# Elbow flexion enables rescuers with low BMI to deliver chest compressions in compliance with CPR guideline recommendations

## TL;DR

Smaller rescuers can maintain effective CPR by using elbow flexion and extension, even when the patient is heavier.

## Contribution

The study identifies elbow flexion as a novel compensatory technique for low-BMI rescuers to meet CPR guidelines.

## Key findings

- Chest compressions met recommended depth and rate with elbow flexion and extension.
- Lower BMI participants used elbow movement more effectively with increased resistance.
- Elbow techniques could improve CPR quality for smaller rescuers in real-life scenarios.

## Abstract

High quality cardiopulmonary resuscitation (CPR) increases survival outcomes. Smaller rescuers have been found to be at risk of providing inadequate CPR, particularly relating to chest compression depth, especially in novice rescuers. This study aims to look at the quality of CPR provided by smaller rescuers, and to investigate any potential compensation techniques used such as elbow flexion and extension, to maintain adequate quality CPR. Healthy adult participants performed three five-minute sequences of CPR on a mannequin with springs of 3 different strengths, in a randomized order. An electrogoniometer attached to the elbow measured the flexion and extension throughout. The results suggest that chest compressions were maintained at recommended depth and rate levels despite the increase in spring stiffness by using elbow flexion and extension, especially in participants with lower BMI and increased spring stiffness. These findings suggest potential compensatory mechanisms that can be used to maintain good CPR in situations of the rescuer being significantly smaller than the patient, similarly to as has been suggested when delivering CPR in hypogravity, thus transferring knowledge from these environments to Earth. Using elbow flexion and extension should be taken into consideration when revising the internationally recognized CPR guidelines.