The Impact of a Preoperative Nerve Block in Foot and Ankle Surgery on the Consumption of Sevoflurane

• Status: Recruiting
• Trial end date: 2021-08-01
• Target enrollment: 0
• Participant gender: All

Summary

Reconstructive foot and ankle surgery is performed under general anesthesia. Included in this spectrum of surgery are ankle arthroplasties, various fusions, corrective arthrodesis, and more. Pain control for after the surgery can be achieved purely with intravenous and oral pain medication or in combination with freezing of the nerves. Nerve freezing (nerve block) placed before surgery has the potential to substantially reduce the amount of inhaled anesthetic given to the patient during surgery. This can benefit the patient with being more awake and crisp more quickly after surgery. It can also reduce cost to the system. A further benefit which has received very little attention so far, is that reducing the amount of inhaled anesthetic given also lowers the environmental footprint created by the anesthetic. For the region of the foot and ankle to be fully frozen, both the sciatic nerve and the saphenous nerve must be successfully blocked. Sciatic nerve blockade is most commonly achieved by blocking the nerve in the popliteal fossa. This block is named popliteal nerve block.

The investigators will examine and quantify the amount of inhaled anesthetic used for each case and will compare how the consumption is affected by whether the nerve blocks are applied before or after surgery. Patients will have two nerve block catheters (popliteal and saphenous catheter) placed under ultrasound-guidance prior to the case by an experienced and specifically trained anesthesiologist. The catheters will be loaded with a solution to which the anesthesiologist is blinded. It will either be local anesthetic or 5% dextrose (sham). The general anesthetic will be conducted according to a research protocol with anesthetic depth being the targeted endpoint. Measurements of the required MAC-Value (minimum alveolar concentration) of inhaled anesthetic will be recorded every five minutes by a study team member. At the end of the case the anesthesiologist will be unblinded to the solution. Should the patient have received sham initially, they will now receive the full dose of local anesthetic prior to being woken up.

• Phase: Phase 2/Phase 3
• Accepts Healthy Volunteers?: Accepts Healthy Volunteers

Details

• Lead Sponsor: University of Alberta
• Treatments: Ropivacaine; Sevoflurane

Criteria

Inclusion Criteria:

• Patients undergoing elective reconstructive foot and ankle surgery

• Patients eligible for popliteal and saphenous nerve block

• All adults 18 years of age or older

• Capable to give consent

Exclusion Criteria:

• Patients who are unable to give consent

• Local anaesthetic allergy

• Hemidiaphragm paresis on the contralateral side to the block/surgery site

• Bleeding diathesis

• Coagulopathy

• Pre-existing neurological deficits

• Patients with a Body Mass Index >35

• Patients with significant comorbidities, physiological limitations, and allergies that are unable to tolerate the protocolized induction and maintenance of anesthesia.