Efficacy of ultrasound imaging in obstetric epidural anesthesia

Study Objective: To assess the clinical use of ultrasonographic localization of the epidural space, and to evaluate the clinical efficacy of ultrasound diagnostics in obstetric anesthesia. Design: Randomized prospective study. Setting: University Clinic of Obstetrics and Gynecology. Patients: 300 parturients, 85 of whom had conventional delivery and 65 who underwent cesarean section. Interventions: Patients underwent ultrasonography for the identification of the intervertebral structures. Puncture depth and angle were measured to improve the placement of the Tuohy needle. Measurements: In the ultrasound group, additional puncture data, optimized Puncture point, expected puncture depth, and angle were used to optimize the puncture technique. To control for side effects, we compiled data on the number of puncture attempts and the number of necessary puncture levels, visual analog scale (VAS) scores, the rate of side effects, and the patient acceptance of the technique. Main Results: The two groups were similar regarding demographic data. Using ultrasound for structure detection, the rate of puncture attempts were significantly (p <. 0.013) reduced from 2.18 +/- 1.07 to 1.35 +/- 0.61. The mean rate of necessary puncture levels was 1.30 +/- 0.55 and with ultrasound detection 1.136 +/- 0.36 (p < 0.029). Complete analgesia was achieved in 147 patients with ultrasound detection versus 138 patients in the Control group (p < 0.03). The maximum VAS pain score in the control group was 1.3 +/- 2.1 versus 0.8 +/- 1.5 in the Ultrasound group (p < 0.006). The rate of side effects were reduced significantly: 99 patients in the Control group had no side effects compared with 120 patients from the Ultrasound group who were free of side effects. Patient acceptance of the technique in the Ultrasound g-roup was significantly higher than in the Control group. Conclusion: The clinical use of ultrasound for epidural catheter placement may improve regional anesthesia. The use of ultrasound resulted in superior quality in all measured endpoints. (C) 2002 by Elsevier Science Inc.