Felipe Prehn Falcão

Evaluation of a Novel Basic Life Support Method in Simulated Microgravity

BACKGROUND If a cardiac arrest occurs in microgravity, current emergency protocols aim to treat patients via a medical restraint system within 2-4 min. It is vital that crewmembers have the ability to perform single-person cardiopulmonary resuscitation (CPR) during this period, allowing time for advanced life support to be deployed. The efficacy of the Evetts-Russomano (ER) method has been tested in 22 s of microgravity in a parabolic flight and has shown that external chest compressions (ECC) and mouth-to-mouth ventilation are possible. METHODS There were 21 male subjects who performed both the ER method in simulated microgravity via full body suspension and at +1 Gz. The CPR mannequin was modified to provide accurate readings for ECC depth and a metronome to set the rate at 100 bpm. Heart rate, rate of perceived exertion, and angle of arm flexion were measured with an ECG, elbow electrogoniometers, and Borg scale, respectively. RESULTS The mean (+/- SD) depth of ECC in simulated microgravity was lower in each of the 3 min compared to +1 G2. The ECC depth (45.7 +/- 2.7 mm, 42.3 +/- 5.5 mm, and 41.4 +/- 5.9 mm) and rate (104.5 +/- 5.2, 105.2 +/- 4.5, and 102.4 +/- 6.6 compressions/min), however, remained within CPR guidelines during simulated microgravity over the 3-min period. Heart rate, perceived exertion, and elbow flexion of both arms increased using the ER method. CONCLUSION The ER method can provide adequate depth and rate of ECC in simulated microgravity for 3 min to allow time to deploy a medical restraint system. There is, however, a physiological cost associated with it and a need to use the flexion of the arms to compensate for the lack of weight.

Effect of microgravity on immune cell viability and proliferation

Exposure to microgravity may produce changes in the performance of the immunological system at the cellular level and in the major physiological systems of the body. Weightlessness suppresses the lymphocytic functions involved in the immunity process, such as cell locomotion and expression of antigen. The present study was designed to investigate whether the proliferation and viability of lymphocytes are reduced by exposure to rotation in a three-dimensional (3-D) clinostat, which is used to simulate the microgravity of cells. The results indicate a nonsignificant decrease in the proliferation and cellular viability to the mitogen stimulation in 24 h of simulated weightlessness (P = 0.146). There was, however, a very significant (P = 0.012) decrease in proliferation and viability after 48 h of rotation in the 3-D clinostat. A comparison between 24 and 48 h of clinorotation indicates a difference between the results (P = 0.003). The present study indicates that the immunological depression associated with the spaceflight is not just related to the psychological and physiological stresses that the astronauts are subjected to, but it also seems to be caused by microgravity per se that affects the proliferation and cellular viability.

Development and validation of an electrically controlled rotatory chair to be used as a simulator for spatial disorientation and motion sickness

The vestibular system, along with the eyes and proprioceptors, is responsible for the maintenance of balance. Two very common causes of accidents and incidents during flights and space missions are spatial disorientation and motion sickness. Since its invention by the physiologist Robert Barany, rotatory chairs have been widely used to train pilots and astronauts in relation to the effects of angular accelerations and microgravity on the semicircular canals. This paper presents the development of an electrically controlled rotatory chair (ECRC), the unique device of this type used as a simulator for spatial disorientation and motion sickness in Brazil. Validation of the ECRC was performed through the evaluation of the effects of a drug (scopolamine) on the prevention of signs and symptoms of motion sickness.

The Effects of Hypergravity and Microgravity on Biomedical Experiments

Abstract Take one elephant and one man to the top of a tower and simultaneously drop. Which will hit the ground first? You are a pilot of a jet fighter performing a high-speed loop. Will you pass out during the maneuver? How can you simulate being an astronaut with your feet still firmly placed on planet Earth? In the aerospace environment, human, animal, and plant physiology differs significantly from that on Earth, and this book provides reasons for some of these changes. The challenges encountered by pilots in their missions can have implications on the health and safety of not only themselves but others. Knowing the effects of hypergravity on the human body during high-speed flight led to the development of human centrifuges. We also need to better understand the physiological responses of living organisms in space. It is therefore necessary to simulate weightlessness through the use of specially adapted equipment, such as clinostats, tilt tables, and body suspension devices. Each of these ideas, and ...

Effects of Hypergravity and Microgravity on Biomedical Experiments, The

Abstract Take one elephant and one man to the top of a tower and simultaneously drop. Which will hit the ground first? You are a pilot of a jet fighter performing a high-speed loop. Will you pass out during the maneuver? How can you simulate being an astronaut with your feet still firmly placed on planet Earth? In the aerospace environment, human, animal, and plant physiology differs significantly from that on Earth, and this book provides reasons for some of these changes. The challenges encountered by pilots in their missions can have implications on the health and safety of not only themselves but others. Knowing the effects of hypergravity on the human body during high-speed flight led to the development of human centrifuges. We also need to better understand the physiological responses of living organisms in space. It is therefore necessary to simulate weightlessness through the use of specially adapted equipment, such as clinostats, tilt tables, and body suspension devices. Each of these ideas, and ...