Pregnant Women

Background The spread of epidural analgesia is facilitated by pregnancy. Changes in the epidural structure during pregnancy may affect the spread of analgesia in pregnant women. To investigate the changes in the epidural space produced by pregnancy, the authors performed epiduroscopy in pregnant women. Methods: Using a flexible fiberscope, the authors evaluated the epidural space in 73 women undergoing lumbar epidural anesthesia. Patients were classified into three groups: a nonpregnant group (n = 211, a first trimester pregnant group (8-13 weeks, n = 23), and a third-trimester pregnant group (27-39 weeks, n = 29). A 17-gauge Tuohy needle was inserted using the paramedian technique and the loss-of-resistance method with 5 ml air. The epiduroscope was introduced into the lumbar epidural space via the Tuohy needle and was advanced approximately 10 cm in a cephalad direction from the needle tip within the epidural space. The differences in the epidural space among the three groups then was evaluated. Hormonal5-’ and mechanical changes8’9 induced by pregnancy have been cited as the reasons for such facilitation. Aortocaval compressionlo3’ and increased maternal blood volume” can result in engorgement of the epidural veins, which is likely to enhance the spread of local anesthetic^.'-^ Investigating the epidural space in a pregnant woman has been difficult because of the hazards of radiation to the fetus. We used epiduroscopy to investigate the differences in the epidural structure among nonpregnant women and women in various stages of pregnancy because this technique is free from the hazards of radiation and provides a clear view of the epidural space.’”16