Interventional Radiology · Quality and safety · 2017 classification, clarified 2023

SIR Adverse-Event Classification

The Society of Interventional Radiology classification grades procedural adverse events by the resulting escalation in care, from mild events to death.

Purpose

To standardise description, severity grading and review of adverse events associated with interventional radiology procedures.

Grade	Severity	Escalation of care and examples
1	Mild	No therapy or only nominal, non-substantial therapy; includes a near miss recognised and corrected before harm.
2	Moderate	Moderate escalation requiring substantial treatment, such as an intervention under conscious sedation, blood-product administration, extremely prolonged outpatient observation or an unplanned overnight admission after an outpatient procedure.
3	Severe	Marked escalation: atypical hospital admission or prolongation for more than 24 hours, transfer from a ward or telemetry unit to intensive care, or a complex intervention requiring general anaesthesia in a previously non-intubated patient.
4	Life-threatening or disabling	Cardiopulmonary arrest, shock, organ failure, unanticipated dialysis, paralysis, or loss of a limb or organ.
5	Death	Patient death or unexpected pregnancy loss.

How to use it

Part A comprises a narrative description of the event, including sedation or anaesthesia events, followed by assignment of the severity grade.
All adverse events occurring within 30 days of the procedure should be described and analysed irrespective of whether causality has been established.
Use the modifier M when multiple adverse events occur; each event should be counted and graded separately whenever possible.
Part B supports quality review by separately considering causality, patient and procedural risk, preventability and whether management was consistent with expected specialist practice.
The severity grade reflects the consequence and escalation of care; it does not by itself determine causality, preventability, negligence or operator performance.

Common mistake

Do not automatically label every intervention or transfusion as Grade 3. Substantial treatment, including transfusion or intervention under conscious sedation, is Grade 2 unless there is marked escalation such as atypical admission beyond 24 hours, intensive-care transfer or a complex intervention requiring general anaesthesia.

Exam pearl

Remember the progression: 1 no or nominal therapy, 2 substantial treatment, 3 marked escalation of care, 4 life-threatening or disabling event, and 5 death.

Viva questions

What is the basis of the SIR adverse-event severity classification?: It grades an adverse event primarily according to its clinical consequence and the degree of escalation in care required.
Enumerate the five SIR adverse-event grades.: Grade 1 is mild, Grade 2 moderate, Grade 3 severe, Grade 4 life-threatening or disabling, and Grade 5 is death.
What distinguishes Grade 2 from Grade 3?: Grade 2 requires substantial treatment or moderate escalation. Grade 3 requires marked escalation, such as atypical admission beyond 24 hours, intensive-care transfer or a complex intervention under general anaesthesia in a previously non-intubated patient.
How is blood-product administration classified?: Blood-product administration is generally a Grade 2 moderate adverse event unless associated consequences independently satisfy a higher grade.
What does the M modifier indicate?: M indicates multiple adverse events. Each event should be counted and graded separately whenever possible.
What is assessed in Part B of the SIR system?: Part B separately analyses causality, patient and procedural risk modifiers, preventability and the management of the adverse event.
Which adverse events should be included in SIR reporting?: All adverse events occurring within 30 days of the procedure should be included, irrespective of whether they are ultimately considered procedure-related.
Does a high SIR severity grade establish operator error?: No. Severity grading describes the event's consequence and escalation of care; causality, preventability and management are assessed separately.