In modern medicine, oxygen is classified as a drug and should be administered based on good drug-prescribing and monitoring practices. The German S3 guideline of supplemental oxygen therapy recommends the prescription of oxygen by a trained physician, specifying a target range of oxygen saturation. Each prescription should be based primarily on the patient's evaluation by a senior clinician or specially trained health care professionals. In a grouped population study of oxygen prescription in patients, Harper et al. (2021) reported the proportion of inpatients with oxygen prescription ranging from 40 to 60%.
The British Thoracic Society Guideline recommends a standard oxygen prescription document for all healthcare facilities. Alternatively, facilities can opt for a designated oxygen section on all drug prescribing documents or sections for oxygen prescription in an electronic prescribing system. Except for sudden illness or critical emergencies requiring quick interventions, a formal oxygen prescription should always be provided before an oxygen therapy course is initiated. These prescriptions should always be signed and specify the administration protocol details, including oxygen concentration, flow rate, target saturation range, and duration of administration. It is essential to ensure all nursing staff understand the aim of the therapy, including all healthcare professionals attending to the patients.
Clinicians are encouraged to disregard the old practice of specifying a fixed oxygen concentration or fraction of inspired oxygen. The method has no clear target for the therapy, making it hard for the nursing team to plan appropriately for monitoring and weaning when necessary. In emergencies, the lack of a formal oxygen prescription should not preclude the administration of supplemental oxygen. In pre-hospital cases, first responders and medical personnel should administer oxygen liberally if required to improve clinical symptoms. However, written documentation, including the duration of emergency administration, oxygen concentration, and flow rate, should be made in all instances of emergency medical interventions. Emergency oxygen administration should be based on the guidance provided on the card for patients with an oxygen alert card until blood gas measurements can be conducted.
In prescribing the delivery system, the attending specialist should consider oxygen requirements, breathing pattern, mouth opening, and risk of hypercapnia. Once therapy is initiated, the medical team should reassess the patient to detect possible signs of clinical deterioration at the early stage of treatment. It is essential in patients with no prior history of supplemental oxygen therapy. Early reassessments should also examine the risks of complications or the need for intensive care (Quinten et al., 2018). The reassessment interval should be determined by the severity of vital signs and the extent of hypoxemia. Patients who are started on oxygen therapy can be reassessed every 4 to 6 hours. The British Thoracic Society guideline recommends a 6-hour assessment interval for patients started on oxygen therapy and continuous monitoring depending on where the treatment was initiated.
Regardless of where therapy was initiated, continuous monitoring is recommended in track and trigger systems if multiple vital signs are outside the normal physiological ranges. In this case, the oxygen concentration required to achieve a target saturation range may depend primarily on the risk of a life-threatening complication or clinical deterioration (Arnolds et al., 2022). Suppose high-flow nasal cannula oxygen (HFNC) is initiated in a patient with no prior history of oxygen therapy under emergency conditions. In that case, the German S3 guideline also recommends continuous SpO2, pulse, and respiratory rate monitoring. Other vital signs, including mental state, blood pressure, and body temperature, should also be monitored (Kang et al., 2020).