February FY24

[A Schutter]

For this month's Journal Club Dahlia Rouchon, CRNA submitted an article titled "Local Anesthetic Pharmacology and Toxicity What Clinicians Need to Know Now." 

Here is a link to the article.

The two questions for discussion are:

1. Why should LA dosing be decreased in the elderly?

2. Why is the risk of cardiac toxicity with bupivicaine overdosage more dangerous when not under GA regarding prodromal signs?

[Sarah Jazzar]

1) Decreased hepatic function and decreased muscle mass (less LA reservoir)
2) Neurologic symptoms of LAST are not present when under GA

[Jessica Hadley]

1. Elderly patients have decreased hepatic function and a decreased muscle mass which leads to a higher plasma concentration following administration.

2. Due to the properties of Bupivacaine, cardiac toxicity can precede CNS symptoms and cause cardiac collapse.

[Wai-Ling Lo]

1. Why should LA dosing be decreased in the elderly?
Elderly patients will often have decreased hepatic function and muscle mass (less reservoir for LA after absorption from the site of injection). Thus, the same injected dose will produce greater peak plasma concentrations in the elderly than in younger patients.

2. Why is the risk of cardiac toxicity with bupivicaine overdosage more dangerous when not under GA regarding prodromal signs?
In experimental studies bupivacaine appears to sensitize the heart to epinephrine-induced arrhythmias. Therefore, patients with bupivacaine overdosage may experience cardiac toxicity without preceding CNS toxicity.

[Jackie Howell]

1. As others have stated, decreased hepatic function and muscle mass.
2. Bupivacaine overdose typically experience CV symptoms or CV collapse before CNS toxicity symptoms.

[kels]

1. Why should LA dosing be decreased in the elderly?
LA dosing should be decreased in the elderly because this population tends to have both decreased hepatic function and muscle mass.

2. Why is the risk of cardiac toxicity with bupivicaine overdosage more dangerous when not under GA regarding prodromal signs?
With overdose of bupivacaine the CV symptoms/collapse tend to precede CNS toxicity symptoms

Neurologic symptoms of LAST are not present when under GA

[Tracey Trainum]

1. Decreased dosing of local anesthetic is necessary in the elderly due to decreased hepatic function/metabolism and decreased muscle mass. A decrease in muscle mass means the local anesthetic will accumulate more (reservoir effect) and the same injected dose will produce greater peak plasma concentrations.

2. With bupivacaine toxicity many patients experience cardiac toxicity without preceding symptoms of CNS toxicity, this is dangerous because there are no "prodromal" symptoms for the patient to report if they are not under GA. CNS symptoms will not be present in a patient under GA.

[aileenm4]

1. elderly patients have both decreased hepatic function and decreased muscle mass (resevior for LA) which leads to greater peak plasma concentration after injection
2. the initial s/s of LA toxic level like tinnitus, metallic taste, feeling of doom and altered LOC are masked under GA

[Amy Swank]

1. Why should LA dosing be decreased in the elderly?
Due to decreased hepatic function and muscle mass with the elderly. This results in greater peak plasma concentrations versus younger patients.


2. Why is the risk of cardiac toxicity with bupivacaine over dosage more dangerous when not under GA regarding prodromal signs?

 Bupivacaine toxicity may cause cardiac toxicity (and cardiovascular collapse), without patients' ability to relay symptoms of CNS toxicity ( such as the feelings of doom, tinnitus, altered LOC). 

[Belinda Gardner]

Good review! Thank you.
1. Increased free plasma concentrations of local anesthetics- elderly patients will often
have decreased hepatic function, decreased muscle mass, which usually
acts as a reservoir for LA after absorption from the
site of injection and will produce greater peak plasma concentrations in the
elderly than in younger, more fit patients.

2.There may not be any prodromoal symptoms with Bupi.