Determination of the Optimal "Next Bolus" Interval for Programmed Intermittent Bolus Epidural Analgesia

The current standard of practice for the maintenance of epidural analgesia is through use of a continuous infusion pump. Enhanced technology now supports the use of programmed intermittent bolus (PIEB) administration. This novel drug delivery system provides small boluses of local anesthetic and opioid at programmed intervals. Several studies suggest that administration of PIEB allows a more extensive spread of local anesthetic in the epidural space and provides superior labour analgesia compared to traditional continuous epidural infusions. PIEB is associated with lower anesthetic consumption, a shorter second stage of labour and greater patient satisfaction. The authors are focusing on a PIEB setting known as the "Next Bolus". "Next Bolus" (NB) determines when the first PIEB bolus is given after the initiation of the epidural and starting the PIEB pump. Currently we set this to be 15-45 minutes. In an attempt to optimize resources, authors hope to determine the optimal NB interval that will provide adequate analgesia but limit overall drug consumption. An optimally timed next bolus should minimize drug costs and limit nurse and physician intervention by decreasing the need for manual boluses.Increased local anesthetic consumption can cause undesirable side effects such as itchiness, decreased blood pressure and motor blockade. By assigning patients to receive the NB at 15, 30 or 45 minutes the authors hope to find the interval that provides analgesia while minimizing side effects, improving patient safety. If the bolus is given too late then there may be increased pain, less patient satisfaction, and the need for more analgesia in the form of Patient Controlled Epidural Anesthesia or a manual bolus.The authors hope that determining the NB will result in an institutional change to improve patient outcomes and facilitate knowledge transfer. This information will be the first available research to help guide other obstetrical centres using PIEB technology in determi