Oxygen supplementation in pulmonary rehabilitation: Time for a Canadian guideline?

The Canadian Respiratory Health Professionals (CRHP),¹ a Clinical Assembly of the Canadian Thoracic Society (CTS),² has long served its membership by providing clinical education and professional development delivered in a variety of formats. These include plenary talks and concurrent sessions for the Canadian Respiratory Conference (CRC),³ projects in partnership with other Assemblies of the CTS, and webinars in both French and English on topics of interest to the membership. In 2017, in discussion with this journal’s Editor-in-Chief, Dr. Peter Paré, a decision was made by the CRHP Leadership Council to give these clinical education events ‘a longer life’ via an invited publication in the CTS journal, the Canadian Journal of Respiratory, Critical Care and Sleep Medicine.

In this issue, the Clinical Respiratory Review on oxygen administration during pulmonary rehabilitation by Lisa Wickerson represents the first such publication, and was born of Wickerson’s CHRP webinar (available for free to CRHP members), and presentation at the 2017 CRC in Montreal, Canada. Using case examples, Wickerson discusses the medical eligibility for ambulatory oxygen, the effect of oxygen use on exercise capacity in COPD and idiopathic pulmonary fibrosis, and the use of different oxygen delivery systems in the context of pulmonary rehabilitation.

Pulmonary rehabilitation (PR) has long been an important topic to the CTS and its Assemblies, as evidenced by the many PR presentations given at CRC over the years, and by the CTS Pulmonary Rehabilitation Survey publications in 2015⁴ and 2017.^5,6 The CTS PR Survey⁴ showed that 2 of most prevalent patient groups participating in pulmonary rehabilitation are people with COPD or interstitial lung disease, with 100% and 75% of programs admitting patients with these diagnoses. These program participants may already be prescribed supplemental oxygen—or the need for it may emerge during exercise testing or training during the program. Therefore, health care professionals in PR programs have the responsibility of assessing, interpreting, and communicating to the referring physician the need and possible dosage for supplemental oxygen during exercise.

Although each province and territory have parameters for determining the need for supplemental oxygen based on testing at rest, sleep or during activity, these parameters differ from province to province,⁷ and offer little guidance on oxygen dose or titration during the different aspects of exercise that occur during PR. Similarly, PR guidelines also do not provide this level of detail.^8,9 Information on the oxygen delivery system that is needed to deliver the right dose to the patient is also rarely, if ever, provided in provincial supplemental oxygen documents.

Program participants may have different oxygen requirements day-to-day, based on overall health, air quality, and disease stability. Also, oxygen requirements may change during exercise: there may be different needs during muscle strengthening exercises versus treadmill or hall walking versus cycling, and understanding how to maximize exercise performance in the context of fluctuating oxygen levels is important. A consistent research finding is the primary tendency for health care professionals in PR programs to use oxygen saturation level as the basis for determining the intensity of the exercise.^6,10 For example, a PR participant who uses 1 lpm supplemental oxygen at rest begins treadmill walking (2 km/hr, 0% grade) and their oxygen saturation drops to 88%. The response of many PR health care professionals is to reduce the treadmill speed in order for the patient’s saturation level to return to >90%, instead of considering altering oxygen dosage or delivery methods to maintain the oxygen saturation level and exercise intensity. Reducing exercise intensity as a response to lower oxygen saturation readings may have the unintended consequence of lower exercise-related outcomes than what might have been possible.

In her article, Wickerson uses two case presentations to discuss the indications for oxygen, the potential benefit, and various delivery mechanisms that would be appropriate for use in patients attending PR. She identifies several gaps in the literature including the use of supplemental oxygen in individuals who are not hypoxemic at rest but who desaturate during exercise in PR. She reinforces the main point that PR provides an excellent opportunity to assess the oxygen prescription and delivery mechanism across a variety of rest and activity scenarios—potentially providing a more detailed characterization of oxygen needs than the original oxygen assessment. She also comments on how specific delivery mechanisms, such as pulsed oxygen systems, may not be effective for all types of chronic disease, based on how the system is designed and the pathophysiology of the patient. These distinctions are not available in existing guidance documents yet are extremely important for PR professionals and participants to understand.

Clearly, guidance is needed. Wickerson concludes her article with a comprehensive list of needs for clinical practice and research, including the determination of an optimal exercise test for determining oxygen requirement (perhaps instead of the non-standardized ‘walking oximetry’?), how to determine exercise intensity balanced with the ability to deliver safe levels of supplemental oxygen, and optimal oxygen devices, considering the patient’s preference and pathophysiology. These needs have been recognized elsewhere. The American Thoracic Society (ATS) recently announced their decision to fund an ATS Pulmonary Rehabilitation Assembly Task Force to develop a Clinical Practice Guideline on supplemental oxygen therapy for adults with chronic lung disease.¹¹ An ATS guideline may be a good fit for use in Canadian PR programs, but differences in provincial jurisdiction, payment, and availability of oxygen delivery systems in Canada may necessitate the need for a Canadian addendum. Regardless, it is apparent that we need clinical decision-making tools on oxygen supplementation for pulmonary rehabilitation—to support our programs and ensure best practice for the benefit of our patients.