The Role of HNHF to Improve Clinical Outcomes Following Severe AECOPD

The Role of Humidified Nasal High-flow to Reduce 30-day Hospital Re-admissions Following Severe Exacerbations of Chronic Obstructive Pulmonary Disease: a Mixed Methods Feasibility Study

Chronic Obstructive Pulmonary Disease (COPD) is a common lung disease, affecting 1.2 million people in the United Kingdom (UK). COPD patients suffer with episodes of worsening breathing symptoms called acute exacerbations (AECOPD). Exacerbations occur more often as the disease progresses and are a leading cause of emergency hospitalisation. Patients recovering from exacerbations are at high risk of deteriorating, with one quarter readmitted to hospital within thirty days. COPD thus imposes immense burdens on the National Health Service and patients. This research will investigate the effects of using humidified nasal high-flow (HNHF) during recovery from severe COPD exacerbations. HNHF delivers warmed, humidified air under flows of up to 60 litres per minute through a nasal interface. This has been shown to improve clinical outcomes, including exacerbation frequency, hospitalisations, breathlessness and quality of life amongst COPD patients with respiratory failure. It is thought to achieve this by improving secretion clearance and providing positive airways pressure which supports the breathing system. Patients admitted to St Thomas' Hospital, London with COPD exacerbations will be recruited. Prior to discharge, participants will be randomised to receive either usual care alone or usual care plus a HNHF device, which they will be trained to use for a regular period daily. Usual care includes inhalers, steroids and may include antibiotics. Participants will be followed up for 30-days after hospital discharge using weekly assessments, daily symptom diaries and wrist-worn watch-like devices that detect physical activity. This will enable evaluation of the clinical effects of HNHF on re-exacerbations, readmissions, breathlessness, physical activity and quality of life. Device usage will also be quantified. Participants who receive devices will be interviewed to explore their experiences. After the 30-day home follow-up period, a sub-group of participants will undergo detailed breathing tests during and after exercise to explore the effects of HNHF on the respiratory system.

Neural respiratory drive, Physiology, Respiratory muscles, COPD exacerbation, Ventilation, Nasal high-flow, High-flow nasal cannula

Humidified nasal high-flow device which delivers warmed, humidified air at flow rates of up to 60 litres per minute via a nasal cannula interface. Intended delivery at 30 L/min at 37 degrees Celsius, if tolerated.

Feasibility outcome measure: assessed by proportion of patients who fulfil eligibility criteria who consent to participate.

Feasibility outcome measure: assessed by completion of symptom diaries. Progression criterion = participant diaries completed by >70% of participants. Assessed at 30-days following hospital discharge.

Feasibility outcome measure: assessed by usage of physical activity monitors. Progression criterion = usage >70% of participants. Measured from physical activity monitor computer downloads at 30-days following hospital discharge.

Feasibility outcome measure: assessed by completion of spirometry. Progression criterion = spirometry measured at every study assessment for >70% of participants.

Feasibility outcome measure: usage hours accessed from the device at completion of participants' study participation for those participants allocated to the intervention arm.

Qualitative evaluation: Use of semi-structured interviews after 30 days post-discharge following index hospitalisation to explore barriers and facilitators to device usage in intervention arm participants.

Clinical outcome measure: the number of acute exacerbations of COPD that do not require hospitalisation will be recorded using symptom diaries.

Clinical outcome measure: breathlessness severity will be assessed using the modified Borg scale (minimum score = 0, indicating no breathlessness, maximum score = 10 indicating maximal intensity of breathlessness).

Clinical outcome measure: breathlessness severity will be assessed using the Multidimensional Dyspnoea Profile.

Clinical outcome measure: daily physical activity (measured in counts per minute) will be quantified using a wrist-worn physical activity monitor which uses a triaxial accelerometer.

Clinical outcome measure: assessed using the Clinical COPD Questionnaire. Scored from 0 to 60, with higher scores indicative of worse disease-specific health-related quality of life.

Proof of concept study outcome: measured during the physiological sub-study involving incremental exercise using a pneumotachograph.

Proof of concept study outcome: measured during the physiological sub-study involving incremental exercise using the modified Borg scale. This zero to ten scale measures breathlessness intensity, with higher scores representing more intense breathlessness. The score will be measured before exercise, at 2 minute intervals during exercise, at exercise cessation and during exercise recovery.

Proof of concept study outcome: measured during the physiological sub-study involving incremental exercise using a parasternal and diaphragm electromyography using surface and nasogastric electrodes, respectively.

Proof of concept study outcome: measured during the physiological sub-study involving incremental exercise using a pressure transducer connected to a nasogastric catheter and a pneumotachograph.

Proof of concept study outcome: time from maximal breathlessness at peak exercise to pre-exercise modified Borg scale.

Inclusion Criteria: Emergency hospital admission with a primary diagnosis of AECOPD Aged 40-80 years ≥10 pack year smoking history Body mass index ≤ 35kg/m2 Cognitively and linguistically able to follow English instructions, provide informed consent and complete the study protocol To be discharged home following the hospitalisation in a home environment deemed safe by the investigator to perform home assessments Patient lives in the catchment area served by the Integrated Respiratory Team at Guy's and St Thomas' NHS Foundation Trust Exclusion Criteria: Chest radiograph excludes pneumothorax Requirement for acute non-invasive ventilation (NIV) during index hospitalisation or established on home positive airway pressure (PAP) Significant chronic respiratory failure (PaCO2 >7.0) Clinically significant obstructive sleep apnoea requiring treatment Allergies to latex, metals or local anaesthetic Broken or inflamed skin at the second intercostal space parasternal chest wall areas Psychological or social factors that would impair compliance with the study protocol Any major non-COPD chronic co-morbidity that may contribute significantly to risk of readmission, including (but not limited to) severe heart failure (left ventricular ejection fraction <30%), malignancy (active treatment or palliation), end stage renal failure and significant neuromuscular disease Planned travel away from home in the 30-day post-discharge period

Suh ES, Mandal S, Harding R, Ramsay M, Kamalanathan M, Henderson K, O'Kane K, Douiri A, Hopkinson NS, Polkey MI, Rafferty G, Murphy PB, Moxham J, Hart N. Neural respiratory drive predicts clinical deterioration and safe discharge in exacerbations of COPD. Thorax. 2015 Dec;70(12):1123-30. doi: 10.1136/thoraxjnl-2015-207188. Epub 2015 Jul 20.

Murphy PB, Kumar A, Reilly C, Jolley C, Walterspacher S, Fedele F, Hopkinson NS, Man WD, Polkey MI, Moxham J, Hart N. Neural respiratory drive as a physiological biomarker to monitor change during acute exacerbations of COPD. Thorax. 2011 Jul;66(7):602-8. doi: 10.1136/thx.2010.151332. Epub 2011 May 19.