Advice
Clinical and technical evidence
Clinical and technical evidence
A literature search was carried out for this briefing in accordance with the interim process and methods statement. This briefing includes the most relevant or best available published evidence relating to the clinical effectiveness of the technology. Further information about how the evidence for this briefing was selected is available on request by contacting mibs@nice.org.uk.
Published evidence
The evidence base for myAIRVO2 includes over 20 studies identified as being potentially relevant, including more than 10 randomised trials. Seven studies were published in abstract form only. Five studies (1 randomised controlled trial and 4 randomised crossover trials) are summarised in this briefing, including 232 patients. Table 1 summarises the clinical evidence as well as its strengths and limitations.
Overall assessment of the evidence
The evidence suggests that myAIRVO2 shows efficacy in treating patients with chronic obstructive pulmonary disease compared with non‑humidified unheated respiratory support. One study reported a reduction in hospital admissions. However, there is little evidence of the long-term effects of myAIRVO2. As well as the lack of long-term studies, it is uncertain how generalisable the studies are to UK NHS practice because none of the studies were done in the UK. Only 1 study assessed myAIRVO2 in a community setting.
Table 1 Summary of selected studies
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Study size, design and location |
Prospective RCT of 200 patients diagnosed with COPD with chronic hypoxaemic respiratory failure. Study done at 4 outpatient clinics in Denmark. |
|
Intervention and comparator(s) |
LTOT with myAIRVO2 (n=100) at home. LTOT (n=100) at home. |
|
Key outcomes |
Rate of AECOPD – myAIRVO2 3.12 vs 4.95 (control) per patient/year (p<0.001). Hospital admissions – 0.79 vs 1.39/patient/year for 12- vs 1‑month use of HFNC respectively (p<0.001). Dyspnoea (mMRC score) – At 3 months, myAIRVO2 group had improved mMRC scores (p<0.05), and from 3 months onward, they had lower mMRC scores vs controls (p<0.001). QoL – myAIRVO group had better SGRQ at both 6 (p=0.002) and 12 months (p=0.033) vs controls. PaCO2 – Over 12 months, PaCO2 decreased in myAIRVO2 group and increased for controls (p=0.005). All-cause mortality – myAIRVO2 15% vs control 12% (p=0.636) Exercise performance – significant difference at 12 months (p=0.005) in favour of myAIRVO2 group (excluding 'non‑walkers'). |
|
Strengths and limitations |
Treatment allocation was fully described. The baseline dyspnoea score was significantly different between groups (p=0.008). Neither the participants nor the assessors could be blinded because it was obvious if they were being treated using the myAIRVO2 device. |
|
Study size, design and location |
Single-centre randomised crossover trial in New Zealand, including 48 patients with stable COPD. |
|
Intervention and comparator(s) |
Participants had all 4 interventions in a randomised order; NHF using myAIRVO2 at 15 litres/min, 30 litres/min, 45 litres/min and room air in a hospital clinical setting. |
|
Key outcomes |
Mean (95% CI) change in PtCO2 at 20 minutes compared with room air:
Mean (95% CI) change in respiratory rate at 20 minutes compared with room air:
|
|
Strengths and limitations |
Treatment allocation was fully described. Crossover design, therefore participants served as their own control, reducing the influence of selection bias. Patients said to be blinded, however it is feasible they could have differentiated between the 4 treatments. |
|
Study size, design and location |
Single-centre randomised crossover trial in Italy, including 14 COPD patients with stable CHRF. |
|
Intervention and comparator(s) |
Participants completed in 5 randomised order, 30‑minute trials (HFOT was delivered at 2 flow rates, 20 and 30 litres/min with the participants' mouth open and closed, and the fifth trial was NIV) in a hospital clinic setting. |
|
Key outcomes |
