An assessment of the feasibility and effectiveness of a method of performing cardiopulmonary resuscitation during microgravity. Simon N Evetts, Lisa M Evetts, T Russomano, J Castro and J Ernsting CB OBE. Microgravity Laboratory, PUCRS, Porto Alegre, Brazil. Human Physiology and Aerospace Medicine Group, King’s College London.

Background  CPR in microgravity.  Current procedures –Restrained. –Unrestrained.  Need for effective unaided, single person CPR in space.

Recent and current CPR guidelines  European Resuscitation Council 1998: – Mouth-to-mouth ventilation requiring tidal volumes of 400 – 500 ml. – Chest compression depth of 40 – 50 mm. –Chest compression rate of ~ 100 compressions.min -1.  European Resuscitation Council 2001: –Tidal volumes of 700 – 1000 ml. –Chest compression depth of 40 – 50 mm. –Chest compression rate in excess of 100 min -1.

Evetts, Russomano, Castro CPR Method. Human subject in microgravity (position only).

ERC Method. Human subject in microgravity (position only).

ERC Method. Manikin use in microgravity (position and CPR).

Study Method  Subjects/investigators.  Laerdal CPR Manikin adaptation.  Pre & post flight procedures.  In flight procedures.  Measurements.

Results Measure+1G Z Microgravity Chest Compressions Depth (mm)43.6 ± ± 1.03 Range (min-max, mm)40.4 – – 51.2 Rate (compressions.min -1 )97.1 ± ± 3.4 Percent correct (depth)90%60% n Volume Volume (ml)507.6 ± ± 50.4 Range (min-max, ml)423 – Percent correct87%69% n3032

Results Measure+1G Z Microgravity Chest Compressions Depth (mm)43.6 ± ± 1.03 Range (min-max, mm)40.4 – – 51.2 Rate (compressions.min -1 )97.1 ± ± 3.4 Percent correct (depth)90%60% n Volume Volume (ml)507.6 ± ± 50.4 Range (min-max, ml)423 – Percent correct87%69% n3032

Results Measure+1G Z Microgravity Chest Compressions Depth (mm)43.6 ± ± 1.03 Range (min-max, mm)40.4 – – 51.2 Rate (compressions.min -1 )97.1 ± 3.0 *80.2 ± 3.4 * Percent correct (depth)90%60% n Volume Volume (ml)507.6 ± ± 50.4 Range (min-max, ml)423 – Percent correct87%69% n3032 * P < 0.05

Results Measure+1G Z Microgravity Chest Compressions Depth (mm)43.6 ± ± 1.03 Range (min-max, mm)40.4 – – 51.2 Rate (compressions.min -1 )97.1 ± 3.0 *80.2 ± 3.4 * Percent correct (depth)90%60% n Volume Volume (ml)507.6 ± ± 50.4 Range (min-max, ml)423 – Percent correct87%69% n3032

Discussion  Reasons for insufficient rate of chest compression and greater variation of measures in microgravity. – Novelty of environment. – Variable acceleration forces. – Shortness of microgravity exposure. – Degree of manikin reliability.

 ERC compared to other methods of performing CPR in microgravity.  Current unpublished findings.  Further research required: – Effects of training and expertise. – Effects of strength. – Effects of anthropometric indices. Discussion

 Effectiveness of the ERC method for all populations will need to be ascertained before it can be considered a viable method.  CPR of this nature is more difficult than at +1G Z and will therefore require appropriate pre-mission training.  Preliminary results indicate that the ERC method of unaided, single person CPR in microgravity is likely to be viable for use in space. Conclusion