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Updated: Jun 9, 2026

Ultrasonographic Assessment During Cardiopulmonary Resuscitation
Published on: October 24, 2020
Quality of chest compressions during continuous CPR; comparison between chest compression-only CPR and conventional
Chika Nishiyama1, Taku Iwami, Takashi Kawamura
1Department of Preventive Services, Kyoto University School of Public Health, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
Objectives:
This study aimed to compare the time-dependent deterioration of chest compressions between chest compression-only cardiopulmonary resuscitation (CPR) and conventional CPR.
Methods:
This study involved 106 and 107 participants randomly assigned to chest compression-only CPR training and conventional CPR training, respectively. Immediately after training, participants were asked to perform CPR for 2 min and the quality of their CPR skills were evaluated. The number of chest compressions in total and those with appropriate depth were counted every 20-s CPR period from the start of CPR. The primary outcome was the CPR quality index calculated as the proportion of chest compressions with appropriate depth among total chest compressions.
Results:
The total number of chest compressions remained stable over time both in the chest compression-only and the conventional CPR groups. The CPR quality index, however, decreased from 86.6+/-25.0 to 58.2+/-36.9 in the chest compression-only CPR group from 0-20 s through 61-80 s. The reduction was greater than in the conventional CPR group (85.9+/-25.5 to 74.3+/-34.0). The difference in the CPR quality index reached statistical significance (p=0.003) at 61-80 s period.
Conclusions:
Chest compressions with appropriate depth decreased more rapidly during chest compression-only CPR than conventional CPR. We recommend that CPR providers change their roles every 1 min to maintain the quality of chest compressions during chest compression-only CPR. (UMIN-CTR C0000000321).
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