Why must you maintain firm pressure over the injection site during and for the first 1-2 minutes after an ASA nerve block?

• A. To encourage diffusion of the anesthetic into the infraorbital foramen
• B. To stop bleeding
• C. To reduce patient discomfort
• D. To prevent infection

Answer: (A)

Maintaining firm pressure at the injection site helps keep the local anesthetic close to the infraorbital nerve as it exits the infraorbital foramen, promoting diffusion of the drug into the infraorbital canal where the nerve fibers are located. This targeted diffusion is what makes the ASA (infraorbital) block reliable, since the anesthetic needs to bathe the nerve within the canal to achieve a good onset and duration. By applying pressure, you limit the drug’s spread into surrounding soft tissues and back along the injection tract, helping it stay where it can affect the nerve most effectively. The 1–2 minute period gives enough time for this diffusion to occur and for the block to establish. While pressure can have minor effects on bleeding and comfort, the primary purpose is to optimize diffusion into the nerve pathway, not to control bleeding, prevent infection, or directly reduce discomfort.