December 9, 2022

Dear Colleagues,

Welcome back to the UH EMS-Institute’s Pharmacy Phriday.  In this installment, we will continue to look at medications used for treatment under the Hydrofluoric (HF) exposure protocol.  You may recall from last week’s article that HF can be found in industrial settings for purposes such as glass etching, metal cleaning, and electronics, etc., as well as in the home in lower concentration items such as rust removers, wheel cleaners, and solvents. 

Exposure to HF can occur via direct skin contact, inhalation, or ingestion exposure, and requires very specialized medical treatment. An early report to the receiving facility will allow them to prepare to receive and treat the patient appropriately.

It is also important to remember that this type of call should be considered a Haz Mat Response.  Basic response information can be obtained by use of the Emergency Response Guide (ERG 157).  Be sure to consider responder safety! 

In the previous installment, we discussed the use of Zephiran Chloride, which is a commercially available product that works well initially and can be used by the EMT.  In some cases, Zephiran is not recommended, or another treatment is a better option.  Another major pharmacologic intervention in the treatment of HF exposures that the paramedic-level provider can use is Calcium Gluconate. It works similarly by binding the fluoride ion in HF to prevent tissue destruction as the chemical penetrates deep into the tissues searching for calcium and magnesium.  Depending on the clinical situation, Calcium Gluconate may be used in a gel, as a flush, or intravenously. 

In the case of skin burns, a Calcium Gluconate gel of 2.5% is another option.  The gel is often prepackaged and can be used immediately, massaging it promptly and repeatedly (every 10-15 minutes) into the burned area until the pain is relieved. Surgical gloves should be worn during the initial application of the gel so the person providing treatment will not receive a secondary exposure.  If the premade gel is not available, it can be made by mixing a 10% Calcium Gluconate solution in 3 times the volume of a water-soluble lubricant.  Many cases involve only small areas of exposure, usually on the digits.  In these situations, the gel can be placed in the fingers of a latex glove and then place the glove on the patient’s affected hands.

In exposures involving the eyes, face, ears, and other sensitive areas, Zephiran is not recommended due to the fact it is very irritating.  In these cases, a Calcium Gluconate 1% flush can be used.  If not pre-mixed, the solution can be made by mixing 50ml of a 10% solution mixed in a 500 ml bag of NS.  In the case of eye injuries, a Morgan Lens can be used to flush the eyes after applying Tetracaine drops for pain and to facilitate the flush.

Exposure can also occur from inhalation of a gaseous form of HF.  In these cases, significant damage to the respiratory system can occur that may include burns, edema, etc.  Nebulized Calcium Gluconate 2.5% along with 100% oxygen is recommended in these cases.  The provider would mix 1 ml of a Calcium Gluconate 10% solution with 3 ml of NS in the nebulizer cup. Due to the high risk of systemic toxicity from inhalation exposures, the provider should also establish IV access and be prepared to provide additional treatments as listed in the protocol (these treatments will be discussed in the next installment of Pharmacy Phriday). 

As we close this installment, there are just a few additional points within the protocol to highlight before we look at systemic toxicity next week:

• Two large-bore IVs are recommended when possible.

• Pain relief with narcotics is also within the protocol.  Within the ED and hospital setting, the effectiveness of a treatment of an HF burn is often based on pain relief.  Therefore, pain relief is sometimes withheld in those settings.  However, the use of narcotics early in the scenario by EMS personnel is very reasonable and beneficial.

• In cases of ingestion, the protocol recommends Milk of Magnesia.  Most patients who have ingested HF vomit spontaneously.  Current recommendations by HF manufacturers and suppliers are to give oral treatments only to conscious patients and under the direct advice of a physician.

• Remember that if no special solutions are immediately available on-site or within your drug box, continue to flush with water!

Until next week, stay safe!

Sincerely,

The UH EMS-I Team

University Hospitals

December 16, 2022

Dear Colleagues,

Welcome back. In this Pharmacy Phriday, we will attempt to finish our review of medications used in treating Hydrofluoric Acid (HF) exposures. In previous editions, we studied the use of Zephiran Chloride soaks, Calcium Gluconate 2.5% gels, Calcium Gluconate 2.5% flushes, and Calcium Gluconate 1% flushes for various exposures. In this installment, we will consider the systemic toxicity of HF exposures and the appropriate treatment in those cases.

As HF penetrates deep into the body seeking calcium and magnesium, the exposure can cause significant systemic toxicity secondary to depletion of total body stores of these minerals resulting in cellular death. The majority of deaths in patients experiencing systemic toxicity from HF exposure are the result of cardiac arrhythmias precipitated by hypocalcemia, hypomagnesemia, and other metabolic changes. 

The systemic toxicity that we are discussing can occur in all types of exposures to HF. Inhalation and ingestion exposures would obviously raise concern for the patient but remember that even skin burns from HF can easily cause systemic concerns. Deaths have been reported from concentrated acid burns as little as 2.5% of body surface area or areas of 25 square inches or larger.

