The Effect of Local Anaesthetic Volume on Nerve Block Duration and Nerve Block Duration Variability. A Randomised, Blinded, Healthy Volunteer Study
Overview
- Phase
- Phase 4
- Intervention
- Ropivacaine
- Conditions
- Postoperative Pain
- Sponsor
- Nordsjaellands Hospital
- Enrollment
- 120
- Locations
- 1
- Primary Endpoint
- Duration of sensory nerve block
- Status
- Completed
- Last Updated
- 9 years ago
Overview
Brief Summary
The aim is to investigate the effect of perineural administration of a series of different volumes of local anaesthesia (ropivacaine 0.2%) on nerve block duration and the variability of the duration in the common peroneal nerve and the sciatic nerve in healthy volunteers.
The hypothesis is that nerve block duration is correlated to local anaesthetic volume, but only to a certain degree. After a sufficient volume a 'saturation level' will be reached, and nerve block duration will not increase further.
Detailed Description
The trial is divided into two similar phases. Each phase will focus on a specific nerve. Phase 1 will focus on the common peroneal nerve and Phase 2 will focus on the sciatic nerve. After baseline measurements, the investigators will insert a peripheral intravenous catheter. Then, the investigators will insert a suture-method peripheral nerve catheter (Certa CatheterTM). Procedures will be done in a sterile manner as a standard of practice. The investigators will use an ultrasound (US)-guided short-axis, needle in-plane technique. For the US-scan, the investigators will use a linear or a curvilinear transducer. During interventions, volunteers will be monitored with continuous pulse oximetry. Placement of the peripheral nerve catheter will be facilitated by US using small injections of mepivacaine (carbocaine 2 %) in the skin and surrounding tissues and only isotonic saline (5 mL) in the perineural space to prevent blocking of the nerve before ropivacaine injection. The catheter orifice will be placed by pulling either end of the catheter and guided by the built-in echogenic markings seen on US. Before injection of ropivacaine, the investigators will do careful aspirations through the catheter in order to prevent intravasal injection. Each ropivacaine injection will be administered via an infusion pump. This will ensure a constant infusion rate set to 10 mL per minute. During infusion, the volunteers will be monitored with continuous pulse oximetry. Before instigation of the ropivacaine infusion, the investigators will use US to verify full absorption of the isotonic saline in the perineural space. For each nerve, the subject will be randomly allocated to and receive one of five possible ropivacaine volumes. All volunteers and outcome assessors will be blinded to the ropivacaine administrations and infusion procedures. Outcome assessors will not be in the room, when the medication is prepared nor given. Preparation will take place behind a curtain and therefore also blinded to the volunteers.
Investigators
Claus Behrend Christiansen
MD
Nordsjaellands Hospital
Eligibility Criteria
Inclusion Criteria
- Not provided
Exclusion Criteria
- Not provided
Arms & Interventions
Peroneal nerve: Ropivacaine 0.2%, 2.5 mL
Perineural injection of ropivacaine 0.2 %, 2,5 mL
Intervention: Ropivacaine
Peroneal nerve: Ropivacaine 0.2%, 5 mL
Perineural injection of ropivacaine 0.2 %, 5 mL
Intervention: Ropivacaine
Peroneal nerve: Ropivacaine 0.2%, 10 mL
Perineural injection of ropivacaine 0.2 %, 10 mL
Intervention: Ropivacaine
Peroneal nerve: Ropivacaine 0.2%, 15 mL
Perineural injection of ropivacaine 0.2 %, 15 mL
Intervention: Ropivacaine
Peroneal nerve: Ropivacaine 0.2%, 20 mL
Perineural injection of ropivacaine 0.2 %, 20 mL
Intervention: Ropivacaine
Sciatic nerve: Ropivacaine 0.2%, 5 mL
Perineural injection of ropivacaine 0.2 %, 5 mL
Intervention: Ropivacaine
Sciatic nerve: Ropivacaine 0.2%, 10 mL
Perineural injection of ropivacaine 0.2 %, 10 mL
Intervention: Ropivacaine
Sciatic nerve: Ropivacaine 0.2%, 15 mL
Perineural injection of ropivacaine 0.2 %, 15 mL
Intervention: Ropivacaine
Sciatic nerve: Ropivacaine 0.2%, 20 mL
Perineural injection of ropivacaine 0.2 %, 20 mL
Intervention: Ropivacaine
Sciatic nerve: Ropivacaine 0.2%, 30 mL
Perineural injection of ropivacaine 0.2 %, 30 mL
Intervention: Ropivacaine
Outcomes
Primary Outcomes
Duration of sensory nerve block
Time Frame: 1-24 hours
Application of a round, cooled glass container in the sensory distribution area of the tested nerve: The lateral part of the lower leg for the common peroneal nerve and beneath the foot for the tibial nerve. Testing will start after onset of sensory nerve block and continue until normal sensation has returned. When testing the sciatic nerve, we will continue testing until normal sensation has returned in both components of the nerve, i.e. the tibial and common peroneal nerve.
Secondary Outcomes
- Length of nerve exposed to local anaesthesia(10 minutes)
- Onset of sensory nerve block(10-180 minutes)
- Onset of motor nerve block(10-180 minutes)
- Degree of sensory nerve block(1-24 hours)
- Degree of motor nerve block(1-24 hours)