The pharmacokinetics of remifentanil make it the only opioid which is consistent with a rapid sequence induction. Its short period of action avoids the manual ventilation of patients before intubation, while providing a peak of action concomitant to the nociceptive stimulation. Patients at high risk of aspiration, including pregnant women, may benefit from this type of morphine at induction. In addition, the fact that remifentanil seems to be associated with relative fetal safety in obstetrical or neonatal context legitimized the development of protocols to study maternal-fetal consequences of the use of remifentanil at induction of AG for emergency caesarean section.