Abstract Introduction Improving emergency protocols during space missions is a topic of current interest with the upcoming long-lasting missions and the advent of space tourism (1–3). In the unique environment of spaceflight, cardiac arrest is a particularly challenging emergency as both the rescuer and the patient are floating due to microgravity, thus requiring the development of specific positions to provide efficient chest compression during cardiopulmonary resuscitation (CPR). As recommended by international guidelines (4), the Hand-Stand method is the current gold standard CPR method since it achieves the best compression depth and rate (5) but necessitates specific training to be accurately performed. Here, we postulated that automatic chest compression devices (ACCDs) routinely used on Earth by physicians facing cardiac arrests, particularly in hostile environments or during refractory (i.e. sustained) cardiac arrests(6-8), could improve CPR in microgravity. We aimed to compare ACCDs versus manual CPR in weightlessness simulated through parabolic flights. Methods This prospective, open, controlled study compared CPR performed by 3 ACCDs (one standard mechanical piston device, one compression band device, and one small-sized piston device) to manual CPR during a CNES (Centre National d’Etudes Spatiales, the French space agency) parabolic flights campaign onboard a modified A310 aircraft turned into a flying laboratory. This setup could re-create accurate microgravity, during the free falling phases of parabolic flight. Chest compression depths and rates were monitored by a high fidelity CPR training manikin. Results (presented as median IQR) The standard piston device had a median compression depth of 53.0 53.0 - 54.0 mm, significantly higher than the other two devices, and than Manual CPR (Handstand method), measured at 29.0 26.0 - 32.0 mm, 29.0 27.5 - 30.7 mm and 34.5 29.6 - 43.3 mm, respectively (p value 0.001). Compression rates were 101 101 - 101, 100 100 - 100 and 80 80 - 80 compressions per minute (cpm) for the standard piston device, compression band device, and small sized piston device, respectively. Manual CPR provided a significantly higher compression rate with 115 109 - 123 cpm (p value 0.001). Conclusion Manual CPR remains undereffective under Zero Gravity and ACCDs, especially the standard piston device (i.e., the only experimental group reproducing CPR matching with international guidelines), should be considered in emergency procedures to manage cardiac arrest in microgravity. Other keystones of cardiac arrest management should also be translated to the spaceflight environment, such as early defibrillation or emergency drug administration if required (epinephrine), as these are already described in the NASA emergency protocols for the International Space Station.Visual abstract
Reynette et al. (2025) studied this question.