As a respiratory nurse specialist the author has an active role in the assessment and management of patients who develop COVID-19-associated respiratory failure requiring continuous positive airway pressure (CPAP) therapy. CPAP is a form of non-invasive positive airway pressure, widely recognised as an essential therapeutic modality for the management of COVID-19-associated respiratory failure. It reduces in-hospital mortality, avoids the need for invasive mechanical ventilation and reduces length of stay in hospital. To date, there is no definitive strategy within national or regional UK guidelines on CPAP initiation and up-titration pressure settings or duration of therapy for COVID-19-associated respiratory failure, leading the author to develop and implement a CPAP protocol proforma in his area of practice.
In a measure to improve patient safety, and ensure correct documentation and implementation of CPAP therapy, the implementation of a CPAP proforma has provided a standardised protocol approach to the initiation, duration and cessation of CPAP therapy for hospitalised patients with COVID-19-associated respiratory failure. In hospital settings where there has been a high rotation of medical and nursing staff, including staff working unsociable hours and working outside of their areas of expertise (as happened during the height of the pandemic), the use of a proforma clearly defining protocol can contribute to safe and high-quality care and help ensure CPAP therapy is provided with continuity and efficacy.
This article contributes to the knowledge base of the nursing community, providing education on the pathophysiology of COVID-19, COVID-19-associated respiratory failure, and the use and benefits of CPAP therapy in severe disease. Nurses providing care for acute COVID-19 patients and those involved in the provision of staff training can consider if the implementation of a CPAP proforma in their clinical area could impact positively on their respiratory service, among healthcare staff and on patient outcomes.
Background and pathophysiology of COVID-19
Never before has the modern healthcare service encountered such a challenge as the COVID-19 global pandemic (Department of Health and Social Care (DHSC), 2020). As of May 2022, coronavirus (SARS-CoV-2) had infected over 518 million people worldwide, and was responsible for just over 6 million deaths (World Health Organization (WHO), 2022). Although there has been consistent decrease in COVID-19 deaths since the beginning of 2022 in the UK (WHO, 2022), coronavirus continued to place a significant burden on the healthcare system, with nearly 7000 patients in NHS hospitals in England, and 190 occupying critical care beds in May 2022. The latest data, from 17 April 2023, suggest that the number of patients admitted to hospital in England has fallen to 4207 (UK Health Security Agency, 2023). On a regional level within Northern Ireland, COVID-19 inpatients added to an already over-occupied system, in May 2022, with local hospital trusts operating beyond available bed capacity (Department of Health (DoH), 2022).
Added to this is the expectation that the NHS must now build a sustainable recovery following the COVID-19 pandemic, addressing new challenges such as restoring care services, meeting the increasing and new care demands of the public, and managing the significant backlog and waiting times in existing care delivery services (NHS England/NHS Improvement, 2021). Although it is acknowledged that the NHS must continue to increase its capacity to deliver new and pre-existing services for the population's health and care needs, it must also remain ready to respond to further COVID-19 surges. This involves treating COVID-19 patients in a timely way, and rapidly implementing now well-established management strategies for patients with severe COVID-19 disease requiring emergency hospitalisation. NHS objectives for 2023 are based on the prediction that the COVID-19 in-hospital impact moves to a low level (NHS England/NHS Improvement, 2021), but NHS staff must still prepare for a resurgence that could again crowd the healthcare system.
With variable and dynamic changes in the rates of infection and incidence, complicated by new mutations and different strains of coronavirus, healthcare services still have a degree of uncertainty and concern that we may again see the peaks of hospitalisations and critical care admissions observed over 2020–2022. Although there has been a significant reduction in the number of individuals developing severe symptoms since the introduction of the COVID-19 vaccines and subsequent booster injections (WHO, 2022), coronavirus is constantly evolving whereby new mutations can increase infectiousness and virulence, potentially leading to a reduction in the efficacy of vaccinations. This means there is always a risk that individuals of all ages can develop severe disease (Walensky et al, 2021).
The last major variant of COVID-19 was omicron, which surpassed earlier dominant strains such as alpha and delta (Centers for Disease Control and Prevention, 2023). Omicron was found to be more transmissible than earlier variants, and although the risk of severe respiratory failure, hospitalisation and death due to omicron infection compared with previous strains is substantially lower (Nyberg et al 2022), variable infection rates among the UK population still impacted heavily on healthcare services. This was due to delays in primary and secondary care appointments and, most notably, in staff absences, creating increased pressure on patient flow throughout hospitals and limitations in critical care admissions due to lower staffing ratios (DHSC, 2022). Coronavirus appears to be here to stay, and we must look towards the future of its ongoing management and safe incorporation within modern health care.
