Optimizing Anesthesia Protocols for ASC Total Knee Arthroplasty

As hospital-based total knee arthroplasty (TKA) continues to transition into ambulatory surgery centers (ASCs), anesthesia teams face new challenges. Outpatient TKA demands a balance between hospital-grade analgesia and rapid recovery suitable for same-day discharge. Establishing a streamlined and evidence-based anesthesia protocol is essential to meet patient expectations, enhance outcomes, and maintain ASC efficiency. This guide outlines the key components required to build a comprehensive protocol from the ground up.

Patient Selection Criteria
Proper patient selection is the foundation of a successful outpatient TKA program. Candidates should generally fall within the following parameters:

• ASA classification I to III with stable comorbidities
• Body Mass Index less than or equal to 40
• Hemoglobin A1c under 7.5 percent
• Confirmed home support with a caregiver for at least 24 hours post-discharge
• Mild to moderate obstructive sleep apnea with compliance to CPAP therapy

Early coordination with the surgical team, ideally two weeks in advance, reduces the risk of cancellations on the day of surgery.

Anesthesia Timeline and Protocol
For an efficient and replicable workflow, each case should follow a structured timeline with clearly assigned tasks for anesthesia providers. The following outline is based on a typical single-case format in a two-room ASC:

• Ninety minutes prior to procedure: Patient arrives. CRNA obtains consent, establishes IV access, and administers 1 gram of oral acetaminophen.
• Sixty minutes prior: Ultrasound-guided adductor canal and IPACK blocks are performed using a total of 30 milliliters of local anesthetic.
• Thirty minutes prior: Preoperative nurse administers 200 milligrams of celecoxib and applies a scopolamine patch.
• At wheels-in: Spinal anesthesia is initiated using 2.5 milliliters of 0.5 percent bupivacaine. Dexamethasone 10 milligrams IV is given concurrently.
• Seventy-five minutes into the case: Following cement application, administer 1 gram of tranexamic acid (TXA) IV over 10 minutes.
• At skin closure: Discontinue propofol infusion and administer 4 milligrams of ondansetron IV.
• Fifteen minutes later: Patient is transferred to PACU. Begin IV ketorolac 15 milligrams.
• Approximately two hours postoperatively: Assess for ambulation readiness and provide support for standing.
• At three and a half hours post-op: Patient may be discharged if Aldrete score is at least nine, pain is controlled under four out of ten, and they have voided.

Multimodal Strategies for Blood Loss, Nausea, and Urinary Retention
Effective anesthesia protocols must proactively address common complications.

• To reduce blood loss, administer 1 gram of TXA prior to skin incision and a second dose three hours postoperatively.
• For postoperative nausea and vomiting, a combination of dexamethasone, ondansetron, and scopolamine significantly lowers incidence.
• To minimize urinary retention, use no more than 2.6 milliliters of bupivacaine for spinal anesthesia and remove Foley catheters intraoperatively.

Postoperative Pain Management Plan
Discharge instructions should include a clearly defined, staggered multimodal regimen:

• Acetaminophen 1 gram every six hours around the clock for 48 hours
• Ibuprofen 600 milligrams every six hours, staggered with acetaminophen
• Oxycodone 5 milligrams every six hours as needed, limited to 20 tablets
• Ice application and leg elevation every two hours

Programs that implement this regimen commonly see an average use of 6 to 8 opioid tablets in the first three postoperative days.

Contingency Planning for Extended Stay
Not all patients will meet same-day discharge criteria. A structured escalation plan should be in place for:

• Uncontrolled pain exceeding 6 out of 10 after two opioid doses
• Severe nausea unrelieved by antiemetics
• Inability to ambulate at least 10 feet
• Oxygen saturation below 92 percent on room air after 30 minutes

Ensure a hospital transfer agreement is established for these scenarios.

Key Performance Indicators for Outpatient TKA Success
Maintaining high performance and patient safety requires continuous tracking of metrics:

• Same-day discharge rate target of 95 percent or greater
• Thirty-day emergency department visit rate under 5 percent
• Thirty-day readmission rate below 2 percent
• Post-anesthesia care unit length of stay under 120 minutes
• Average opioid use of fewer than 10 tablets from postoperative day zero to day three

Weekly team huddles involving anesthesia, nursing, physical therapy, and surgeons help identify improvement opportunities.

Conclusion
A well-designed anesthesia pathway, from preoperative block to discharge criteria, enables ASCs to deliver safe, efficient, and patient-centered total knee arthroplasty. Dedicated CRNA teams play a vital role in maintaining protocol consistency and enabling rapid recovery, while surgeons remain focused on procedural outcomes.

For centers seeking to launch or expand an outpatient joint replacement program, Advanced Anesthesia Services provides the experienced CRNAs, ultrasound-guided block support, and performance tracking tools required for a seamless and scalable solution.