A Dose Finding Study of Remifentanil and Propofol for Lumbar Punctures in Children

The Minimum Effective Dose of Remifentanil When Co-administered With Propofol for Lumbar Puncture in Children: A Dose-finding Study

This study will examine whether the combination of two anaesthetic medications, propofol and remifentanil, is suitable for short duration surgical procedures, providing a shorter recovery time and fewer side effects than either drug used alone.

Propofol is the primary medication used by anesthesiologists at HSC to provide sedation for lumbar puncture. Propofol provides amnesia, anxiolysis, and hypnosis, but because propofol has no analgestic properties patients often respond to the pain of LP needle insertion. To ensure patient immobility, the dose of propofol is often increased, resulting in a duration of action that is excessive for lumbar puncture. Remifentanil is an ultra-short acting opioid which can be used to provide analgesia and sedation for short painful procedures with minimal residual pain. However, when used as the sole agent, remifentanil is associated with a high incidence of respiratory depression and/or arterial oxygen desaturation and does not provide amnesia or anxiolysis. The combination of propofol and remifentanil may be particularly suitable for short duration procedures, providing a shorter recovery time and fewer side effects than either drug used alone. The objective is to determine the minimum effective dose of remifentanil required to prevent movement for insertion of a lumbar puncture needle when co-administered with propofol. The results obtained from this study will be used in a future study of the recovery characteristics of propofol and remifentanil in children undergoing lumbar puncture.

First patient in this arm will receive a bolus of propofol 4 mg/kg followed by remifentanil 0.5 mcg/kg. Subsequent patients randomized to this arm will receive propofol 4 mg/kg but the dose of remifentanil will be determined using the Dixon up-and-down method (i.e. based on the response of the previous patient)

First patient in this arm will receive a bolus of propofol 2 mg/kg followed by remifentanil 1 mcg/kg. Subsequent patients randomized to this arm will receive propofol 2 mg/kg but the dose of remifentanil will be determined using the Dixon up-and-down method (i.e. based on the response of the previous patient)

The first patient in this group will receive 4 mg/kg propofol and 0.5 ug/kg respectively. The dose of remifentanil in subsequent patients will be determined by the Dixon up-and-down method.

The first patient in this group will receive 2 mg/kg propofol and 1.0 ug/kg respectively. The dose of remifentanil in subsequent patients will be determined by the Dixon up-and-down method.

Minimum effective dose (Dixon methodology) and ED98 required to prevent movement during lumbar puncture needle insertion

Inclusion Criteria: Clinical diagnosis of a hemato-oncological disorder Scheduled to undergo a lumbar puncture Aged 4-11 years Male or female Unpremedicated Willing and able to provide informed consent (or informed consent by parents) Exclusion Criteria: Children who are known or suspected to be difficult to ventilate by face mask Children who are deemed medically unfit to receive either of the two study medications Children who are obese (weight for height > 95th percentile, Children who do not have an indwelling intravenous line

Hayes JA, Lopez AV, Pehora CM, Robertson JM, Abla O, Crawford MW. Coadministration of propofol and remifentanil for lumbar puncture in children: dose-response and an evaluation of two dose combinations. Anesthesiology. 2008 Oct;109(4):613-8. doi: 10.1097/ALN.0b013e31818629f3.