High-flow therapy at home: Dr Díaz-Lobato discusses its increasing adoption

• How were hypoxemic COPD patients treated before HFT at home became available?

The classic treatment for respiratory failure in patients with hypoxemic COPD is oxygen therapy: patients are treated with oxygen for a minimum of 15 hours a day, although in most cases it is for 24 hours a day. The rationale is that, if the patient’s respiratory system is not able independently to maintain an adequate level of oxygenation in the blood, then we can ensure acceptable levels of blood oxygenation are maintained by making the patient breathe air with a high concentration of oxygen. We can monitor this with pulse oximeters that measure oxygen saturation or with BGA (blood gas analysis) that measures PO2 in arterial blood.

Oxygen therapy is a passive treatment, in the sense that the patient must do the work required to achieve good oxygenation and overcome any breathing difficulties or moments of resistance. HFT can go a step further as it is a ventilatory support technique. This treatment helps the patient to breathe, transforming breathing from a passive process into an active process. In other words, it doesn’t just help the patient to achieve proper oxygenation, it also features other mechanisms of action that benefit the patient and facilitate the breathing. In this sense, when we think of a patient with COPD and the main limitations it places on breathing and blood oxygenation, and we think about what HFT can contribute, we clearly see that at a theoretical level there are significant differences that favour this treatment over standard, conventional oxygenation.

There are already articles and papers published in the scientific literature that show HFT benefits. However, we are waiting for the scientific community to publish more rigorous work that would establish solid scientific evidence and provide a specific indication for this treatment to be used for the types of patient that we have discussed.

• What challenges have you faced with hypoxemic COPD patients?

When we have a new therapy that is starting to be tested with patients, we face clinical challenges regarding the efficacy of the therapy and the ability of patients to tolerate the treatment. As regards the patient, we have seen that the therapy is very well tolerated and that tolerance for HFT is much better than for alternative therapies. In fact, the rate of refusal for this therapy is much lower than for other treatments. In acute hospital settings, patients do not want to return to alternative therapies once they have experienced HFT.

We also experience challenges of an administrative nature in terms of procuring or financing the therapy. These challenges will clearly vary by location. A funding formula will have to be found because, at present, the role of HFT cannot be disputed.

• Why did you decide to use HFT with your patients

I have always worked in pulmonology in the field of respiratory failure. I was present in the early days of non-invasive mechanical ventilation and when I found out that there was an emerging therapy – high-flow therapy – that we didn’t know anything about, I contacted the companies that had the equipment so we could try it with our patients and verify its efficacy.

After many years treating all types of patients and 10 years of exploration, we have acquired a body of scientific evidence that is heavily focused on acute patients and the mechanisms of action of HFT. We now have a foundation for understanding why HFT can be of use in respiratory disease scenarios and why it has become a first line treatment for patients with acute hypoxemic respiratory failure in our experience. We are also building a foundation of scientific evidence on chronic stable patients who are receiving long-term HFT at home, rather than being treated during an acute episode in a hospital setting.

• What steps did you take in order to introduce HFT?

We started at the local level as the first step is to convince the hospital management and the head of service. It is also important to get the patients on board, but it is relatively easy to explain to them that there is a therapy that could be beneficial. Once the patients give their consent it is straightforward as, for the most part, their condition improves in our experience.

Once hospitals start to treat patients and see the benefits it brings, they begin to incorporate these therapies into different hospital services. At this point, a hospital can have high-flow equipment not only in the pulmonology department but also in critical areas, intensive care, emergency care, internal medicine, geriatrics. In other words, the hospital management understands that this new therapy is effective, that it is increasingly supported by scientific evidence, and that it is useful.

It has been relatively easy to get hospitals to equip themselves with high-flow equipment but it is a different story for HFT at home. HFT falls within the boundaries of what is considered to be a home respiratory therapy and, as such, specific processes must be respected before it can be offered in the homes of patients. Depending on the country, these therapies can be deployed, installed and maintained by different providers that deliver respiratory therapies at home. We have to take steps so that the authorities include this therapy in their funding arrangements, in the same way that they do for classic home-based therapies. We are currently at this critical juncture in Spain.

