Chronic obstructive pulmonary disease (COPD) is characterized by increased dyspnea (uncomfortable, labored breathing) and anxiety, and low physical activity (PA) levels. Breathing ensures adequate supply of oxygen to tissues, and just as important, maintains carbon dioxide (CO2) levels in a narrow range. Both COPD and anxiety cause dysfunctional breathing patterns (e.g., rapid, effortful, irregular breathing), which contribute to abnormal levels of CO2. But current pulmonary rehabilitation (PR) protocols do not address the breathing irregularity and anxiety simultaneously. Rapid, shallow breathing in severe COPD allows insufficient time to empty the lungs, causing retention of CO2 (hypercapnia). Hypercapnia causes a vicious cycle of increased ventilation, dyspnea and panic, increasing the risk of ventilatory pump failure. We designed a high priority, novel mind-body intervention called Capnography-Assisted Learned, Monitored (CALM) Breathing, which targets CO2 levels (eucapnic breathing) through real-time end-tidal CO2 (ETCO2), respiratory rate (RR), and airflow pattern biofeedback. CALM Breathing promotes slow, efficient breathing mechanics, interoceptive function, and dyspnea self-efficacy to relieve dyspnea and anxiety. Biofeedback simplifies physiological information through visualization to promote learning, nudge self-regulated breathing success, and optimize exercise prescription. CALM Breathing is a complementary intervention to standard of care pharmacotherapy and PR. The tailored 4-week CALM Breathing intervention pre-PR includes coaching and 10 core, slow breathing exercises performed at rest in recovery postures and with movement (ribcage stretches and brief ?5- min light-moderate intensity PA) in eight, twice weekly, 1-hour sessions. Participants also perform audio- guided breathing exercises at home with a RR biofeedback device for adherence and quality checks. We will evaluate the feasibility and acceptability of CALM Breathing in a single-blind randomized clinical trial (RCT) with 40 adults with COPD and elevated anxiety sensitivity. Participants will be recruited from NYU Langone Health's outpatient pulmonary rehabilitation patient referral list and randomized into two groups: CALM Breathing and Wait-List. We will test feasibility based on participant recruitment efficiency and retention; CALM Breathing adherence rates and intervention fidelity scores; and facilitation of PR initiation by week 6?10. Acceptability will be evaluated based on CALM Breathing attendance, drop-out rate, satisfaction ratings, and themes derived from semi-structured interviews. Feasibility and acceptability results that meet a priori success benchmarks will support a future well-powered efficacy trial that measures dyspnea with activities and six- minute walk distance as primary outcomes; anxiety symptoms, PA, generic and COPD-specific quality of life, ETCO2 and RR, and lung function as secondary clinical outcomes; PR uptake and utilization; and interoceptive awareness, anxiety sensitivity, dyspnea self-efficacy, nasal symptoms, and depression as mediator variables. The innovative CALM Breathing intervention may lead to a fundamental paradigm shift in COPD treatment.
Relevance to Public Health An estimated 15 million Americans (6.3% of the adult population) have chronic obstructive pulmonary disease (COPD), which is a leading cause of death and disability. The primary symptom of COPD is breathlessness, which has devastating effects on patients' physical and emotional well-being. Capnography-Assisted Learned, Monitored (CALM) Breathing therapy has the potential to significantly relieve dyspnea and anxiety symptoms, and improve quality of life and pulmonary rehabilitation uptake and utilization, thereby transforming the lives of people with COPD.
