Conscious Awareness During Deep Hypothermic Circulatory Arrest
In our studies of cardiac arrest and its effects on consciousness, our data led us to hypothesize that higher-quality resuscitation is associated with a higher level of conscious awareness during cardiac arrest and resuscitation, which in turn is associated with improved survival, less severe brain injuries, and a smaller incidence of disorders of consciousness.
A novel way to study consciousness in a setting that biologically mimics clinical death besides cardiac arrest is to study patients undergoing deep hypothermic circulatory arrest (DHCA), a medical technique in which a patient’s temperature is cooled to approximately 20 degrees Celsius (68 degrees Fahrenheit), shutting down blood circulation and major organ function. This approach is often used by surgeons who need to operate on major blood vessels.
Because DHCA biologically mimics clinical death, but is very well controlled, it provides an excellent opportunity to study consciousness and awareness in a population, which unlike cardiac arrest has a very high survival rate. We are developing new methods to determine what happens to consciousness before, during, and after this shutdown. We are using various technologies including portable EEG, cerebral oximetry, and visual and audio tools to test implicit and explicit learning as well as recall and memory.
This study complements our work in AWARE II, and we anticipate that we will discover exciting new aspects of the human mind.