CPR effectiveness in microgravity: comparison of three positions and a mechanical device.
OBJECTIVE
Cardiopulmonary resuscitation (CPR) in microgravity via closed chest compression is thought to be possible by several techniques. This study examined the handstand, side, and waist straddle maneuvers, and a bear hug technique in performing CPR and meeting American Heart Association (AHA) recommendations in microgravity. We also hypothesized that one rescuer using a CPR bellows adjunct device is equivalent to two rescuers.


METHODS
A pre-intubated mannequin model resting on the crew medical restraint system from the International Space Station was instrumented with transducers to measure airway pressure and chest compression depth. Microgravity conditions were provided through repetitive parabolic flight on the KC-135A. On identifying the most effective position, standard two-rescuer CPR was compared with one-rescuer CPR augmented with a bellows-on-sternum CPR adjunct device (Kendall CardioVent, Kendall Medizinische Erzeugnisse GMBH, Neustadt/Donau, Germany).


RESULTS
Handstand position compression depth was 1.58 in +/- 0.20 in SD (4.01 cm +/- 0.51 cm), side straddle was 0.78 in +/- 0.44 in SD (1.98 cm +/- 1.12 cm), and waist straddle was 1.21 in +/- 0.47 in SD (3.07 cm +/- 1.19 cm) across rescuers with heights of 164-174 cm. Rates of compression were 98.3 +/- 6.3 SD, 100.0 +/- 3.0 SD, and 102.6 +/- 12.1 SD compressions per minute, respectively. Compression depth for one rescuer utilizing the Kendall CardioVent device in the handstand position was 1.48 in +/- 0.14 in SD (3.76 cm +/- 0.36 cm). Compression depth for two rescuers was 1.58 in +/- 0.20 in SD (4.01 cm +/- 0.51 cm) (p < 0.01).


CONCLUSIONS
CPR in microgravity is most reliably performed in the handstand position and meets AHA guidelines for closed chest compression depth. One-rescuer CPR incorporating the Kendall CardioVent device appears promising in microgravity. CPR adjunct devices would positively impact resuscitative procedures like CPR by small crews with inherent manpower requirements.
Jay
Gregory D
GD
Department of Medicine, Section of Emergency Medicine, Brown University, Providence, RI, USA. GJay@lifespan.org
Lee
Peter
P
Goldsmith
Heather
H
Battat
James
J
Maurer
Joseh
J
Suner
Selim
S
D016887:Cardiopulmonary Resuscitation / Q000295:instrumentation* / Q000379:methods*; D004867:Equipment Design; D006801:Humans; D008348:Manikins; D011187:Posture; D014893:Weightlessness