• What were the main concerns of the team?

We are used to integrating technology and non-invasive mechanical ventilation. When we first came across high-flow equipment, the first thing we noticed was how simple it is to use. This has been a great advantage that has undoubtedly supported the extensive roll-out of HFT in hospitals and will be very significant in its adoption in the home. The technology can be controlled in a very agile and rapid way and this has greatly facilitated support for HFT among all the professionals who are responsible for treating these patients. In fact, this is equipment that does not create additional workload for nursing professionals.

• What did you have to consider in terms of reimbursement and administrative and financial requirements?

In the hospital environment, we had to work out how to get the equipment. This was done in different ways, for example by donations, rentals and direct purchases as well as the acquisition of consumables. At hospitals, we simply asked the management and explained why it was required and what it is for – it was very straightforward to justify our request – and waited for their approval. We haven’t encountered any problems bringing HFT to hospitals.

In the home environment, on the other hand, we had to work with the central administration and health authorities so that funding for HFT would be provided on a daily or monthly basis. This required a different negotiating strategy as the companies that are responsible for these home therapies have to maintain and take care of the equipment and consumables and support patient monitoring. At the moment, the monitoring of chronic patients at home is not being considered so all of this is pending agreement.

• What process did you use to evaluate this idea?

The first thing we did when we started to work with HFT was to select patients who were suitable candidates for this type of therapy. Then we organised training for the professionals who will deliver treatment using this kind of therapy: nurses, emergency services and critical care. Finally, we defined a clinical protocol for managing the therapy. The protocol had to specify how it should be used, which parameters to set, how to perform monitoring, how to assess whether the therapy is effective or not, how to wean patients off therapy, how to judge whether the patient has improved enough to be discharged from this therapy or, if their condition hasn’t progressed, whether the patient should continue the therapy at home. This last step would entail a different action protocol that takes into consideration other aspects, for example, who will be responsible for the therapy at home, who will be responsible for resolving technical problems with the equipment at home, who will supply consumables when they are required and who will follow up the patient at their home.

• Who works in your service?

The pulmonology service is made up of all the professional staff: pulmonologists, nurses, assistants, orderlies, physiotherapists, etc. So when HFT is introduced into the hospital, rather than being a therapy that is exclusively for the medical staff or the nursing staff, it is a therapeutic procedure that involves all of the professionals who work across the service. As a result, they react positively to the therapy. The ‘rejection of the unknown’ that usually occurs at the start of something new lasted very little time because the results and benefits were very positive and people could see how it worked from the outset.

In summary, it was very well received by all members of the team as it has allowed them to perform higher quality work with good results, it has been very well accepted by the patients and it has also reduced the workload for our staff.

• What are the main indications for using HFT at home?

At the moment, home HFT is being used with very specific groups of patients. Paediatric patients with respiratory failure are being equipped with high flow at home when it is the only way to keep them out of hospital. It is also being used for adult patients who are in intensive care units or intermediate care units in hospital and will have a very high need for either oxygen or ventilatory support at home. During the COVID-19 pandemic, it has been useful to be able to refer patients for home-based treatment with HFT in order to keep them outside the hospital environment. Stable patients, chronic patients, those with COPD or other chronic respiratory problems can be kept stable at home with this therapy. Home-based treatment for these types of patients has yet to be promoted but it would focus primarily on hypoxemic COPD patients who have frequent crises or exacerbations that oblige them to visit the emergency department or be admitted to hospital, as well as patients who have problems related to lung secretions and respiratory infections. At present, those patients who have experienced an exacerbation but are now improving could continue their treatment at home with high flow therapy.

• What is your objective when implementing HFT at home?

