- Email: [email protected]
Pulmonary Rehabilitation
Pulmonary Rehabilitation* Donald A. Mahler, MD, FCCP
There has been a resurgence of interest in pulmonary rehabilitation mainly because the prevalence of COPD has increased, scientific stu dies document consistent benefits (incr eased exercise endurance and reduced dyspnea), and thoracic su rgeon s recognize that preoperative and postoperative conditioning enhances the results of lung volu me reduction surgery and lung transplantation. Although education and ps ychosociallbehavioral interventions are important components of a multidimensional program, exercise training of the upper and lower extremities is essential to achieve the described improvements. Current programs vary considerably in the frequency, intensity, and duration of exercise reconditioning. Two "key" questions relating to pulmonary rehabilitation are as follows. What is an appropriate training intensity? How should patients monitor the training intensity? Maintenance exercise programs and the development of home- or community-based programs will be important future developments. (CHEST 1998; 113:263S-268S)
T changed he reality of pulmonary rehabilitation has since th e 1974 definition p roposed by th e American College of Chest Physicians Co mmittee on Pulm onary Reh abilitation .' Several factors have con tributed to th e resurging interest in pulmonary rehabilitat ion over the past years. Fi rst, the prevalence of patients with CO PD has increased . Second, there is greater awareness th at such patients are deconditioned. s Third, the eme rge nce of lung volum e reduction surgery for patients with advanc ed emphysema has prompted institutions to develop andlor expand both preoperative and postoperative pul monary rehabilitation:' F ourth, manage d healthcare programs have encour aged admi nistrators to consider pulmonary reh abilitation program s as an integral part of health-care delivery/p reventive medicine. And fifth , publications have highlight ed th e principles and practice of pulmonary rehabilitation .v? Th ese as well as other considerations led to th e 1994 Workshop on Pul monary Reh abilit ation Resea rch sponsored by th e National In stitutes of Health. At this meeting, a new definition was developed : "Pulmonary reh abilitation is a multidimensiona l continu um of services directed to persons with pul monary disease and their families, usually by an interdisciplinary team of specialists, with the goal of achieving and maintaining the individ ual's maximum level of indep end en ce and function ing in the community.?" Thi s newer definition incorp orates the key concepts of involvem ent of patients and fam ilies, a continuum of multidisciplinary activities, and th e ' From the Section of Pulmonary and Critical Care Medicine, Dartm outh-H itchcock Medi cal Ce nte r, Leb anon , NI-1.
expe rtise of an interdisciplin ary team . An additional impet us has been the 1995 American Thoracic Society statem ent that pul mona ry rehabilitation is an established com ponent of th e care and treatment of patients with COPD Y Th e pri mary goals of pu lmonary rehabilitat ion programs are as follows: to relieve symptoms, parti cularly dyspnea; imp rove fun ctional ability; and enhance health- related qu ality of life. P ATIENT SELECTION
Selection crite ria for parti cipation in a pulmonary rehab ilitation program inclu de any symptomatic individu al with stable chro nic respirat ory disease (no age limitation ), and that th e patient is motivated to parti cipate in a self-care p rogram . INITIAL EVAL UATION
Th e major components of the initi al patient evaluation are listed in Table 1. Th e medi cal histo ry should include measurem ent of dyspn ea ' ? and health-related quali ty of life (H RQ L). l1 Appropriate instruments should be selected that are valid for th e pop ulation and are responsive (able to detect clinically import ant changes). Baselin e physiologic testing of lung function and cardiopulmonary exercise responses are imp ort ant . Fin ally, assessment of anxiety, depression, social and family suppo rt , as well as coping skills shou ld be mad e. O UT COM E M E ASUR E S
An Outcomes Committee of the American Association of Ca rdiovascular and Pulmonary RehabilitaCHEST / 113 / 4 / APRIL, 1998 SUPPLEMENT
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Table I-Components of th e Initial Ev aluation of Pati ents for Pulmonarsj Rehabilitation Co mpo ne nts
