Effects of Audio Tone Guidance on Performance of Positive-pressure Ventilation using a Bag-valve Device

ABSTRACT

PURPOSE: The 2010 guidelines for cardiopulmonary resuscitation recommend a ventilation rate of 8 to 10/min for patients with an advanced airway; however, hyperventilation occurs in most cases. This study was conducted as an attempt to determine the effects of feedback under audio tone guidance on performance of positive-pressure ventilation using a bag-valve device and to apply this technique in clinical practice in order to reduce hyperventilation. METHODS: A total of 36 seniors at our medical school participated in the study. After receiving instruction in performance of positive-pressure ventilation using a bag-valve device, they performed ventilation using a cardiac arrest model with an advanced airway (Test 1). After they took Test 1 without any feedback, they were randomly assigned to the feedback group (Group A) and the control group (Group B) and took Test 2. In Group A, a high-pitched sound was delivered every 7 s for guidance of ventilation. RESULTS: In Group A, ventilation rate approximated feedback rate, whereas, in Group B, it showed a significant decrease, from 8.3+/-2.0 to 7.7+/-2.0/min (p<0.01). The mean ventilation volume did not differ between pre- and post-feedback. The mean inspiration time showed a decrease in both groups. However, no significant difference in mean inspiration time was observed between the two groups. CONCLUSION: Audio tone guidance can control the ventilation rate accurately without any significant change in ventilation volume and inspiration time.