Caring for COVID-19 patients: impact on staff
The author's district general hospital in Northern Ireland became the ‘COVID-19 hospital’ during the pandemic, whereby it only admitted patients who were COVID-19 positive. This had a significant impact on healthcare staff, and required significant dedication to rapidly provide training on COVID-19-associated respiratory failure management to medical and nursing staff who were not previously respiratory trained. This included nurses and doctors who voluntarily returned to work from retirement, and clinicians working in education and research being redeployed to clinical areas to care for critically unwell patients. ‘Hyperacute’ nursing bays were created for patients with severe disease requiring complex respiratory care, who were managed with non-invasive respiratory support techniques such as CPAP (non-invasive ventilation) and high-flow nasal oxygen (HFNO) therapy. Similar to NHS centres across the rest of the UK, the COVID-19 pandemic has had a significant impact on the hospital's healthcare team, with many infected patients requiring advanced and intense medical and nursing care.
Willan et al (2020) supported the need for additional staff during the COVID-19 pandemic, recognising the increased risk of infection among healthcare workers and estimated predicted staff absence rates as high as 20%. Doctors and nurses who had recently retired being asked to return to work, medical students being allowed to graduate early and the deployment of army medical officers to hospital wards demonstrated the critical need to supplement the NHS hospital workforce. Redeployment of clinicians to areas of the greatest need presented significant risk, with some nursing and medical staff lacking confidence in some clinical skills and practising outside their defined areas of expertise (Willan et al, 2020).
The author, as part of a multidisciplinary respiratory team, recognised the necessity for additional training to be provided rapidly to ensure safe care delivery for hospitalised COVID-19 patients, most notably in the application of non-invasive respiratory support therapies. This understandably increased the demand on the author's respiratory service, requiring regular training sessions on non-invasive respiratory support in COVID-19 for all clinicians, and the development of clinical protocols and tools that could be used to support staff in their delivery of safe patient care.
COVID-19 pathophysiology
Coronavirus primarily targets the epithelium of the respiratory tract, resulting in asymptomatic illness through to symptoms of mild, moderate or severe disease (Hopkinson et al, 2021). Fabbri et al (2022) suggested a wide clinical spectrum of COVID-19 health insults, describing mild flu-like symptoms to severe viral pneumonia that requires hospital admission, high-flow supplemental oxygen administration and, in more severe cases, invasive mechanical ventilation (Guan et al, 2020).
Up to 20% of individuals infected with COVID-19 may develop severe symptoms (Parasher, 2021). This occurs when the virus invades and replicates within the alveoli of the lung, releasing inflammatory cells (Whyte et al, 2020). As a result of this inflammatory storm, there is diffuse alveolar damage and destruction, interstitial oedema, ventilation perfusion mismatch and altered pulmonary perfusion, leading to acute severe respiratory failure (Camporota et al, 2020). Amirfarzan et al (2021) described the physiological effects of COVID-19 as alveolar gas exchange airway collapse secondary to inflammation and oedema, resulting in severe hypoxaemia and acute respiratory distress. Furthermore, in severely infected patients, there is an increased risk of developing acute respiratory distress syndrome (ARDS) (Xu et al, 2020), a life-threatening condition caused by massive alveolar damage that negatively affects the ability of the lungs to provide the body's vital organs with sufficient oxygen (Huang et al, 2020).
Although any individual could be at risk of COVID-19 infection, there is a significant population who are at higher risk of developing severe disease resulting in respiratory failure requiring emergency hospitalisation. WHO (2022) defined this population as those aged over 60 and/or those with health conditions such as lung or heart disease, diabetes and conditions affecting the immune system. Such individuals are recognised as being the major population driving the COVID-19 fatality rate (Wilder-Smith, 2021), due to the fact that the SARS-CoV-2 virus is more contagious, spreads more rapidly, and has a far greater global impact than the other more commonly known respiratory illnesses such as flu (Stojanovic et al, 2021).