Medical history ami ph ysical examination Mea sur e dyspn ea Mul tidim ension al clinical instrumen ts Ratings du ring exercise Measur e HRQL Disease-specific instruments Gen eric instru me nts Diagnostic testing Pulm on ary funct ion tests Cardiopulmonary exe rcise tests Pulse oximetry or arte rial blood gases Psychosocial assessme nt Evaluate anxiety/de pres sion Assess social and family support Co ping and self-care skills
tion 12 recommende d that pulmonary rehabilitation p rograms evaluate dyspn ea, HR QL, and exercise ability as domains for potential improvem ent (Table 2). Dyspnea can be meas ured based on activities of daily living or du ring a specific task. Th e committe e recommended th e Baseline and Tra nsition Dyspnea Indexes!" or the dyspnea componen t of the Chronic Respiratory Questionnaire (CRQ )14 as appropriate mu ltidim ensional instruments. Dyspnea du ring a specific task (eg, an exercise test) can be quan tified using the 0 to 10 category-ratio scale developed by Borg l 5 or a visual analog scale. A met a-analysis of selected studi es of pulm onary rehab ilitation dem onstra ted a consistent reduction in dyspn ea ratings using the CR Q.16 Disease-specific and generic instru ments are available to measure HRQL before and after pulmonary reh abilit ation.! ' Th e C RQ14 and the St. Geo rge's Respiratory Qu estion naire!" were recommended by
the Ou tcomes Committee. Although gen eric HRQL instruments may provide com plementary inform ation, th ey appear to be less responsive to therapeutic interventions. The Medical Outcomes Study sho rtform 36-item survey' " is an example of a generic questionnai re th at may be used to assess HRQL in patients with CO PD.I!) An effective pul monary rehabilitation program usually results in an improvement in exercise endurance, bu t little or no cha nge in maximal capacity. Th e 6-min walking test is a Simple and inexpensive metho d to measure an individual's exercise ability. However , test results are influenced by patient effort and motivation. Th erefore, measurement of workload and expired gases can provide objec tive ph ysiologic data to measure changes in exercise capacity. A sub maximal, constant workload test on the cycle ergometer or treadmill may be the most appropriate test to examine changes in exercise endurance as a result of pul monary reh abilitation." Finally, beh avioral outcom es are import ant , but may be difficult to quantify. Smoking cessation, nutritiona l support, adherence with medications and exercise training , and any changes in anxiety and depression should be evaluated and changes should be documented.
COMPONENTS OF P ULMONARY R EH ABILITATION
Edu cation
Although patient education is considered important , it is not an essential part of pul monary rehabilitation. Many, if not most, reh abilitation program s provide education to patients on various topics, including pathoph ysiology of CO PD , breathin g retraining, medications (particularly the technique of using a mete red-dose inhaler ), nutrition, ene rgy
Table 2-Instruments To Measure Three Outcomes of Pulmonary Rehabilitation Programs* Outcome Dyspn ea
HR QL
Exe rcise ability
In st ruments For activities of daily living Baseline and T ransition Dysp nea Indexes '? Dyspnea co mpon e nt of C RQ 14 F or spe cific exe rcise task o to IO category-ratio scale l 5 Visual analog scale 16 Disease specific C RQI4 St. George' s Respiratory Qu estionnair e ' ? Pn lmon ary Fun ctional Status Scale'" Pulmon ary Functional Status and Dyspnea Qu cstion naire -? 6-minute walk A cardiopulmonary exe rcise test eithe r at submaximal or maximal workload
*The Outcom es Committee of the American Association of Cardiovascular and Pu lmonary Rehabilitati onl- has recomm end ed that one of mor e of the above inst rum ents he used to measure each of the three outcom es or dom ains.
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Mechanisms and Management of COPD
conservation, use of supplemental oxygen , travel , advice on intimacy, and strategies to relieve breathlessness . To my knowledge, only five studies have examined the effects of education alone on outcomes in patients with CO PD .20-24 There was mild improvement in dyspnea reported in three studies,20-22 whereas the other studi es showed either no ben efit on coping skills-" or an increase in psychological distr ess following education.e' Therefore, education is not considered adequate by itself to improve outcomes in patients with COPD, but nevertheless it should be included as a component in a multidimensional pulmonary rehabilitation program.
