Femoral Peri-arterial Local Anesthetic Injection Via Peri-arterial Perineural Catheter Reverses Tourniquet Associated Ischemic Hypertension

This is a research study to find out if injection of numbing medication by the large artery going down your leg will improve high blood pressure caused by the tourniquet.

Depending on whether you enroll in this study, you may receive an injection of local anesthetic (numbing medication) or saline (salt water) by your femoral artery (the large artery going down your leg). This is to see how this injection impacts your blood pressure during surgery as the surgeons use a tourniquet (device that squeezes your leg) to help decrease the bleeding during surgery. Oftentimes the tourniquet causes your blood pressure to go up, but the numbing medication may help return your blood pressure close to its normal level. The rest of your anesthesia care, including other nerve blocks and general anesthetic, will be the same as it would be without participating in the study. You will be enrolled in this study for 24 hours.

Inclusion criteria

Patients that will be included in the study are English speaking 18-75 year old ASA 1-3 patients undergoing total ankle arthroplasty.

Exclusion criteria

• ASA 4 or 5
• Diagnosis of chronic pain
• Daily chronic opioid use (over 3 months of continuous opioid use).
• Inability to communicate pain scores or need for analgesia.
• Infection at the site of block placement
• Age under 18 years old or greater than 75 years old
• Pregnant women (as determined by standard of care day-of surgery urine bHCG)
• Intolerance/allergy to local anesthetics
• Weight <50 kg
• Suspected, or known addiction to or abuse of illicit drug(s), prescription medicine(s), or alcohol within the past 2 years.
• Uncontrolled anxiety, schizophrenia, or other psychiatric disorder that, in the opinion of the investigator, may interfere with study assessments or compliance.
• Current or historical evidence of any clinically significant disease or condition that, in the opinion of the investigator, may increase the risk of surgery or complicate the subject's postoperative course