How deep is too deep?

October 21, 2013

Can a general anaesthetic really be likened to turning a light switch on and off, or toggling between asleep and awake? The answer is no.

Just like there are different levels of sleep there are also different states of mind a general anaesthetic can cause. The technical term for this is ‘depth of anaesthesia’.

As described by Dr Emery Brown there are 5 key objectives an anaesthetist tries to achieve; a state of mind where the patient is unconscious, has no memory, no pain, no movement, and stays physiologically stable. To achieve all 5 of these, anaesthetists must choose a depth appropriate to the patient and operation type. Obviously all 5 of these components are extremely important to the patient and therefore anaesthetists often play conservative, which may put patients into a deeper “sleep” than is perhaps required.

A link between the depth of anaesthesia and prevalence of long-term cognitive changes has been previously proposed but not substantiated. Over the years the ability to measure the depth of anaesthesia has greatly improved and the spin off effect is that this proposed link can be further explored. A world first study looking at how deep is too deep and the long term effects, has recently been launched by the Australian and New Zealand College of Anaesthetists (ANZCA). The study aims to recruit 6500 patients over the age of 60 from around the world to monitor post-surgery for effects that may relate to the depth of anaesthesia.

Perioperative Solutions hopes to assist with this study by enrolling patients at Adelaide private hospitals.

Posted in Blog by Douglas Fahlbusch