One of the signs and symptoms of systemic toxicity can include tetany. Tetany is a symptom that involves involuntary muscle contractions and overly stimulated peripheral nerves. It is caused by electrolyte imbalances, most often low blood calcium levels. Symptoms associated with tetany can include:

• numbness

• spasms of the hands and feet (like the spasms we sometimes see in a patient hyperventilating) 

• twitching of facial muscles

Other severe symptoms can include:

• laryngospasms

• seizures, to name a few

Another symptom of system toxicity from HF can include EKG changes due to electrolyte imbalances. Cardiac monitoring is important to assess for clinically significant electrolyte imbalances. EKG changes that may indicate these imbalances can include prolonged ST segments, QT prolongation, and Torsades de Pointes, to name a few. Be aware that not all these symptoms will be present in all cases of profound hypocalcemia following HF exposure.

Treatment in systemic toxicity is focused on replacing the calcium or magnesium stores in the body. Calcium gluconate at 0.2 to 0.3 ml/kg administered as a slow IV is used to address the calcium deficiencies. If Calcium Gluconate is unavailable, Calcium chloride can manage underlying hypocalcemic effects much like in other emergencies involving calcium deficiencies.    

It is important to note the difference between Calcium Gluconate and Calcium Chloride. Do not confuse these medications. Calcium Chloride is three times higher in concentration and requires different dosing! Providers are encouraged to verify what form of calcium they are provided in their drug boxes and medication supplies and what dosing is recommended for each.

As we end this installment of Pharmacy Phriday, we would point out that today (Dec 16th) is National Ugly Sweater Day. So be on the lookout for the ugliest sweater you have ever seen. And if you do not really care much about sweaters, know that today is also National Chocolate Covered Anything Day! So, consider having some chocolate as well!

Till next time, stay safe!

Sincerely,

The UH EMS-I Team

University Hospitals

December 16, 2022

Dear Colleagues,

Welcome back to Pharmacy Phriday.  Over the past few weeks, we have reviewed the use of Calcium Gluconate for Hydrofluoric Acid (HF) exposures.  This week we will look at what is probably a more common use for calcium in the prehospital setting, although still rare, that being in cardiotoxic poisonings.  The majority of UH squads probably are supplied Calcium Chloride for this use rather than the Calcium Gluconate reviewed over the past weeks.  As mentioned in the previous installment, be sure to check your supply!  Each of these medications requires different dosing.

UH protocol indications for the use of calcium include the commonly labeled uses of hypocalcemia (whether due to calcium channel blocker poisoning or other causes) and hypermagnesemia.  The current protocols, as well as the new 2023 protocols, also include calcium’s use or consideration in what is considered off-label yet common uses, which include poisoning or overdose of cardiac drugs such as calcium channel blockers, beta blockers, sodium channel blockers, and potassium channel blockers as well as other causes of hyperkalemia, and the dialysis patient in arrest. 

Calcium is indicated in many of these circumstances as it is an essential mineral and electrolyte that impacts the cardiac action potential and has inotropic properties that increase the force of the myocardium’s contractions.  It can also affect peripheral vascular resistance. 

Treatments for beta blockers and calcium channel blockers are similar, sometimes requiring the “kitchen sink” in correcting electrolyte imbalances and resulting in myocardial depression, bradycardia, and hypotension.  The order of medications will change somewhat, starting with a push dose Epinephrine in the beta blocker protocol and starting with calcium in the calcium channel blocker protocol.  In both cases, calcium may be beneficial due to the inotropic and systemic vascular resistance properties mentioned above.

Dialysis patients are prone to chemical imbalances, and calcium can benefit many of them. Patients who missed dialysis may be hypocalcemic and/or hyperkalemic. Calcium should be administered alongside Albuterol to patients with wide QRS complexes or peaked T waves. For deteriorating patients exhibiting a super wide ECG or sine waves on their EKG (probably indicating a peri-arrest situation), protocols jump to calcium and Sodium Bicarbonate to prevent cardiac arrest. If your dialysis patient is in full arrest, they should also receive the combination of calcium and Sodium Bicarbonate. 

CAUTION:  DO NOT MIX THESE DRUGS!  FLUSH THE IV LINE BEFORE GIVING THE OTHER MEDICATION!!

Calcium solutions should only be administered via the IV or IO route.  Never give Calcium IM.  Tissue necrosis and sloughing are serious complications.  This is also of concern if the IV infiltrates.  It is widely suggested that when administering calcium, the provider uses large veins.  The use of small hand or foot veins is not recommended. Be sure to monitor the IV site closely during administration. If there are signs the medication has infiltrated, the provider should stop immediately and discontinue the IV line.  Do not flush the line anymore. 

When administering calcium, the medication should be given slowly. Avoid rapid boluses, as this can cause arrhythmias. Monitor the patient’s vital signs, with special attention to the ECG and blood pressure.  Signs and symptoms of other adverse reactions to watch for include hot, tingling sensations, nausea, and seizures. 

The usual dosing for Calcium Chloride in the adult patient is 1 Gram given as a slow push over 2 minutes.  The pediatric dosing is 20mg/kg over 10 minutes, to a max dose of 1 Gram.  Once again, confirm the calcium solution provided.  Calcium Chloride is three times as potent compared to Calcium Gluconate and requires different dosing.

Calcium is contraindicated in patients using Lanoxin, Digitek, and other common digoxin medications.

In closing, we want to wish you and your families a safe and happy holiday season!  Thank you again for all you do!

Sincerely,

The UH EMS-I Team

University Hospitals