Final answer:
Bupivacaine injected into the epidural vein can cause systemic toxicity, with effects on the central nervous system and cardiovascular system such as convulsions and cardiac arrest. It is important to prevent this by using a test dose to detect unintended intravascular injection.
Step-by-step explanation:
Injection of bupivacaine into the epidural vein is a matter of significant concern in the medical field because bupivacaine is intended for epidural space administration, not for intravenous use. If bupivacaine mistakenly enters the bloodstream, especially in a large quantity, it can lead to systemic toxicity. Symptoms of bupivacaine toxicity may include central nervous system effects such as drowsiness, confusion, convulsions, respiratory depression, and even cardiovascular effects like hypotension, arrhythmias, or cardiac arrest. To prevent such events, it is common practice to administer a test dose with a drug such as epinephrine included to detect unintentional intravascular injection before administering the full dose of bupivacaine.