Table 2

Systems of classification by state-based anaesthesia mortality committees

Deaths attributable to anaesthesia
Category 1	Where it is reasonably that death was caused by the anaesthesia or other factors under the control of the anaesthetist.
Category 2	Where there is some doubt whether death was entirely attributable to the anaesthesia or other factors under the control of the anaesthetist.
Category 3	Where it is reasonably certain death was caused by both medical/surgical and anaesthesia factors.
Explanatory notes: The intention of the classification is not to apportion blame in individual case but to establish the contribution of the anaesthesia factors to the death. The above classification is applied regardless of the patient’s condition before the procedure. However, if it is considered that the medical condition makes a substantial contribution to the anaesthesia-related death, subcategory H should also be applied. If no factor under the control of the anaesthetist is identified which could or should have been done better, subcategory G should also be applied.
Death in which anaesthesia played no part
Category 4	Death where the administration of the anaesthesia is not contributory and surgical or other factors are implicated.
Category 5	Inevitable death, which could have occurred irrespective of anaesthesia or surgical procedures.
Category 6	Inevitable death, which could not reasonably be expected to have been foreseen by those looking after the patient, was not related to the indication for surgery and was not due to factors under the control of the anaesthetist or surgeon.
Unassessable death
Category 7	Those that cannot be assessed despite considerable data, but where the information is conflicting or key data are missing.
Category 8	Cases that cannot be assessed because of inadequate data.

*Adapted from Australia and New Zealand College of Anaesthesia mortality classification table.15