2002 OPEN FORUM Abstracts
A Bench Evaluation of Disposable PEEP Valves
Kent Miller, CBET, RRT; Valerie Stevenson, RRT; Elizabeth Grab, RRT; Respiratory Care Department, University of Michigan Health Systems, Ann Arbor Michigan
Background: Acutely ill mechanically ventilated patients may require PEEP>5 cm H2O to maintain oxygenation. PEEP should be maintained during transport with manual ventilation. Disposable PEEP valves are available to use with disposable manual resuscitation bags. Although manufacturers may recommend that a pressure manometer be used in-line to monitor the desired PEEP level, this study was done to evaluate the performance of disposable PEEP valves.
Methods: A disposable PEEP valve from 5 manufacturers was evaluated; all valves were new and in original packaging. They were inspected for physical damage or defects. A calibrated manometer was connected to the resuscitation bag to obtain measurement of actual PEEP readings. PEEP of 5, 10, 15, & 20 cm H2O were evaluated with each valve. O2 flows of 10 and 15 L/min were used at each PEEP level. At each PEEP level, the resuscitation bag was first compressed 5 times to establish a baseline pressure. During actual measurements, the bag was compressed 5 times every 5 seconds and pressure read at the end-exhalation. Valves used: Nellcor Puritan Bennett #135138-00, AMBU #199 003 000, Nutec #N3330,Mercury Medical #10-55330, Vital Signs #7620, SIMS-Portex #008001.
Results: Evaluation of the recorded data demonstrated 3 PEEP valves showing higher PEEP levels then set; 1 disposable PEEP valve showed lower PEEP levels then set; and 1 disposable PEEP valve showed PEEP levels consistent with what was set. The figure shows data at 15 L/min:
Discussion: The set PEEP level on a disposable PEEP valve may not correlate with measured PEEP levels. Some of the products evaluated revealed a greater than 50% degree of variability in set vs measured. This degree of variability may become clinically significant and have negative consequences in critically ill patients. Most suppliers indicated on their package insert that an independent manometer was recommended but the strength of the recommendation varied. Based on the results of this evaluation, we recommend that clinicians utilizing a disposable PEEP valve evaluate the valves performance when in use.