Repeatability of Pulse Oximetry Measurements in Children During Triage in Two Ugandan Hospitals

Background In low- and middle-income countries, health workers use pulse oximeters for intermittent spot measurements of SpO2. However, the accuracy and reliability when used for spot measurements has not been determined. We evaluated the repeatability of spot measurements, and the ideal observation time of measurement to guide recommendations during spot check measurements. Methods Two one-minute measurements were done for the 3,903 subjects enrolled in the study, collecting 1Hz SpO2 and signal quality index (SQI) data. The repeatability between the two measurements was assessed using an intraclass correlation coefficient (ICC), calculated using a median of all seconds of non-zero SpO2 values for each recording (any quality, Q1), and again with a quality filter only using seconds with SQI ≥ 90% (good quality, Q2). The ICC was also calculated for both these conditions using subsets of the minute, in increasing increments of 5 seconds, up to the whole minute. Lastly, the whole minute ICC was calculated with good quality (Q2), including only records where both measurements had a mean SQI > 70% (Q3). Findings The repeatability ICC with condition Q1 was 0.591 (95% confidence interval (CI) = 0.570, 0.611). Using only the first 5 seconds of each measurement reduced the repeatability to 0.200 (95% CI = 0.169, 0.230). Filtering with Q2, the whole minute ICC was 0.855 (95% CI = 0.847, 0.864). The ICC did not improve beyond the first 35 seconds. For Q3, the repeatability rose to 0.908 (95% CI = 0.901, 0.914). Conclusions Training guidelines must emphasize the importance of signal quality and duration of measurement, targeting a minimum of 35 seconds of adequate-quality, stable data. In addition, the design of new devices should incorporate user prompts and force quality checks to encourage more accurate pulse oximetry measurement. Trial Registration [Clinical Trials.gov][1] Identifier: [NCT04304235][2], Registered 11 March 2020. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial Clinical Trials.gov Identifier: [NCT04304235][2], Registered 11 March 2020. ### Funding Statement Funding Source: This research was funded by the University of British Columbia Work Learn International Undergraduate Research Award, the Wellcome Trust UK, Mitacs accelerate and Sepsis Canada. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics considerations This study was approved by the institutional review boards at the University of British Columbia in Canada (ID: H19-02398; H20-00484), the Makerere University School of Public Health in Uganda and the Uganda National Council for Science and Technology. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data analyzed in the study are available upon reasonable request to the authors [1]: http://ClinicalTrials.gov [2]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT04304235&atom=%2Fmedrxiv%2Fearly%2F2022%2F12%2F28%2F2022.12.21.22283800.atom