# High-Flow Nasal Oxygen as an Adjunct to Pulmonary Rehabilitation in an Interstitial Lung Disease Predominant Cohort Awaiting Lung Transplantation: Service Description and Preliminary Findings

## TL;DR

This paper describes a pulmonary rehabilitation service using high-flow nasal oxygen for lung transplant candidates and finds that those who survived to transplant had fewer comorbidities.

## Contribution

The study introduces a novel use of high-flow nasal oxygen in pulmonary rehabilitation for lung transplant candidates and identifies a survival association with fewer comorbidities.

## Key findings

- Patients who underwent lung transplantation had fewer comorbidities compared to those who died while waiting.
- Survivors tended to be younger and had better 6-minute walk distances before starting high-flow nasal oxygen.
- Dyspnea and body mass index were not associated with survival in this cohort.

## Abstract

Background/Objectives: At Fiona Stanley Hospital’s pulmonary rehabilitation program, people awaiting lung transplantation (LTx), whose exertional oxygen requirements are unable to be met with traditional oxygen interfaces, utilize high-flow nasal oxygen (HFNO) to exercise. In this paper, we aim to: (i) describe the characteristics of our service and of the people who have utilized HFNO; and (ii) explore differences between those who survived vs. did not survive whilst awaiting LTx. Methods: We conducted a description of the service and a retrospective analysis (from January 2021 to April 2024). The service description included: facility, equipment/cost, staffing/patient ratio, exercise program characteristics, and safety. Inclusion criteria for the analysis were: people actively listed for LTx and completion of three or more exercise sessions on HFNO. Data extracted included patient characteristics, comorbidities, 6-min walk distance (6MWD) prior to commencing HFNO, and survival pre-LTx. Differences between those who survived vs. did not survive whilst awaiting LTx were explored. Results: Nineteen patients were included (13 males; age 60 ± 12 yr; 18 with interstitial lung disease). The median [IQR] number of exercise sessions on HFNO was 15 [9; 25]. Eight (42%) patients died whilst awaiting LTx. In those who survived, the median time to LTx was 46 [25; 268] days. Compared to those who died, those who underwent LTx had fewer comorbidities (median: 2 [1; 4] vs. 4 [3; 5], p = 0.03). They also tended to be younger and have greater absolute 6MWD prior to commencing HFNO (mean difference, 95%CI: age −8.6 yr, −19.3 to 2.1; 6MWD 55 m, −74 to 185). Associations between dyspnea or body mass index with survival were not demonstrated. This analysis is hypothesis-generating rather than inferential, given the limited sample size. Conclusions: Our unique service of high-flow nasal oxygen (HFNO) use in patients participating in pulmonary rehabilitation whilst awaiting lung transplantation is described. Preliminary analysis suggests that, in people utilizing HFNO whilst awaiting LTx, those who underwent LTx had fewer comorbidities than those who did not survive the waitlist period. Larger studies are needed to explore further differences between those who survive vs. those who do not survive whilst awaiting LTx.