Reliability of Single-Use PEEP-Valves Attached to Self-Inflating Bags during Manual Ventilation of Neonates – An In Vitro Study

Abstract

IntroductionInternational resuscitation guidelines suggest to use positive end-expiratory pressure (PEEP) during manual ventilation of neonates. Aim of our study was to test the reliability of self-inflating bags (SIB) with single-use PEEP valves regarding PEEP delivery and the effect of different peak inflation pressures (PIP) and ventilation rates (VR) on the delivered PEEP.MethodsTen new single-use PEEP valves from 5 manufacturers were tested by ventilating an intubated 1kg neonatal manikin containing a lung model with a SIB that was actuated by an electromechanical plunger device. Standard settings: PIP 20cmH2O, VR 60/min, flow 8L/min. PEEP settings of 5 and 10cmH2O were studied. A second test was conducted with settings of PIP 40cmH2O and VR 40/min. The delivered PEEP was measured by a respiratory function monitor (CO2SMO+).ResultsValves from one manufacturer delivered no relevant PEEP and were excluded. The remaining valves showed a continuous decay of the delivered pressure during expiration. The median (25th and 75th percentile) delivered PEEP with standard settings was 3.4(2.7–3.8)cmH2O when set to 5cmH2O and 6.1(4.9–7.1)cmH2O when set to 10cmH2O. Increasing the PIP from 20 to 40 cmH2O led to a median (25th and 75th percentile) decrease in PEEP to 2.3(1.8–2.7)cmH2O and 4.3(3.2–4.8)cmH2O; changing VR from 60 to 40/min led to a PEEP decrease to 2.8(2.1–3.3)cmH2O and 5.0(3.5–6.2)cmH2O for both PEEP settings.ConclusionSingle-use PEEP valves do not reliably deliver the set PEEP. PIP and VR have an effect on the delivered PEEP. Operators should be aware of these limitations when manually ventilating neonates.

Delivery of positive end-expiratory pressure to preterm lambs using common resuscitation devices

“…Previous studies show some degree of variability between valves 22–24. We are concerned that one newly purchased valve from one model did not provide any PEEP, consistent with a report of other brands 23. We had previously tested this SIB model showing that it had limitations, compared with other SIBs in generating consistent PIP and prolonged inflations 40.…”

Delivery of Positive End-Expiratory Pressure Using Self-Inflating Bags during Newborn Resuscitation Is Possible Despite Mask Leak

“…Studying five different single-use PEEP valves for SIBs and the effects of different PIP and ventilation rates on a manikin, Hartung et al [11] concluded that the PEEP valves could not reliably deliver the set PEEP. In contrast, in a manikin study using prototypes of the new silicone PEEP valve used in our study, Thallinger et al [17] concluded that inexperienced participants were able to generate reliable PEEP with a SIB without external gas flow.…”

“…In many low-income settings, such equipment is neither available nor affordable, and bag-mask ventilation (BMV) with a self-inflating bag (SIB) is the only alternative. Previous studies on newborn manikins or lung simulators have reported that PEEP valves for SIBs deliver unreliable PEEP with high variability depending on mask leak and the BMV rate [9][10][11][12].…”

Neonatal ventilation with a manikin model and two novel PEEP valves without an external gas source

“…Tracy et al 31 found that experienced neonatal medical staff delivered consistent levels of PEEP close to the set level by the manufacturer when ventilating a leak-free test lung with Ambu PEEP valves on a self-inflating bag. Hartung et al 25 reported that 10 new single-use PEEP valves from different manufacturers did not deliver the set PEEP when ventilating intubated neonatal manikin with a leak-free system.…”