DOSE–RESPONSE OF ROPIVACAINE ADMINISTERED CAUDALLY TO CHILDREN UNDERGOING SURGICAL PROCEDURES UNDER SEDATION WITH MIDAZOLAM
1. In a double-blind randomized controlled design, 50 children were allocated to receive bupivacaine 0.25% or ropivacaine 0.25%, 0.32%, 0.40% or 0.50% by caudal block.
2. Caudal block was performed after induction of anaesthesia with 2–5% sevoflurane, atropine 10 µg/kg and midazolam 100–300 µg/kg. During the surgical procedure, patients were maintained under spontaneous ventilation and no intravenous or inhalatory anaesthetic agent was administered. For transoperative sedation, midazolam 100–300 µg/kg was administered every 0.5–1.0 h. Transoperative cardiovascular response, postoperative analgesia and local and systemic complications were evaluated.
3. Groups were similar (P > 0.05) in sex, age, weight and in the time elapsed from caudal block to the beginning of the surgical procedure. The surgical time was significantly lower in the ropivacaine 0.25% group. The duration of analgesia was 24 h with ropivacaine 0.25% and approximately 10 h in the other four groups (P < 0.001). Linear regression analysis revealed a significant relationship between the postoperative analgesic period produced by ropivacaine and the surgical time (r = − 0.48, two-sided P = 0.002). Systolic and diastolic blood pressures remained in the physiologically normal range for the duration of the transoperative period. Vomiting was present in only one patient receiving ropivacaine 0.50%.
4. In children, the duration of analgesia produced by caudal block with ropivacaine may be affected by surgical time. At surgical times of 0.5–1 h, ropivacaine 0.25% produced at least 24 h postoperative analgesia. At similar surgical times, ropivacaine 0.32%, 0.40% and 0.50% produced similar analgesic times to bupivacaine 0.25%.
Document Type: Research Article
Affiliations: 1: Hospital de Gineco-Pediatría no. 48, IMSS, 2: Centro Médico de León, León, Guanajuato, and 3: Department of Anaesthesia and Respiratory Therapy, Hospital Infantil de México Federico Gómez, México DF, México
Publication date: July 1, 2004