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Propofol and alfentanil in children: infusion technique and dose requirement for total i.v. anaesthesia
B L Browne1, C Prys-Roberts, A R Wolf
1Sir Humphry Davy Department of Anaesthesia, Bristol Royal Infirmary.
Insights
This study determined propofol dosage for total intravenous anesthesia in children using two alfentanil infusion rates. Higher alfentanil infusion rates required lower propofol doses for effective anesthesia.
Area of Science:
- Anesthesiology
- Pediatric Anesthesia
- Pharmacology
Background:
- Total intravenous anesthesia (TIVA) is crucial in pediatric surgery.
- Optimizing anesthetic agent combinations ensures patient safety and efficacy.
- Alfentanil and propofol are commonly used for TIVA in children.
Purpose of the Study:
- To estimate the propofol dose required for total intravenous anesthesia in children aged 3-12 years.
- To compare propofol requirements when co-administered with two different alfentanil infusion regimens.
Main Methods:
- A prospective study involving 59 children (3-12 years) undergoing surgery.
- Two series of alfentanil administration: Series 1 (85 mcg/kg loading, 65 mcg/kg/hr infusion) and Series 2 (65 mcg/kg loading, 50 mcg/kg/hr infusion).
- Propofol was administered with a loading dose and a three-stage infusion; probit analysis determined ED50 and ED95 for propofol.
Main Results:
- In Series 1, the median effective dose (ED50) of propofol was 6.0 mg/kg/hr, and the 95% effective dose (ED95) was 8.6 mg/kg/hr.
- In Series 2, the ED50 of propofol was 7.5 mg/kg/hr, and the ED95 was 10.5 mg/kg/hr.
- Higher alfentanil infusion rates were associated with lower propofol requirements.
Conclusions:
- Alfentanil infusion rate significantly influences propofol dosage requirements for TIVA in children.
- Adjusting alfentanil infusion can help optimize propofol administration, potentially improving anesthetic management.
- These findings contribute to refining TIVA protocols in pediatric populations.
Abstract:
We estimated the dose of propofol (initial dose followed by a stepped infusion) when given with two different infusion rates of alfentanil for total i.v. anaesthesia in 59 children aged 3-12 yr. Patients in series 1 (four groups) received an alfentanil loading dose of 85 micrograms kg-1 and an infusion of 65 micrograms kg-1 h-1. Patients in series 2 (groups 5 and 6) received an alfentanil loading dose of 65 micrograms kg-1 and infusion of 50 micrograms kg-1 h-1. Parents gave their informed consent. Premedication comprised temazepam 0.3 mg kg-1. Glycopyrronium 5 micrograms kg-1 was administered and anaesthesia induced and maintained with alfentanil (loading dose and infusion) followed by propofol (loading dose and three-stage manual infusion scheme). Suxamethonium 1 mg kg-1 was used to facilitate tracheal intubation and the lungs were ventilated artificially to normocapnia with 30% oxygen in air. Probit analysis was used to determine the dose requirement of propofol. In series 1, the ED50 was 6.0 mg kg-1 h-1 (95% confidence limits 5.5-6.2 mg kg-1 h-1) and ED95 8.6 (6.8-7.8) mg kg-1 h-1. Corresponding values for series 2 were ED50 7.5 (8.0-9.8) mg kg-1 h-1 and ED95 10.5 (9.6-13.1) mg kg-1 h-1.