Ultrasound-guided Axillary Plexus Block - Dose Reduction of Prilocaine

This study has been completed.
Sponsor:
Information provided by:
Helios Research Center
ClinicalTrials.gov Identifier:
NCT01309360
First received: March 4, 2011
Last updated: July 6, 2011
Last verified: June 2011
  Purpose

Clinical aim: Does reducing the dose of local anesthetic in ultrasound-guided axillary plexus anesthesia have any effect on the success rate and additional parameters of block quality? Methodology: In this prospective cohort study three groups of 40 outpatients each were administered dosages of 1% prilocaine of either 40mL, 30mL or 20mL for axillary plexus anesthesia. Met-Hb was measured prior to administration of the block and then hourly until the Met-Hb concentration fell. Parameters of block quality and any adverse effects were recorded. The level of significance was defined with α ≤ 0.05.


Condition Intervention Phase
Other Surgical Procedures
Drug: midazolam
Drug: prilocaine 1%
Phase 4

Study Type: Interventional
Study Design: Allocation: Non-Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Single Blind (Subject)
Primary Purpose: Treatment
Official Title: Ultrasound-guided Block of the Brachial Plexus Using Prilocaine: Effects of Local-anesthetic Dose Reduction on Parameters of Block Quality and Adverse Effects in Outpatients

Resource links provided by NLM:


Further study details as provided by Helios Research Center:

Primary Outcome Measures:
  • Number of Participants With Complete Sensory Block [ Time Frame: 60 minutes after administration of the local anesthetic ] [ Designated as safety issue: No ]
    The number of outpatients with complete sensory block of all 4 nerves (n.musculocutaneous, n.radialis, n.ulnaris,n.medianus) was registrated in each group.

  • Number of Participants With Complete Motor Blocks [ Time Frame: Within 60 minutes after administration of the local anesthetic ] [ Designated as safety issue: No ]
    To examine the extent of the motor block the manual muscle function test after Vladimir Janda was used. As a complete motor block was defined, when no motion (grade zero after Janda) of muscles innervated by the four blocked nerves (musculocutaneous, median, radial and ulnar nerve) was observed within 60 minutes after administration of the local anesthetic.

  • Onset Time. [ Time Frame: within 60 minutes after administration of the local anesthetic ] [ Designated as safety issue: No ]
    Time from beginning of administration of the local anesthetic until complete sensoric block.


Secondary Outcome Measures:
  • Maximum Concentrations of Methemoglobin [ Time Frame: 0,1,2,3,4 hours post-dose ] [ Designated as safety issue: Yes ]
    Concentration of Methemoglobin (Met-Hb) was measured using spectrophotometry prior to the anesthesia (baseline value) and then hourly after performing the block until a clear decrease became apparent. The maximum amount was reached in every case two or three hours after administration of the local anesthetic.

  • Number of Participants With Objective Adverse Events as a Measure of Safety and Tolerability [ Time Frame: Outpatients were followed for the duration of hospital stay, an average of six hours. ] [ Designated as safety issue: Yes ]
    In groups A, B and C was determined the rate of objective clinical signs of increased Met-Hb-levels : drops in oxygen saturation <93% using pulseoximetry or lip cyanosis.

  • Number of Participants With Subjective Adverse Events as a Measure of Safety and Tolerability. [ Time Frame: Outpatients were followed for the duration of hospital stay, an average of six hours. ] [ Designated as safety issue: Yes ]
    In groups A, B and C was determined the rate of subjective clinical signs of increased Met-Hb-Levels : headaches or dizziness, when correlated with the peak-Met-Hb-Level.


Enrollment: 120
Study Start Date: September 2009
Study Completion Date: April 2010
Primary Completion Date: April 2010 (Final data collection date for primary outcome measure)
Arms Assigned Interventions
Active Comparator: group A : 40ml Prilocaine 1%
40 outpatients : 40ml Prilocaine 1% were administered for axillary plexus block
Drug: midazolam
Prior to performing the regional anesthesia the investigators administered midazolam as a premedication by mouth (3,75-7,5mg) or intravenously (2-3mg).
Other Name: Dormicum
Drug: prilocaine 1%
40 outpatients : 40ml prilocaine 1% were administered for axillary plexus block
Other Name: Xylonest 1%
Active Comparator: group B : 30ml Prilocaine 1%
40 outpatients : 30ml prilocaine 1% were administered for axillary plexus block
Drug: midazolam
Prior to performing the regional anesthesia the investigators administered midazolam as a premedication by mouth (3,75-7,5mg) or intravenously (2-3mg).
Other Name: Dormicum
Drug: prilocaine 1%
40 outpatients : 30ml prilocaine 1% were administered for axillary plexus block
Other Name: Xylonest 1%
Active Comparator: group C : 20ml Prilocaine 1%
40 outpatients : 20ml prilocaine 1% were administered for axillary plexus block
Drug: midazolam
Prior to performing the regional anesthesia the investigators administered midazolam as a premedication by mouth (3,75-7,5mg) or intravenously (2-3mg).
Other Name: Dormicum
Drug: prilocaine 1%
40 outpatients : 20ml prilocaine 1% were administered for axillary plexus block
Other Name: Xylonest 1%

Detailed Description:

Background

With the availability of high resolution portable ultrasound equipment, the use of sonography in the field of anesthesia has become more widespread in recent years. The investigators would like to draw attention to a meta-analysis of prospective randomized studies by Abrahams et al. as being representative of the numerous publications available. Compared to nerve stimulation, ultrasound-guided nerve blocks have a higher success rate with significantly fewer vascular punctures and shorter procedure times. However, the administration of ultrasound-guided regional anesthesia necessitates considerable equipment acquisition and training expenses. Nevertheless, the suggested benefits resulting from savings in time and local anesthetic, increased patient satisfaction and avoidance of complications should be considered in addition to the results from Abrahams et al.

