Poster Number-51 - Ultrasound-guided transversus abdominis plane block with liposomal bupivacaine in patients undergoing elective cesarean section via spinal anesthesia

Cesarean section surgery is a very common surgery in the United States and can affect women negatively during their recovery period. Many women experience moderate to severe post-cesarean pain post-operatively (1). Pain after cesarean section is caused from somatic pain due to abdominal wall incision as well as visceral pain from the uterus incision. Several previous studies have used a multimodal pain approach to better improve post-operative pain as well as to decrease the potential of opioid misuse with the current on-going opioid epidemic in the United States. A retrospective health claims study including 201,662 patients who underwent cesarean delivery determined that these women have a 28% increased risk for chronic opioid use compared with those not undergoing a surgery (2).

   Multimodal pain approaches typically include a combination of nonsteroidal anti-inflammatory drugs, acetaminophen, systemic opioids, intrathecal opioids, local infiltration around surgical site, and/or various anesthesia regional blocks. Various combinations of these help to control both somatic and visceral pain from cesarean section as well as decrease opioid consumption and their potential side effects.  One study illustrated that in cesarean delivery, intra-incisional infiltration of liposomal bupivacaine after completion of surgery had shown to reduce opioid consumption when compared with usual care (3). Enhanced recovery after surgery protocols (ERAS) programs that include transversus abdominis plane blocks are instituted across the country and in multiple specialties of medicine. One study illustrated the analgesic efficacy of the US-guided TAP block after Caesarean delivery have opioid-sparing effects, reduced antiemetic use, and improved satisfaction with pain relief while inpatient (4).

   We compared the effects of TAP block with liposomal Bupivacaine in patients undergoing elective cesarean section via spinal anesthesia to those who did not receive the TAP block. We focused on opioid consumption while inpatient, pain scores, length of hospital stays, and patient satisfaction.  Previous studies have illustrated that TAP blocks decrease opioid consumption while inpatient; however, there does not appear to be studies that look at patient’s opioid consumption outpatient.  We also focused on opioid consumption and pain scores in the outpatient setting at their two-week follow-up. 

Methods:

This single-center prospective study was approved by the University of Mississippi Medical Center Institutional Review Board. We recruited 30 patients (age 18 – 45 years) who were scheduled for elective cesarean section under spinal anesthesia from January 1, 2022 to June 30, 2022. The exclusion criteria were: Emergent cesarean section, Pre-Eclampsia, COVID undergoing cesarean section, under 18 years, and/or allergies to the pain medications used. Patients were offered the TAP block versus no TAP block post-cesarean section. Patients who chose TAP block were placed in the experimental group while the patients who did not want a TAP block were placed in the control group.   All study participants received a spinal containing Bupivacaine 0.75% (1.4 cc < 5 feet tall or 1.6cc > 5 feet tall), Fentanyl 10 mcg, Morphine 150 mcg, and Epinephrine 100 mcg for elective cesarean section. When surgery was complete, the experimental group patients received bilateral TAP blocks with liposomal Bupivacaine under SonoSite ultrasound guidance before leaving the operating room. The dose of liposomal Bupivacaine administered was 266mg total which was diluted with normal saline to equal 60ml.  Patients received 30ml liposomal Bupivacaine/Normal saline mixture bilaterally.

   For pain assessment, the patients were asked to rate their pain at rest on a 0 to 10 pain scale (0 = no pain; 10 = imaginable pain) before leaving the operating room and the post-operation recovery room. All participants were then transferred to the inpatient floor for further recovery. All patients received oral Ibuprofen 800 mg TID, Tylenol 1 g TID, and Oxycodone 5mg q4h PRN while inpatient. Patient’s pain with ambulation was re-assessed at 24 hours, 48 hours, and at time of discharge using the numeric 0 to 10 pain scale.  Patients were discharged with a prescription of Percocet 5 mg q6h PRN (20 tablets) and Ibuprofen 800 mg q8h PRN.  

   Data was obtained from operative note, nursing notes and medicine administration times from EPIC. Patients were followed up at two weeks post-operation for pain scores, opioid consumptions, and satisfaction scores.  

Results:

There were 31 patients total with 19 being in the experimental (TAP block group) and 12 in the control group (No TAP block). At time of OR discharge, both groups had zero pain scores which is what we used for a baseline. Pain scores at time of PACU discharge, 24 hours, and at 48 hours were decreased in the TAP block group on average when compared to the control group. The time to first supplemental analgesia on average was increase to about 10 hours in the TAP group. In the control group, they typically received supplemental analgesia within 1.5 hours. Morphine equivalents that were consumed at 24 hours, 48 hours, and at time of discharge were decreased in the TAP group. At two weeks follow, pain scores in the TAP group were less than the control group; however, there was no difference in opioid consumption. Length of hospital stay and patient satisfaction scores between the two groups were the same.  

Conclusion: Patients who received ultrasounds guided TAP block with liposomal Bupivacaine after elective cesarean section surgery illustrated lower pain scores and decreased opioid consumption while inpatient. At the two-week follow-up, the patients who received the TAP block had lower pain scores then the control group; however, there did not appear to be a difference in opioid consumption. Also, there was no difference in hospital stay or patient satisfaction scores.

References: 1. Pan PH, Tonidandel AM, Aschenbrenner CA, Houle TT, Harris LC, Eisenach JC. Predicting acute pain after cesarean delivery using three simple questions. Anesthesiology. 2013;118(5):1170-1179.
2. Sun EC, Darnall BD, Baker LC, Mackey S. Incidence of and risk factors for chronic opioid use among opioid-naïve patients in the post-operative period. JAMA Intern Med. 2016; 176(9):1286-1293.
3. Parikh P, Sunesara I, Singh Multani S, Patterson B, Lutz E, Martin JN Jr. Intra-incisional liposomal bupivacaine and its impact on postcesarean analgesia: a retrospective study. J Matern Fetal Neonatal Med. 2017 Nov 7; Epub.
4. Belavy D, Cowlishaw PJ, Howes M, Phillips F. Ultrasound-guided transverse abdominis plane block for analgesia after Caesarean delivery. Br J Anaesth. 2009;103:726-30.