Management of respiratory failure in COVID-19
There have been major advances in the treatment of COVID-19, including a significant reduction in the number of individuals developing severe symptoms since the introduction of the COVID-19 vaccines and booster injections (WHO, 2022). This has been further complemented by advances in pharmacological treatments now available (National Institute for Health and Care Excellence (NICE), 2023). However, for some individuals, especially those deemed clinically vulnerable who become infected with COVID-19 and progress to develop severe symptoms with acute hypoxaemic respiratory failure and/or ARDS, the management and respiratory support strategies first implemented in 2020 remain relatively unchanged.
Oxygen therapy is the main intervention to best manage acute hypoxaemic respiratory failure regardless of the underlying acute pathology, including COVID-19. It is well known that oxygen therapy should be commenced immediately in all care settings to individual patients who have acute respiratory symptoms and low blood oxygen levels (hypoxaemia), defined as peripheral oxygen saturations below 94% or a partial pressure of arterial oxygen below 8.0 kilopascal (kPa) (O'Driscoll et al, 2017). This applies to all adult patients with the exception of those at risk of developing hypercapnic respiratory failure, where oxygen should be delivered to achieve peripheral oxygen saturations of 88-92% (O'Driscoll et al, 2017). Oxygen therapy is readily available in acute healthcare settings, and should consist of oxygen-delivering interfaces such as nasal cannula, simple face masks, venturi masks and non-rebreather masks fitted with a reservoir bag (O'Driscoll et al, 2017).
In the instance of severe COVID-19 disease, especially when the virus precipitates ARDS, there may be little to no improvement in oxygenation despite high-flow oxygen therapy. In such cases, the patient should be considered for higher forms of non-invasive respiratory support, with best practice guidance advising the use of CPAP therapy (British Thoracic Society (BTS), 2018; NICE, 2023).
CPAP
CPAP therapy is widely recognised as being instrumental in the management of COVID-19-associated acute hypoxaemic respiratory failure (Cascella et al, 2023). A large multi-centre randomised controlled trial has concluded that, among patients with acute hypoxaemic respiratory failure due to COVID-19, the use of CPAP significantly reduces the need for invasive mechanical ventilation and is superior to high-flow oxygen therapy in selected patients (Perkins et al, 2022). This study now informs best practice evidence, and is recommended in the national guideline for the management of COVID-19 in hospitalised patients (NICE, 2023).
CPAP is a form of non-invasive positive airway pressure that delivers a set pressure of airflow to the respiratory airways through a tight-fitting mask that covers the nose and mouth (NICE, 2023). The pressure delivered is maintained throughout both phases of respiration, recruiting small gas exchange airways that are collapsed and inflamed by the COVID-19 virus (Amirfarzan et al, 2021). This process of alveolar recruitment increases the transfer of oxygen into the bloodstream, improving ventilation perfusion mismatching and supplying the body tissues with oxygen, thus improving oxygen saturation (Privitera et al, 2020). CPAP is an intervention designed to improve blood oxygenation and reduce respiratory symptoms, and is used as a method that provides respiratory support until a patient responds to medical treatment. CPAP can therefore be used for prolonged periods during the acute phase of COVID-19 respiratory illness, and then the treatment is gradually reduced as the patient demonstrates the ability to adequately oxygenate for periods without the therapy.
National guidelines recommend the commencement of CPAP in COVID-19-associated respiratory failure when patients are unable to maintain a target oxygen saturation of more than 94% while receiving less than 40% inspired supplemental oxygen concentration (Messer et al, 2021). This informed the UK national COVID-19 rapid guideline, which advised a trial of CPAP therapy in hypoxaemic COVID-19-infected patients who do not respond to supplemental oxygen of 40% concentration or more (NICE, 2023). COVID-19 respiratory support pathways have been created providing a flowchart system for healthcare teams to follow as a guide to when to escalate to higher forms of non-invasive respiratory support strategies including CPAP (Messer et al, 2021). The healthcare trust in which the author operates follows the same recommendations, whereby CPAP has been initiated when oxygen requirements have increased past the 40% oxygen concentration threshold.
