June 9, 2023

Dear colleagues:

Welcome to UH EMS Institute’s Pharmacy Phriday. In the last installment, we reviewed Tetracaine and its use for eye injuries. In this week’s installment, we will review Lidocaine, another medication in the “caine” family that may be known to older providers as an antiarrhythmic but is now considered more as an anesthetic used during IO infusions. Like Tetracaine, Lidocaine works by blocking sodium channels that prevent depolarization of the nerves causing a local anesthesia effect. 

The prevalence of the use of the intraosseous (IO) route for emergency administration of medications continues to grow. Studies can be found that look at its use for trauma patients and unconscious or semi-conscious patients with difficult IV access. Within the UH protocols, an IO is indicated for life-threatening illness or injury in an adult or child where traditional vascular access has failed or is unlikely. Establishing an IO is a quick procedure with typically high success rates.

Pain associated with an IO insertion and infusion in conscious patients is a well-documented reality that must be addressed. This pain can be substantially reduced by the use of Lidocaine through the IO port prior to the infusion. The injection of 2% intravenous Lidocaine into the IO needle for relief of injection pain has become a standard practice and is approved within the UH protocols for the paramedic and advanced EMT provider.

The dosage for Lidocaine for this use with an IO is 20-40 mg (1-2 ml as provided in the 2% solution), with a slow push to allow it to work. In the pediatric patient, the dosing is 0.5 mg/kg, up to a maximum pf 40 mg, again as a slow push. Lidocaine has a rapid onset, but protocols and other resources suggest allowing the medication to dwell shortly to allow it to take effect before flushing, some suggesting up to two minutes.  

As a sodium channel blocker that affects the depolarization in the cardiac action potential, Lidocaine can also be used as an antiarrhythmic. The medication will suppress the heart’s ventricles irritability and raise the fibrillation threshold in cases of pulseless V-Fib/V-Tach as well as wide complex tachycardias with a pulse. Lidocaine should only be used in these instances when amiodarone is not available or if its use is contraindicated. One of those contraindications to the use of amiodarone mentioned in our UH protocols is in the pregnant patient. 

When using Lidocaine for cardiac dysrhythmias in the adult patient, the dose is 1.0-1.5 mg/kg, IV/IO, followed by a half dose of 0.5-0.75 mg/kg every 5-10 minutes to a max dose of 3 mg/kg. Half dosing is recommended for patients over 70 years of age, those with liver disease, or those suffering from heart failure. 

When using Lidocaine for dysrhythmias in the pediatric patient, the dosing is 1.0 mg/kg, followed by 0.5 mg/kg in 5-10 minutes to a max dose of 3 mg//kg. Per UH protocols, if the pediatric patient converts to a non-bradycardic rhythm, a maintenance dose is given by bolus at 0.5 mg/kg IV/IO every 10 minutes up to two times.

As with many other antiarrhythmics, Lidocaine is contraindicated in cases of bradycardia, AV blocks, idioventricular escape rhythms, or in cases of shock or hypotension. Side effects with the use of Lidocaine include many of these contraindications, as well as effects of its anesthetic effect that could include nausea and vomiting, dizziness, slurred speech, drowsiness, confusion, respiratory depression, or seizures. 

Till the next installment, stay safe!

Sincerely,



The UH EMS-I Team

University Hospitals

October 18, 2024

Welcome to UH EMS Institute’s Pharmacy Phriday. In a recent installment, we discussed the use of Lidocaine to address pain associated with an intraosseous (IO) infusion. In this week’s installment, we will quickly review Lidocaine’s use with an IO and in various cardiac cases.  

Pain associated with an IO insertion and infusion in conscious patients is a well-documented reality that must be addressed. This pain can be substantially reduced by the use of Lidocaine through the IO port before the infusion. Lidocaine works by blocking sodium channels that prevent depolarization of the nerves, causing a local anesthesia effect. 

The dosage of Lidocaine for use with an IO is 20-40 mg (1-2 ml as provided in the 2% solution), with a slow push to allow it to work. In pediatric patients, the dose is 0.5 mg/kg, up to a maximum of 40 mg, and again, it is a slow push. Lidocaine has a rapid onset, but protocols and other resources suggest allowing the medication to dwell shortly to enable it to take effect before flushing (some suggesting up to two minutes). Within the UH Protocols, this use of Lidocaine is approved for use by the AEMT as well as the Paramedic. 

As a sodium channel blocker, Lidocaine can also affect the depolarization of the myocardium in the cardiac action potential cycle, making it useful as an antiarrhythmic. The medication will suppress the ventricles’ irritability and raise the fibrillation threshold in cases of pulseless V-Fib/V-Tach as well as wide complex tachycardia with a pulse. Amiodarone is the preferred medication for these cases, but Lidocaine can be used when:  

• Amiodarone is not available 

• Amiodarone is contraindicated (such as in the pregnant patient) 

• V-Fib/V-Tach is refractory or recurrent after exhausting the V-Fib/Pulseless V-Tach algorithm  

When using Lidocaine for cardiac dysrhythmias in adult patients, the dose is 1.0-1.5 mg/kg, IV/IO, followed by a half dose of 0.5-0.75 mg/kg, every 5-10 minutes as needed to a max dose of 3 mg/kg. Half-dosing is recommended for patients: 

• Over 70 years of age 

• With liver disease 

• Suffering from heart failure 

When using Lidocaine for dysrhythmias in pediatric patients, the dosing is 1.0 mg/kg, followed by 0.5 mg/kg in 5-10 minutes as needed, to a max dose of 3 mg/kg. Per UH protocols, if the pediatric patient converts to a non-bradycardic rhythm, a maintenance dose is given by bolus at 0.5 mg/kg IV/IO, every 10 minutes up to two times. 

As with many other antiarrhythmics, Lidocaine is contraindicated in cases of: 

• AV Blocks  

• Bradycardia 

• Idioventricular escape rhythms 

• Cases of shock or hypotension 

Side effects with the use of Lidocaine include many of the above contraindications, as well as anesthetic effects that could include nausea and vomiting, dizziness, slurred speech, drowsiness, confusion, respiratory depression, or seizures. 

October is Sudden Cardiac Arrest (SCA) Awareness Month and it is observed to increase public awareness of the signs and symptoms of SCA, promote early recognition of SCA, and encourage immediate action. In observance of this occasion, we will continue a review of our cardiac arrest medications through the rest of the month. We encourage you to review the various algorithms related to SCA and promote CPR training within your communities.  

Till our next installment stay safe!

Sincerely, 

The UH EMS-I Team 

University Hospitals