Blood Levels of Local Anaesthetic in Knee Arthroplasty

Completed

• Conditions: Arthritis of Knee
• Interventions: Drug: Ropivacaine

• Registration Number: NCT01873313
• Lead Sponsor: Golden Jubilee National Hospital

Brief Summary

The primary goal is to evaluate ropivacaine blood concentrations during and after local anaesthetic (ropivacaine) infiltration - the Caledonian technique - for total knee replacement surgery. The investigators plan to measure these levels by testing blood samples taken over a timed period.

This will allow us to confirm whether the current regimen of local anaesthetic use is within safe limits.

Detailed Description

Local anaesthetic (LA) toxicity may occur when the blood levels of a drug become particularly high. There is a need to confirm that the technique is safe to use. In addition, journal case reports may only describe serious side-effects of toxicity such as abnormal heart rhythms whilst more subtle clinical signs are rarely reported.

The investigators would like to study whether or not toxic levels may be approached in some patients or whether more subtle toxicity symptoms and signs are missed. For example, irregular heartbeat, low blood pressure or confusion/agitation.

Therefore, the investigators intend to study ropivacaine blood levels in patients receiving a total knee replacement in the Golden Jubilee National Hospital. A series of timed samples will be taken during the perioperative period. The anaesthesia and surgery will be performed as routine and no new treatment will be involved. Patient demographics, ropivacaine blood levels and clinical observations following LA administration will be collected.

Study Timeline

• Study Start: 2012-08
• Primary Completion: 2013-01
• Study Completion: 2013-01
• Status Verified: 2013-06
• Study First Submitted: 2013-06-06
• Study First Submitted QC: 2013-06-06
• Study First Posted: 2013-06-10
• Last Update Submitted: 2013-06-10
• Last Update Posted: 2013-06-11

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Male or female patients greater than 65 years of age

Exclusion Criteria

• Patients with a known sensitivity/allergy to ropivacaine or amide-type local anaesthetics
• Patients who are not suitable for the Caledonian technique
• Patients who refuse or are unable to give consent
• Patients undergoing bilateral hip replacements
• Patients with known heart, liver or kidney failure

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Arm && Interventions

Group	Intervention	Description
Ropivacaine	Ropivacaine	Injection of local anaesthetic (ropivacaine) into the knee joint following knee arthroplasty. Total dose 200mls of 0.2% ropivacaine or 400mg at the time of surgery plus up to 5 top-up boluses (40mls of 0.2% ropivacaine or 80mg) postoperatively.

Primary Outcome Measures

Name	Time	Method
Plasma levels of ropivacaine	First 24 hours after surgery	Plasma levels of ropivacaine were analysed to determine total and free levels

Secondary Outcome Measures

Name	Time	Method
Evidence of dysrrhythmias as measured by 24-hour Holter monitoring	First 24 hours after surgery	24-hour Holter monitoring was conducted to detect any potential sequelae of local anaesthetic toxicity
Clinical observations	First 24 hours after surgery	Clinical observations, including potential symptoms and signs of local anaesthetic toxicity, were recorded at the same time as blood sampling

Trial Locations

Locations (1)

Golden Jubilee National Hospital; 🇬🇧 Clydebank, West Dunbartonshire, United Kingdom