Even though no clear guidelines exist regarding the structure of the team itself, several key members are essential to developing a successful pulmonary rehabilitation program. The team usually includes providers, physiotherapists, occupational therapists, respiratory therapists, exercise physiologists, nurses, psychologists, behavior specialists, nutritionists, and social workers. This allows for a multi-modal approach.

The provider in charge serves as the medical director, who is responsible for the intake assessment, development of the plan along with the team, and monitoring of the progress and necessary adjustments to the treatment protocol. The psycho-social morbidity associated with progressive advanced lung disease needs to be understood when making treatment plans. A decrease in anxiety, depression, and improvement in cognition has been demonstrated with comprehensive pulmonary rehabilitation.[13] Thus, input from psychologists and social workers is an essential part of pulmonary rehabilitation as much as exercises and the physical aspect of it.

The patient selection process involves evaluating patients' diagnosis and disease severity based on pulmonary function tests. Initial assessment of every patient includes- Borg scale of perceived exertion during supervised baseline incremental exercise test, dyspnea scores during initial maximal exercise capacity, a baseline 6-minute walk test, and Saint George Respiratory Questionnaire (SGRQ) to estimate the quality of life.[13][14][15]

An individualized exercise program is developed based on the assessments mentioned above. Additionally, it is necessary to evaluate the need for supplemental oxygen, rule out cardiovascular limitations, and also assess the safety of exercise interventions. Although a formal cardiopulmonary exercise testing is not necessary for all patients, it helps assess factors contributing to exercise limitations, the safety of exercise, and also prescribing appropriate exercise plan.[14] It may also help in assessing exercise-induced bronchospasm, unmasking cardiac dysrhythmias, and cardiac ischemia.[15][14]

Exercise training focusing on endurance, strength training, and flexibility is the cornerstone of pulmonary rehabilitation. The load during exercise is assessed based on initial assessment and also individual requirements. The load must reflect an individual's daily requirements and escalate as the exercise program progresses incrementally with close monitoring. The goal is to improve patients' aerobic capacity and muscle strength.[1] The crux of endurance training is the conditioning of muscles of ambulation and augmentation of cardiorespiratory fitness, translating to an increase in physical activity with decreased dyspnea and fatigue.[1][16]

Cycling and walking exercises remain the most common form of endurance exercises.[1] Frequency of three to five times per week is recommended for endurance exercise training at an intensity of more than 60% maximal work rate for 20 to 60 minutes.[17] The target training intensity is approximately a Borg dyspnea score of 4 to 6 or a rating of perceived exertion of 12 to 14, which is considered moderate to severe intensity.[18] Interval training is an alternate option to standard endurance training in individuals who have difficulty with continuous training. In interval training, periods of intense training are separated by rest or training at a lower intensity. It also allows achieving most of the benefits of endurance training while reducing dyspnea and fatigue.[19][20][21] 

Resistance training/strength training is another modality of exercise used in pulmonary rehabilitation. It involves training with resistive loads with repetitions, and loads are increased progressively to achieve maximal benefits.[22] Lesser dyspnea is noted in resistance training compared to endurance training and is sometimes better tolerated by patients.[23] Resistance training also helps improve muscle mass and bone mineral density.[24][25][26] The American College of Sports Medicine recommends 1 to 3 sets of 8 to 12 repetitions done on 2 or 3 days each week to improve muscle strength as part of resistance training.[27] About 60 to 70% of one-repetition maximum is considered a suitable initial load.[28] 

The exercise load and repetitions are increased over time in a supervised fashion to help build up strength, muscle mass, and endurance.[27] The best strategy is to include endurance training or interval training along with resistance training in an individual exercise plan as it is known to confer the best benefit than individuals components by themselves.[29] Supplemental oxygen delivery during exercise depends on patients' requirements during rest and during exercise. It has been noted that in COPD patients, supplemental oxygen during exercise in hypoxemic and even in non-hypoxemic patients results in improved exercise tolerance and higher intensity training. It may be due to a decrease in pulmonary artery pressures, carotid body inhibition, and decreased ventilatory drive, and also reduced lactic acid production.[1][30]

Pulmonary rehabilitation is not limited to exercise only. Education, psychosocial support, and nutrition are crucial to achieving patient well-being. Advanced lung diseases have significant psychological and social impacts. It may be more severe if patients need supplemental oxygen.[31] Anxiety and depression are noted among patients with progressive chronic lung diseases.[32]

Alterations in functionality and social life can worsen deconditioning and motivation needed to participate in pulmonary rehabilitation exercises. Hence, it is equally important to focus on the psychological impact of the disease. Pulmonary rehabilitation confers significant benefits in anxiety and depression associated with COPD and also other chronic lung diseases.[13] Breathing techniques are also discussed with the patients to help reduce anxiety and panic. Patients are often screened for untreated depression and anxiety via standardized questionnaires and assessed post-rehabilitation for improvements.[33] If needed, referrals are made to psychologists to help in the management of these co-morbidities.

