Programmed Intermittent Epidural Bolus Time Interval and Injection Volume

Studies suggest that administration of maintenance epidural solutions as programmed or automated intermittent boluses, rather than continuous infusions, result in lower bupivacaine consumption, decreased need for manual boluses by the anesthesiologist, and greater patient satisfaction. In this technique, the epidural maintenance dose is administered as a bolus by the infusion pump at regular intervals instead of as a continuous infusion. However, the optimal combination of bolus volume and dosing interval has not been determined. At one end of the spectrum, a small volume and short bolus dose interval will likely behave like a continuous infusion. At the other end of the spectrum, a large volume and long bolus dose interval may lead to an increased incidence of breakthrough pain. The purpose of this randomized, double-blind trial was to determine how manipulation of the programmed intermittent time interval and volume influences total drug use, quality of analgesia, and patient satisfaction during maintenance of labor analgesia. We hypothesized that manipulation of the programmed intermittent bolus time interval and volume during the maintenance of epidural labor analgesia influences total drug use, quality of analgesia and patient satisfaction.