Klemenc-Ketis and colleagues' novel report of hypercapnia and hypokalemia associated with near-death experiences (NDEs)  was somewhat surprising, as Sabom  had previously reported lower than regular carbon dioxide ranges measured currently on the time of the patient's NDE, and Parnia and colleagues, in a prospective study of 63 cardiac arrest survivors, had uncovered no significant association of both potassium or carbon dioxide with NDEs .Klemenc-Ketis and colleagues' conclusion that hypercapnia plays a position in provoking NDEs is one particular achievable interpretation of your correlation they located. It is actually also plausible that hypercapnia is simply an indicator of another component that may be linked causally to NDE reviews.
By way of example, the authors noted that hypercapnia indicates improved cardiac output and perfusion pressure, which would reduce the amnesia that may be generally observed in cardiac arrest, so that patients might be far more likely to don't forget what took place during the arrest. The association involving NDEs and hypercapnia may consequently indicate only that patients who are able to recall extra of their cardiac arrest Cetirizine DiHCl also report much more NDEs. Gliksman and Kellehear reviewed studies displaying that levels of carbon dioxide while in the blood are certainly not always exact estimates of amounts in the brain , which more complicates the interpretation on the recent findings.The compact sample dimension of this research, the contradictory proof from other studies, as well as the unclear association concerning amounts of carbon dioxide while in the blood and in the brain suggest caution in interpreting the findings and recommend the require for more research.
Authors' responseZalika selleck chemicals Klemenc-Ketis, Janko Kersnik and Stefek GrmecBruce Greyson proposes an alternate explanation for the effects of our review , which could also be plausible. Namely, greater levels in the partial pressure of end-tidal carbon dioxide (petCO2) may also be indicators of improved cardiac output, as talked about in our report  and confirmed in our prior studies . Larger incidence of reported NDEs in patients with hypercapnia may for that reason indicate only better memory in the actual NDE occasion, but this needs to be confirmed with even further scientific studies.A research about the effects of meditation on respiration and temporal lobes indicated that higher partial pressure of carbon dioxide (pCO2), that's a result of particular breathing tech niques throughout meditation, may possibly are already vital in provoking cognitive and emotional adjustments .
Also, increased amounts of pCO2 presumably have an excitatory impact over the limbic method, which may well lead to mystical (NDE-like) experiences . The attainable connection concerning the limbic method and NDE-like experiences has already been reported .Increased petCO2 and pCO2, aside from far better cardiac output, could hence indicate also a possible connection concerning carbon dioxide as well as the incidence of NDEs. Considering that individuals with asphyxia cardiac arrest had been observed to have greater petCO2 than individuals with primary cardiac arrest , the patients with asphyxia cardiac arrest might also have larger incidence of NDEs - which, if confirmed, may possibly enable to clarify the part of carbon dioxide in NDEs.
This theory ought to be further investigated in more substantial and multicentre research, but while in the light of patient-oriented care it is actually crucial to keep in mind the existence of NDEs in cardiac arrest sufferers and also to create protocols of care for this kind of patients.AbbreviationsNDE: near-death encounter; pCO2: partial strain of carbon dioxide; petCO2: partial strain of end-tidal carbon dioxide.Competing interestsThe authors declare that they have no competing interests.NotesSee relevant research by Klemenc-Ketis et al., http://ccforum.com/content/14/2/R56