Table 3. Interview themes mapped to COM-B sources of behaviour.

	Themes	Sub-themes	COM-B sources of behaviour (in bold) and Intervention functions (Michie et al, 2011)	Multi-component intervention
1	The harmful patient experience persists, with consumer insights not leveraged to effect change	Feeling invisible	Capability (psychological) Education, training, enablement	Education of staff Education and training of inserters Education of patients
		Risk and anticipation of failed PIVC Attempts	Opportunity (social) Restriction, environmental restructuring, enablement	DIVA identification (e-health record)
		Inflexible processes which don’t consider patients’ needs	Opportunity (physical) Restriction, environmental restructuring, enablement
2	‘Escalation’ is just a word on the front lines	Providing day-to-day care for DIVA patients	Motivation (reflective) Education, persuasion, incentivisation, coercion	Education of staff Audit of insertion success per ward
		Reliance on “have a go’ culture	Motivation (reflective) Education, persuasion, incentivisation, coercion	Education of staff Audit of insertion success per ward
		Forced to inset PIVCs in an environment lacking resources and support	Opportunity (physical) Restriction, environmental restructuring, enablement	DIVA standard of care and guidelines
3	Heightened risk of insertion failure without resources and training	Awareness of the benefit of a DIVA pathway	Motivation (reflective) Education, persuasion, incentivisation, coercion	Education of staff Audit of insertion success per ward
		Education and equipment to support a skilled workforce	Capability (psychological) Education, training, enablement Opportunity (physical) Restriction, environmental restructuring, enablement	Education of staff Bedside US equipment etc
		Inserter role and accreditation clarity	Opportunity (physical) Restriction, environmental restructuring, enablement	Initial and ongoing competency Accreditation
4	Paving the way forward–‘measures need to be in place to prevent failed insertion attempts	System approach including protocols	Capability (psychological) (physical) Education, training, enablement	Point-of-care resources and tools–evidence-based DIVA assessment and pathway tool; videos, example scenarios
		DIVA identification processes	Capability (psychological) Education, training, enablement Capability (physical) Training, enablement Opportunity (physical) Restriction, environmental restructuring, enablement	Simulation training sessions and clinical skills assessment Peer training models DIVA standard of care and guidelines Evidence-based DIVA assessment and pathway tool

DIVA = Difficult intravenous access; PIVC = Peripheral intravenous catheter.