A Pain Study Comparing Two Commonly Used Medications to Treat Pain After Bowel Surgery
Condition: Postoperative Pain
MeSH terms: Pain, Postoperative
Study type: Interventional

Summary: 
      This research study is testing whether the local anesthetic lidocaine is as effective as
      ropivacaine for post-operative pain control in continuous thoracic paravertebral nerve
      blocks. Ropivacaine and Lidocaine are FDA-approved drugs that has been successfully used in
      this hospital for post-operative pain control for the past few years, thus has become the
      standard drugs used for this nerve block. Lidocaine has numerous potential advantages over
      ropivacaine, such as faster onset of action, better safety profile and greater
      anti-inflammatory action. Catheters placed near both sides of a patient's spine for
      postoperative pain control are called thoracic paravertebral nerve blocks and are a part of
      routine care. Through those catheters, a "numbing" medication, or local anesthetic, to block
      the transmission of pain from the surgical incision to the spinal cord, thus reducing pain.
      The research part of the study is whether subjects will receive either the local anesthetic
      lidocaine or ropivacaine. The goal of this study is to determine whether the lidocaine
      controls pain better and facilitates a faster recovery after abdominal surgery than
      ropivacaine.

      In this research study, the investigators will compare patient-reported pain scores, any
      additional pain medication requirements for adequate pain control, time it takes for bowel
      function to return to normal following surgery, as well as the incidence of any side effects,
      such as numbness and weakness, subjects may experience between those receiving lidocaine
      versus those receiving ropivacaine. The investigators will screen 100 patients and enroll 60
      subjects into this study.
    

Detailed description: 
      After determining eligibility, subjects will be enrolled in one of the two study groups on
      the day of surgery using a sealed envelope determined by a computer-generated list that made
      assignments randomly based on enrollment number. The study groups are defined as:

      Study group: Lidocaine 0.25%(L) 32 patients Control group: Ropivacaine 0.2%(R) 32 patients

      Paravertebral nerve block catheter placement and activation:

      After standard monitors and supplemental oxygen are applied, the patient will be placed in a
      sitting position. The two points of needle entry will be marked on the skin corresponding to
      each of the bilateral paravertebral catheter placements. The thoracic spine level will be at
      the anatomic level corresponding to the midpoint of the incision as determined by the surgeon
      preoperatively (range T7 to T11). The needle entry sites will be 2.5 cm lateral on each side
      of the midpoint of the spinous process of the corresponding thoracic vertebrae. The area will
      be prepared and draped in a sterile fashion, and 1% lidocaine infiltrated subcutaneously at
      each point of anticipated needle entry. For each of the two catheter placements, a sterile 18
      gauge Tuohy needle (B. Braun Medical, Inc., Perifix Continuous Epidural Anesthesia Set,
      Product Code CE18T) will be introduced perpendicularly to the skin until the transverse
      process is encountered, and the depth to the skin will be noted. The needle will then be
      readjusted in a caudad direction and inserted inferior to the corresponding transverse
      process to a depth approximately 1 cm deep to the transverse process. After final needle
      placement, a hanging drop technique will be used to rule out intrapleural placement while the
      patient inhales and exhales deeply. Next 5 mL of 0.5% Ropivacaine will be injected
      incrementally through each needle after negative aspiration, followed by insertion of the
      nerve block catheter to a depth 5 cm beyond the tip of the needle. An additional 10 mL of
      0.5% Ropivacaine will then be injected in 5 mL increments with negative aspiration in
      between, through each catheter yielding a total activation dose of 15 ml of 0.5% Ropivacaine
      on each side. The catheters will be secured with Steri-strips and a transparent occlusive
      dressing. Vital signs will be monitored by the nurse at regular intervals until the patient
      is taken to the operating room.

