Transverse Abdominis Plane (TAP) Block After Cesarean Delivery
Condition: Postoperative Pain; Pregnancy; Obesity
MeSH terms: Pain, Postoperative
Intervention: 0.9% Normal Saline; 0.2% Ropivacaine; 0.5% Ropivacaine; 0.75% Ropivacaine
Intervention description: The abdominal muscle layers will be located by placing the ultrasound transducer perpendicular to the coronal anatomic plane at the T-10 dermatome level in the patient's midaxillary line. Under ultrasound guidance, a 70mm or 90mm, 21 gauge blunted Stimuplex needle will be advanced from the skin until the tip reaches the fascial layer between the internal oblique and transversus abdominis. 15ml of the study drug will be injected incrementally. The needle will then be removed and the process repeated in the same manner on the patient's opposite side.; The abdominal muscle layers will be located by placing the ultrasound transducer perpendicular to the coronal anatomic plane at the T-10 dermatome level in the patient's midaxillary line. Under ultrasound guidance, a 70mm or 90mm, 21 gauge blunted Stimuplex needle will be advanced from the skin until the tip reaches the fascial layer between the internal oblique and transversus abdominis. 15ml of the study drug will be injected incrementally. The needle will then be removed and the process repeated in the same manner on the patient's opposite side.; The abdominal muscle layers will be located by placing the ultrasound transducer perpendicular to the coronal anatomic plane at the T-10 dermatome level in the patient's midaxillary line. Under ultrasound guidance, a 70mm or 90mm, 21 gauge blunted Stimuplex needle will be advanced from the skin until the tip reaches the fascial layer between the internal oblique and transversus abdominis. 15ml of the study drug will be injected incrementally. The needle will then be removed and the process repeated in the same manner on the patient's opposite side.; The abdominal muscle layers will be located by placing the ultrasound transducer perpendicular to the coronal anatomic plane at the T-10 dermatome level in the patient's midaxillary line. Under ultrasound guidance, a 70mm or 90mm, 21 gauge blunted Stimuplex needle will be advanced from the skin until the tip reaches the fascial layer between the internal oblique and transversus abdominis. 15ml of the study drug will be injected incrementally. The needle will then be removed and the process repeated in the same manner on the patient's opposite side.
Intervention MeSH terms: Ropivacaine
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Investigator)
Enrollment: 120.0
Sex: Female
Minimum age: 18 Years
Healthy volunteers: No
Keywords: Cesarean Delivery; Ropivicaine; TAP block

Summary:

      Since there have been no published dose-response studies investigating the effective
      analgesic dose of ropivacaine for use in a TAP block for post-Cesarean delivery analgesia,
      the investigators propose a study primarily examining the effect on 24 hour post-Cesarean
      delivery opioid consumption of using either a placebo, 0.25% ropivacaine, 0.5% ropivacaine,
      or 0.75% ropivacaine for TAP blocks.
    

Eligibility criteria:

        Inclusion Criteria:

          -  ASA II-III patient

          -  > 18 years of age who is pregnant

          -  presenting for a cesarean delivery via Pfannenstiel incision who is eligible to
             receive a spinal anesthetic with 0.75% bupivacaine and fentanyl and whose is not
             eligible to receive intrathecal morphine due to a BMI >40 kg/m2.

        Exclusion Criteria:

          -  < 18 years of age

          -  contraindication to placement of a spinal anesthetic

          -  contraindication to use of non-steroidal anti-inflammatory drugs (NSAIDs)

          -  patients receiving medical therapies considered to result in tolerance to opioids

          -  patients with a history of established chronic pain, (e.g. chronic low back pain,
             fibromyalgia or headaches), defined as requiring regular medical follow-up with pain
             specialists, as well as recent use (within the year preceding pregnancy) of opioid
             analgesics as an outpatient

          -  patients with a history of diabetes mellitus

          -  patients undergoing a vertical midline skin incision

          -  patients who are undergoing a cesarean delivery after a failed vaginal trial of labor

          -  patients who had a prior epidural placed for labor analgesia during the same hospital
             encounter.