title: Developing a strategy to improve ventilation in an unprotected airway with a modified mouth-to-bag resuscitator in apneic patients.
abstract: The strategies to ensure safety during ventilation of an unprotected airway are limiting airway pressure and/or inspiratory flow. In this prospective, randomized study we assessed the effect of face mask ventilation with small tidal volumes in the modified mouth-to-bag resuscitator (maximal volume, 500 mL) versus a pediatric self-inflatable bag versus automatic pressure-controlled ventilation in 40 adult apneic patients during induction of anesthesia. The mouth-to-bag resuscitator requires the rescuer to blow up a balloon inside the self-inflating bag that subsequently displaces air which then flows into the patient's airway. Respiratory variables were measured with a pulmonary monitor (CP-100). Mouth-to-bag resuscitator and pressure-controlled ventilation resulted in significantly lower (mean +/- sd) peak airway pressure (8 +/- 2 and 8 +/- 1 cm H(2)O), peak inspiratory flow rate (0.7 +/- 0.1 and 0.7 +/- 0.1 L/s), and larger inspiratory time fraction (33% +/- 5% and 47% +/- 2%) in comparison to pediatric self-inflating bag ventilation (12 +/- 3 cm H(2)O; 1 +/- 0.2 L/s; 27% +/- 4%; all P < 0.001). The tidal volumes were similar between groups. No stomach inflation occurred in either group. We conclude that using a modified mouth-to-bag resuscitator or automatic pressure-controlled ventilation with similar small tidal volumes during face mask ventilation resulted in an approximately 25% reduction in peak airway pressure when compared with a standard pediatric self-inflating bag.
authors.affiliation: Department of Anesthesiology and Critical Care Medicine, Medical University, Innsbruck, Austria.
authors.forename: Achim
authors.initials: A
authors.lastname: von Goedecke
authors.forename: Christian
authors.initials: C
authors.lastname: Keller
authors.forename: Horst G
authors.initials: HG
authors.lastname: Wagner-Berger
authors.forename: Wolfgang G
authors.initials: WG
authors.lastname: Voelckel
authors.forename: Christoph
authors.initials: C
authors.lastname: Hörmann
authors.forename: Angelika
authors.initials: A
authors.lastname: Zecha-Stallinger
authors.forename: Volker
authors.initials: V
authors.lastname: Wenzel
mesh_terms: D000328:Adult; D000399:Air Pressure; D001049:Apnea / Q000628:therapy*; D016887:Cardiopulmonary Resuscitation; D023381:Endpoint Determination; D005260:Female; D006323:Heart Arrest / Q000628:therapy; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006993:Hypnotics and Sedatives; D008297:Male; D008874:Midazolam; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010100:Oxygen / Q000097:blood; D011229:Preanesthetic Medication; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods*; D015656:Respiratory Mechanics / Q000502:physiology; D018401:Sample Size; D013990:Tidal Volume / Q000502:physiology
chemical_list: D006993:Hypnotics and Sedatives; D008874:Midazolam; D010100:Oxygen