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Completed

NCT Number: NCT02755532

Bupivacaine Pharmacokinetics in Ultrasound-guided Axillary Brachial Plexus Block.

Introduction: The risk of systemic toxicity when using bupivacaine is a persistent problem, making its pharmacokinetic study crucial to the safety of regional anesthesia (RA). Little evidence exists regarding the effect of different concentrations of this drug on peak plasma levels. The present study compares two bupivacaine concentrations to establish how the concentration and exchange area affect the peak plasma level of this drug during axillary brachial plexus block. Latency and postoperative analgesia periods were also compared.

Methods: 32 patients were randomly assigned to two groups. In the 0.25% group, 10 ml of 0.25% bupivacaine was injected per nerve; in the 0.5% group, 5 ml of 0.5% bupivacaine was injected per nerve. Peripheral blood samples were collected every 15 min during the first hour and every 30 min during the second hour to establish serum level dosage. High-performance liquid chromatography coupled with mass spectrometry was used for the analysis.

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Key information

Conditions

Pharmacokinetics Anesthetics, Local

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • candidates for elective surgery of the distal forearm and hand for whom brachial plexus anesthesia and analgesia were indicated.
  • physical status of I or II according to American Society of Anesthesiologists (ASA) criteria
  • body mass index (BMI) of less than 35 kg/m2
  • Signed the free and informed consent document.

Exclusion criteria

  • cognitive impairment
  • infection at the block puncture site
  • coagulopathy
  • history of bupivacaine allergy

Treatment and study plan

Bupivacaine 0,25%

Drug

Venous blood samples were collected prior to blocking , every 15 min during the first hour after completion of the blocking and every 30 min during the second hour after completion using an exclusive cannula. Then, 5 ml was drawn off and was stored in two EDTA tubes (BD, Franklin Lakes, NJ, USA). The EDTA tubes were centrifuged at 3,500xg for 10 min to obtain the blood plasma. This plasma was then stored in cryogenic tubes in a freezer at -80 °C until the time of the analysis. A high-performance liquid chromatography apparatus (Shimadzu, Kyoto, Japan) coupled to a Bruker mass spectrometer (MS), model Amazon (USA), with electrospray source ionization and a sequential mass spectrometry system (MS/MS) were used for the analysis. After obtaining the precursor ion, a fragment was obtained via a collision-induced dissociation process. The following molecular ions were selected: 289.0 m/z==>140.1 m/z. The methodology was validated according to the international FDA recommendations.

Bupivacaine 0,5%

Drug

Venous blood samples were collected prior to blocking , every 15 min during the first hour after completion of the blocking and every 30 min during the second hour after completion using an exclusive cannula. Then, 5 ml was drawn off and was stored in two EDTA tubes (BD, Franklin Lakes, NJ, USA). The EDTA tubes were centrifuged at 3,500xg for 10 min to obtain the blood plasma. This plasma was then stored in cryogenic tubes in a freezer at -80 °C until the time of the analysis. A high-performance liquid chromatography apparatus (Shimadzu, Kyoto, Japan) coupled to a Bruker mass spectrometer (MS), model Amazon (USA), with electrospray source ionization and a sequential mass spectrometry system (MS/MS) were used for the analysis. After obtaining the precursor ion, a fragment was obtained via a collision-induced dissociation process. The following molecular ions were selected: 289.0 m/z==>140.1 m/z. The methodology was validated according to the international FDA recommendations.

Primary outcomes

  1. Peak Venous Plasma level of bupivacaine.

    Time frame: 2 hours

    The aim of this study was to evaluate the difference in peak plasma levels obtained after ultrasound guided axillary brachial plexus block using two different bupivacaine concentrations to maintain the infused mass. Venous blood samples were collected prior to blocking , every 15 min during the first hour after completion of the blocking and every 30 min during the second hour after completion using an exclusive cannula. Then, 5 ml was drawn off and was stored in two EDTA tubes (BD, Franklin Lakes, NJ, USA). The EDTA tubes were centrifuged at 3,500xg for 10 min to obtain the blood plasma. This plasma was then stored in cryogenic tubes in a freezer at -80 °C until the time of the analysis. A high-performance liquid chromatography apparatus (Shimadzu, Kyoto, Japan) coupled to a Bruker mass spectrometer (MS), model Amazon (USA), with electrospray source ionization and a sequential mass spectrometry system (MS/MS) were used for the analysis.

Secondary outcomes

  1. Latency - The latency period was defined as the time interval between time zero and the time when surgical anesthesia was obtained.

    Time frame: 30 minutes

    This evaluation occurred every 5 min until the 30th min after blocking. During this period, if surgical anesthesia was not obtained, then a complementary bupivacaine injection was administered distal to the axilla and the patient was excluded from the protocol. Surgical anesthesia was defined as a motor scale of 2 or lower; an absence of cold and pinprick sensation.

Sponsors and collaborators

Lead sponsor

Federal University of São Paulo

Other

Collaborators

  • Fundação de Amparo à Pesquisa do Estado de São Paulo

Registry information

Official study title

A Clinical and Pharmacokinetic Study to Evaluate the Influence of Two Bupivacaine Concentrations on Peak Plasma After Ultrasound-guided Axillary Brachial Plexus Block

Important dates

Study start
2014
Primary completion
2015
Study completion
2015
First posted
Apr 29, 2016
Registry last updated
Apr 29, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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