Flow chart participant recruitment.

a Confirmation that a medical device meets the safety, health and environmental protection requirements of the European Economic Area (EEA) [28]. b devices intended for monitoring possibly dangerous changes in vital parameters [29].</p

Five-number summary of satisfaction scores overall and per device group, country, and cadre.

Five-number summary of satisfaction scores overall and per device group, country, and cadre.</p

Frequency of task completion and task completion rates per checklist item.

Frequency of task completion and task completion rates per checklist item.</p

Description of checklist variables.

Timely recognition and referral of severely ill children is especially critical in low-resource health systems. Pulse-oximeters can improve health outcomes of children by detecting hypoxaemia, a severity indicator of the most common causes of death in children. Cost-effectiveness of pulse-oximeters has been proven in low-income settings. However, evidence on their usability in community health settings is scarce.This study explores the usability of pulse-oximeters for community health and primary care workers in Cambodia, Ethiopia, South Sudan, and Uganda. We collected observational data, through a nine-task checklist, and survey data, using a five-point Likert scale questionnaire, capturing three usability aspects (effectiveness, efficiency, and satisfaction) of single-probe fingertip and multi-probe handheld devices. Effectiveness was determined by checklist completion rates and task completion rates per checklist item. Efficiency was reported as proportion of successful assessments within three attempts. Standardized summated questionnaire scores (min = 0, max = 100) determined health worker’s satisfaction. Influencing factors on effectiveness and satisfaction were explored through hypothesis tests between independent groups (device type, cadre of health worker, country). Checklist completion rate was 78.3% [CI 72.6–83.0]. Choosing probes according to child age showed the lowest task completion rate of 68.7% [CI 60.3%-76.0%]. In 95.6% [CI 92.7%-97.4%] of assessments a reading was obtained within three attempts. The median satisfaction score was 95.6 [IQR = 92.2–99.0]. Significantly higher checklist completion rates were observed with single-probe fingertip devices (p</div

Effectiveness outcome: Frequency of full task completion, task completion rates with 95% confidence intervals and p-values.

Effectiveness outcome: Frequency of full task completion, task completion rates with 95% confidence intervals and p-values.</p

STROBE statement—checklist of items that should be included in reports of <i>cross-sectional studies</i>.

STROBE statement—checklist of items that should be included in reports of cross-sectional studies.</p

Frequency of task completion and task completion rates per checklist item, pairwise deletion.

Frequency of task completion and task completion rates per checklist item, pairwise deletion.</p

Efficiency outcome: Frequencies and percentages of successfull measurements.

Efficiency outcome: Frequencies and percentages of successfull measurements.</p

Frequency of task completion and task completion rates per checklist item by age group.

Frequency of task completion and task completion rates per checklist item by age group.</p

Pulse oximeter devices used in the study, overview.

Pulse oximeter devices used in the study, overview.</p