TITLE:
An in Vitro Evaluation of Pressure Generated by Programmed Intermittent Epidural Bolus (PIEB) or Continuous Epidural Infusion (CEI)
AUTHORS:
Silvia Stirparo, Stefania Fortini, Stefania Espa, Antonio Cenedese, Giorgio Capogna
KEYWORDS:
Labor Analgesia; Epidural
JOURNAL NAME:
Open Journal of Anesthesiology,
Vol.3 No.4,
June
4,
2013
ABSTRACT: PIEB has been
reported as being superior to CEI for labor analgesia. The aim of this study
was to measure the pressures generated by two commercially available pumps
(CADD PIB, Smiths and Gemstar, Hospira) when delivering PIEB or CEI at 2
commonly used rates of infusion (10 or 5 mL). The two pumps were set to deliver
fluid at four rates (CEI: 5 or 10 mL/h; PIEB: 5 or 10 mL every h) and connected to a pressure transducer (PCB
Piezotronics 1500 connected to a NI USB-6251 Screw Terminal) to determine the
pressures applied during each infusion. The peak pressure generated during the PIEB mode was consistently higher when compared to
the CEI mode in both pumps. When comparing the two pumps in the PIEB 10 mL
every hour mode, the peak pressures were approximately the same, while the
pressure pattern differed. For each cycle the pressure generated by Gemstar
oscillated from 25 mmHg to 0 mmHg; whereas with the CADD pump the baseline
pressure was above 0. The Gemstar pump piston frequency (1.2 Hz) was twice as
high as the CADD (0.5 Hz), so the volume delivered per cycle was lower. In the
PIEB 5 mL every hour mode the peak pressures followed the same wave patterns.
However, unlike the 10 mL mode, the pump piston frequency was approximately the
same in both pumps. In
both the CEI 5 or 10 mL/h modes, the CADD peak pressure was four times greater
than the Gemstar. Both cycled between their respective peak pressures and 0
mmHg. Since the peak
pressure of the CADD was approximately the same with PIEB and CEI, we
speculated that the most important factor affecting the distribution of the
solution in the epidural space was not the peak pressure per se, but the
mode of delivery of the bolus.