Challenges of continuous spinal anesthesia for cesarean section in a morbidly obese woman
Abstract Number: 97
Abstract Type: Case Report/Case Series
Advantages of continuous spinal anesthesia (CSA) for a C-section in morbidly obese women include optimal titration of local anesthetics, unlimited surgical time, and possibly extended post-operative analgesia (1).
We present a 39 yo woman with a BMI of 81 (185kg) scheduled for repeat C-section for which CSA was considered to be optimal. In the sitting position, using a 17G Weiss epidural needle (5inch BD Perisafe™) at the L3-L4 interspace, the epidural space was found at full depth of the needle (13cm) using a saline loss of resistance technique. Further insertion of the Weiss needle to ∼14cm allowed dural puncture and free CSF flow. Insertion of a 19G Arrow FlexTip Plus™ epidural catheter was impossible despite several attempts at that level. A puncture at a higher intervertebral level with free CSF flow at ∼14cm did not allow threading of the catheter. A 3rd attempt at L3-L4 in the left lateral position allowed CSF free flow at ∼14cm. Only after turning the needle caudally was threading of a 20G catheter (BBraun Perifix®) possible, which was left at 20cm (skin). After CSF return, hyperbaric bupivacaine (0.75%) 5mg & fentanyl 15mcg was injected, resulting in a T12 block to pin-prick. Bupivacaine titration (2.5mg) to a total of 15mg (2ml) resulted in a T10 block. After further confirmation of CSF return, isobaric bupivacaine 10mg (2ml) was injected, with no effect on upper dermatome levels (T10). A general anesthetic was provided, which was uneventful. The catheter was kept post-op and provided adequate analgesia (intrathecal morphine 0.1mg twice, 18h apart). There was no postdural puncture headache despite three 17G punctures and relatively large amount of CSF 'loss' during the multiple attempts to thread the various catheters.
Radiological imaging was performed the next day (Figure). The catheter was inserted at L3-L4, located intrathecally with a tip at T12. There was no visible spinal stenosis up to T11 (higher stenosis could not be ruled out).
CSA can fail to provide surgical anesthesia for C-section despite CSF return and radiological confirmation of correct intrathecal location of the catheter. The use of imaging to provide an explanation for this unexpected failure proved to be limited as thoracic level imaging was unfortunately not performed. Imaging of the entire thoracic-lumbar region should be requested if a thoracic stenosis is suspected.
1 Palmer CM. Continuous spinal anesthesia and analgesia in obstetrics, Anesth Analg 2011.