Bilateral Transversus Abdominis Plane Blocks for Post Cesarean Delivery Analgesia in a Super Obese Parturient
Abstract Number: 133
Abstract Type: Case Report/Case Series
A 19 y/o G1P0 presented for induction of labor versus Cesarean delivery (CS) at 38 5/7 weeks gestation. Past medical history included morbid obesity, obstructive sleep apnea (OSA) on CPAP, hypertension and suicide attempts. On physical exam her weight was 272.6 kg (601 lbs), height 193 cm (BMI =73.2), and airway Mallampati I. Induction of labor was performed in an operating room secondary to transport concerns should urgent CS be required. An intrathecal catheter was placed for labor analgesia. After 4.5 hours, the fetal heart tracing became nonreassuring and urgent CS was required. The intrathecal catheter was bolused with 10.5 mg bupivacaine and 25 mcg fentanyl. A vertical skin and a classical uterine incision were performed because of body mass. Intrathecal morphine was not administered secondary to concerns of postoperative hypoventilation. Bilateral transversus abdominis plane (TAP) blocks under ultrasound guidance were performed with 40 cc of 0.25% bupivacaine on each side with a 6 cm 22g needle and a SonoSite MicroMaxx machine, with a C60e 5-2MHz 60-mm broadband curved array. Three hours later, decreased sensation to cold on the right from T10-T12 and the left side from T8-T12 was present. Aside from sparing the right upper portion of her vertical incision, she was comfortable and was ambulating without difficulty later the same day. TAP blocks have been shown to improve analgesia and decrease intravenous PCA morphine requirements when compared with placebo after CS. However, the performance of the blocks on a patient of this size has yet to be described. Modification to the technique described in the literature was required to perform this block including use of the above described curvilinear probe rather than the linear probe (8-12MHz linear array). The average depth of a TAP block is about 2-4 cm, but the depth required in this patient was 5-6 cm after significant probe pressure and retraction of the pannus by a sterile assistant. In patients with OSA and morbid obesity, TAP blocks may provide adequate analgesia and decreased risk for postoperative hypoventilation from intrathecal or intravenous opioids.
Figure 1 Upper left: In-plane ultrasound-guided TAP block performed on patient's left side. Two sterile hands used to retract excess abdominal mass. Upper right: Proceduralist visualizes 6 in needle with curvilinear 2-5 Mhz probe. Bottom: Side profile of patient post-cesarean section.