Known or potential factors influencing perioperative mortality rates
| Preoperative factors | Operative factors | ||
| Patient factors | Comorbidities | Urgency | Planned |
| Age | Emergent | ||
| Severity and nature of illness | |||
| Health systems factors | Prehospital transport | Surgical approach | Open |
| Delay to presentation | Minimally invasive | ||
| Appropriate centre for condition | Intrinsic procedure risk | By specialty | |
| By procedure | |||
| By complexity score | |||
| Surgeon skill | Specialist versus non-specialist surgeon | ||
| Surgeon versus non-surgeon physician | |||
| Physician versus non-physician surgeon | |||
| Trainee versus fully-trained surgeon | |||
| Inter-surgeon variation | |||
| Anaesthetic modality | General, regional, local | ||
| Anaesthetist skill | Specialist versus non-specialist anaesthetist | ||
| Anaesthetist versus non-anaesthetist physician | |||
| Physician versus non-physician provider | |||
| Trainee versus fully-trained anaesthetist | |||
| Inter-anaesthetist variation |