The T REX Pilot Study: a Study to Investigate the Use of an Alternative Anaesthetic in Infants.

Animal studies suggest general anaesthetics harm the developing brain. It is unclear if
these findings are relevant to humans but the issue has become a major concern. Recent data
have found that monkeys exposed to anaesthesia as infants grow up to have slower learning
than those not exposed.

The aim of the TREX pilot study is to determine the feasibility of an alternative
anaesthetic regimen for lower abdominal/lower extremity surgery in infants 1-12 months of
age.

An alternative anaesthetic regimen comprises a dexmedetomidine-based anaesthetic, augmented
with an opioid (remifentanil) and a regional nerve block (such as a caudal).

This open label prospective single arm pilot study will enrol 50 infants aged 1-12 months
scheduled for lower limb, urologic, or lower abdominal surgery. After sevoflurane induction,
the infants will have a caudal anaesthetic and intravenous dexmedetomidine and remifentanil.

The outcome will be need for intervention for light anaesthesia, intervention for
haemodynamic changes and rate of abandoning the protocol. Recovery times will also be
recorded.

Inclusion Criteria:

- Infants aged 1 to 12 months (corrected age)

- ASA I or II

- Infants undergoing lower abdominal/lower extremity surgery anticipated to be > 120
minutes in duration

- Surgery requires caudal regional nerve block

Exclusion Criteria:

- ASA III or higher

- Any contraindication to caudal analgesia

- Any contraindication to an inhalational induction with sevoflurane

- Allergies to any medication in study protocol

- Planned admission to an ICU postoperatively (except level II or III neonatal ICU)

- Planned tracheal intubation postoperatively

- Mechanical ventilation postoperatively