Table 1

Definitions of the adapted Electronic Postoperative Morbidity Score (ePOMS) used for daily assessment of complications in a retrospective cohort of operated chronic subdural haematoma

Domain	Diagnostic criteria	Notes
Respiratory	Need for supplementary oxygen
Respiratory	Need for supplementary oxygen		Cardiovascular	HR >100 SBP <100 Positive troponin test
Neurological	Need for 1:1 nursing observation Motor/Verbal Score worse than referral Focal neurology	Surrogate for hyperactive delirium Documented mismatch between left/right sided arm/leg strength at any stage	Cardiovascular	HR >100 SBP <100 Positive troponin test
Neurological			Renal	Rise in creatinine to ≥1.5× baseline	Last recorded creatinine prior to surgery
GI	Administered antiemetic	Defined by the following WHO ATC codes: a04*, a03fa01, r06ae03, n05ad08	Renal	Rise in creatinine to ≥1.5× baseline	Last recorded creatinine prior to surgery
GI	Administered antiemetic		Pain	Need for intravenous opioids or local anaesthetic infusion on a given day	Drugs identified by following WHO ATC codes: n02aa01, n02ab03, n01bb01
Recurrence†	Reoperation	ePOMS originally identifies severe wound infection by need for further surgery. In this context reoperation for the same procedure is being used to identify reaccumulation of cSDH	Pain
Recurrence†	Reoperation		Infection	Temperature ≥38°C Receiving antibiotics on a given day	Antibiotics defined by following WHO ATC codes: j01‡
Haematological	Transfused with blood product	Including red cells, platelets, FFP, cryoprecipitate	Infection	Temperature ≥38°C Receiving antibiotics on a given day	Antibiotics defined by following WHO ATC codes: j01‡

If multiple potential criteria are listed then an individual is positive in that domain if any of these are met.
*Indicates additional criterion included in this variant of ePOMS from those previously published.
†In the original ePOMS this would correspond to the wound category.
‡Indicates that all drugs below this level of ATC code were included. A dictionary of relevant ATC codes is available in the online supplementary material.
FFP, fresh frozen plasma; GCS, Glasgow Coma Scale; GI, gastrointestinal; HR, heart rate; SBP, systolic blood pressure; WHO ATC, World Health Organization anatomical therapeutic chemical classification.