352 Minimum Weight for Effective Chest Compressions and Alternative Methods for Smaller Rescuer Cardiopulmonary Resuscitation

Abstract

The quality and quantity of chest compressions determine blood flow in cardiopulmonary resuscitation (CPR). Efficacious chest compressions rely on body mechanics such that the weight of the resuscitator matters; very small people have insufficient weight to generate sufficient downward chest compression force. The purpose of this study is to investigate how a resuscitator’s weight affects chest compression efficacy; and to determine the minimum weight required to perform adequate chest compressions. For those below this minimum weight (such as in children or smaller-bodied rescuers), we investigate alternative means to perform chest compressions. We enrolled volunteers age 8 years and above to perform video-recorded, compression-only CPR on an audible click-confirming chest compression manikin with background music to facilitate the chest compression rate for 2 minutes. All volunteers were provided with brief training, practice, and rest sessions prior to the recorded session. For all subjects, weight, height, age, sex, and CPR certification status were recorded. Subjects who failed to meet the criteria for efficacious chest compressions proceeded to two alternate chest compression modalities. In the first, subjects jumped up and down on the lower sternum while holding on to a horizontal support bar for balance. In the second, subjects used a squat-bounce method: sitting directly on the chest and using their legs, arms, and body weight to give compressions. Videos were reviewed to determine chest compression depth, rate, position, and recoil. An effective compression was one in which all four criteria were met. We enrolled 57 study subjects ranging from weights of 19 kg to 76 kg, which included 23 adults. Effective standard chest compressions declined at weights below 40 kg and no effective standard compression sessions occurred at weights below 29 kg (Figure 1). Adequate standard chest compressions declined at heights below 145 cm and no effective standard compression sessions were given at heights below 137 cm. For the 23 subjects who failed standard chest compressions, 19 (83%) were in the age group 8-10. There was no significant difference in the percentage of effective chest compressions with regard to sex in any method. Of the 23 subjects who failed, only 1 (4%) subject had taken a CPR certification course. Of the 23 subjects who failed standard chest compressions, 20 (87%) delivered effective compressions using the jumping modality. For 8 subjects who failed standard chest compressions, 7 (88%) delivered effective compressions using the squat-bouncing modality. Standard chest compression efficacy declines below 40 kg and cannot be performed adequately below 29 kg. For small resuscitators unable to perform standard compressions, jumping and squat-bouncing modalities resulted in sufficient chest compressions the majority of the time in this model; however, there are concerns regarding chest recoil and the potential for injury to the chest and abdomen.