Table 3

Summary of major subthemes

Domain	Subthemes	Explanation	Example questions from interview guide
Feasibility	Cost/resources	Includes cost and maintenance/storage of LUS equipment, sufficient number of adequately trained staff, potential increased workload and time	What should happen to make LUS successful? Do you foresee any problems with keeping the LUS device in the hospital when not in use? Do you think that LUS could be integrated into this facility? What would be some of the challenges/ barriers? How much training (hours and/or days) do you think that learning to use LUS would take?
	Support from policymakers	Allocating sufficient resources to LUS equipment purchase and promoting use of LUS broadly across public hospital sector
	Acceptance of caregivers	Buy-in from recipients of LUS
Usability	Device management	Performing LUS image/video clip capture	Tell me about your experience with ultrasound. What was easy and/or difficult to learn regarding LUS? How much time did a LUS examination take? What level of healthcare provider do you think should perform/ interpret LUS?
	Image interpretation	Making diagnosis using available LUS images/video clips
	Integration into existing workflow	Using LUS as point-of-care tool within existing clinic structure
Acceptability	Perceived value	Reasons respondent gave for liking and/or wanting LUS implemented within healthcare setting	What did you think about LUS? What do you like about LUS? What do you dislike? Did you have any concerns about LUS during your child’s visit? How do you think that the LUS would impact your child’s care (caregivers) or ability to care for children (HCPs)? How does your experience with LUS compare to CXR?
	Affective attitude	Extent respondent liked or did not like LUS
	Patient comfort	How child and caregiver tolerated LUS examination
	General understanding	Respondent’s ability to articulate indications and expectations of LUS

CXR, chest radiography; LUS, lung ultrasound.