To date, there is no definitive strategy within national or regional UK guidelines on CPAP pressure settings for COVID-19-associated respiratory failure. NHS England/NHS Improvement (2020) recommended initial CPAP settings of 10 cmH2O and a minimum of 60% entrained oxygen concentration, with escalation guidance of increasing CPAP support up to 15 cmH2O and oxygen concentration of 100%. The Scottish Intercollegiate Guidelines Network (2020) follows a similar protocol, suggesting CPAP pressure settings of 10-15 cmH2O and entrained oxygen therapy of 10-15 litres per minute. The author's regional healthcare trust's protocol in Northern Ireland advises initiation of a CPAP pressure of 5 cmH2O to allow for comfort, tolerance and assessment for response, with up-titration of 10 cmH2O as required to achieve target oxygenation. This strategy has proven effective, with a local observational study on the early initiation of CPAP in COVID-19-associated respiratory failure demonstrating favourable outcomes, including survival, avoidance of intubation and reduced hospital length of stay (Carroll et al, 2021).
The recommended duration of CPAP therapy for patients with severe respiratory failure in COVID-19 is absent from best practice guidelines. However, in the early stages, most patients will be highly dependent on positive end expiratory pressure (PEEP) therapy, and will experience the return of severe respiratory symptoms and hypoxaemia when CPAP is removed.
The protocol followed in the author's hospital had a target duration for CPAP therapy, recommending greater than 16 hours daily of CPAP use with structured breaks as tolerated by the patient. CPAP duration and PEEP level is tapered daily as the patient's symptoms and supplemental oxygen demand improves, until oxygen requirements are less than 40% concentration via venturi mask or 4 litres per minute via nasal cannula for more than 24 hours without CPAP therapy. This approach was influenced by pre-existing duration and weaning of bi-level non-invasive ventilation, as recommended by the British Thoracic Society (Davidson et al, 2016), a strategy with which the nursing, medical and physiotherapy team in the author's clinical setting were, fortunately, already familiar.
Development of a CPAP protocol/proforma
In a measure to improve patient safety, and ensure correct documentation and implementation of CPAP therapy, the use of a CPAP proforma provides a standardised protocol approach to the initiation, duration and cessation of CPAP therapy. In hospital settings where there can be a high rotation of doctors and nurses, including staff working unsociable hours, the use of a proforma that clearly defines the protocol can contribute to safe and high-quality care and help ensure CPAP therapy is provided with continuity and efficacy.
The benefit of proformas for the delivery of non-invasive ventilation (NIV) is well established and supported by recommendations from the National Confidential Enquiry into Patient Outcomes and Death (NCEPOD, 2017), which conducted a detailed review of the quality of care provided to patients receiving acute NIV therapy and subsequently recommended that the introduction of a standardised proforma identifying targets of treatment represents an opportunity to improve care delivery. Dhara et al (2019) successfully implemented a NIV proforma, concluding that it had significantly improved compliance with national NIV guidance and patient care.
The need for a proforma specific to the CPAP protocol was considered essential to support healthcare staff in the delivery of CPAP therapy, especially for those who were unfamiliar with its use. As no clear guidance exists for initiation settings and up-titration of CPAP therapy, a novel proforma was developed using a protocol created by the local respiratory team. The design used the template from an existing proforma for NIV therapy that is not only well established in the culture of the local hospital setting, but is also in a format that is already familiar to the healthcare staff. The protocol developed is a local one, is based on best available evidence and is under constant review. Its use is always based on patient assessment and tailored to meet individual needs (see Figure 1).
Implementation of the CPAP proforma
Since 2020, the author has helped deliver in-hospital training to more than 200 medical and nursing professionals in the use of CPAP for COVID-19-associated respiratory failure. The proforma was used as a tool for training, prompting consideration for inclusion/exclusion criteria, escalation planning, an initiation and up-titration settings protocol, and weaning and cessation of CPAP therapy. The overarching principle of the proforma is that, when implemented, it can help ensure that CPAP is delivered safely and correctly, and may therefore achieve the best possible outcomes aligned with national guidance, including decreased in-hospital mortality, reduced need for invasive mechanical ventilation, and reduced overall hospital length of stay (NICE, 2023).
Qualitative data exploring the benefits of the proforma were collected through questionnaires distributed to nursing and medical teams following training on the CPAP protocol and use of the CPAP proforma. The aim in collecting staff feedback was to determine if the proforma provided a structured and safe approach to the prescription of CPAP therapy, including indications, contraindications, up-titration of CPAP therapy and determining an escalation plan. The questionnaires demonstrated that, following training on the CPAP protocol via use of the proforma, 88% of healthcare staff stated that their understanding of inclusion and exclusion criteria, initiation and up-titration of pressure settings and duration of CPAP therapy improved from ‘poor’ to ‘good’, and 12% reported their improved understanding as ‘excellent’. All staff who completed the questionnaire agreed with the following statements, that the proforma:
- Clearly identifies the hospital CPAP protocol
- Clearly prompts the consideration of an escalation plan, and
- Helps support safe prescription of COVID-19 CPAP therapy.
