Comparison of mouth-to-mouth, mouth-to-mask and mouth-to-face-shield ventilation by lay persons.
OBJECTIVE
A prospective randomised study on 70 volunteers without previous first aid education (42 males, 28 females, mean age 17) was performed to compare mouth-to-mouth ventilation (MMV, n = 24) versus mouth-to-pocket-mask ventilation (MPV, n = 25) and mouth-to-face-shield ventilation (MFV, n =21), and to evaluate if an instruction period of 10 min would be sufficient to teach lay persons artificial ventilation. Every volunteer performed three ventilation series using a bench model of an unprotected airway.


RESULTS
MMV and MPV show higher mean tidal volume (TV) than MFV (values of series 3: 976 +/- 454 and 868 +/- 459 versus 604 +/- 328 ml, P = 0.002 and P = 0.025, respectively). We found a higher inter-individual variation in TV than in previous studies (P = 0.031). The recommended TV of 700-1000 ml was reached in only 23%, most frequently with MPV (MMV 16.7%, MPV 32%, MFV 19%) but the difference was not significant (P = 0.391). However, we found a significantly higher percentage with a TV below 700 ml with MFV (MMV 33.3%, MPV 36%, MFV 66.7% P = 0.047) and a significantly higher percentage of TV exceeding 1000 ml with MMV (MMV 50%, MPV 32%, MFV 14.3%) (P = 0.039). "Stomach" inflation was highest with MMV (79.2%) followed by MPV (52%) and MFV (42.9%) (P = 0.034). We found further differences between the sexes; males produced a higher TV (P = 0.003) and a higher percentage of stomach inflation (P = 0.029).


CONCLUSIONS
MPV showed the best ventilation quality. It resulted in a more adequate TV than MMV and MFV and lower stomach inflation than MMV. Only a relatively low percentage of ventilations were within the recommended range for TV and this may be related to the short training duration. We found different performances between the sexes, a high inter-individual variation and mainly a low ventilation quality. Therefore, further studies have to focus more on teaching duration, sex differences and ventilation quality.
Paal
Peter
P
Department of Anaesthesiology and Intensive Care Medicine, South Tyrolean Alpine Association, International Commission for Mountain Emergency Medicine ICAR MEDCOM, Innsbruck Medical University, Innsbruck, Austria. peter.paal@uibk.ac.at
Falk
Markus
M
Sumann
Günther
G
Demetz
Florian
F
Beikircher
Werner
W
Gruber
Elisabeth
E
Ellerton
John
J
Brugger
Hermann
H
D000293:Adolescent; D000328:Adult; D016887:Cardiopulmonary Resuscitation / Q000193:education* / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012121:Respiration, Artificial / Q000295:instrumentation / Q000379:methods*; D012737:Sex Factors; D013334:Students