Which statement is true regarding an overdose of local anesthesia?

The statement "Most overdoses occur when using no vasoconstrictor" is true regarding an overdose of local anesthesia. When vasoconstrictors, such as epinephrine, are added to local anesthetic solutions, they help to constrict blood vessels. This results in a reduced systemic absorption of the anesthetic agent into the bloodstream, which can significantly lower the risk of overdose. Without a vasoconstrictor, the local anesthetic can be absorbed more rapidly, increasing the likelihood of reaching toxic levels, especially if injected in high doses or multiple sites.

In terms of other choices, while using a smaller gauge needle is often advisable for various clinical reasons, it doesn't inherently limit the rate of injection compared to larger gauge needles. The speed of injection should be controlled by the clinician’s technique rather than solely the gauge of the needle.

Regarding the timing of injection, while it's beneficial to inject slowly to mitigate discomfort and allow the anesthetic to work effectively, the specific time frame of 30 seconds for a carpule isn't a universal standard applicable to all situations.

Elderly patients are indeed at higher risk for complications due to various factors, including anatomical changes and comorbidities, but most overdoses are chiefly linked to