Closed loop ansthesia delivery systems typically use TIVA, using propofol or other intra venous drugs. I want to now if there is any system which use inhalational anesthetics to alter the plane of anesthesia .
The problem with TIVA is that you need "something" to inform you about the depth of anesthesia. Entropy, while existing on some monitors is quite unfamiliar and as such not used, as far as I know. Not sure how exact it is, but because it is simple to use the BIS has been widely accepted. There are some modern anesthesia machines that use one system or another of feedback. This is called AGC = anesthesia gas control. The clinician needs to chose what level of MAC is desired and the machine does it alone using the data from the gas analyzer. If you want to alter the plane of anesthesia you just need do modify the target the machine needs to keep. The real problem, though, is that not all the machines are designed as closed loop (actually closed circuit) and surprisingly the gas analyzer is still missing in many places. Hope it helps.
Dear Dr. Sachin George,
It might be interesting for you to read the paper and possibly some citations provided there:
https://www.researchgate.net/publication/273155423_EEG_entropy_measures_in_anesthesia
According to my knowledge, it sounds like a good starting point to understand the concept of Entropy in conjunction with brain and EEG recordings.
Hopefully, it will help,
Jiri :-)
Do not hesitate to ask more. The field of entropy applied to biosignal processing is a dynamically evolving area, now.
Article EEG entropy measures in anesthesia
Sometime ago Prof Kenny in Glasgow was working on closed-loop anaesthesia using TIVA and auditory evoked potentials - we had the AEP kit in a couple of theatres although it sat there gathering dust. AEP had the advantage of responding to changes in depth of anaesthesia faster than BIS or entropy from my recollection, but getting a safe 'closed loop' proved elusive. The work may well have moved on since then, but Gavin Kenny's work would be a good place to start.
Entropy: A concept that is not a physical quantity
https://www.researchgate.net/publication/230554936_Entropy_A_concept_that_is_not_a_physical_quantity
there you have it: Article Feasibility of Closed-loop Titration of Propofol and Remifen...