2.1. Study population
labor
CARDIOVASCULAR DISEASES, ENDOCRINE DISEASES, BLIND, HEART, DISEASES
This was a prospective, randomized, double blind clinical trial which was approved by the institutional Ethics Committee of the fifth People Hospital of Jinan (Ethics No: 21-5-01). (11/12/2021) and Jinan Maternal and Children Care Hospital, Shandong first Medical University (Ethics No: 2021-1-041). (11/15/2021). The written informed consent was obtained from all subjects before the study. The trial was registered at the Chinese Clinical Trials Registry (ChiCTR2100053337; XinWang, Yaqiu Guo; 11/19/2021).In this study, 120 healthy parturients who were scheduled to undergo labor analgesia in the fifth People Hospital of Jinan (n = 60) and Jinan Maternity and Children Care Hospital (n = 60) from November 2021 to February 2022 were enrolled. The inclusion criteria were as follows: patients had American Society of Anesthesiologists grade I–II and New York Heart Association Heart Function grade I; the height was 155 to 175 cm; the weight was 55 to 95 kg; subjects had a singleton pregnancy of 37 to 42 weeks; subjects voluntarily received epidural labor analgesia when the cervical diameter was 1 to 3 cm; subjects had no cardiovascular diseases, endocrine diseases, mental diseases, and deformities. The exclusion criteria were as follows: subjects had induced labor; the body mass index was >40 kg/mA total of 120 parturients were randomly divided into EA group (n = 40), DPE1 group (n = 40), and DPE2 group (n = 40) according to the computer-generated random numbers. The group assignment was hidden in an opaque, numbered envelope and opened by the anesthesiologist before the start of analgesia, and the investigators who evaluated the results were blind to the grouping. Two full-time anesthesiologists performed the puncture operation, and both were anesthesiologists with an intermediate professional title and had experience in anesthesia for more than 6 years. The intervertebral space of lumbar vertebrae 2 to 3 (L2–L3) was selected for puncture of the epidural space with a 16-G puncture needle. After using a loss of resistance to saline technique to confirm the success of epidural puncture, in the EA group, the experimental dose was delivered by bolus injection after the epidural catheter was inserted into the epidural space in the cranial direction by 4 cm; the experimental dose was 5 mL of 1% lidocaine, and the bolus injection was performed at 1 mL/second. In the DPE1 group, the dura mater was punctured with a 25-G dural puncture needle to access the subarachnoid space, and the successful puncture was determined as cerebrospinal fluid outflow. Then, the puncture needle was withdrawn, the epidural catheter was inserted into the epidural space by 4 cm in the cranial direction, and the experimental dose was delivered by epidural catheter. The experimental dose here was the same as that in the EA group. The injection was performed at 1 mL/second. In the DPE2 group, the dura mater was punctured with a 25-G dural puncture needle to reach the subarachnoid space, and the puncture needle was removed. The experimental dose was directly delivered by bolus injection from the epidural puncture needle, and the experimental dose was the same as that in the EA and DPE1 groups. The injection was also performed at 1 mL/second. After drug injection, the epidural catheter was inserted into the epidural space by 4 cm in the cranial direction. After bolus injection, if no abnormality was found within 10 minutes, programmed intermittent epidural bolus plus patient-controlled EA was initiated. According to the height of the parturient, the background dose was set as 0.083% ropivacaine at 10 mL/50 minutes, the patient-controlled dose was 8 mL, and the locking time was 30 minutes.