title: Repeated thermo-sterilisation further affects the reliability of positive end-expiratory pressure valves.
abstract: OBJECTIVE
  Positive end-expiratory pressure (PEEP) valves are used together with self-inflating bags (SIB) to provide a preset PEEP during manual ventilation. It has recently been shown that these valves deliver highly variable levels of PEEP. We hypothesised that material fatigue due to repeated thermo-sterilisation (TS) may contribute to varying reliability of PEEP valves.
  
  
  METHODS
  In a laboratory study 10 new PEEP valves were tested before and after 10, 20 and 30 cycles of routine TS (7 min at 134°C) by using a neonatal lung model (compliance 0.2 mL/kPa). Settings were positive inflation pressure = 20 and 40 cm H(2)O, PEEP = 5 and 10 cm H(2)O, respiratory rate = 40 and 60/min, flow = 8l/min. PEEP was recorded using a respiratory function monitor.
  
  
  RESULTS
  Before TS, a mean (standard deviation) PEEP of 4.0 (0.9) and 7.7 (1.0) cm H(2)O was delivered by the 10 valves when the PEEP was set to 5 and 10 cm H(2)O, respectively. One new valve only delivered 2.0 (0.0) and 5.0 (0.0) cm H(2)O when the PEEP was adjusted to 5 and 10 cm H(2)O, respectively. Four of the 10 investigated valves showed significant variations in PEEP (coefficient of variation >10%) throughout the autoclaving process. One valve completely lost its function after the 20th TS. Common defects were tears in the softer materials or displacement of the rubber seal. Six of the 10 valves continued to provide PEEP in spite of repeated TS.
  
  
  CONCLUSIONS
  The reliability of PEEP valves is affected by repeated TS. Multi-use PEEP valves should be tested for reliable PEEP provision following TS.
authors.affiliation: Department of Neonatology, Charité University Medical Center, Berlin, Germany.
authors.forename: Julia Christine
authors.initials: JC
authors.lastname: Hartung
authors.forename: Georg
authors.initials: G
authors.lastname: Schmölzer
authors.forename: Gerd
authors.initials: G
authors.lastname: Schmalisch
authors.forename: Charles Christoph
authors.initials: CC
authors.lastname: Roehr
mesh_terms: D004867:Equipment Design; D004868:Equipment Failure; D006801:Humans; D007231:Infant, Newborn; D008953:Models, Anatomic; D011175:Positive-Pressure Respiration / Q000295:instrumentation*; D015203:Reproducibility of Results; D013242:Sterilization / Q000379:methods
keywords: PEEP; airway; neonate; resuscitation; valve.