Carl's Podcast

1. What happens in the brain under anesthesia? It slows down, EEG power spectra change in predictable ways, brainstem reflexes (including airway reflexes) are blunted, and you anesthesia (hypnosis/unconsciousness), analgesia (lack of pain), amnesia (you don't form new memories)
2. Does general anesthesia cause incontinence? Are we talking bowel or bladder? Either way, I don't see it often. In fact, POUR is one of the more common complications of anesthesia, which is the opposite of bladder incontinence. Very interesting though that people don't lose control of these sphincters when they lose other reflexes that are seemingly more important.
3. Are medically induced comas just continuing the use of GA? Sometimes. Anesthesia agents can be used targeting burst suppression or flatline brain activity on EEG, or a patient can be actively cooled down. In both cases, you are trying to decrease the CMRO2, which is the cerebral metabolic rate of oxygen consumption, or how much O2 the brain uses. Your brain is 2% of your body mass, but uses 20% of the body's oxygen. 40% of the brain's metabolic demand is for so called housekeeping functions, or just keeping all the cells alive, the other 60% is for electrical activity or signaling, which is the brain's job.
4. How common are medical issues related to anesthesia? Common, but the ones people are usually scared about are extremely uncommon. The most common problems with anesthesia are sore throat, nausea, vomiting, damage to tongue, lips, or teeth, post-op delirium, and POUR.
5. Why are people loopy when they wake up? Residual anesthetic agent.
6. Do people dream under anesthesia? Hard to say... dexmedetomidine sedation is the closest to REM sleep, and so may induce dreaming. Ketamine can cause hallucinations and going into the K-hole, but those are more like nightmares.
7. Why don't we use laughing gas anymore? We do! But it's sort of fallen out of favor with most people because it's bad for the environment and has some unwanted side effects.