Refractory cardiac arrest is most likely after the rapid unintentional IV injection of which of the following local anesthetics?

Refractory cardiac arrest is most likely after the rapid unintentional IV injection of which of the following local anesthetics?

• A. Lidocaine
• B. Bupivacaine
• C. Ropivacaine
• D. Levobupivacaine

Answer: (B)

Refractory cardiac arrest from a local anesthetic most often points to systemic local anesthetic toxicity (LAST) after inadvertent intravascular administration. The heart is particularly vulnerable to sodium channel blockade, which slows or blocks impulse conduction and can lead to dangerous arrhythmias and arrest. Among these agents, bupivacaine stands out because it is extremely potent and highly lipid-soluble, with a strong affinity for cardiac voltage-gated sodium channels and a slow dissociation from them. This means that once it enters the circulation rapidly, it can produce profound myocardial depression and life-threatening arrhythmias that are difficult to reverse, even with standard resuscitation maneuvers. The other agents listed—lidocaine, ropivacaine, and levobupivacaine—have lower cardiotoxic potential, so they are less likely to cause this rapid, severe cardiac arrest in the same scenario.

Refractory cardiac arrest from a local anesthetic most often points to systemic local anesthetic toxicity (LAST) after inadvertent intravascular administration. The heart is particularly vulnerable to sodium channel blockade, which slows or blocks impulse conduction and can lead to dangerous arrhythmias and arrest. Among these agents, bupivacaine stands out because it is extremely potent and highly lipid-soluble, with a strong affinity for cardiac voltage-gated sodium channels and a slow dissociation from them. This means that once it enters the circulation rapidly, it can produce profound myocardial depression and life-threatening arrhythmias that are difficult to reverse, even with standard resuscitation maneuvers. The other agents listed—lidocaine, ropivacaine, and levobupivacaine—have lower cardiotoxic potential, so they are less likely to cause this rapid, severe cardiac arrest in the same scenario.