HRV Biofeedback as an Asthma Treatment Alternative to Albuterol

Introduction: The Asthma Burden and Treatment Limitations

Asthma is an increasingly problematic condition for Americans, impacting the lives of more than 25 million individuals in the United States — roughly 19 million adults and 7 million children. It accounts for more than 14 million doctor visits annually, more than 400,000 hospitalizations, and nearly 2.5 million emergency room visits (American College of Allergy, Asthma & Immunology, 2014). Moreover, asthma is responsible for claiming 3,600 lives per year. In total, the yearly economic cost of asthma is estimated to be $56 billion (American College of Allergy, Asthma & Immunology, 2014).

While there are effective ways to treat asthma, these are not without side effects and cost-related issues. Dependency upon external intervention via drugs such as albuterol is the main method of treating asthma symptoms today, with the corticosteroid inhaler — an anti-inflammatory medication — being the most common form of intervention. However, it presents a number of risks: what happens if a patient loses their inhaler and suffers an asthmatic attack? What if the long-term cost of using the inhaler becomes prohibitive? By making oneself dependent upon a resource that may not always be available, one takes on significant health risk over a substantial period of time.

The reason that the majority of persons who suffer from asthma accept this risk and adopt a lifestyle dependent upon external medications like albuterol is that these treatments are the ones most widely promoted by the established medical community. They are presented to patients as the only suitable or viable means of controlling asthma. Other options available to asthma patients include immunotherapy and allergy shots, but these too carry attendant risks and may not be acceptable to the majority of patients. By depending upon interventions such as those described, asthma patients remain in a reactive rather than a proactive position — they are not in control, because they rely upon external means for support.

By presenting the alternative method of heart rate variability biofeedback (HRV-BF) treatment, which patients can be trained to use themselves, individuals could place themselves in a more favorable position regarding their asthma by taking direct control of their condition and their body's reactions without depending upon external supports. Medical researchers have shown that HRV-BF is a viable solution to helping persons who suffer from asthma become more proactive in managing their condition and to rely upon themselves rather than on external medication (Lehrer, 2013).

HRV-BF: Mechanism and Therapeutic Rationale

It is within this alternative treatment paradigm that HRV-BF shows potential as a significant means of reducing the effects of asthma and treating its symptoms in a low-cost manner. HRV-BF even has the potential to eliminate the need for high-level doses of medication prescribed to patients annually (Lehrer, 1997). By using a breathing technique that focuses on controlling the heart rate and thereby regulating the exchange of gas that passes through the body's airways, the individual can use conscious regulation to achieve the same outcome as external medication. The advantage is that the patient practicing HRV-BF does not have to rely upon medication and is thus freer to exert greater influence and control over his or her own body. The disadvantage is that the effectiveness of HRV-BF is not yet fully corroborated by the scientific community, and more studies are therefore needed to evaluate its effectiveness.

HRV-BF differs from the two most common standard forms of asthma treatment currently accepted within the medical field: anti-inflammatory medications and bronchodilator medications. Albuterol, for example, is a common bronchodilator that serves to relax the airway muscles, allowing air to flow more efficiently to the lungs. It is not, however, free of side effects — both major and minor — and may act as an irritant to some users. HRV-BF could serve as a method of controlling asthma and reducing the patient's dependency upon products like albuterol.

This study poses the question of whether HRV-BF is an efficient means of positively impacting asthma patients by reducing their dependency upon bronchodilators. Albuterol in particular is used in this study, which measures the amount of albuterol used by patients both before and after the HRV-BF intervention. The amounts are recorded by the patients themselves in a daily diary maintained over the course of the study.

The purpose of this study is to assess the therapeutic impact of HRV-BF on asthma patients. The HRV-BF methods employed are means by which the patient is able to synchronize his or her breathing rate with his or her heart rate. As the heart rate typically accelerates when breathing in and decelerates when breathing out, a synchronization of heart rate and breathing results in respiratory sinus arrhythmia, which is positively associated with individual health (Lehrer, 1997). The goal for asthma patients utilizing HRV-BF is to enable them to control their heart rate and breathing rate and thereby strengthen the airways impacted by inflammation.

