HMV in COPD: Research and Evidence
The provision of respiratory support in the home is referred to as home mechanical ventilation (HMV). HMV requires a ventilator (breathing machine) and is most commonly used with a tight-fitting mask around the nose or nose and mouth.
HMV was first used during the Polio pandemic in the mid-20th century. Since this time, it has been established as routine treatment for a range of neuromuscular diseases such as muscular dystrophy and motor neurone disease.
Over the last few years, HMV has been shown to be beneficial in patients with chronic obstructive pulmonary disease (COPD). HMV has been shown to improve symptoms and reduce COPD exacerbations – worsening of symptoms that may result in a hospital admission.
However, early studies of HMV for COPD patients were unable to show that this treatment helped patients. Looking in detail at these studies found that only certain patients with COPD i.e. those with high levels of carbon dioxide (CO2) in their blood referred to as hypercapnic respiratory failure benefitted from HMV.
Another important finding of these early studies was that it was important that HMV treatment was overseen by an expert team who could ensure that the breathing machine was set at and subsequently adjusted to the best levels for each COPD patient.
Since this early work, several large studies have been performed. One study conducted in Germany found benefit in patients with severe COPD and high levels of CO2 in the blood but who experienced infrequent exacerbations of their COPD. This research showed clearly that setting the ventilator correctly was important to ensure patients receive benefit from HMV.
A UK based trial has helped to guide doctors on which patients benefit most and how to deliver HMV. This study called the HOT-HMV study included patients with a recent severe COPD exacerbation who required treatment with a breathing machine (ventilator) during an admission to hospital. Patients were reviewed in a specialist service 2-4 weeks after initial hospital treatment to see if they continued to have high levels of CO2 in the blood
This study showed some important results for patients. Significantly those patients who received the HMV treatment remained out of hospital for an average of 90 days longer than those patients in the study that did not receive HMV. They were also approximately 50% less likely to be readmitted to hospital in the following year.
Further work on the trial results found that patients who are able to use HMV for longer periods (>4 hours per day) were more likely to gain further benefit with fewer exacerbations (1-2 fewer exacerbations per patient per year) and improved quality of life.
The reduction in hospital admissions and number of COPD exacerbations means that HMV therapy in this group of patients could also save the healthcare system money. UK and international guidance on how best to manage COPD patients now recommend HMV be offered to appropriate patients with COPD – i.e. those with ongoing high levels of CO2 in their blood.
To ensure the right patient gets the right treatment at the right time, treatment pathways are important tools that will help ensure COPD patients are appropriately assessed for HMV. See Figure 1 as an example of a treatment pathway for assessing COPD patients for HMV therapy.
There are different ways that this can be achieved but for most patients, this will mean a face to face appointment. At this appointment, usually 2-4 weeks after improving from the severe exacerbation that needed ventilator therapy, blood CO2 levels will be checked. If found to have CO2 high levels, then a referral will be made to a specialist centre that can start and monitor HMV therapy.
- Murphy PB, Rehal S, Arbane G, Bourke S, Calverley PMA, Crook AM, Dowson L, Duffy N, Gibson GJ, Hughes PD, Hurst JR, Lewis KE, Mukherjee R, Nickol A, Oscroft N, Patout M, Pepperell J, Smith I, Stradling JR, Wedzicha JA, Polkey MI, Elliott MW, Hart N. Effect of Home Noninvasive Ventilation With Oxygen Therapy vs Oxygen Therapy Alone on Hospital Readmission or Death After an Acute COPD Exacerbation: A Randomized Clinical Trial. JAMA 2017: 317(21): 2177-2186.
- Kohnlein T, Windisch W, Kohler D, Drabik A, Geiseler J, Hartl S, Karg O, Laier-Groeneveld G, Nava S, Schonhofer B, Schucher B, Wegscheider K, Criee CP, Welte T. Non-invasive positive pressure ventilation for the treatment of severe stable chronic obstructive pulmonary disease: a prospective, multicentre, randomised, controlled clinical trial. Lancet Respir Med 2014: 2(9): 698-705.
- Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. 2021 [cited 2021 28.6.2021]; Available from: https://goldcopd.org/2021-gold-reports/
In this ResMed webinar, Dr. Eline Gantzhorn and Dr. Patrick Murphy discuss the cost per QALY (Quality-Adjusted Life Year) of home-based COPD treatment and its implications for future use. In particular, they look at the variable factors across patients and geographical regions.