A Pain Study Comparing Two Commonly Used Medications to Treat Pain After Bowel Surgery

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,

Inclusion Criteria:

- ASA I-III subjects

- Ages 18-80 years

- Weight between 60 and 110 Kg

- At least 60in (152cm) tall

- Scheduled for elective open colonic surgery at UPMC Presbyterian Shadyside Hospital in
Pittsburgh, Pennsylvania

Exclusion Criteria:

- Age younger than 18 years or older than 80 years

- Any contraindication to the placement of bilateral thoracic paravertebral catheters

- American Society of Anesthesiologists physical status IV or greater

- Chronic painful conditions

- Preoperative opioid use

- Coagulation abnormalities or patients who are expected to be on therapeutic
anticoagulants postoperatively

- Allergy to any of the drugs/agents used study protocol

- Personal or family history of malignant hyperthermia

- Serum creatinine greater than 1.3 g/dl

- Pregnancy

- Having an altered mental status (not oriented to place, person, or time)

- Emergency surgery and those with sepsis, unstable angina, congestive heart disease,
valvular heart disease, and severe COPD

- Patient's inability to provide adequate informed consent

- Non-english speaking

- Patient refusal