Oxygen is vital for life, and it is one of the most common interventions used in healthcare worldwide (Kelly and Maden, 2015). Oxygen is routinely used for acutely ill patients, with the primary goal of correcting alveolar and/or tissue hypoxia. It is also used in the home after careful evaluation by a Home Oxygen and Review Service (HOS-AR) (in the UK) to ensure that normal or near-normal oxygen saturations are achieved (National Institute for Health and Clinical Excellence (NICE), 2019).
Oxygen is seen as beneficial by most health professionals but, worryingly, it is widely considered to be completely harmless (National Institute for Health Research (NIHR), 2018). Further, the perceived benefits of oxygen seem to be driving poor practice and a self-perpetuating cycle of perceived barriers to perception change (Kelly et al, 2018). It must be kept in mind always that oxygen is a drug and should be treated as such through correct prescribing, administration and monitoring (NICE, 2019). All health professionals who administer and prescribe oxygen therapy must be aware of side effects and potential detrimental effects, as with any drug.
Writing on behalf of the British Thoracic Society (BTS), O'Driscoll et al (2017) recommended immediate high-concentration oxygen for critically ill patients, which should then be titrated to achieve target oxygen saturations. These target ranges vary according to the patient and their underlying disease, with recommendations of between 94% to 98% for most acutely ill patients and 88% to 92% for those at risk of hypercapnic respiratory failure (high blood carbon dioxide (PaCO2>6.6 kPa)), which is most commonly seen in patients with chronic obstructive pulmonary disease (COPD) (BTS, 2017). According to the NIHR (2018), despite these recommended targets, acutely ill patients who require hospital admission are often administered excess oxygen, which has been found to increase the risk of death (NIHR, 2018). In the UK, COPD accounts for 10% of all hospital medical admissions (over 90 000 annually), with approximately one-third of patients in ambulances and a quarter of patients in emergency rooms treated with supplemental oxygen (Turner et al, 2015; Chu et al, 2018). A BTS audit of emergency oxygen use in UK hospitals showed that 31% of patients are without a prescribed target range within the hospital setting (Hardinge et al, 2015). In addition, 8.8% of patients using oxygen were found to be at risk of iatrogenic (caused by treatment) hypercapnia due to being above the recommended target saturation range by more than 2%, despite recognised hypercapnic risk (Hardinge et al, 2015).
Hyperoxaemia, or abnormally high blood oxygen levels, has been associated with adverse clinical outcomes in not only patients with COPD, but also those with stroke and heart failure (Chu et al, 2018). A recent meta-analysis suggested that hyperoxaemia is associated with increased mortality at least in patients after cardiac arrest, stroke and traumatic brain injury (Chu et al, 2018). Additionally, supplemental oxygen therapy in patients with ST-elevation–myocardial infarction but without hypoxia may increase early myocardial injury and has been found to be associated with larger myocardial infarct size assessed at 6 months (Stub et al, 2015).
Physiological effects of excess oxygen
For long now, it has been known that prolonged exposure to high concentrations of oxygen in animal models leads to diffuse alveolar damage, alveolar collapse, haemorrhage, infiltration of inflammatory cells, apoptosis, necrosis and injury to the endothelium and epithelium in the lungs, which ultimately causes death (in the rat model, death occurs after 4 days of exposure to 73% oxygen at 1 atm) (O'Driscoll et al, 2017). Oxygen at above-normal partial pressure, leading to hyperoxaemia, can cause oxygen toxicity or oxygen poisoning in humans as well (Cooper and Shah, 2019), characterised by disorientation, breathing problems and vision changes, such as myopia, among other adverse effects. Prolonged exposure to above-normal oxygen partial pressures or shorter exposure to very high partial pressures can cause oxidative damage to cell membranes, leading to the collapse of the alveoli in the lungs (Cooper and Shah, 2019).
Conversely, severe hypoxaemia may lead to brain damage and death. O'Driscoll et al (2017) stated that many of the physiological effects of hypoxaemia are mediated by low PaO2, irrespective of oxygen content. For example, even when the total blood oxygen content is normal in the presence of polycythaemia (abnormally increased concentration of haemoglobin in the blood), hypoxaemia will still exert a physiological effect, for example, stimulation of ventilation. The risks of hypoxaemia, however, are usually mediated by low tissue PaO2, which may occur as a consequence of a low PaO2 and other mechanisms such as severe anaemia and low cardiac output (O'Driscoll et al, 2017).
