Expert: Dr Ian Jackson - please note UK based - 8/24/2008

Question
Dear Ian,
           My question Where do the planes
Plane 1 moderate sedation and analgesia
Plane2 Dissociation sedation and analgesia
Plane 3 Total anaesthesi(analgesia)
Plane 4 Light anaesthesia

Fall into generally outlined stages of analegesia, deliruim,surgical anaesthesia and medulllary paralysis.

The above mentioned planes are for conscious sedation.Hoiw do i fit these planes in relation to the stages of anaesthesis.do these 4 planes take place during the STAge of analgesia

Thanking you
Imran

Answer
Hi Imran
Interesting question and in reality in modern anaesthesia the planes of anaesthesia mean nothing as we use IV induction agents to jump the patient straight to Plane 4 and beyond! They were used to describe induction of anaesthesia with ether and chloroform which was very slow.
Classically the planes were described as
Plane 1 - from onset of automatic breathing until cessation of eyeball movement.
Plane 2 - from cessation of eyeball movement till start of intercostal paralysis
Plane 3 from above until completeion of intercostal paralysis
Plane 4 from complete intercostal paralysis to diaphragmatic paralysis.
I do not believe that you can link these palnes as you suggest and analgesia is certainly not great in Plane 1 - no old timer anaesthetist would let the surgeon near the patient during that dangerous phase.
Conscious sedation is totally different - by defionition conscious sedation means the patient is 'conscious'. This means they can respond appropriately to command e.g. squeeze my hand. If they cannot then you have gone beyond conscious sedation and into the realms of general anaesthesia.
I suspect many practitioners of 'conscious sedation' do this!
Hope this helps a bit.
Kind regards
Dr Ian Jackson