Transcutaneous CO2 tension effects of clonidine in paediatric caudal analgesia

Abstract

In adults, clonidine when added to bupivacaine, results in no detectable respiratory depressant effect except when carbon dioxide challenge is performed. However, to date no investigations have quantified this in children. Twenty-four children (nine months to seven years) were randomized in a double-blind study into two groups. After induction, a caudal block was performed with 1 ml.kg-1 0.25% bupivacaine. Clonidine 1 microgram.kg-1 was added in the clonidine group, and 1 ml normal saline in the placebo group. Patients were monitored in the recovery room for three h from arrival to discharge with continuous pulse oximetry, respiratory rate, a transcutaneous CO2 tension (tcPCO2) every 15 min, and a four point sedation score every 30 min. Mean tcPCO2 and respiratory rate values were not different between the two groups. Apnoea and desaturation less than 97% were not observed. The sedation score decreased with time in both groups, and the score time interval was significantly higher in the clonidine group (P < 0.05). All the patients left the recovery room with a sedation score of 1, excepting four in the clonidine group with a sedation score of 2. Clonidine 1 microgram.kg-1 with 0.25% bupivacaine mixture in caudal analgesia in children did not induce an increase in tcPCO2 despite prolonged sedation.

A Study of Comparison of Post-Operative Analgesia after Single-Shot Caudal Epidural Block Using Bupivacaine with or without Clonidine in Children

“…The slope of the ventilatory response to CO 2 decreased significantly from 2.06±0.70 (baseline) to 1.37±68, 1.25±0.65, and ±1.330.67 L/min/mm Hg (mean±SD, P less than 0.05) at 15, 60, and 120 min. 15 In this study, we did not find any effects on respiratory rate and SpO 2 , although sedation was more pronounced in the Clonidine group for the first 2 hours post-operatively.…”

Comparison of recovery after intermediate duration of anaesthesia with sevoflurane and isoflurane

“…When MAC awake (0.6 MAC for sevoflurane and 0.4 MAC for isoflurane) was obtained in both groups, the patient was turned to spontaneous ventilation (20). However, low residual concentration of halogenated agent can induce respiratory depression which seems more marked in the sevoflurane group (21); this may also be increased by midazolam premedication (22) and/or sedation due to caudal clonidine injection (23), medication not used in the previous study in children (5). Indeed, a vicious circle would be initiated: late elimination of residual sevoflurane concentration due to the ventilatory depression.…”

Human cardiovascular dose–response to supplemental oxygen

“…P tc CO 2 was therefore assessed in this study. Transcutaneously measured CO 2 ‐levels are considered highly reliable and accurate (Dupeyrat et al. 1998).…”