Lower Extremity Exercise Training Both uncontrolled and controlled studies25-31 demonstrate that lower extremity exercise training improves exercise tolerance. Although most studi es show no change in peak oxygen consumption (\10 2), submaximal exe rcise endurance improves consistently after pulmonary rehabilitation. In addition, randomized controlled studi es of comprehensive pulmonary rehabilitation show an improvem ent in dyspnea during exercise in th e laboratory and with activities of daily living.25,27-3o,32 The possible mechanisms for improved exercise capacity and reduced severity of breathlessness are summarized in Table 3. Casaburi et al26 demonstrated physiologic training respons es (an increase in peak \102; a decrease in exercise ventilation; and an increase in lactate threshold) in a supervised, inpatient rehabilitation program in patients with mild-tomod erate COPD. More recently, Maltais et a}31 showed that endurance tra ining reduced exerciseinduced lactic acidosis and improved skeletal muscle oxidative activity in 11 patients with moderate-tosevere COPD . Th ese two studi es de monstrate clearly that physiologic training may occur with exercise training in patients with COPD. Other investigators have reported that relief of dyspnea was due to the corresponding fall in ventilatory demand duri ng exercise ( ~ minute ventilation/work rate) as a result of enhanced mechanical efficiency.27,3o Both
Table 3-Possible Mechanisms for Improvements in Exercise Capacity and Dyspnea With Pulmonary Rehabilitation Mechani sms Physiologic training response Enhanced mechanical e fficiency Redu ced imp ed ance to breathin g Improved respiratory muscle function Toleran ce or desensitization
O'Donnell et a}3o and Ramirez-Ven egas et a}33 have suggested that enhanced respiratory muscle function , as may occur with pulmonary rehabilitation, can also contribute to improved breathlessness. Finally, psychological factor s, including the development of tolerance or desensitization to dyspn ea, may enable patients to perform highe r levels of work with reduced symptoms,32,34 Published studies and clinical programs of pulmonary rehabilitation vary considerably in the methods of exercise traini ng. The rang es of frequency (once a week to daily), intensity (50% of peak \102 to maximal tolerated effort), and duration (5 to 10 min as tolerated up to 45 min ) illustrate the variability. Pulmonary rehabilitation programs may last from 4 to 46 weeks, although most programs are 6 to 8 weeks long. The predominant modes of exercise training are treadmill walking, and cycle ergometry. General guide lines for exercise prescription are provided in the Appendix. A key question related to pulmonary rehabilitation is: "What is an appropriate training intensity?" Intensity and duration of exercise train ing are clearly interrelated. However, most programs emphasize that patients increase duration because such improvem ents have great er impact on activities of daily living. The American College of Sports Medicine has recommended that the minim al intensity for healthy individuals is 50% of peak \102 with an upper limit of 85% of peak \102 .35 Another approach is "maximum limits tolerated by symptoms."36 For example, the patient should walk as fast as possible for 5 min on the treadmill or in a corridor, and then duration could be gradually increased over days to weeks. In one study by Ries and Archibald.i'? the average walking speed on the treadmill by patients with COPD that could be sustained for 5 min was 1 mph (range, 0.6 to 3.5 mph ). Maltais et a}37 examined the ability of 42 patients with COPD to train at an inten sity of 80% of maximal power output on the cycle ergometer for 25 to 30 min over a 12-week program . Although the training intensity for each session averaged 60±23% of maximal power output at week 12, there was a significant improvem ent in exercise capacity and a concomitant reduction in exercise ventilation and arterial lactic acid concentration with training. Based on these collective data , a reasonabl e approach is that the physician or exercise specialist select the initial training intensity based on the individu al patient's daily activity level, results of the cardiopulmonary exercise test , and a discussion with the patient regarding his/h er specific goals. Another important conside ration is, "How should patients monitor the training intensity?" Th e traditional method in health y individu als has been to use CHEST / 113 /4 / APRIL, 1998 SUPPLEMENT
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a target heart rate to regulate/monitor the intensity/" Yet , patients with COPD are limited by the mechanics of breathing, oxygen desaturation, and/or dyspnea rath er than cardiovascular factors . An alternative approach is to use dyspnea ratin gs as a target , just as ratings of perceived exertion have been used as a guide for intensity of effort in health y persons and in those with cardiac diseas e .P" Horowitz et aP9 have shown that dyspnea ratin gs on the 0 to 10 categoryratio scale obtained from an increm ental exercise test can be used to achieve a desired intensity; however , the accuracy was better at a higher exercise level (approximately 80% of peak \102) compared with a lower intensity (approximately 50% of peak \10 2 ) , Practice sessions may also be required for some patients to learn and to receive feedb ack to improve their ability to use the scale.
logical distress are low self-esteem , poor body image, loneliness, and reduced social support. Many pulmonary rehabilitation programs incorporate psychosocial and behavioral _~omponents in addition to upp er and lower extremity exercise training. Strategies include evaluation and possible treatment of anxiety and/or depression, teaching relaxation skills, discussion of family and sexual relations , and providing emotional support. Specific behavioral interventions are smoking cessation, nutritional support, and compliance with the exercise program. Although the scientific evidence to support psychosocial and behavioral interventions is weak, many patient s and staff associated with programs believe that patients with COPD experience such benefits from their participation in pulmonary rehabilitation. Certainly, randomized controll ed trials are necessary to examine these components.