Nutrition and education are other aspects of pulmonary rehabilitation that are integral to the success of the program. Weight loss and muscle mass loss is a common occurrence in advanced pulmonary diseases. This is multifactorial, often related to increased load on respiratory muscles and also poor oral intake.[34] Detailed dietary history and nutritionist input are helpful in many patients. Patient education involving an understanding of the disease process, treatment options, and rationale, self-management, the role of supplemental oxygen helps participants feel empowered and become active participants in the program.[35]

A written individualized action plan is part of the educational component of the pulmonary rehabilitation program. It involves understanding the symptoms of exacerbations and triggers. It has management strategies for early exacerbations.[36] Many of the patients enrolled in pulmonary rehabilitation have advanced progressive lung disease with other co-morbidities. Advanced care planning is an aspect of comprehensive care that is often overlooked. Advanced care planning involves discussions related to patient care but not restricted to end of life care and advanced directives.[37][38] It can also include discussions about the process of dying and the prevention of suffering.[1]

A maintenance strategy is essential in a pulmonary rehabilitation program. Without a maintenance plan, the benefits appear to diminish by 6-12 months. Quality of life is maintained slightly better than exercise capacity.[39] The maintenance program should include home exercises, a plan for managing the disease process, and a robust psychosocial support network. A structured program with maintenance exercise and self-management plan is essential to have sustained benefits. Ultimately the goal of a pulmonary rehabilitation program is to create a lifestyle change. This requires a dedicated plan followed by continuous reinforcement.

Complications from pulmonary rehabilitation are mostly due to improper patient selection. Following patient selection, it is essential to create a safe and effective individualized plan. It is vital to screen the participants for co-morbidities, as many of the patients with advanced lung diseases have cardiac and musculoskeletal ailments. Cardiovascular ischemic events and arrhythmias in patients at risk who were not appropriately screened.

Vitals and oxygen levels require monitoring during exercises, and supplemental oxygen should be provided and titrated as needed. The patient's limitations due to muscle wasting and weakness have to be considered to avoid falls and injuries. If available, cardiopulmonary exercise testing before enrollment might help unmask underlying ischemia, cardiac dysrhythmias, musculoskeletal issues.[14] However, most complications can be avoided with appropriate patient selection, careful planning, and close monitoring.

 The benefits of the pulmonary rehabilitation program are measured using different parameters. Most of the initial studies in pulmonary rehabilitation were done in patients with COPD, but that has changed recently. Pulmonary rehabilitation is being utilized for patients with different lung diseases, and outcomes may be driven inherently by the underlying disease process.

Survival benefit is one of the important outcomes looked at in pulmonary rehabilitation. In one study, pulmonary rehabilitation initiated within three months of hospital discharge was noted to have a lower risk of mortality at one year; however, other studies have challenged that.[40][41] Quality of life and exercise capacity are important parameters that can be measured. Pulmonary rehabilitation has been shown to improve quality of life as measured on the Chronic Respiratory Disease Questionnaire (CRQ) and St. George's Respiratory Questionnaire (SGRQ).[42][43] 

Multiple studies have shown improvements in maximal exercise capacity and functional exercise capacity with pulmonary rehabilitation in patients with various chronic lung diseases, including post-lung transplant.[44][45][46] Pulmonary rehabilitation was shown to affect the decline of FEV1 over time in COPD patients.[47] Psychosocial benefits from rehabilitation are as important as physical benefits as they are interconnected. Worsening depression and anxiety can adversely affect a person's ability to partake in rehabilitation activities and continuing maintenance programs. Multiple studies have shown clinically relevant improvement in anxiety and depression symptoms.[13]

Chronic respiratory diseases, such as COPD, also have a major monetary impact. Healthcare costs attributable to COPD are estimated to reach approximately $49 billion by 2020 as per the Center for Disease Control (CDC).[48] It includes all aspects of care, including frequent emergency room visits, hospital admissions, exacerbations, and medications. Besides pharmacological interventions, pulmonary rehabilitation is a useful tool that can help reduce exacerbations, readmissions, and hospital length of stay. A written action plan helps reduce health care utilization, costs, and early recovery by early recognition and treatment of exacerbations.[49] The multidisciplinary approach in a pulmonary rehabilitation program can decrease the use of health services and readmissions.[36][50][51]

With smoking contributing to the bulk of the COPD cases and its role in the progression of the disease, pulmonary rehabilitation program provides a unique opportunity to address smoking cessation. Smokers are motivated to stop smoking in a rehabilitation environment with the effects of positive reinforcement.[52] Smoking cessation is often a part of the action plan at the program. The availability of multiple disciplines in pulmonary rehabilitation also provides an opportunity for patients to partake in advanced care planning. Patients enrolled in pulmonary rehabilitation were conducive to having a more detailed advanced care discussion.[53] 

With the increasing volume of evidence in favor of early initiation of pulmonary rehabilitation, the British Thoracic Society guidelines recommend that patients hospitalized for acute exacerbation of COPD should be offered pulmonary rehabilitation at hospital discharge to commence within one month of discharge.[54]

A pulmonary rehabilitation program is a multi-disciplinary team-based intervention. It involves the input of various professionals who work towards a common goal, and studies have shown that working as a team helps improve outcomes.[55] [Level 3] 

The initial assessment and plan take into account the input of a provider from a clinical standpoint. An exercise physiologist working with a physical therapist helps plan the exercise program. Respiratory therapists help with patients’ underlying lung disease and breathing techniques to provide symptom relief.

Psychiatrists and psychologists' assessment before, during, and after is important as depression, anxiety and mental health issues associated with chronic diseases need to be addressed concurrently. Social workers help with addressing issues at home and social hindrances in achieving the ultimate goal of delivering high-quality care. No intervention is successful without a proper follow-up, appropriate medication reconciliation, and education which is imparted by a nursing team.

Many of the professionals in the team are not locked in their roles. Working in a team, they can identify and often fill in the roles of other team members. In a system with so many moving parts, communication is the key. Roadblocks in each step or intervention have to be discussed with other members of the team as it helps in problem-solving and customizing it to patients' needs. Periodic meetings are beneficial to discuss the progress and modifications needed.