Evidence-Based Anaesthetic Monitor
A quantum leap in Anaesthetic Monitoring - The EBMi that will take care of you and your patients

Welcome to Custos

This software is capable of processing the routinely collected data from an anaesthetic monitor and by weighing up the evidence of changes over time can suggest a diagnosis.

Please note: Custos is an aid; the anaesthetist still has the total responsibility for the interpretation of the diagnostic output. Any clinical decision, action, or inaction will be totally the responsibility of the user.


Unlike many medical scenarios an anaesthetic can go bad really quickly. Things have changed, somewhat over the years. Simulators and workshops on cardiopulmonary resuscitation are now almost routine in many teaching centres but what you need is an ever vigilant 'friend’ in theatre with you, not only as a real novice but also as seasoned expert.

Monitors give us huge amounts of data and from these data we draw conclusions about the state of the patient. However, threshold alarms do not indicate the changes that have taken place or their significance. It is the change in the physiological variables that is of clinical use, not only the change of one variable but the way in which variables change together. This describes a coordinated response of the patient to the various events that take place during anaesthesia and surgery.

Alarms usually consist of a variety of ‘musical’ tones; some are of a single note, some vary to create a pattern. However it takes a very keen ear to be able to differentiate between them. Bleeps are not wanted, we want information.

This software has its origins in crisp and fuzzy logic, belief and plausibility, artificial neural networks, runs analysis, standard statistics and in depth knowledge of anaesthesia.

Why is this needed? When distracted by a conversation, scrubbed putting in a central line, struggling with a recalcitrant infusion pump, drawing up more drugs, or at four in the morning when all we really want to do is get to bed, is when a monitor that is forever vigilant could be invaluable. It won’t just bleep it will tell you what is wrong.

The CEO of Apple, Steve Jobs, said you should be able to describe your product in 140 characters. Here it is - evidence based monitoring is a development you will say ...

"How could I practise safely without it? For the novice anaesthetist a guardian, for the experienced a vigilant friend, for the patient a physiological seat belt.”