Preliminary evaluation of a prototype tube-valve-mask ventilator for emergency artificial ventilation

Ann Emerg Med. 1991 Mar;20(3):262-6. doi: 10.1016/s0196-0644(05)80936-9.


Study objective: The objective was to design a prototype tube-valve-mask ventilator that would permit relatively inexperienced operators to provide adequate emergency artificial ventilation, namely, adequate ventilatory volumes and a high oxygen and low carbon dioxide delivery.

Design: The tube-valve-mask ventilator is powered by the exhaled air of the operator and uses a tube to act as an oxygen reservoir (1,300 mL) that is filled between breaths. Mouth-to-mouth breathing was the standard against which the tube-valve-mask ventilator and the other accepted methods of mouth-to-mask and bag-valve-mask were assessed.

Setting: Comparison studies were conducted during simulated two-person CPR using a training mannikin equipped to measure ventilation volume and delivered oxygen and carbon dioxide concentrations.

Type of participants: Seventeen volunteer first-year nursing students were used as operators.

Interventions: The order in which the pairs of operators performed each of the techniques was randomized.

Measurements and main results: The ventilation volume and the percentage of oxygen and carbon dioxide delivered by each technique were as follows (mean +/- SD): Mouth-to mouth (760 +/- 290 mL, 17 +/- 1% O2, 3.4 +/- 0.4% CO2), mouth-to-mask (910 +/- 350 mL, 41 +/- 8% O2, 2.5 +/- 0.4% CO2), bag-valve-(soft) mask (550 +/- 230 mL, 94 +/- 3% O2, 0.03 +/- 0.02% CO2), bag-valve-(rigid) mask (560 +/- 300 mL, 96 +/- 3% O2, 0.03 +/- 0.02% CO2), and tube-valve-mask (860 +/- 290 mL, 91 +/- 7% O2, 0.2 +/- 0.2% CO2).

Conclusion: In the hands of relatively inexperienced operators, mouth-to-mouth, mouth-to-mask, and tube-valve-mask techniques provide adequate ventilation volumes to a mannikin. This was not the case with the bag-valve-mask systems (800 mL; P = .05 by t test). Of the systems that provide adequate ventilation volume, the tube-valve-mask appears, superior in that higher oxygen and lower carbon dioxide concentrations can also be obtained (P = .05 by paired t test).

Publication types

  • Clinical Trial
  • Randomized Controlled Trial

MeSH terms

  • Breath Tests
  • Carbon Dioxide / analysis
  • Equipment Design
  • Evaluation Studies as Topic
  • Humans
  • Lung Volume Measurements
  • Masks / standards*
  • Oxygen / analysis
  • Respiration, Artificial / instrumentation*
  • Resuscitation / instrumentation*


  • Carbon Dioxide
  • Oxygen