The data were analysed by assessing differences between baseline and the 5 trials. TI,p (seconds) – no difference between trials. TE,p (seconds) breathing frequency (breaths/min) – was significantly prolonged compared with baseline for all the settings. Tidal volume (ml) – significantly higher compared with baseline for all settings. Pdi swing (cmH2O) – reduced compared with baseline in all trials. PTPdi/min (cmH2Oxs/min) – reduced compared with baseline in all trials. PEEPi,dyn (cmH2O) – significantly reduced compared with baseline in all trials. PaCO2 (mm Hg) – decreased but not significantly. HFOT at 30 litres/min and NIV compared with standard oxygen. PaO2 (mm Hg) – no difference in HFOT 20 closed group, lower in the HFOT 30 group and significantly higher in NIV group compared baseline. Comfort score – did not vary among the different trials. |
|
Strengths and limitations |
Blinding and dropout rates were not reported. Crossover design, therefore participants served as their own control, reducing the influence of selection bias. Small numbers of participants and only short-term effects reported. |
|
Study size, design and location |
Single-centre pilot randomised crossover trial in Italy, including 12 patients with severe COPD. |
|
Intervention and comparator(s) |
Participants completed in a randomised order 2 constant-load, symptom-limited exercise tests at 75% of maximum workload achieved with the incremental test, with (HFNC-test) and without (control-test) HFNC using myAIRVO2 in a hospital clinic setting. |
|
Key outcomes |
Exercise duration – mean difference 109±104, p<0.015, resulting in a mean increase of 41±36%. Dyspnoea – p=0.002 Leg fatigue – p=0.002 SaO2 – p<0.005. |
|
Strengths and limitations |
Treatment allocation was not described fully. Crossover design, therefore participants served as their own control, reducing the influence of selection bias. The washout period was 24 hours. Unclear if this exercise test would be generalisable to rehabilitation. |
|
Study size, design and location |
Single-centre pilot randomised crossover trial in New Zealand, including 30 patients with COPD. |
|
Intervention and comparator(s) |
Intervention: NHF using air supplemented with the equivalent FiO2 to a total flow of 30 litres/min from an AIRVO2 through an Optiflow nasal interface in a hospital clinic setting. Comparator: current LTOT in a hospital clinic setting. |
|
Key outcomes |
RR – p=0.001 SaO2 – p=0.06 Dyspnoea – p<0.001 Tidal volume – p=0.003 End-expiratory lung impedance – p<0.001. |
|
Strengths and limitations |
Treatment allocation fully described in supplementary document. Crossover design, therefore participants served as their own control, reducing the influence of selection bias. Male-only participants, therefore difficult to generalise results to female participants. This is a short-term study, therefore it is unclear if these benefits can be realised long term. |
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Abbreviations: AECOPD, acute exacerbation of COPD; CHRF, chronic hypercapnic respiratory failure; CI, confidence interval; COPD, chronic obstructive pulmonary disease; FiO2, fraction of inspired oxygen; HFNC, high-flow nasal cannula; HFOT, high-flow oxygen therapy; LTOT, long-term oxygen therapy; mMRC, modified Medical Research Council; NHF, nasal high-flow; NIV, non-invasive ventilation; PaCO2, partial pressure carbon dioxide; PaO2, partial pressure oxygen; Pdi swing, transdiaphragmatic pressure; PEEPi,dyn, dynamic intrinsic positive end-expiratory pressure; PTPdi, diaphragm pressure time product; QoL, quality of life; RCT, randomised controlled trial; RR, respiratory rate; SaO2, oxygen saturation; SGRQ, St George's Respiratory Questionnaire; TE,p, patient's own expiratory time; TI,p, patient's own inspiratory time; vs, versus. |
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Recent and ongoing studies
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Feasibility of using daily home HNHF-O2 during sleep and/or daytime in hypercapnic COPD patients following recent hospitalization for AECOPD for 90 days. ClinicalTrials.gov identifier: NCT03221387. Estimated completion date: September 2018. Indication: COPD. Devices: myAIRVO2. USA.