      Postoperative Management:

      Post Anesthesia Care Unit (PACU):

      Following routine intraoperative general anesthesia care, management in the post-anesthesia
      care unit will follow the standard of care for colorectal surgery. Bilateral paravertebral
      infusions of ropivacaine 0.2% or lidocaine 0.25% will be started at 7 mL/hr on each side for
      the patients depending which to group they were randomized. The patients in both groups will
      also be given access to PCA dilaudid (0.2 mg bolus, 8 min lockout, no basal infusion, no
      1-hour limit) once verbal pain score is ≤4. Additional pain relief is available via
      nurse-administered 10 mL/hour boluses of ropivacaine 0.2% or lidocaine 0.25% via the catheter
      pumps (5 mL each side for paravertebral group).This will be continued until the patient is
      able to tolerate oral pain medication. A single IV bolus of ketorolac at 7.5 mg will be
      available for additional pain management. Patient reported pain scores and total analgesic
      requirements will be recorded. Once adequate analgesia is established without any signs of
      adverse effects from the nerve blocks, the patients will be transferred to a hospital floor
      bed.

      Floors:

      After discharge from the PACU, additional pain relief is available via nurse-administered 3
      mL boluses of local anesthetic via the catheter pumps (3 mL each side for paravertebral
      group) given no more than hourly. In addition, nurse-administered intravenous boluses of
      dilaudid 0.3 mg every 30 minutes as needed up to 2 doses while the patient has PCA, and 0.8-1
      mg every hour as needed up to 4 doses in 2 hours once the patient is taking oral pain therapy
      and is off the PCA. All patients will be assessed daily by members of the acute
      interventional perioperative pain service. Also, a member of the acute pain service will be
      on-call 24 hours if inadequate pain control or side effects arise. The infusion rates via the
      paravertebral catheters may be adjusted at the discretion of the pain service up to a rate of
      10 mL/hr of either lidocaine 0.25% or ropivacaine 0.2% on each side (standard infusion rate
      used at UPMC). The PCA dose may be adjusted as deemed necessary by the acute pain team in
      order provide adequate analgesia. In addition 7.5mg IV of ketorolac may be administered every
      6 hours for the first 48 hours. Once the patient is able to tolerate oral liquids as
      determined by the surgeon, the PCA will be discontinued and oxycodone 5 mg available to the
      patient every 4 hours as needed for mild-moderate pain or oxycodone 10 mg every 6 hours as
      needed for severe pain. These doses may be adjusted as necessary by the pain service. All
      paravertebral catheters will be stopped and removed on the day after the patient has his/her
      first bowel movement or post-operative day #4, whichever occurs first. Pain scores collected
      by the nurses and supplemental analgesic requirements will be the data points for this study.
      Also, return of flatus and first bowel movement as documented in the AIPPS and surgery team's
      daily round notes will be recorded during the length of the hospitalization respectively.

      For each patient, the investigators collected numerical rating scores (NRS) for pain at rest
      and during movement at baseline, at postanesthesia care unit discharge, at 24 hours and 48
      hours after the end of surgery,
    

Intervention name(s): Ropivacaine; Lidocaine
Intervention type(s): Drug; Drug
Intervention description(s): 0.5% Ropivacaine will be infused through a catheter placed in the thoracic paravertebral space to block the transmission of pain signals at the level of the spinal nerves from the abdominal incision. It is the local anesthetic used as the standard drug in paravertebral nerve blocks at our institution. It is also used in other nerve block infusions at our hospital and institutions across the country. It will be used as the standard drug to which lidocaine is compared.; Lidocaine will be infused through a catheter placed in the thoracic paravertebral space to block the transmission of pain signals at the level of the spinal nerves from the abdominal incision.
At a concentration of 0.5%, Lidocaine has been deemed safe to use for peripheral nerve blocks and analgesia. There are several studies to support this as listed in the references. Compared to ropivacaine, lidocaine is shorter-acting, less cardiotoxic, and safer to use.
Other intervention name(s): Naropin®; Ropivacaine hydrochloride; Xylocaine
Intervention MeSH terms: Lidocaine; Ropivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Postoperative Pain; Bowel Surgery; Regional Anesthesia