In October 2019, Siler and colleagues published the results of a prospective crossover pilot study in the Journal of Clinical Respiratory Diseases and Care titled “Assessing the Clinical Effect of High Velocity Nasal Insufflation on Improving Ambulation in Patients with Dyspnea: a Feasibility Study.” The results suggest that Vapotherm high velocity therapy, which in the study is referred to as high velocity nasal insufflation (HVNI), improves ambulation for acute-care inpatients by helping them walk farther and longer when compared to oxygen treatment.1 The authors hypothesized that high velocity therapy may get better results than standard oxygen treatment during ambulation, because it provides not just oxygenation, but also ventilatory support.2
This is exciting news as it shows the mobile version of Vapotherm’s® Precision Flow®system, which is a form of noninvasive ventilation (NIV) for spontaneously breathing patients2, is now feasible during ambulation in the acute care setting and may provide clinical advantages.
The study compared oxygen treatment as usual (TAU) to treatment with high velocity therapy in 25 patients during ambulation in both inpatient and outpatient settings.1 The primary outcome was how far and for how long patients could ambulate on high velocity therapy versus TAU using a modified version of the 6-minute walk test. Vital signs and recovery time were measured as secondary outcomes. For inpatients (n=16), high velocity therapy improved patient distance walked by 12.4% and duration of time walked by 8.5%. It also improved recovery time—decreasing it by 32.5%—and increased patient speed by 7.1%. Although use was feasible among outpatients, the outpatient group didn’t show these improvements. For these outpatients (n=9), high velocity therapy decreased distance walked by 9.66%, walk duration by 18.6%, speed by 7.7%, and increased recovery time by 2.5% when compared to TAU. The authors discuss several potential reasons for this trend outside the acute care setting, one of which is that, “[t]he outpatients who were selected fell into GOLD 3 or 4 COPD criteria for Dyspnea and were not as physiologically limited at baseline as the inpatients, thus the extra equipment during the HVNI arm of the test may have been more cumbersome and inhibited their progress.”
The patients included in the study all had a primary or secondary diagnosis of COPD, COPD exacerbation, asthma, and/or pneumonia. There were no differences between the patients’ baseline physiologic parameters (e.g. heartrate, respiratory rate, etc.) before the high velocity therapy and TAU walking tests. Figure 1 illustrates the improved performance in the inpatient group.
Figure 1: Performance and recovery outcomes. Inpatient (n=16) only data presented. TAU: Solid Fill & dotted power trendline. High velocity therapy: Open Fill & dashed power trendline
The study had limitations. For example, several of the patients had comorbidities, such as diabetes, and/or were on medications that may have been a confounding variable in physiologic parameters. Another limitation was the small sample size which precludes any conclusions from being definitive. However, given its design as a feasibility study, the results are promising for both current practice and future research, especially in inpatient environments.
Given the importance of ambulating patients and limiting bedrest, having Mask-Free NIV™ for spontaneously breathing patients as an ambulation option could potentially improve current ambulation programs by enabling inpatients to exercise. The economic impact could reverberate through the whole hospital, as successful ambulation programs have been linked to overall cost savings.3,4