The BTS recommends that in the community setting, oxygen alert cards should be provided to patients at risk of hypercapnic respiratory failure, in order to mitigate inappropriate oxygen prescription in the emergency setting (Hardinge et al, 2015). Oxygen use in ambulances is very common, equivalent to 2.2 million episodes annually in the UK, and studies have suggested that use of oxygen for patients with COPD is suboptimal: they are either given too much or too little (Hale et al, 2008). Since the initial recommendation from the BTS, however, the uptake of alert cards has been slow (anecdotally). There could be multiple reasons for this, for instance, patients losing the cards, paramedics failing to locate the cards and relatives not presenting the cards to the emergency services; all these can potentially lead to inappropriate oxygen prescription and put lives at risk.
To overcome the problems associated with oxygen alert cards, front-line clinicians at Derby Teaching Hospitals NHS Foundation Trust have developed a system of colour-coded silicone wristbands that clearly state a patient's target saturation range. These wristbands have been designed to ensure that the correct level of oxygen is prescribed, limiting the possibility of both oxygen toxicity and under-oxygenation, both of which can cause harm to patients. To adopt this concept, oxygen alert wristbands (OxyBands) were introduced locally by the respiratory team for patients with a history of hypercapnic respiratory failure in the community setting (Figure 1). A single colour was used, and the target saturations ranged from 88% to 92%. The aim of this project was determine whether this patient safety tool could prevent inappropriate emergency oxygen prescription and administration.
Aim
OxyBands aim to alert health professionals who are delivering oxygen to patients to ensure that oxygen is administered and titrated safely to the appropriate target saturations. According to O'Driscoll et al (2017), the monitoring of oxygen saturation should take place at all observation rounds. This, therefore, prompted the introduction of the OxyBand during hospital admission with continuation into the community setting. This is vital, as it has been recognised that the mortality rates among COPD patients can be reduced substantially through the correct use of oxygen as part of a care bundle (Turner et al, 2015).
Methods
This pilot study was conducted between June and December 2017. Prior to the introduction of the OxyBand, extensive education was provided to the local HOS-AR services, the North West Ambulance Service and the emergency departments of the two local acute trusts. Posters identifying the OxyBand as well as contact details for the local HOS-AR services were made available for any queries. Patients gave informed consent to wear the OxyBand at all times, and no objections were made.
All patients attending the Knowsley Community Respiratory Service (KCRS) who have previously had raised PaCO2>6.6 kPa and were receiving home oxygen were included and provided with a type II respiratory failure pack (Figure 2), as recommended by O'Driscoll et al (2017), as well as the OxyBand.
Two questionnaires were used for this pilot study. The first one was used to evaluate clinicians working within respiratory medicine and emergency services regarding their knowledge about oxygen prescription in the emergency setting. The second one was used to evaluate patients' perception about the OxyBand.
Twenty random cases of oxygen prescription in the emergency setting were evaluated prior to and after the introduction of the OxyBand.
Results
Case review
A review of 20 randomly selected cases from the KCRS workload showed that inappropriate oxygen was prescribed on nine occasions (9/20) where the recorded oxygen saturations exceeded the target range (88%–92%) based on clinical guidelines. In all these cases, the patients had not presented their oxygen alert cards to the clinicians at presentation.
Following the introduction of OxyBand, a case reviewed showed that inappropriate oxygen was prescribed on only one (1/20) occasion, where the patient failed to wear the OxyBand. The demographics of the patients who were provided with OxyBands are given in Table 1.
| Age (years) | 75±25 |
| Male: female | 20: 24 |
| Mean FEV1% predicted | 38 |
| Mean MRC score | 5 |
| Mean oxygen saturation % on oxygen (range) | 91 (90–94) |
| Mean COPD assessment test score | 22 |
| Smoking status |
5 |
| History of type II respiratory failure | n=44 |
COPD: chronic obstructive pulmonary disorder
Clinician questionnaire results
Thirty-six clinicians completed the questionnaire; there were 18 doctors, 13 nurses and five paramedics. Although majority of the clinicians (32 out of 36) understood the potential risk of prescribing uncontrolled oxygen to patients with a prior history of type II respiratory failure, many of them failed to recognise the appropriate target oxygen saturations: two answered 88–92% for known CO2 retainers and 94–98% for non-retainers, 33 answered 88–92% regardless of CO2 status and one stated they were unsure. Thirty-four clinicians had seen the wrist bands in use and thought they were beneficial. Many of the clinicians were unaware of the existence of the oxygen alert card (Table 2).
