title: An audible indication of exhalation increases delivered tidal volume during bag valve mask ventilation of a patient simulator.
abstract: Self-inflating manual resuscitators (SIMRs) can mislead caregivers because the bag, unlike a Mapleson-type device, reinflates even without patient exhalation. We added a whistle as an audible indicator to the exhalation port of a SIMR. In randomized order, each participant provided two sets of breaths via mask ventilation with a SIMR, one with and one without audible feedback, to a Human Patient Simulator modified to log lung volume changes. The last three breaths in each set were used to compare average tidal volume (Vt) under both conditions. Eighty-seven advanced cardiac life support trainees (54 males, 33 females) with clinical experience averaging 6.4 +/- 9.4 yr were recruited. Average Vt delivered with the standard SIMR was 486 +/- 166 mL and 624 +/- 96 mL with the modified SIMR. Average Vt delivered by a modified SIMR was significantly larger by 40% when it followed standard SIMR use and 19% when using the modified SIMR first. Use of a SIMR with an audible indicator of exhalation significantly (P < 0.001) increased mask ventilation of a patient simulator, suggesting that mask ventilation of a patient with a SIMR may also be increased by objective, real-time feedback of exhaled Vt.
authors.affiliation: Department of Anesthesiology, University of Florida College of Medicine, Gainesville, Florida, USA. slampotang@anest.ufl.edu
authors.forename: Samsun
authors.initials: S
authors.lastname: Lampotang
authors.forename: D E
authors.initials: DE
authors.lastname: Lizdas
authors.forename: N
authors.initials: N
authors.lastname: Gravenstein
authors.forename: S
authors.initials: S
authors.lastname: Robicsek
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation / Q000379:methods*; D000328:Adult; D045853:Exhalation / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology*; D006801:Humans; D008297:Male; D008397:Masks; D008875:Middle Aged; D016544:Patient Simulation; D012123:Pulmonary Ventilation / Q000502:physiology; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods*; D013990:Tidal Volume / Q000502:physiology*