This will be a prospective, observational, single-center study to evaluate the accuracy of sensory testing by blunt 16-gauge plastic cannula during the 15 minutes after spinal injection for predicting spinal failure. While previous studies assessed the minimal sensory level required for painless cesarean delivery at skin incision or delivery, no studies have assessed the accuracy of sensory testing at an earlier time point.
Primary Objective: 1\. Evaluate the accuracy of sensory testing with blunt plastic 16-gauge cannula during the 15 minutes after spinal injection for predicting spinal failure. Cephalad sensory dermatomal levels will be assessed at 1 (t1), 3 (t3), 5 (t5), 7 (t7), 9 (t9), 11 (t11), 13 (t13), and 15 (t15) minutes after intrathecal 1.6 ml 0.75% bupivacaine in 8.25% dextrose combined with 15 mcg fentanyl and 150 mcg morphine (study solution). Spinal failure, which is defined as inability to achieve a T4 level to pinprick by the 15-minute timepoint or intraoperative pain (VAS \> 0) requiring treatment Secondary Objectives: 1. Conversion to another anesthetic technique (general anesthesia or activation of the epidural catheter) 2. Inadequate anesthesia (analgesic supplementation with ketamine, \> 20 mg propofol, \> 2 mg midazolam, \> 10 mg parental morphine equivalents, or intraperitoneal chloroprocaine). 3. Patient satisfaction upon arrival to the postanesthesia care unit, rated on a 1-5 Likert scale A sample size calculation Population: 250 pregnant females undergoing non-emergency cesarean section delivery in the Labor \& Delivery Operating Rooms at Oregon Health \& Science University. Number of Sites: Single center trial Study Duration: Institutional Review Board approval has been obtained. Study initiation, enrollment, and data collection is expected to take 24 months. Data analysis, manuscript writing, editing, submission and revision to a peer-reviewed journal is expected to take an additional 6 months. In summary, the study should be completed in under 3 years. Subject Participation Duration: Total time of subject participation including time for recruitment, enrollment, data collection during the preanesthesia consult, and post-consult data collection will be less than 3 hours. Estimated Time to Complete Enrollment: Estimated time from enrollment into study of the first subject to enrollment into study of the last subject is 24 months.
Study Type
OBSERVATIONAL
Enrollment
250
Patients will receive standard intrathecal medications for urgent and scheduled cesarean delivery at the study site. All study subjects will receive bupivacaine, fentanyl, and morphine.
Oregon Health and Science University
Portland, Oregon, United States
Number of participants with spinal failure
A composite outcome that will be categorized as "yes" if there is either preoperative or intraoperative spinal failure. Preoperative failure will be defined as failure to achieve a T4 level to pinprick by the 15-minute timepoint. Intraoperative failure will be defined as pain (VAS \> 0) that requires anesthesia provider medication administration. Pain will be queried at time of skin incision, fetal delivery, uterine exteriorization, uterine interiorization or end of uterine closure, and end of skin closure. If VAS \> 0, the anesthesia provider will ask the patient if they would like analgesic medication. Discomfort at any other time during the cesarean delivery that is treated with neuraxial or intravenous analgesia will also count. Pain will be rated according to the scale: 0 = no pain, 10 = worst pain imaginable
Time frame: 90 minutes
Number of participants with conversion to another anesthetic technique
Conversion to general anesthesia or activation of the epidural catheter for intraoperative pain
Time frame: 90 minutes
Number of participants with inadequate anesthesia
Analgesic supplementation with ketamine, \> 20 mg propofol, \> 2 mg midazolam, \> 10 mg parental morphine equivalents, or intraperitoneal chloroprocaine
Time frame: 90 minutes
Patient satisfaction assessed by 5-point Likert scale, minimum value=1, maximum value=5, with higher values representing better patient satisfaction
Patient satisfaction upon arrival to the post-anesthesia care unit, rated on a 1-5 Likert scale with higher values representing better patient satisfaction
Time frame: 2 Hours
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