Upper Extremity Exercise Trainin g
Many patients with severe COPD experience breathl essness when using their upp er extremities to perform activities (eg, lifting or carrying objects). By anchoring the arms , muscles of the shoulder girdle (eg, pectoralis muscles ) can pull on the rib cage and contribute to ventilation. Upp er extre mity exercise training can augment the strength and endurance of these muscles, and thereby enhance inspiration. The ben efits of upp er extre mity exercise training are an increase in the ability to perform ann work and decreased \10 2 for the same amount of work. 40 ,4l Although anecdotal reports by patients indicate improvements in dyspnea and functional outcomes with upp er extremity exercise training, to my knowledge, there are no randomized controlled trials that demonstrate such ben efits in these measures. Th e two most common methods to train the uppe r extre mities are arm e rgome try (cycle with th e arms at 50 rpm with resistance loads added as tolerated for a 20- to 30-min duration ) and resistan ce training (l to 2 sets of 8 to 12 repetitions for each major muscle group against gravity or using 1- to 2-kg weights ). Patients should be instructed to coordinate breathing with movem ent of the arm s (entrainment) . Usuall y, expiration occurs with exte nsion of the upper extre mities . Tol erance of upper extre mity exe rcise training is based on arm discomfort and/ or dyspn ea. Psychosocial and Behavioral Comp onents
Anxiety and depression are common in patients with COPD . Such psychological distr ess can contribute to restricted activities of daily living and may be more predictive of functional capacity than physiologic factors are .42,43 Oth er manifestations of psycho2665
CONCLUSIONS
The scientific basis for pulmonary rehabilitation has developed substantially over the past decade." Exercise training has been recognized as an essential component of pulmonary rehabilitation, and accepted outcome measures have been established to evaluate potenti al improvements . An increased number of patients with chronic respirato ry disease, the eme rgence of lung volume reduction surgery and lung transplantation as possible treatment modalities, and a focus on the cost of health-care resources should expand the present role of pulmonary rehabilitation programs. Certainly , extended exercise pro grams will be important for patients to maintain short-ter m gains. Future efforts will likely be directed at understanding/improving adherenc e to exercise reconditioning and at developing home- or community-based programs for patient convenience and cost containment.vv'" ApPENDIX
Guidelines for Exercise Prescription for Patients With Chronic Respiratory Disease A. Flexibility Exercises- stretching of th e major muscle gro ups of both upp er and lower extre mitie s. Flexibility/ str etching should be incorporated as part of th e warmup be fore ae robic tr aining and as part of the coo ldown after aero bic training. B. Aerobic Exercises 1. Mode-should incorpo rate large muscle groups that can be continuous and rhythm ic in nature. Types of exercise includ e walking, cycling, rowing, swimming, etc. An indoor exercise activity is an important option for most patients with respiratory disease in case of inclem ent weath er. 2. Frequ ency- recomm end ed minim al frequ ency of train ing Mechanisms and Management of COPD
is th ree to five times per week. An alternate-day schedu le approximates this goal. Eventually, exercise should become part of a daily routine . 3. Intensity Minimal intensity-50% of peak V0 2 Another approac h is to exercise at "maximum limits tolerated hy symptoms ." For example, patien ts should walk as fast as tolerated for 5 min on the treadmill or in a corridor, and then duration can be increased grad ually. 4. Duration-minimal recom mended duration is 20 to 30 min of continuous exercise. Repetitive exercise-rest may be necessary for some patients at the initial session (eg, walk for 5 min, rest for 2 min; then walk again for 5 min, rest for 2 min). It may take weeks to months for some patients to achieve 20 min of continuous aetivitv. 5. Use of supplem ental oxygen. Oxyge~ should be prescribed based on standard criteria (ie, Pa02 0:;55% or arteria l oxygen saturation 0:;88%). The appropriate flow rate for O2 shou ld be adjusted to maintain arterial oxygen saturation :2:90% as monitored by oximetry. This mate rial was adapt ed from references 4 through 7, 35, and 38. REFERENCES 1 American Thoracic Society. Pulmonary rehabili tation. Am Rev Respir D is 1981; 124:663-66 2 Maltais F, Simard A, Simard C, et al. Oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in norma l subjects and in patients with COPD. Am 1 Respir Crit Care Med 1996; 153:288-93 3 Cooper JD, Trulock EP , Triantafillou AN, et aI. Bilateral pneumonectomy (volume reduction) for chronic obstructive pulmonary disease. 