In line with the patient selection criteria that we apply, the main objective is to achieve better control of the disease. This manifests itself in two ways. On the one hand, we aim to improve the patient’s quality of life by reducing dyspnea, increasing their capacity for exercise by helping them to feel more confident when they leave their house, and enabling them to lead a life with fewer limitations. On the other hand, we want to reduce the number of exacerbations, that is, the number of times the patient has to be admitted to hospital.

• What are the main impacts and outcomes for patients?

For patients, the main impact is clinical. These patients suffer from breathing problems that affect their quality of life. If a patient meets the selection criteria for therapy, we can have a high degree of confidence that they will improve. What’s more, their situation will improve without the patient having to pay a high price for that improvement. With high flow, the patient knows that the therapy should have a positive clinical impact and can also feel confident that the treatment will be well tolerated.

• Are your COPD patients on HFT always long-term oxygen therapy patients?

At present, most of them are. The COPD patients who we are treating at home are patients who meet criteria for home oxygen therapy and use oxygen therapy at home. These are patients who, despite using oxygen therapy, have poorly controlled oxygenation levels or experience frequent hospital admissions. In this kind of situation, where the patient already has oxygen at home and is receiving treatment but their condition is not improving, we try HFT. Moreover, the data we have from scientific publications on this therapy tell us that this treatment will improve the patient’s oxygenation as well as other aspects of their respiratory failure, such as ventilatory mechanics, work of breathing, quality of life, exercise tolerance and capacity, lung function, etc. In other words, this is a high-spectrum treatment that provides the patient with benefits beyond more oxygenation, so it is used with the aim of improving the patient’s quality of life and, ultimately, better controlling the disease.

• What are the main advantages of HFT compared to long-term oxygen therapy alone?

The conventional treatment – oxygen therapy – consists of giving the patient oxygen. The patient receives oxygen-enriched air but the patient’s respiratory mechanism still has to do all the work. With HFT, on the other hand, the air that the patient is going to breathe can be enriched with oxygen but the therapy also has numerous additional mechanisms that set it apart from conventional therapy. These mechanisms support lung recruitment, that is, many more alveoli open, the gas exchange surface increases and the patient, with the same amount of oxygen, benefits from much better oxygenation. In addition, airway resistance is reduced meaning that the air can enter the lung more easily. For COPD patients, who have air trapping and pressure problems at the end of expiration, HFT limits this intrathoracic pressure and improves the air trapping. If the patient is hypercapnic, HFT will help the patient to eliminate CO2, which is why it is classed as a type of ventilatory support rather than as oxygen therapy. In addition, since the air is humidified it can also have beneficial effects per se and help to reduce secretions, work of breathing, respiratory infections, and so on.

• Which parameters require particular attention when you use HFT with COPD patients at home?

In my experience, HFT is very easy to regulate because you only have to consider three parameters. The most important one is flow, as most of the beneficial effects of the therapy depend on the flow. We have to focus on the needs of the patient with COPD which, in most cases, tends to be air trapping. In this situation, the flow has to be regulated so as to cancel or reduce the air trapping for long-term therapy at home. The second parameter to regulate is temperature, which depends on the patient’s tolerance. Temperature can be adapted in line with the patient’s tolerance of the flow. The third parameter is the concentration of oxygen that is added through the high flow equipment. In the home environment, this parameter enables us to maintain adequate oxygen saturation levels for the patient.

• What role does humidification play in HFT treatment for COPD?

Humidification has a key role. One of the main characteristics of HFT is that the gas that the patient breathes is humidified in nearly the same way as it is inside the lung. This humidification of the air has beneficial effects for the patient in its own right as it improves the overall performance of the respiratory process.

• What additional features are essential for an HFT device?

High-flow equipment must be simple and comfortable to use, especially if it is to be used in the home environment and over the long term. The equipment must be stable and robust and must not break down. In addition, it must offer the three parameters that were mentioned previously as well as therapy monitoring parameters so the patient can be monitored. However, the most important thing to have is a high-quality team.