The effect of clonidine as an adjuvant in Transversus Abdominis Plane block after Cesarean delivery
Abstract Number: F-51
Abstract Type: Original Research
Pain control in post-partum patients can pose a challenge after Cesarean section. Patients want to be awake enough to care for their baby, without the side effects of opioids given to them in the postoperative period. Transversus Abdominal Plane (TAP) blocks can be effective as part of a multimodal approach to provide postoperative pain control in this patient population. Multiple adjuvants can potentially extend the duration of analgesia from the block. One in particular, clonidine, has been shown to increase the duration of other regional blocks, but has not been specially studied in TAP blocks in this patient population. We conducted a double-blind, randomized, prospective study on the addition of clonidine to TAP blocks on postoperative opioid consumption and pain scores in the first 24 hours after Cesarean section.
Patients presenting for elective Cesarean delivery were randomly assigned to one of two groups: postoperative TAP block with the clonidine or postoperative TAP block with saline. Patients received spinal anesthesia with 12 mg bupivacaine and 15 mcg fentanyl for their primary anesthetic. Before leaving the operating room, patients received ultrasound-guided TAP block with 30cc ropivacaine 0.5% with 1:200K epinephrine and 4 mg dexamethasone (total dose divided bilaterally) with 50 mcg (0.5mL) of clonidine or 0.5 mL of saline given to the anesthesia provider by the pharmacy in identical, unmarked syringes. All caregivers and patients were blinded to study group. Multi-modal analgesia was offered to the patients consisting of acetaminophen, ibuprofen and hydromorphone PCA for the first 24 hours after Cesarean section and total dose was recorded. Primary outcome was amount of opiate pain medication given at 24 hrs. Secondary outcomes were pain scores, maternal satisfaction and side effects including nausea, vomiting, itching and drowsiness.
Twenty-four patients received either TAP block with clonidine (n=12) or TAP block with saline (n=12). There were no significant differences between groups in terms of age, BMI and parity. Pain scores at 24 hours and total hydromorphone use was collected among the two groups. At 24 hours, there was no significant difference in maternal pain scores between the two groups (mean score 3.33 out of 10 in clonidine group vs 3.83 out of 10 in saline group, p=.39). Mean total hydromorphone use was also similar in both groups (5.04 mg in clonidine group vs 6.66 mg in saline group, p=.4).
TAP blocks can be part of multimodal analgesia for postoperative patients following Cesarean section as a means to decrease opioid consumption. Clonidine has been shown to increase the duration of peripheral nerve blocks when used as an adjuvant. However, in this patient population clonidine did not seem to make a significant difference in the duration of analgesia provided by TAP block. Mean total opioid consumption was similar in both groups as well as maternal pain scores.