1 Thorac Cardiovasc Surg 1995; 109: 106-19 4 Ries AL. Position paper of the American Association of Cardiovascular and Pulmonary Reha bilitation: scientific basis of pulmonary rehabilitation . J Cardiop ulm Rehabil 1990; 10:418-41 5 Casaburi R, Petty TL. Principl es and practice of pulmonary rehabilitation . Philadelphia: Saunders , 1993 6 Hodgkin JE, Connors GL, Bell CWo Pulmonary rehabilitation: guidelines to success. 2nd ed. Philade lphia: IB Lippincott, 1993 7 Fishman AP, ed. Pulmonary rehabilitation: lung biology in hea lth and disease (vol 91). New York: Marcel Dekker, 1996 8 Fishman A. Pulmonary rehabilitation research. Am J Respir Crit Care Med 1994; 149:825-33 9 American Thoracic Society. Statement: stand ards for the diagnosis and eare of patien ts with chronic obstructive pulmonary disease . Am J Respir Crit Care Med 1995; 152:S77120 10 Mahler DA, Harvel' A. Dyspnea. In: Fishman AP, ed. Pulmonary reha bilitation: lung biology in health and disease (vol 91). New York: Marcel Dekker, 1996; 97-116 11 Curtis JR. Assessing health-related quality of life in chronic pu lmonary disease. In: Fishman AP, ed. Pulmonary reh abilitation: lung biology in health and disease (vol 91). New York: Marcel Dekker, 1996; 329-53 12 Pashkow P, Ades PA, Emery CF, et al. (Outcomes Comm ittee of the AACVPR). Outcome measur em ent in cardiac and pu lmonary reha bilitation. J Cardiopulm Rehabil 1995; 15: 394-405 13 Mahler DA, Wein be rg D H, Wells CK, et al. The measurement of dyspnea : cont ents , interobs erver agreement, and physiologic correlations of two new clinical inde xes. Chest 1984; 85:751-58
14 Guyatt GH , Ber man LB, Townsh end M, et al. A meas ure of quality of life for clinical trials in chronic lung disease. Thorax 1987; 42:773-78 15 Borg GAV. Psychoph ysical bases of perceived exertion. Med Sci Sport s Exerc 1982; 14:377-81 16 Lacasse Y, Wong E, Guyatt GH , et al. Meta-analysis of respiratory rehabilitation in chronic obstructive pulmonary disease. Lancet 1996; 348:1115-119 17 Jones PW, Quirk F H, Baveystock C M, et al. A self-complete measure of health statu s for chronic airflow limitation . Am Rev Respir Dis 1992; 145:1321-27 18 Ware Jr JE, Sher bourne CD . The MOS 36-item short-form health survey (SF-36): I. Conceptual framework and item selection . Med Care 1992; 30:473-81 19 Mahler DA, Mackowiak JI. Evaluation of the short-form 36-item questionnaire to measure health-related quality of life in pat ients with CO PD. Chest 1995; 107:1585-89 20 Rosser R, Denford J, Heslop, et al. Brcathless ness in and psychiatric morb idity in chro nic bronchitis and emphysema: a study of psychotherapeutic management. Psychol Med 1983; 13:93-110 21 Frith P, Walker P, Rowland S, et aI. Using an education program for improving quality of life in patients with chronic obstructive pulmonary disease [abstract]. Chest 1993; 103:181S 22 Sassi-Dambron D E, Eakin EG , Hies AL, et al. Tre atm ent of dyspnea in COPD: a contro lled clinical trial of dyspnea management strat egies. Chest 1995; 107:724-29 23 Janelli LM, Scherer UK, Schmieder LE . Can a pu lmonary health teaching program alter pati ents' ability to cope with CO PD? Rehab Nurs 1991; 16:199-202 24 Scherer YK, [ anelli LM, Schm ieder LE. Chronic obstructive pulmonary disease- does participating in a help yourself to better breathing program make a difTerence? J Cardiopulm Reh abil 1989; 9:492-96 25 Strijbos JB, Sluiter NJ, Postma DS, et al. Objective and subjective performance indicators in COPD . Eur Hespir J 1989; 2:666-69 26 Casaburi R, Patessio A, Ioli F, et al. Beductions in exercise lactic acidosis and ventilation as a resu lt of exercise tra ining in patients with obstructive lung disease. Am Hev Hespir Dis 1991; 143:9-18 27 Reardon J, Awad E, Normandin E, et al. Th e effect of comprehe nsive outpatient pu lmonary reh abilitation on dyspnea. Chest 1994; 105:1046-52 28 Goldstc in RS, Gork EH , Stubbing D, et al. Handomized controlled trial of respiratory rehabilitation. Lance t ]994; 344:1394-97 29 Hies AL, Kaplan HM, Limberg TM , et al. Effects of puhno nary rehabilitation on physiologic and psychosocial outcomes in patients with chronic obstructive pnlmo nary disease. Ann Intern Med 1995; 122:823-32 30 O'Donnell DE , McGuire M, Samis L, et al. The impact of exercise reconditioning on breathlessness in severe chro nic airflow limitation . Am 1 Hespir Crit Care Med 1995; 152: 2005-]3 31 Maltais F , LeBlanc P, Simard C, et al. Skeletal muscle adaptation to endurance training in patients with chronic obstructiv e pulmonary disease. Am J Respir Care Med 1996; 154:442-47 32 Carrieri-Kohlman V, Gor mley JM, Doug las MK, et al. Exercise training decreases dyspnea and the distr ess and anxiety associated with it: monitorin g alone may be as effective as coaching. Chest 1996; 110:1526-35 33 Hamirez-Venegas A, Ward JL, Olmstead E M, et al. The effe ct of exerc ise trainin g on dyspnea measures in pati ents with chronic obstructive pulmonary disease. 1 Cardiopu lm Reha b 1997; 17:103-09 CHEST / 113 /4 / APRIL, 1998 SUPPLEMENT
