All are used for local infiltration except –
**Core Concept**
Lidocaine and bupivacaine are two common local anesthetics used for regional anesthesia, including local infiltration. Local infiltration involves injecting an anesthetic agent into the tissue surrounding a surgical site to prevent pain during the procedure.
**Why the Correct Answer is Right**
Local anesthetics work by blocking the sodium channels on the neuronal membrane, which prevents the depolarization of the nerve and thus the transmission of pain signals. Lidocaine and bupivacaine are both amide-type local anesthetics that act on the sodium channels to produce their effects. They are commonly used for local infiltration, as well as other forms of regional anesthesia such as epidural and spinal anesthesia.
**Why Each Wrong Option is Incorrect**
**Option A:**
This option is incorrect because the term "epinephrine" is actually used as a vasoconstrictor in local anesthesia, not as an anesthetic itself. It is often added to local anesthetics to prolong their duration of action and reduce systemic toxicity.
**Option B:**
This option is incorrect because epinephrine is indeed used in local anesthesia, particularly when combined with local anesthetics like lidocaine and bupivacaine. It helps to prolong the duration of action of the anesthetic by reducing blood flow to the area.
**Option C:**
This option is incorrect because adrenaline (epinephrine) is indeed used in local anesthesia, particularly when combined with local anesthetics like lidocaine and bupivacaine. It helps to prolong the duration of action of the anesthetic by reducing blood flow to the area.
**Clinical Pearl / High-Yield Fact**
When choosing a local anesthetic for infiltration anesthesia, the clinician should consider the duration of the procedure, the site of the procedure, and the patient's medical history. For example, lidocaine may be preferred for shorter procedures, while bupivacaine may be preferred for longer procedures.
**Correct Answer: D.**