| Yes | No | |
|---|---|---|
| Aware of the risk of giving uncontrolled oxygen | 32 | 4 |
| Aware of the oxygen alert card | 25 | 11 |
| Aware of the correct target oxygen saturation ranges | 30 | 6 |
| Felt the OxyBand would be beneficial to patient safety | 34 | 2 |
Patient questionnaire results
The OxyBand was generally well accepted by the patients (Table 3). In addition, there was substantial positive feedback from the patients:
‘I feel like it will keep me safer if I were to become unwell or collapse’
‘Excellent idea as it helps family understand the importance’
‘I never take my band off’
| Yes | No | Unsure | |
|---|---|---|---|
| Aware of the risk of giving uncontrolled oxygen | 37 | 3 | 4 |
| Agree that the OxyBand has improved their understanding of oxygen use | 41 | 3 | 0 |
| Find the OxyBand comfortable to wear | 42 | 0 | 2 |
| Agree with the colour choice of the OxyBand | 42 | 1 | 1 |
Unfortunately, the numbers rubbed off two of the OxyBands. Therefore, it is recommended that these are checked pr ior to administration and at each clinic appointment.
Discussion
The results of the present study showed that OxyBands have the potential to improve patient safety, perhaps over oxygen alert cards, as they provide a visual prompt for emergency staff and other health professionals to be mindful of inappropriate oxygen prescriptions to patients at risk of hypercapnic respiratory failure; the band is also less likely to be mislaid than oxygen alert cards. Overall, the findings of this pilot study have been positive and indicate that wider uptake of OxyBands is a possibility. The guideline recommendation of the use of oxygen alert cards has many drawbacks, as exemplified by the fact that these cards are not always presented by the patients to health professionals in the event of an emergency. It could be that the patients are too unwell to do so or have perhaps forgotten about the importance of presenting the oxygen alert card to mitigate inappropriate treatment. Additionally, despite the inception of oxygen alert cards more than 10 years ago, many clinicians reported being unaware of their existence, and this is certainly a matter of concern.
OxyBands were generally well accepted by the study cohort; 95% of the study cohort found them comfortable to wear and said that the bands improved their understanding about safe oxygen administration. The results showed that the participating clinicians were knowledgeable about the risks of over-administration of oxygen and the target oxygen saturation rates, but this was not unexpected, given that all of them were working in respiratory and emergency services. However, health professionals from various other specialisms also deal with patients requiring emergency oxygen therapy, for example, ward staff. Therefore, it is important to assess and ensure awareness of the risks of oxygen over-administration among other health professions. Training on safe oxygen prescribing should be part of the mandatory training for all health professionals.
The OxyBand has some limitations. First, the numbers can be rubbed off, and this something that needs to be discussed with the manufacturer, who may be able to provide a robust solution. Second, the colour choice of the OxyBand was not to everybody's taste. The patients who disliked the grey colour fell into a red versus blue split, which could have been an influence of the passionate football following in Merseyside. Third, OxyBand is made of silicone, and non-specific skin irritation can be a possibility. Other aspects, such as the pH of the skin, microbes, sweat, skin lotions and personal hygiene, can all cause irritation. Further, irritation can increase when sweating is more prominent, for example, in higher temperatures. Finally, patients can potentially misplace the OxyBand, nullifying its potential benefits.
For those individuals who are likely to misplace the oxygen alert cards or OxyBands, tattooing the oxygen target saturation is an option, but not a recommended idea. Tattoos cannot be misplaced or easily removed, and emergency responders are unlikely to miss seeing an oxygen tattoo on the chest prior to attempting administrating emergency oxygen. However, target oxygen saturation, like all medical orders, need to be changeable depending on the clinical scenario. If patients are permanently committed to preferences expressed at one time, they may be reluctant to express any interest in foregoing interventions. Circumstances change, removing an OxyBand or destroying an oxygen alert card is straightforward and free. Removing a tattoo, in contrast, is an expensive and time-consuming process.
Conclusion
Overall, the OxyBand is well accepted by patients and clinicians and has given both parties the confidence of utilising this innovation in a short space of time. This is an inexpensive and simple change in the authors' practice, but has a huge potential to improve safe oxygen prescribing.
The next steps are to further examine the effectiveness of this intervention with a larger sample size and to disseminate the intervention to other emergency services in the country. The results of the present study indicated that clinicians were confident about oxygen prescribing practice, but all of them were working in respiratory and emergency services. Further exploration of non-specialists, community matrons and GPs needs to be undertaken as part of the initiative. Additionally, the durability of OxyBands needs to be assessed and reviewed to support their widespread implementation.