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34 Haas F, Salazar-Schicchi J, Axen K. Desensitization to dyspnea in chronic obstructive pulmonary disease. In: Casaburi R, Petty TL , eds. Principl es and practice of pulmonary rehabilitation. Philadelphia: Saunders, 1993; 241-51 35 American College of Sports Medicine . Position stand : the recommended quantity and quality of exercise for developing and maintaining cardiorespiratory and muscular fitness in healthy adult s. Med Sci Sports Exerc 1990; 22:265-74 36 H.ies AL, Archibald CJ. Endurance exercise training at maximal targets in patients with chroni c obstructive pulmon ary disease . JCardiopulm Rehabil 1987; 7:594-601 37 Maltais F, LeBlanc 1', Jobin J, et al. Intensity of training and physiologic adapt ation in patients with chronic obstructive pulm onary disease. Am J Hespir Crit Care Med 1997; 155: 555-61 ~18 Scott JA, Mahler DA. How to prescribe exercise for patients with COPD. J Respir Dis 1996; 17:527-36 39 Horowitz MB, Littenberg B, Mahler DA. Dyspnea ratings for prescribing exercise intensity in patient s with COPD. Chest 1996; 109:1169-75 40 Ries AL, Ellis B, Hawkins RW. Upper extremity exercise trainin g in chroni c obstructive pulmonary disease. Chest 1988; 93:688-92 41 CouserJI Jr, Martin ez FJ, Celli BR. Pulmonary rehabilit ation
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42 43
44
45
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that includes arm exercise reduces metabolic and ventilatory require ments for simple arm elevation. Che st 1993; 103: 37-41 Beck JG, Scott SK, Teague RB, et al. Cor relates of daily impairment in COPD. Rehab Psychol 1988; 33:77-84 Weaver TE , Narsavage GL. Physiological and psychological variables related to functional status in chronic obstructive pulmonary disease. Nurs Res 1992; 41:286-91 ACCP/AACVPR Pulmonary Reh abilitation Guidelines Panel. Pulmon ary rehabilitation: joint ACCP/AACVPR evidencebased guidelines. Chest 1997; 112:1363-96 Wijkstra PJ, Willem T, Mark VD, et al. Long-term effect s of horne rehabilit ation on physical performance in chronic obstructive pulm onary disease. Am J Respir Crit Care ivied 1996; 153:1234-41 Camb ach W, Chadwick-Straver RVM, Wafcnaar RC, et al. The effects of a commu nity-based pulmonary rehabilitation program on exercise tolerance and quality of life: a randomized controlled trial. Eur Respir J 1997; 10:104-13 Lareau S, Carrieri-Kohlm an V, Janson-Bjerklie S, et al, Development and testing of the pulmonary functional status and dyspnea questionnaire (PFSDQ). lI eart Lung 1994; 23:242-50
Mechanisms and Management of COPO
There has been a resurgence of interest in pulmonary rehabilitation mainly because the prevalence of COPD has increased, scientific stu dies document consistent benefits (incr eased exercise endurance and reduced dyspnea), and thoracic su rgeon s recognize that preoperative and postoperative conditioning enhances the results of lung volu me reduction surgery and lung transplantation. Although education and ps ychosociallbehavioral interventions are important components of a multidimensional program, exercise training of the upper and lower extremities is essential to achieve the described improvements. Current programs vary considerably in the frequency, intensity, and duration of exercise reconditioning. Two "key" questions relating to pulmonary rehabilitation are as follows. What is an appropriate training intensity? How should patients monitor the training intensity? Maintenance exercise programs and the development of home- or community-based programs will be important future developments. (CHEST 1998; 113:263S-268S)
T changed he reality of pulmonary rehabilitation has since th e 1974 definition p roposed by th e American College of Chest Physicians Co mmittee on Pulm onary Reh abilitation .' Several factors have con tributed to th e resurging interest in pulmonary rehabilitat ion over the past years. Fi rst, the prevalence of patients with CO PD has increased . Second, there is greater awareness th at such patients are deconditioned. s Third, the eme rge nce of lung volum e reduction surgery for patients with advanc ed emphysema has prompted institutions to develop andlor expand both preoperative and postoperative pul monary rehabilitation:' F ourth, manage d healthcare programs have encour aged admi nistrators to consider pulmonary reh abilitation program s as an integral part of health-care delivery/p reventive medicine. And fifth , publications have highlight ed th e principles and practice of pulmonary rehabilitation .v? Th ese as well as other considerations led to th e 1994 Workshop on Pul monary Reh abilit ation Resea rch sponsored by th e National In stitutes of Health. At this meeting, a new definition was developed : "Pulmonary reh abilitation is a multidimensiona l continu um of services directed to persons with pul monary disease and their families, usually by an interdisciplinary team of specialists, with the goal of achieving and maintaining the individ ual's maximum level of indep end en ce and function ing in the community.?" Thi s newer definition incorp orates the key concepts of involvem ent of patients and fam ilies, a continuum of multidisciplinary activities, and th e ' From the Section of Pulmonary and Critical Care Medicine, Dartm outh-H itchcock Medi cal Ce nte r, Leb anon , NI-1.
