Medical Student University of Hawai'i John A Burns School of Medicine University of Hawai'i at Manoa John A Burns School of Medicine Honolulu, Hawaii, United States
Background: Chest compression efficacy determines blood flow in CPR and relies on body mechanics; i.e., the resuscitator's weight matters. Individuals of insufficient weight are incapable of generating sufficient downward chest compression force.
Objective: Tto investigate how a resuscitator’s size affects chest compression efficacy, determine the minimum weight required to perform chest compressions, and, for those below this minimum weight (e.g., children or small adults), investigate an alternate means to perform chest compressions.
Design/Methods: We enrolled volunteers age 8 years and above to perform video-recorded, music-facilitated, compression-only CPR on an audible click-confirming manikin for 2 minutes, following brief training, practice, and rest sessions. Subjects who failed this, proceeded to alternate modalities: Chest compressions by jumping on the lower sternum (while holding on to a horizontal support bar for balance) and squat-bouncing (bouncing the buttocks on the chest), were assessed for efficacy via video review.
Results: We enrolled 57 subjects (prior to the pandemic halt to in-person research). In the 30 subjects above 40 kg, all were able to complete nearly 200 compressions in 2 minutes. Below 40 kg, there were declining rates of success. Below 30 kg, only one subject (29.9 kg weight) out of 14 subjects could achieve 200 effective compressions. Nearly all of the 23 subjects who could not perform conventional chest compressions were able to achieve effective chest compressions using the alternate methods. Figure 1 plots effective compressions by weight. 1A shows all subjects performing conventional compressions. 1B shows the compressions delivered via jumping in those who failed conventional compressions. 1C shows the subset using the squat-bouncing method. Figure 2 how the two alternate compression methods for children were performed (left=jumping, right=squat-bouncing). Conclusion(s): A weight below 40 kg resulted in a declining ability to perform standard chest compressions effectively. For small resuscitators, the jumping and squat-bouncing methods resulted in sufficient compressions most of the time; however, chest recoil and injuries are concerns.
Authors/Institutions: Tiffany Lau, University of Hawai'i at Manoa John A Burns School of Medicine, Honolulu, Hawaii, United States; Anthony Lim, University of Hawai'i at Manoa John A Burns School of Medicine, Honolulu, Hawaii, United States; Kyra Len, University of Hawai'i at Manoa John A Burns School of Medicine, Honolulu, Hawaii, United States; Loren G. Yamamoto, University of Hawai'i at Manoa John A Burns School of Medicine, Honolulu, Hawaii, United States