This was a retrospective observational study approved by the Nara Medical University Institutional Review Board, Kashihara, Nara, Japan (Chairperson Prof. M Yoshizumi, Approval No. 1480 on February 20, 2017). Patients who underwent cesarean delivery under spinal anesthesia and a postoperative evaluation by anesthesiologists at Nara Medical University between January 2009 and December 2013 were considered candidates. Patients were excluded because of missing data, multiple pregnancies, headache prior to cesarean delivery, or conversion from spinal to general anesthesia during surgery.
In our hospital, extreme emergency cesarean delivery (stat cesarean delivery) is performed on patients under general anesthesia. Therefore, anesthesiologists are usually able to explain the single-shot spinal techniques as well as the side effects and complications associated with spinal anesthesia to patients. In case a patient requires epidural catheter placement, anesthesiologists explain the advantages and disadvantages of epidural catheter placement.
An intravenous catheter was inserted before arrival at the operating theater. Patients were then placed in the supine position for attachment of standard anesthesia monitors. Spinal anesthesia was performed by using a 25-G Quincke needle via the L3-4 or L4-5 interspace following lidocaine infiltration in the lateral position. Anesthesia was provided with 10–15 mg hyperbaric bupivacaine 0.5%, 100 μg morphine, and 10 μg fentanyl. Anesthesiologists usually explain to manage postoperative pain with intrathecal morphine. However, some pregnant women searched the way of postoperative pain relief before visiting anesthetic clinic. In case that patients requested epidural anesthesia, we made it consistent with patient’s intentions. When patients requested epidural anesthesia, an epidural catheter was inserted via the L1-2 or L2-3 interspace before spinal anesthesia. Intraoperative management, such as management of fluid status and blood pressure, was at the discretion of each anesthesiologist. After the operation, patients with an epidural catheter began epidural analgesia (0.2% ropivacaine) under the following conditions: bolus 5 mL, continuous infusion 4 mL/h, and lockout 60 min.
From 2 to 7 days after delivery and before discharge, anesthesiologists queried patients about paresthesia during needle insertion and lightning pain during spinal and/or epidural anesthesia, postpartum headache, and postoperative nausea, vomiting, pain, numbness of lower limbs, and itching with two choices “yes” or “none.” “Lightning pain” was defined as sudden and sharp pain accompanying needle puncture, and “paresthesia” was defined as an uncomfortable pain accompanying needle. Patients were then asked to evaluate overall anesthetic satisfaction by using a 4-point Likert scale (satisfaction, neutral, mild dissatisfaction, and dissatisfaction).
Additional information regarding maternal demographics (age, height, weight, parity, gestational weeks, and comorbidity), intraoperative data (surgical duration, time of day, block height, failed block, intraoperative use of sedatives or analgesics, and intraoperative use of antiemetic), neonatal Apgar score at 5 min postdelivery, and neonatal weight were collected from electronic medical records. The operative time of day was divided into four categories: daytime elective surgery, daytime emergency surgery, nighttime emergency surgery, and surgery on holidays. A failed block was defined as the need to repeat the spinal technique. The block height was divided into more than or equal to the level of Th4 or not.
Statistical analysis
Data are presented as the mean (standard deviation) or number. Univariate and multivariate logistic regression analyses were used to identify factors associated with perioperative anesthetic satisfaction. We defined the satisfied group as those patients who answered “satisfaction” to the question on the 4-point Likert scale. Univariate analysis was performed by using the chi-square test, Fisher’s exact test, Mann–Whitney U test, or unpaired t test, as appropriate. All explanatory factors were included in multivariate logistic regression analysis. Discrimination of the final models for the satisfied and dissatisfied groups was assessed by using the likelihood ratio test. Calibration of the models was tested by using the Hosmer–Lemeshow test. The area under the receiver operating characteristic curve was computed as a descriptive tool for measuring model bias. In the first step, we analyzed all patients (receiving spinal anesthesia only and combined spinal–epidural anesthesia (CSEA)). In the second step, patients undergoing spinal anesthesia only were analyzed in the same way to eliminate the effects of epidural anesthesia. All data were analyzed by using SPSS version 22.0 (IBM Inc., Armonk, NY, USA), and p values of < 0.05 (two-tailed) were considered as indicative of statistical significance.