Comprehensive Nursing Pharmacology Q 170
The client asks the nurse to explain the action of infiltration anesthesia. The nurse’s response is based on the knowledge that infiltration anesthesia:
A. Is applied only to mucous membranes to provide local anesthesia.
B. Blocks a specific group of nerves in tissues close to the operative area.
C. Blocks sensation to an entire limb, or a large area of the face.
D. Produces numbing to large, regional areas such as the lower abdomen and legs.
Correct Answer: B. Blocks a specific group of nerves in tissues close to the operative area.
Infiltration anesthesia blocks a specific group of nerves close to the operative area by diffusion of a drug into the tissues. It is used to anesthetize small areas. Lower concentrations of local anesthetics are typically used for infiltration anesthesia. Infiltration anesthesia is accomplished with the administration of the local anesthetic solution intradermally (ID), subcutaneously (SC), or submucosally across the nerve path that supplies the area of the body that requires anesthesia.
Option A: Topical anesthetics are applied to mucous membranes. Topical anesthetics reversibly block nerve conduction near their site of administration, thereby producing temporary loss of sensation in a limited area. Nerve impulse conduction is blocked by decreasing nerve cell membrane permeability to sodium ions, possibly by competing with calcium-binding sites that control sodium permeability. This change in permeability results in decreased depolarization and an increased excitability threshold that, ultimately, prevents the nerve action potential from forming.
Option C: Nerve blocks provide anesthesia to a large surface area. Peripheral nerve blocks are a type of regional anesthesia. The anesthetic is injected near a specific nerve or bundle of nerves to block sensations of pain from a specific area of the body. Nerve blocks usually last longer than local anesthesia.
Option D: Spinal anesthesia affects large, regional areas. Spinal anesthesia is a neuraxial anesthesia technique in which local anesthetic is placed directly in the intrathecal space (subarachnoid space). The subarachnoid space houses sterile cerebrospinal fluid (CSF), the clear fluid that bathes the brain and spinal cord.