Effects of training time and feedback on ventilation skills in lay rescuers

Lay rescuers have difficulties acquiring ventilation skills during training. Non-feedback manikins are still widely employed, although skill acquisition is suboptimal. We analysed if a longer training time and verbal feedback, given by an instructor, improved ventilation skill acquisition with non-feedback manikins.

Forty-three high school students without prior medical training participated in this prospective randomised trial. Under one-to-one instructor guidance, 25 volunteers were trained on a manikin with a mouth-to-mask device for 10 min, and 18 volunteers for 20 min. After training, volunteers were assessed and verbal feedback was given: ventilate more if the mean tidal volume <0.5 L, ventilate less if >0.7 L or ventilate the same for 0.5-0.7 L. The volunteers were then reassessed.

At the assessment, tidal volume, minute volume, peak airway pressure, ventilation rate and stomach inflation rate were comparable between the 10 and 20 min groups. After verbal feedback, at reassessment both groups increased tidal volume (assessment 0.75+/-0.24 vs reassessment 0.80+/-0.16 l/min; p=0.007), minute volume (9.1+/-3.0 vs 10.0+/-2.4 l/min; p=0.001), peak airway pressure (17.0+/-5.2 vs 18.3+/-3.4 cmH(2)O; p=0.003) and stomach inflation rate (67 vs 88%; p=0.02), while ventilation rate (12.3+/-2.1 vs 12.6+/-2.3 ventilations/min; p=NS) remained comparable.

Both 10 and 20 min ventilation training times resulted in comparable skills. Volunteers hyperventilated the manikin and produced excessive stomach inflation in this model. This increased even further after verbal feedback.