Blood Levels of Local Anaesthetic in Knee Arthroplasty (BLOCKS)

Blood Levels of Local Anaesthetic in Knee Arthroplasty: A Pharmacological Study of Ropivacaine Blood Levels During the Caledonian Technique for Knee Arthroplasty

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.

Study Overview

• Status: Completed
• Conditions: Arthritis of Knee
• Intervention / Treatment: Drug: Ropivacaine

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 Type: Observational
• Enrollment (Actual): 20

Contacts and Locations

Study Locations

• United Kingdom
  • West Dunbartonshire
    • Clydebank, West Dunbartonshire, United Kingdom, G81 4dy
      • Golden Jubilee National Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 65 years and older (Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Patients undergoing elective knee joint replacement where they will be receiving the Caledonian technique

Description

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 Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
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.	Drug: Ropivacaine; Other Names: Naropin

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Plasma levels of ropivacaine	Plasma levels of ropivacaine were analysed to determine total and free levels	First 24 hours after surgery

Secondary Outcome Measures

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

Collaborators and Investigators

• Sponsor: Golden Jubilee National Hospital
• Collaborators: University of Strathclyde; B. Braun Medical Inc.
• Investigators: Principal Investigator: Michael Gill, MBChB, NHS Research Scotland

Study record dates

Study Major Dates

• Study Start: August 1, 2012
• Primary Completion (Actual): January 1, 2013
• Study Completion (Actual): January 1, 2013

Study Registration Dates

• First Submitted: June 6, 2013
• First Submitted That Met QC Criteria: June 6, 2013
• First Posted (Estimate): June 10, 2013

Study Record Updates

• Last Update Posted (Estimate): June 11, 2013
• Last Update Submitted That Met QC Criteria: June 10, 2013
• Last Verified: June 1, 2013

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Joint Diseases; Musculoskeletal Diseases; Arthritis; Physiological Effects of Drugs; Central Nervous System Depressants; Peripheral Nervous System Agents; Sensory System Agents; Anesthetics; Anesthetics, Local; Ropivacaine
• Other Study ID Numbers: 12/ANAES/01