm 3 of 5% calcium gluconate Distal to injury Limited utility esp in digits

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

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

Dermal HF n Digital blocks useful n n Single digit/tip Delayed presentations No systemic toxicity “Bier” blocks n n 25 m. L of 2. 5% Ca. Glu Limited utility: tourniquet

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

Acknowledgements n n n Lewis Nelson Susi Vassallo NYCPCC