Blood Levels of Local Anaesthetic in Knee Arthroplasty Using a Continuous Infusion Device

• Conditions: Osteoarthritis, Knee
• Interventions: Drug: Ropivacaine

• Registration Number: NCT01935648
• 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 hip 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 First Submitted: 2013-07-29
• Status Verified: 2013-09
• Study Start: 2013-09
• Study First Submitted QC: 2013-09-02
• Last Update Submitted: 2013-09-02
• Study First Posted: 2013-09-05
• Last Update Posted: 2013-09-05
• Primary Completion: 2014-01
• Study Completion: 2014-01

Recruitment & Eligibility

• Status: UNKNOWN
• Sex: All
• Target Recruitment: 30

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 hip arthroplasty. Total dose 200mls of 0.2% ropivacaine or 400mg at the time of surgery. This will be followed by a continuous infusion of 10mls/hour 0.2% ropivacaine for the subsequent 24 hours.

Primary Outcome Measures

Name	Time	Method
Plasma levels of ropivacaine	Start of surgery until 24 hours postoperatively	Plasma levels of ropivacaine will be analysed to determine total and free levels. These will be taken following tourniquet release at the following time points: 5, 10, 15, 20, 25, 30 minutes then 1, 4, 12 and 24 hours. Note: Each patient will also have a baseline blood sample taken.

Secondary Outcome Measures

Name	Time	Method
Symptoms of local anaesthetic toxicity	Start of surgery until 24 hours postoperatively	Patients will be specifically questioned (at each time point) on whether they have any of the following symptoms: Perioral tingling, dizziness, blurred vision, nausea
Signs of local anaesthetic toxicity	Start of surgery until 24 hours postoperatively	Patients will be specifically assessed (at each time point) for the following signs: Confusion/agitation, (loss of consciousness, seizure activity, cardiac arrest)
Continuous 24 hour electrocardiograph monitoring	First 24 hours after surgery	Electrocardiograph data will be reported using analysis software to provide a summary of heart rhythm over the study period. Both minor abnormalities (ectopic beats) and major abnormalities (loss of sinus rhythm, heart block) will be detected and reported.
Vital signs of heart rate and blood pressure	Start of surgery until 24 hours postoperatively	Vital signs will be recorded (at each time point) when blood samples are taken.

Trial Locations

Locations (1)

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