expe rtise of an interdisciplin ary team . An additional impet us has been the 1995 American Thoracic Society statem ent that pul mona ry rehabilitation is an established com ponent of th e care and treatment of patients with COPD Y Th e pri mary goals of pu lmonary rehabilitat ion programs are as follows: to relieve symptoms, parti cularly dyspnea; imp rove fun ctional ability; and enhance health- related qu ality of life. P ATIENT SELECTION
Selection crite ria for parti cipation in a pulmonary rehab ilitation program inclu de any symptomatic individu al with stable chro nic respirat ory disease (no age limitation ), and that th e patient is motivated to parti cipate in a self-care p rogram . INITIAL EVAL UATION
Th e major components of the initi al patient evaluation are listed in Table 1. Th e medi cal histo ry should include measurem ent of dyspn ea ' ? and health-related quali ty of life (H RQ L). l1 Appropriate instruments should be selected that are valid for th e pop ulation and are responsive (able to detect clinically import ant changes). Baselin e physiologic testing of lung function and cardiopulmonary exercise responses are imp ort ant . Fin ally, assessment of anxiety, depression, social and family suppo rt , as well as coping skills shou ld be mad e. O UT COM E M E ASUR E S
An Outcomes Committee of the American Association of Ca rdiovascular and Pulmonary RehabilitaCHEST / 113 / 4 / APRIL, 1998 SUPPLEMENT
2635
Table I-Components of th e Initial Ev aluation of Pati ents for Pulmonarsj Rehabilitation Co mpo ne nts
Medical history ami ph ysical examination Mea sur e dyspn ea Mul tidim ension al clinical instrumen ts Ratings du ring exercise Measur e HRQL Disease-specific instruments Gen eric instru me nts Diagnostic testing Pulm on ary funct ion tests Cardiopulmonary exe rcise tests Pulse oximetry or arte rial blood gases Psychosocial assessme nt Evaluate anxiety/de pres sion Assess social and family support Co ping and self-care skills
tion 12 recommende d that pulmonary rehabilitation p rograms evaluate dyspn ea, HR QL, and exercise ability as domains for potential improvem ent (Table 2). Dyspnea can be meas ured based on activities of daily living or du ring a specific task. Th e committe e recommended th e Baseline and Tra nsition Dyspnea Indexes!" or the dyspnea componen t of the Chronic Respiratory Questionnaire (CRQ )14 as appropriate mu ltidim ensional instruments. Dyspnea du ring a specific task (eg, an exercise test) can be quan tified using the 0 to 10 category-ratio scale developed by Borg l 5 or a visual analog scale. A met a-analysis of selected studi es of pulm onary rehab ilitation dem onstra ted a consistent reduction in dyspn ea ratings using the CR Q.16 Disease-specific and generic instru ments are available to measure HRQL before and after pulmonary reh abilit ation.! ' Th e C RQ14 and the St. Geo rge's Respiratory Qu estion naire!" were recommended by
the Ou tcomes Committee. Although gen eric HRQL instruments may provide com plementary inform ation, th ey appear to be less responsive to therapeutic interventions. The Medical Outcomes Study sho rtform 36-item survey' " is an example of a generic questionnai re th at may be used to assess HRQL in patients with CO PD.I!) An effective pul monary rehabilitation program usually results in an improvement in exercise endurance, bu t little or no cha nge in maximal capacity. Th e 6-min walking test is a Simple and inexpensive metho d to measure an individual's exercise ability. However , test results are influenced by patient effort and motivation. Th erefore, measurement of workload and expired gases can provide objec tive ph ysiologic data to measure changes in exercise capacity. A sub maximal, constant workload test on the cycle ergometer or treadmill may be the most appropriate test to examine changes in exercise endurance as a result of pul monary reh abilitation." Finally, beh avioral outcom es are import ant , but may be difficult to quantify. Smoking cessation, nutritiona l support, adherence with medications and exercise training , and any changes in anxiety and depression should be evaluated and changes should be documented.
