Caudal Block for Postoperative Analgesia Clinical Trial
Official title:
Comparison of Optic Nerve Sheath Diameter in Children Receiving Caudal Block According to Anesthetic Agents: Total Intravenous Anesthesia vs. Volatile Anesthesia
Caudal block is commonly used for postoperative analgesia in paediatric patients. A higher volume (1.5 ml/kg) of local anaesthetic for caudal block has been reported to not only increase the level of cranial spread but also provide better quality and longer duration of analgesia in comparison with the conventional volume (1.0 ml/kg). However, caudal block with a high volume of local anaesthetic can increase intracranial pressure (ICP). Previous studies have shown that propofol anesthesia lowers ICP when compared with volatile anesthesia. Therefore, this study was designed to test if propofol can reduce the magnitude of ICP increase following caudal block when compared with a volatile anesthetic, sevoflurane. There is increasing evidence that optic nerve sheath diameter (ONSD) measured by ultrasonography correlates with degree of ICP and is able to detect intracranial hypertension. Therefore, ONSD will be measured as a surrogate of ICP.
Equal number of patients are randomly assigned to the P or S group. The participants in the P and S group are anesthetized with propofol and sevoflurane, respectively. Irrespective of assigned group, all participants receive caudal block with 1.5 ml/kg of 0.15% ropivacaine (up to 30 ml per individual participant). All anesthetic procedures except for main anesthetic agent are the same in all participants. ONSD is measured at the following time points: before (T0), immediately after (T1), and 10 min (T2) and 30 min(T3) after caudal block. Two measurements of each optic nerve sheath are acquired in each eye. The mean value of the four measurements is considered as the ONSD at each time point. ;