PECS Block: Plasma Bupivacaine Level
Condition: Nerve Blocks
Study type: Interventional
Phase: Early Phase 1

Summary: 
      The purpose of this study is to determine peak plasma bupivacaine concentrations in a similar
      fashion for PECS I/II blocks. The investigators hypothesis is that the mean peak plasma
      levels for patients undergoing PECS I/II blocks will be less than the levels reported to
      cause early neurotoxicity of [2.2 (0.9) micrograms/ml]6 in patients receiving intravenous
      bupivacaine infusions.
    

Detailed description: 
      Regional anesthesia techniques are common modalities used to provide analgesia following both
      upper and lower extremity surgeries. It is also often used for truncal procedures for the
      same purpose. A relatively new truncal block, first described in 2012 by Blanco, called the
      pectoralis nerve block (PECS I and II block) has been used successfully for breast
      surgery1-3. Despite its description and success in clinical practice, the extent of systemic
      absorption from this truncal plane block has not been described to date. However, in a study
      published in the British Journal of Anesthesia, this has been done for another truncal plane
      block, the transverse abdominus plane (TAP) block where the local anesthetic was noted to
      peak and had a mean total concentration of ropivacaine occurring at 30 minutes after the
      block4. During this study, samples were taken at 10, 20, 30, 45, 60, 90, 120, 180, and 240
      minutes. The investigators anticipate that since this is a similar truncal plane block,
      absorption will be comparable in terms of timing. However, the concentration of drug absorbed
      may be different given the proximity to the ribs, intercostal and thoracic vasculature, and a
      higher concentration of local given the smaller plane for local anesthetic spread. Given that
      the investigators want to find the peak of the curve and the peak concentration of
      bupivacaine from the PECS block, the investigators feel will need 5 samples at the times
      outlined below. This number of samples was chosen to approximate a study published in 2004
      where ten subjects received ropivacaine for scalp blocks and serum ropivacaine levels were
      measured at 15, 30, 45, 60, 90, and 120 minutes5. The investigators feel that the 120 minute
      measurement is well beyond the peak plasma level of bupivacaine given the findings in the TAP
      and scalp studies. Therefore,the investigators will collect the following samples at these
      times after the block is completed: 5, 10, 20, 40, 60, and 90 minutes. The purpose of this
      study is to determine peak plasma bupivacaine concentrations in a similar fashion for PECS
      I/II blocks. The investigators hypothesis is that the mean peak plasma levels for our
      patients undergoing PECS I/II blocks will be less than the levels reported to cause early
      neurotoxicity of [2.2 (0.9) micrograms/ml]6 in patients receiving intravenous bupivacaine
      infusions.
    

Intervention name(s): Unilateral PECS I and II block; Bilateral PECS I and II block; Bupivacaine
Intervention type(s): Procedure; Procedure; Drug
Intervention description(s): A truncal block called the pectoralis nerve block (PECS I and II block). Unilateral. Using Bupivacaine; A truncal block called the pectoralis nerve block (PECS I and II block). Bilateral. Using Bupivacaine.; Bupivacaine solution 0.25%. At the PECS I site each patient will receive 10 cc of local anesthetic solution, and at the PECS II site an additional 20 cc of local anesthetic solution will be placed.
Intervention MeSH terms: Bupivacaine
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Other
Keywords: PECS I and II; PECS blocks