The recent article by Mashour et al. on consciousness and the dying brain caught my eye, as I have had such a personal experience.

Once I suffered from gastro-esophageal reflux after eating spicy meals. I occasionally experienced bile reflux during my sleep, would wake up coughing, and observed the pillow next to my face was wet with green gastric fluid. One night, the same happened again, and I developed total laryngospasm. I could not cough or breathe. I got out of bed and stood facing the bed, leaning onto it with my hands. I was vividly awake and realized I was in a serious situation with total laryngospasm. Soon, my feelings of panic soothingly switched into feelings of indescribable calmness and pleasure. It was an experience unmatched by anything in my life before. I felt peace, calmness, contentment, satisfaction, happiness, and joy, all to a high degree for which there are no adequate superlative adjectives in the English language. The experience lasted a minute. Then, everything gradually became dark for me and ended.

My wife had woken up, too, and looked at me, bewildered. She later described how I slowly lapsed forward facedown onto the bed. I lay still for a minute, then slowly started making respiratory movements and little coughs. The coughs became more energetic, and finally, I stood up, coughing vigorously.

I was fine once my lungs were cleared out of the gastric bile. I was shocked to have nearly died. Thirty years later, my memories of that intriguing experience are clear. My recollections of the extremely pleasurable happiness I experienced before losing consciousness are vivid. Additionally, I was highly motivated to address all my health factors and never again had a near-death experience. I never aspirated bile again. I fear not my final death later in my life if that one-time hypoxic cerebral pleasurable experience is to be repeated. It felt divine.

As an experienced anesthesiologist with extensive hands-on experience with laryngeal masks and teaching novices, I have seen total laryngospasms in many anesthesia patients. I have often observed that hypoxia finally resolves the total laryngospasm with the development of total flaccidity. Of course, we always provided patient airway support and reoxygenation immediately upon the laryngospasm resolving itself or with succinylcholine administration. We never saw brain damage. 

In 2017, Chawla et al. described research using electroencephalographic research in intensive care unit patients.  End-of-life electrical surges are observed in about 50% of patients without preceding diagnoses of brain death after their cessation of heartbeat. In already brain-dead diagnosed patients, no end-of-life electrical surges were ever seen after cessation of heartbeat. It is probable those end-of-life electrical surges seen on electroencephalogram correlate with emotional experiences from hypoxia-induced large surges of cerebral cortical dopamine and serotonin neurotransmitter release, causing experiences like I had with my near-death hypoxia and survived to describe.

The study by Mashour et al. that I am responding to focuses on the neurobiology of consciousness in the dying brain. The end-of-life cortical electrical surges are associated with the activation of glutamate-gated neuron channels. Brain electrical surges start within 3 to 6 min after losing measurable blood pressure. There is an “explosive surge” in global brain connectivity before cortical isoelectricity finally develops. The effects are similar to what psychostimulants can induce, like ketamine. Animal research correlates the near-death cortical electrical spike with explosive surges in released dopamine, adenosine, serotonin, and noradrenaline in the frontal and occipital cortices. Interestingly, full patient resuscitation is sometimes achievable even after the cortical isoelectric stage is reached during hypoxia.

Thank you, Mashour et al., your study review is fascinating. We can finally possibly understand the perceived out-of-body, probably hypoxic, near-end-of-life experiences that people have reported for thousands of years and vividly recall.