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Reduction in standard MAC and MAC for intubation after clonidine premedication in children
S Inomata1, S Kihara, Y Yaguchi
1Department of Anaesthesiology, University of Tsukuba, Ibaraki, Japan.
Insights
Oral clonidine effectively reduced the minimum alveolar concentration for endotracheal intubation (MACEI) and skin incision (MAC) in children. These anesthetic-sparing effects were dose-dependent, with higher clonidine doses yielding greater reductions.
Area of Science:
- Anesthesiology
- Pediatric Anesthesia
- Pharmacology
Background:
- Clonidine is an alpha-2 adrenergic agonist with sedative and analgesic properties.
- Its potential to reduce anesthetic requirements in pediatric patients requires further investigation.
Purpose of the Study:
- To evaluate the dose-dependent effects of oral clonidine on the minimum alveolar concentration (MAC) for endotracheal intubation (MACEI) and skin incision (MAC) in children.
Main Methods:
- A randomized, placebo-controlled study involving 90 children (aged 2-8 years) receiving placebo, oral clonidine 2 µg/kg, or 4 µg/kg 100 minutes before anesthesia.
- Anesthesia was maintained with sevoflurane in oxygen and air. MAC values were determined using Dixon's up-and-down method.
Main Results:
- Mean MACEI decreased from 2.9% (placebo) to 2.5% (2 µg/kg) and 1.9% (4 µg/kg) (P < 0.05).
- Mean MAC decreased from 2.3% (placebo) to 1.8% (2 µg/kg) and 1.3% (4 µg/kg) (P < 0.05).
- The MACEI/MAC ratio remained unchanged.
Conclusions:
- Oral clonidine significantly reduces sevoflurane MAC requirements for intubation and skin incision in a dose-dependent manner in children.
- Clonidine demonstrates anesthetic-sparing effects without altering the ratio of MACEI to MAC.
Abstract:
We examined the relative effects of different doses of oral clonidine on the MAC for endotracheal intubation (MACEI) and the MAC for skin incision (MAC) in children. We studied 90 children (15 in each group) (age range 2-8 yr, weight 10-27 kg, height 89-124 cm) who received one of three preanaesthetic medications: placebo (control), oral clonidine 2 micrograms kg-1, or oral clonidine 4 micrograms kg-1 100 min before anaesthesia. Anaesthesia was induced and maintained with sevoflurane in oxygen and air without i.v. anesthetics and neuromuscular relaxants. The end-tidal sevoflurane concentration was kept constant for > or = 15 min before tracheal intubation or skin incision. MACs were determined using Dixon's 'up-and-down method'. Mean (SD) MACEIs of sevoflurane were 2.9 (0.1)%, 2.5 (0.1)% and 1.9 (0.1)% (P < 0.05), and MACs were 2.3 (0.1)%, 1.8 (0.1)% and 1.3 (0.1)% (P < 0.05), respectively, in control, clonidine 2 micrograms kg-1 and clonidine 4 micrograms kg-1 groups. The MACEIs and MACs decreased dose-dependently. The MACEI/MAC ratio (1.4) was not affected by clonidine.