The gaps in the literature associated with HRV-BF relate to the impact of the intervention on the airways. This study therefore intends to examine the effect of HRV-BF on patients' airways through their recorded dependency upon albuterol — specifically, whether that dependency changes as a result of the intervention. The HRV-BF process can be learned in a few short sessions with a clinician and may thus be compared to the principle of teaching a person to fish: "Give a person a fish, you feed him for a day; teach a person to fish, you feed him for life." By teaching the technique of synchronizing breathing and heart rate, the patient can gain control of asthma rather than depend on a bronchodilator indefinitely.

The three main factors evaluated in the study were: (1) the effect of HRV-BF on home peak flows (peak expiratory flow taken at home); (2) the effect of HRV-BF on exhaled nitric oxide; and (3) the effect of HRV-BF on albuterol use, along with comparisons of albuterol's effect after HRV-BF intervention.

The first factor is prioritized because during asthma exacerbations peak expiratory flow decreases and may therefore be considered a relative measurement of asthma severity. Home peak flows are recorded during mornings, evenings, and symptomatic episodes using a piko-1 meter, which minimizes patient recording error.

The second factor is examined because exhaled nitric oxide is an indirect measure of airway inflammation — greater inflammation produces greater exhaled nitric oxide. This was measured by having patients exhale into a NIOX machine. Exhaled nitric oxide was recorded both before and after biofeedback treatment on 55 subjects. Airway inflammation is considered the principal cause of asthma and is thought to increase vulnerability to asthma exacerbations.

The third factor is assessed because albuterol is a short-acting beta-2 selective agonist used as a rescue inhaler. Comparing HRV-BF to albuterol on this basis allows evaluation of the overall effectiveness of HRV-BF as a rescue intervention.

Study Hypotheses

Primary hypothesis: HRV-BF reduces airway reactivity as assessed by the methacholine challenge test (MCT PC20FEV1) among steroid-naive patients with mild or moderate asthma more than a placebo biofeedback procedure (PBO-BF), and does so with an effect size on PC20FEV1 corresponding to at least 75% of the response to a 4-week course of inhaled budesonide at 720 mcg/day.

Secondary hypothesis: HRV-BF reduces airway inflammation, as assessed by exhaled nitric oxide (eNO), by at least 35% of the response to a 4-week course of inhaled budesonide at 720 mcg/day. A lower percentage threshold was chosen for eNO than for PC20FEV1 because eNO is a direct measure of inflammation, whereas PC20FEV1 — and biofeedback effects — are more likely to be determined by multiple factors.

Exploratory hypotheses: HRV-BF produces greater improvement in asthma symptoms, asthma quality of life (QoL), rescue albuterol use, perceived stress, and pulmonary function measured both by forced oscillation (FO) and spirometry than the PBO-BF procedure.

References

American College of Allergy, Asthma & Immunology. (2014). Asthma facts. Retrieved from http://acaai.org/news/facts-statistics/asthma.

Drugs.com. (2015). Albuterol side effects. Retrieved from http://www.drugs.com/sfx/albuterol-side-effects.html.

Lehrer, P. (1997). Relationship between changes in EMG and respiratory sinus arrhythmia in a study of relaxation therapy for asthma. Applied Physiology and Biofeedback, 22(3).

Lehrer, P. (2007). Biofeedback training to increase heart rate variability. In Principles and practice of stress management (3rd ed., pp. 227–248). Guilford.

Lehrer, P. (2012). Study protocol: Heart rate variability biofeedback — its role in asthma therapeutics (pp. 1–44).

Lehrer, P. (2013). History of heart rate variability biofeedback research: A personal and scientific voyage. Biofeedback, 41, 88–97.