Table 2.

Extended Eindhoven classification model [14, 16, 17]. Distribution of root causes

Main category	Sub category	Code	Description	Deceased patients (n = 11) Frequencies (%)	Survival patients (n = 72) Frequencies (%)
Technical				0	0
	External	T-ex	Technical failures beyond the control of the organisation.
	Design	TD	Failures to poor design of equipment etc.
	Construction	TC	Correct design inappropriately constructed or placed.
	Materials	TM	Material defects not classified under TD or TC.
Organisational				2 (10.5%)	20 (15.2%)
	External	O-ex	Failures at an organisational level beyond the control and responsibility of the investigating team.	1 (5.3%)	2 (1.5%)
	Transfer of knowledge	OK	Failure resulting from inadequate measures to train or supervise new or inexperienced staff.
	Protocols	OP	Failures relating to the quality or availability of appropriate protocols.		2 (1.5%)
	Management priorities	OM	Internal management decisions which reduce focus on patient safety when faced with conflicting priorities.	1 (5.3%)	16 (12.1%)
	Culture	OC	Failure due to attitude and approach of the treating organization.
Human				3 (15.8%)	26 (19.7%)
	External	H-ex	Human failures beyond the control of the organisation/department		2 (2.5%)
	Knowledge-based behaviour	HKK	Failure of an individual to apply their knowledge to a new clinical situation
	Qualifications	HRQ	An inappropriately trained individual performing the clinical task
	Co-ordination	HRC	A lack of task co-ordination within the healthcare team.		7 (5.3%)
	Verification	HRV	Failure to correctly check and assess the situation before performing interventions	1 (5.3%)	6 (4.5%)
	Intervention	HRI	Failure resulting from faulty task planning or performance	1 (5.3%)	11 (8.3%)
	Monitoring	HRM	Failure to monitor the patient’s progress or condition	1 (5.3%)
Patient	Patient-related	PRF	Failures related to patient characteristics or conditions, which are beyond the control of staff and influence clinical progress	3 (15.8%)	16 (12.1%)
	Disease-related	DRF	Failures related to the natural progress of disease which are beyond control of patient, its carers and staff	9 (47.4%)	65 (49.2%)
X	Unclassifiable	X		2 (10.5%)	5 (3.8%)
Total				19	132