All the respondents stated that they ‘strongly agreed’ with the use of the CPAP proforma in clinical practice.
The CPAP proforma provides a clear and structured approach to CPAP prescription to ensure the best outcome for patients can be achieved. Its implementation has facilitated a standardised approach to delivering the CPAP protocol whereby all patients are enabled to receive the same initiation and up-titration protocol of positive pressure settings, have a documented escalation plan and receive the recommended duration of therapy. The CPAP proforma is an essential tool to aid clinicians in delivering advanced respiratory support to critically unwell respiratory patients. However, to fully ascertain the impact the proforma has had in clinical practice further research is required.
Implications for clinical practice
During the COVID-19 pandemic healthcare teams across the UK had to implement an acute CPAP service for critically ill individuals with COVID-19-associated respiratory failure. Many healthcare staff had been required to access rapid, novel training on the implementation of CPAP therapy, many of whom were unfamiliar with this treatment. This was in addition to a plethora of other new skills needed to care for COVID-19 patients. There can be potential risks to patient safety if CPAP is not delivered correctly, and the implementation of any tool that can help to minimise or reduce risk can be considered essential, especially given the challenging and, in some instances, desperate circumstances, particularly in the first wave and during surges of the pandemic.
Development of a CPAP proforma was undertaken for this reason, and has proven beneficial to healthcare staff in providing a protocol that has positive implications for clinical practice through delivering safe and effective CPAP therapy to COVID-19 patients. The proforma can also be used as a training and education tool for medical and nursing staff.
This article contributes to the knowledge base of nursing, providing education on the pathophysiology of COVID-19, COVID-19 associated respiratory failure, and the use and benefits of CPAP therapy in severe disease. Nurses providing care for acute COVID-19 patients and those involved in the provision of staff training can consider if the implementation of a CPAP proforma in their clinical area could impact positively on their respiratory service, among healthcare staff and on patient outcomes.
Conclusion
Although there have been significant advances in the prevention and treatment of COVID-19, there still remains a population, albeit reduced, of individuals who experience severe disease and develop COVID-19-associated respiratory failure in 2023. The management strategies for this have remained unchanged over the past 2 years, with clear evidence that CPAP therapy can reduce mortality risk and the need for invasive mechanical ventilation. With concerns in early 2020 that critical care environments would be in catastrophic occupancy crisis, the introduction of CPAP therapy in designated areas outside of the intensive care unit helped to reduce this burden. In achieving this it is important to appreciate that provision of CPAP therapy has required extensive training and support for healthcare teams across the UK, with many areas having to rapidly adapt to facilitate a new, dynamic and acute CPAP service. It has been necessary to provide training to healthcare staff in providing CPAP therapy and the implementation of a protocol proforma in the author's hospital, which clearly identifies targets for therapy, has contributed to a safe and structured approach to the delivery of CPAP to COVID-19 patients. Support for the implementation of a CPAP proforma has been shown from qualitative feedback from healthcare staff, showing strong support for the use of the proforma in clinical practice. The CPAP proforma is a valuable tool to aid clinicians in delivering advanced respiratory support to patients with severe COVID-19 disease.
KEY POINTS
- Radical advances in the prevention and treatment of COVID-19 have resulted in significant reductions of hospitalisation and mortality rates in those infected
- Acute hypoxaemic respiratory failure continues to be a serious complication for those who develop severe COVID-19 disease
- Best practice evidence recommends that early use of continuous positive airway pressure (CPAP) in this group can reduce mortality risk, the need for invasive mechanical ventilation and hospital length of stay
- Implementation of a CPAP proforma can provide a standardised protocol approach to the initiation, duration and cessation of CPAP therapy for hospitalised patients with COVID-19-associated respiratory failure, contributing to safe and high-quality care
CPD reflective questions
- What issues have you encountered in the management of hospitalised patients with COVID-19, including early recognition for the need of continuous positive airway pressure (CPAP) therapy for patients who develop severe disease?
- Do you have a local protocol for using CPAP in hospitalised patients with COVID-19 associated respiratory failure?
- Do you think a CPAP proforma would help provide a standardised approach to the management of COVID-19-associated respiratory failure?
- Do you think a CPAP proforma would help improve patient safety?