Oxygen saturation levels are key to noticing someone's respiratory health decline as a result of a range of a respiratory diseases and infections, with COVID-19 currently being among the most deadliest of these. The article specifically looks at the role of healthcare assistants working in environments such as care homes and the community, often without the presence of a nurse and provides a thorough overview of pulse oximetry and it's role in assessing the severity of a condition and in helping with other criteria to determine whether to refer for further assessment/treatment.
Palmer, S. J. The importance of pulse oximetry. British Journal of Healthcare Assistants, 14 (9) p 429 - 432.