Table 3

Summary of most useful indicators of oxygen access

Domain	Indicator	Potential sources
Use	*Proportion of patients with hypoxaemia receiving oxygen therapy.* *Proportion of acutely unwell patients screened using pulse oximetry.* Additional considerations: - presence of oxygen clinical guideline, including routine pulse oximetry - rational use (oxygen provision with vs without indication) - flow rates and duration of therapy (useful for quantification of oxygen need and quality improvement) - equity between populations (hospital department, age, sex, ethnic background, socioeconomic status) - training and skills of healthcare workers	Clinical audit, routine health information system, HCW survey
Availability	*Proportion of wards with functional oxygen source and delivery devices.* *Proportion of wards with functional pulse oximeter and probes.* Additional considerations: - pulse oximeter and oxygen source presence and function (including oxygen purity testing for oxygen concentrators) - delivery devices (cannula, mask, CPAP, flowmeter assembly, etc) - maintenance personnel (local capacity and access to expert help) - equipment inventory and preventive maintenance schedules - spare parts: access and cost	Physical inspection+device testing, technician survey
Cost	*Daily cost of oxygen therapy to patients* *Annual expenditure on oxygen equipment and maintenance/repairs.* Additional considerations: - equity and non-payment action (hospital department, age, poor) - whole of life cycle (capital and operating costs): oxygen source; refill cost; spare parts and maintenance; power; consumables.	Patient accounts and general finance ledger, administrator survey

CPAP, continuous positive airway pressure ; HCWs, healthcare workers.