June 23, 2023

Dear colleagues:

Welcome to this edition of Pharmacy Phriday.  In the last edition, we reviewed the use of ASA and closed with a brief discussion of possible ASA overdoses.  Such overdoses are not an uncommon occurrence, be it accidental or intentional. 

Aspirin or salicylate toxicity is a common cause of poisoning in children and adolescents. These products are readily found in the home in over-the-counter medications and products that include ASA, wintergreen, Pepto-Bismol, Alka-Seltzer, Ben Gay, and other herbal oils and supplements, just to name a few.   Data from poison control centers indicate that 1 of 4 medication-related deaths are related to ASA alone or in combination with other medications.  Prompt diagnoses and action are necessary for favorable outcomes in these cases.  A delay in diagnosis can increase mortality by 15-25%. Treatment with Sodium Bicarb is a critical part of a successful outcome for these patients.  In the 2023 UH EMS Protocols (uhems.org/protocols), the “Toxic Ingestion/Exposure/Overdose” protocols were expanded to address such cases. 

To many of our “older or experienced” providers, Sodium Bicarb was a drug used late in cardiac arrests when considering the “H’s & T’s” of ACLS.  Over time, the use of the medication was focused on patients who were more likely to be acidotic, such as adult patients on dialysis and patients with specific EKG abnormalities like a sine wave.  Even more recent considerations for the use of Sodium Bicarb within EMS protocols now include toxic exposures or overdoses in the adult or pediatric patients with evidence of a tricyclic antidepressant or sodium channel blocker overdose. These uses remain in the protocols and are, in fact, used more frequently than one might think.

Sodium Bicarbonate is given for various reasons in various conditions.  As an alkalinizer, it is used in cases of metabolic acidosis to correct the body’s pH.  In the case of toxicity with sodium channel blockers and Tricyclate Antidepressants (TCA), Sodium Bicarb is given to increase extracellular sodium in addition to alkalization of the body’s pH.  In cases of ASA or salicylate toxicity Sodium Bicarb is administered for the alkalization effect that prevents the toxin from crossing the blood-brain barrier and increases clearance of the toxin through the urinary system. 

Dosing for Sodium Bicarbonate is 1 mEq/kg IV/IO, regardless of the patient’s age or the condition being treated. Adults have a maximum dose of 200 mEq, and pediatric patients have a maximum dose of 50 mEq. Remember to flush IV lines prior to and following administration, as Sodium Bicarb may cause a precipitate to form with some other medications.

One additional note regarding the administration of Sodium Bicarb in the setting of calcium channel blockers or TCA toxicity is worth mentioning.  In such cases, a classic sign of the toxicity is a widened QRS (>120ms or 3 small boxes) and a tall terminal R wave in the aVR lead.  IV sodium bicarbonate is indicated with such presentation of hemodynamic and ECG abnormalities due to the very high risk of an adverse outcome without aggressive treatment.  In these cases, the medication is titrated and administered as a slow IV push until the QRS narrows. 

In these emergencies, Sodium Bicarb is a crucial part of the treatment for a successful outcome, but many other considerations, medications, and concerns must be included in the treatment plan.  Online medical direction is often beneficial in such complicated cases.  To complete a more in-depth review of some of these emergencies, visit the UH Prehospital Paradigm Podcast on cardiotoxins HERE or ask your EMS coordinator to review the UH CE presentation on toxicology presented in March of 2022.

Till the next time, stay safe!

Sincerely,

The UH EMS-I Team

University Hospitals

September 19, 2022

Dear Colleagues,

One of the important ways the body can remain healthy is by keeping things in balance. Homeostasis is the process of maintaining tight parameters for essential elements like water and vital systems such as blood pressure. Acid-base balance is no different. Hydrogen ions (acids) in the body are in constant struggle with bicarbonates (alkali) in an effort to maintain a steady pH. In fact, pH stands for “potential of hydrogen.” 

The pH of the body should stay between 7.35 and 7.45, and there are three mechanisms to ensure this happens. The first is the buffer system. Bicarbonate and carbonic acid patrol the bloodstream and tweak the pH when it starts to go astray. If the buffer system cannot keep it in check, the respiratory system takes over. We can see the results of breathing on pH when a patient with a slow respiratory rate due to an opioid overdose builds up carbon dioxide (respiratory acidosis) or a person hyperventilating blows off too much (respiratory alkalosis). Capnography is a great tool to monitor this. Finally, the renal system can adjust the pH by dumping or sparing various ions. When this system falls short (kidney failure), it doesn’t take much for the patient to become very ill (metabolic acidosis/alkalosis).

Sodium bicarbonate has been in EMS protocols for quite some time. Early on, it was used in cardiac arrests to counter the effect of respiratory acidosis due to the patient not breathing. The thinking was that there would be a better chance to resuscitate a patient if their pH was within normal parameters. Unfortunately, we don’t really know what the pH is until labs are run.

Recently, sodium bicarb has been targeted to specific patients who are more likely to be acidotic. Those include adult patients on dialysis who have specific EKG abnormalities like a sine wave or those in cardiac arrest. It also is warranted in adult or pediatric patients with evidence of a tricyclic or sodium channel blocker overdose. In this example, it’s the sodium in the sodium bicarbonate that is effective.

Dosing for sodium bicarbonate is set at 1 meq/kg IV/IO regardless of patient age or which protocol. Adults have a maximum dose of 200 meq for cardiac arrest and titrated to effect for overdoses. Pediatric patients max out at 50 meq. Remember to flush lines prior to and following administration because bicarb and other medications that may be given, like calcium, do not play nicely together. 

Sincerely,

The UH EMS-I Team

University Hospitals