Knee block anesthesia for arthroscopic procedures

AORN Journal,  July, 2005  by Connie Archer Sargent,  M. Tim Dunfee

• E-mail
• Print
• Link

Joint space injections require local anesthetics containing epinephrine to provide local vasoconstriction, which minimizes any vision-obscuring bleeding, so the arthroscopic procedure can be accomplished without the aid of a tourniquet. If the epinephrine does not control bleeding adequately, use of a tourniquet may be necessary. Most patients can only tolerate the use of a tourniquet for a short period of time, however, so conversion to a general anesthetic in this instance is likely, although this situation is rare. It is common for blood to ooze at the skin injection sites when local anesthetics that do not contain epinephrine are used. Local anesthetics containing epinephrine should be avoided for the subcutaneous injection, however, because of the potential for skin erythema, bullae, and necrosis. Using an adequate quantity of local anesthetic and taking care to infiltrate widely into the pain-sensitive skin and joint capsule makes the knee block a highly successful form of anesthesia.

Block administration commonly takes eight to 10 minutes, after which the anesthesia care provider or nurse flexes and extends the patient's knee several times to help distribute the medicine throughout the knee joint. By this time, the sedating medications usually are significantly dissipated, and the patient is alert and oriented and able to lift his or her own leg. The nurse covers the patient's knee with a sterile towel to collect potential drainage. The nurse continues to monitor and document the patient's vital signs and does not leave the patient's side until the effects of the IV medications have resolved and the patient is alert. This may take only a few minutes. Some patients talk while undergoing knee block anesthesia, others sleep during the procedure. Often, patients ask if the procedure has been started as they awake from the sedatives at the end of the procedure. The patient then rests under observation until he or she is transported by stretcher to the OR.

SURGICAL PROCEDURE

The circulating nurse and anesthesia care provider help the patient move from the stretcher onto the OR bed. The circulating nurse and all surgical team members participate in the surgical time out after which the surgeon or circulating nurse applies a tourniquet in the event that it will be needed. They then place the patient's leg into an orthopedic leg holder attached to the bed. The circulating nurse preps the patient's leg, and then the scrub person and surgeon drape the surgical area. Before starting the arthroscopy, the surgeon tests the cannula sites with a needle to see if the areas are numb or if additional local anesthetic is needed. Lidocaine without epinephrine is injected at this time if needed. If poor visibility is encountered due to bleeding in the joint, some surgeons instill lidocaine with epinephrine through the cannula. If this is done, the surgeon will wait a short time before proceeding. Only if this action fails to provide better visibility will the tourniquet be inflated.