The aim of the present work was to investigate whether an ultrasound-guided block combined with a reduced dose of the local anesthetic prilocaine altered the success rate or other parameters of block quality. Any adverse effects and the methaemoglobin concentration were also recorded.

Methodology

After receiving ethics committee approval and after informing patients, ultrasound-guided axillary plexus anesthesia was carried out on 120 adult outpatients in ASA risk groups I-II. The surgical spectrum covered procedures on the distal forearm or the hand (carpal tunnel syndrome, ganglion extirpation, removal of material, etc.). Provision of information and inclusion in the study was done in the anesthesia outpatients' clinic as part of the standard preoperative preparation. Prior to administering the regional anesthesia the investigators administered midazolam as a premedication by mouth (3,75-7,5mg) or intravenously (2-3mg). Application of the local anesthesia was done prospectively and single blind in 3 cohorts with decreasing dosage. The patients received either 400mg (group A), 300mg (group B) or 200mg (group C) of prilocaine 1%. The block was performed under sterile conditions using a portable ultrasound device (Sonosite S-Nerve) and a 24 G short bevel cannula with flexible tubing. The block was performed using combined out-of-plane (n. musculocutaneous) and in-plane techniques (n.radialis, n.medianus, n.ulnaris), usually from a single puncture site. The outpatients were cared for in the anesthesia care unit preoperatively and postoperatively until their discharge. NIBP, pulse oxymetry and ECG were continuously monitored. The discharge criteria were widespread regression of the block with a subjective feeling of well-being including adequate analgesia and stable vital signs with methemoglobin (Met-Hb) concentrations ≤ 5%. Met-Hb levels were measured using spectrophotometry prior to the anesthesia (baseline value) and then hourly after performing the block until a clear decrease became apparent. A complete sensory block of all 4 nerves within 60 minutes of administration of the local anesthetic was rated as a successful block.

For the statistical analysis the investigators selected distribution-free, nonparametric test methods. The Mann-Whitney U test was used when comparing 2 groups and the Kruskal-Wallis test or Fisher's exact test was used when comparing more than 2 groups. The level of significance was defined with α ≤ 0.05. With multiple paired comparisons the significance level was adjusted using the Bonferroni correction. The Bravais-Pearson correlation coefficient rho describes the relationship between the maximum Met-Hb value and the weight-based prilocaine dose in mg/kg.

  Eligibility

Ages Eligible for Study:   18 Years to 75 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No
Criteria

Inclusion Criteria:

  • elective surgery on the distal forearm or the hand
  • adult outpatients, age 18-75 years old
  • ASA-risk groups I-II (American Society of Anesthesiologists)
  • Body Mass Index 17-35
  • informed consent

Exclusion Criteria:

  • severe coagulopathy
  • local or systemic inflammatory response
  • ASA-risk groups ≥ Grad III
  • severe anemia
  • heart failure
  • manifest shock
  • other drugs with influence on methaemoglobinemia (nitrates, sulfonamides etc.)
  • domestic care after surgery not ensured
  • drug allergy : local anesthetics
  • severe polyneuropathy
  • pregnancy, lactation period
  • participation in other studies
  • non-cooperative patients
  • addiction to drugs or alcohol
  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01309360

Sponsors and Collaborators
Helios Research Center
Investigators
Principal Investigator: Ronald Seidel, Dr. med. Klinik für Anästhesiologie und Intensivtherapie, Helios Kliniken Schwerin, Wismarsche Strasse 393-7, DE-19049 Schwerin
Study Director: Georg Rehmert, Dr.med. Klinik für Anästhesiologie und Intensivtherapie, Helios Kliniken Schwerin, Wismarsche Strasse 393-7, DE-19049 Schwerin
  More Information

No publications provided

Responsible Party: Dr.med. Ronald Seidel, Klinik für Anästhesiologie und Intensivtherapie, Helios Kliniken Schwerin, Wismarsche Strasse 393-7, DE-19049 Schwerin
ClinicalTrials.gov Identifier: NCT01309360     History of Changes
Other Study ID Numbers: A 2009 24
Study First Received: March 4, 2011
Results First Received: May 4, 2011
Last Updated: July 6, 2011
Health Authority: Germany: Federal Institute for Drugs and Medical Devices

Keywords provided by Helios Research Center:
ultrasound
methaemoglobin
prilocaine
regional anesthesia
ASA risk groups I-II
adult outpatients
surgical spectrum covered procedures
distal forearm
hand

Additional relevant MeSH terms:
Midazolam
Prilocaine
Adjuvants, Anesthesia
Central Nervous System Agents
Therapeutic Uses
Pharmacologic Actions
Hypnotics and Sedatives
Central Nervous System Depressants
Physiological Effects of Drugs
Anti-Anxiety Agents
Tranquilizing Agents
Psychotropic Drugs
Anesthetics, Intravenous
Anesthetics, General
Anesthetics
GABA Modulators
GABA Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action
Anesthetics, Local
Sensory System Agents
Peripheral Nervous System Agents

ClinicalTrials.gov processed this record on October 16, 2014