RESUMEN
After the accident on Apolo1, with 100% oxygen in the cabin, all spaceships now travel with a sea level pressure and 20.9% oxygen. Extravehicular activity requires lowering the pressures. It is complex and time consuming. Permanently reducing the cabin pressure would be a great advantage. A paper by NASA in 2013, proposed for the spaceflight environment: 8 psia / 32% O2 (reducing the sea level pressure (14.7 psi / 20.9% O2), but increasing the fraction of oxygen in order to replicate the sea level PaO2). However, we question this proposal, as it is based on the fear of hypoxia. Our proposal back in 2007 suggested that space travel should take place in a hypobaric environment of 9.5 psi / 20.9% O2 (like in the city of La Paz-Bolivia (3,600m) [11,811ft]). The logic behind it is that at all altitudes on planet Earth, life thrives in a 20.9% Oxygen, 79% Nitrogen. PaCO2 also needs to be considered. In a physiological manner, over 200 million inhabitants of high altitude above 2,000m [6,561ft], have perfectly normal lives. The astronauts could benefit of a Extra-Vehicular Activity (EVA) suit pressure of only 149 mmHg [2.8psi] (lighter, much more comfortable and efficient spacesuits) and space travel anemia could be reduced. The preparation prior-to-space travel could be carried out by adapting and living in a high altitude environment. We consider chronic hypoxia a fundamental step in BioSpaceForming (Adaptation to life in space). As all living beings start to move out of Earth into space, they will have to change their biology and adapt to new conditions.
Después del accidente del Apolo 1, ocurrido con 100 % de oxígeno en la cabina, todas las naves espaciales viajan con una presión de nivel del mar y 20,9 % de oxígeno. La actividad extravehicular requiere que se reduzcan las presiones. Es un proceso complejo que consume mucho tiempo. Reducir la presión de la cabina de manera permanente sería una gran ventaja. En un artículo de la NASA de 2013 se proponen las siguientes condiciones para el entorno de los vuelos espaciales: 8 psia / 32 % O2 (reduciendo la presión de nivel del mar (14,7 psi / 20,9 % O2), pero incrementando la fracción de oxígeno para replicar la PaO2 de nivel del mar). Sin embargo, nosotros nos cuestionamos esa propuesta, ya que está basada en el miedo a la hipoxia. La propuesta que hicimos en 2007 sugería que los vuelos espaciales se realizaran en un entorno hipobárico de 9,5 psi / 20,9 % O2 (como en la ciudad de La Paz, Bolivia (3 600 m) [11 811 ft]). El fundamento lógico es que en el planeta Tierra la vida se desarrolla a todas las alturas con 20,9 % oxígeno, 79 % nitrógeno, aunque también hay que tener en cuenta la PaCO2. Desde el punto de vista fisiológico, más de 200 millones de habitantes de grandes alturas de más de 2 000 m [6 561 ft] tienen una vida perfectamente normal. Para la Actividad Extra-Vehicular (EVA) a los astronautas les convendría más que el traje tuviera una presión de sólo 149 mmHg [2,8 psi], es decir, un traje más ligero y mucho más cómodo y eficiente, a la vez que se reduciría la ocurrencia de anemia espacial. La preparación previa al vuelo espacial podría basarse en la adaptación a un entorno de gran altitud y la vida en el mismo. Consideramos que la hipoxia crónica es un paso fundamental en la adaptación biológica y la supervivencia en el espacio. Todo organismo vivo que se traslade de la Tierra al espacio debe cambiar su biología y adaptarse a las nuevas condiciones.
RESUMEN
Lung disease with chronic hypoxia has been associated with cognitive impairment of the subcortical type. Objectives: To review the cognitive effects of chronic hypoxia in patients with lung disease and its pathophysiology in brain metabolism. Methods: A literature search of Pubmed data was performed. The words and expressions from the text subitems including ?pathophysiology of brain hypoxia?, ?neuropsychology and hypoxia?, ?white matter injury and chronic hypoxia?, for instance, were key words in a search of reports spanning from 1957 to 2009. Original articles were included. Results: According to national and international literature, patients with chronic obstructive pulmonary disease and sleep obstructive apnea syndrome perform worse on tests of attention, executive functions and mental speed. The severity of pulmonary disease correlates with degree of cognitive impairment. These findings support the diagnosis of subcortical type encephalopathy. Conclusion: Cognitive effects of clinical diseases are given limited importance in congresses and symposia about cognitive impairment and its etiology. Professionals that deal with patients presenting cognitive loss should be aware of the etiologies outlined above as a major cause or potential contributory factors, and of their implications for treatment adherence and quality of life.
As doenças pulmonares que cursam com hipóxia crônica tem sido associadas à alteração cognitiva do tipo subcortical. Objetivo: Revisar os efeitos cognitivos da hipóxia crônica em pacientes com doenças pulmonar e sua fisiopatologia. Métodos: Foi utilizado o banco de dados do Pubmed. As palavras e expressões foram os temas dos subitens da revisão como, por exemplo, ?fisiopatologia e hipóxia cerebral?, ?neuropsicologia e hipoxia?, ?lesões de substância branca e hipóxia crônica?, variando de 1957 to 2009. Artigos originais foram incluídos. Resultados: De acordo com a literatura nacional e internacional, pacientes com doença pulmonar obstrutiva crônica e síndrome da apnéia obstrutiva do sono apresentam desempenho pior em testes neuropsicológicos que avaliam atenção, funções executivas e velocidade de processamento mental. Esses achados configuram uma encefalopatia do tipo subcortical. Conclusion: É dada importância limitada às conseqüências cognitivas das doenças clínicas em congressos e simpósios sobre cognição e suas etiologias. Profissionais que lidam com pacientes que apresentam perda cognitiva devem suspeitar das etiologias mencionadas acima com causa principal ou como co-fatores, assim com suas implicações na aderência ao tratamento e qualidade de vida.