COMPONENTS OF P ULMONARY R EH ABILITATION
Edu cation
Although patient education is considered important , it is not an essential part of pul monary rehabilitation. Many, if not most, reh abilitation program s provide education to patients on various topics, including pathoph ysiology of CO PD , breathin g retraining, medications (particularly the technique of using a mete red-dose inhaler ), nutrition, ene rgy
Table 2-Instruments To Measure Three Outcomes of Pulmonary Rehabilitation Programs* Outcome Dyspn ea
HR QL
Exe rcise ability
In st ruments For activities of daily living Baseline and T ransition Dysp nea Indexes '? Dyspnea co mpon e nt of C RQ 14 F or spe cific exe rcise task o to IO category-ratio scale l 5 Visual analog scale 16 Disease specific C RQI4 St. George' s Respiratory Qu estionnair e ' ? Pn lmon ary Fun ctional Status Scale'" Pulmon ary Functional Status and Dyspnea Qu cstion naire -? 6-minute walk A cardiopulmonary exe rcise test eithe r at submaximal or maximal workload
*The Outcom es Committee of the American Association of Cardiovascular and Pu lmonary Rehabilitati onl- has recomm end ed that one of mor e of the above inst rum ents he used to measure each of the three outcom es or dom ains.
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conservation, use of supplemental oxygen , travel , advice on intimacy, and strategies to relieve breathlessness . To my knowledge, only five studies have examined the effects of education alone on outcomes in patients with CO PD .20-24 There was mild improvement in dyspnea reported in three studies,20-22 whereas the other studi es showed either no ben efit on coping skills-" or an increase in psychological distr ess following education.e' Therefore, education is not considered adequate by itself to improve outcomes in patients with COPD, but nevertheless it should be included as a component in a multidimensional pulmonary rehabilitation program.
Lower Extremity Exercise Training Both uncontrolled and controlled studies25-31 demonstrate that lower extremity exercise training improves exercise tolerance. Although most studi es show no change in peak oxygen consumption (\10 2), submaximal exe rcise endurance improves consistently after pulmonary rehabilitation. In addition, randomized controlled studi es of comprehensive pulmonary rehabilitation show an improvem ent in dyspnea during exercise in th e laboratory and with activities of daily living.25,27-3o,32 The possible mechanisms for improved exercise capacity and reduced severity of breathlessness are summarized in Table 3. Casaburi et al26 demonstrated physiologic training respons es (an increase in peak \102; a decrease in exercise ventilation; and an increase in lactate threshold) in a supervised, inpatient rehabilitation program in patients with mild-tomod erate COPD. More recently, Maltais et a}31 showed that endurance tra ining reduced exerciseinduced lactic acidosis and improved skeletal muscle oxidative activity in 11 patients with moderate-tosevere COPD . Th ese two studi es de monstrate clearly that physiologic training may occur with exercise training in patients with COPD. Other investigators have reported that relief of dyspnea was due to the corresponding fall in ventilatory demand duri ng exercise ( ~ minute ventilation/work rate) as a result of enhanced mechanical efficiency.27,3o Both
Table 3-Possible Mechanisms for Improvements in Exercise Capacity and Dyspnea With Pulmonary Rehabilitation Mechani sms Physiologic training response Enhanced mechanical e fficiency Redu ced imp ed ance to breathin g Improved respiratory muscle function Toleran ce or desensitization
O'Donnell et a}3o and Ramirez-Ven egas et a}33 have suggested that enhanced respiratory muscle function , as may occur with pulmonary rehabilitation, can also contribute to improved breathlessness. Finally, psychological factor s, including the development of tolerance or desensitization to dyspn ea, may enable patients to perform highe r levels of work with reduced symptoms,32,34 Published studies and clinical programs of pulmonary rehabilitation vary considerably in the methods of exercise traini ng. The rang es of frequency (once a week to daily), intensity (50% of peak \102 to maximal tolerated effort), and duration (5 to 10 min as tolerated up to 45 min ) illustrate the variability. Pulmonary rehabilitation programs may last from 4 to 46 weeks, although most programs are 6 to 8 weeks long. The predominant modes of exercise training are treadmill walking, and cycle ergometry. General guide lines for exercise prescription are provided in the Appendix. A key question related to pulmonary rehabilitation is: "What is an appropriate training intensity?" Intensity and duration of exercise train ing are clearly interrelated. However, most programs emphasize that patients increase duration because such improvem ents have great er impact on activities of daily living. The American College of Sports Medicine has recommended that the minim al intensity for healthy individuals is 50% of peak \102 with an upper limit of 85% of peak \102 .35 Another approach is "maximum limits tolerated by symptoms."36 For example, the patient should walk as fast as possible for 5 min on the treadmill or in a corridor, and then duration could be gradually increased over days to weeks. In one study by Ries and Archibald.i'? the average walking speed on the treadmill by patients with COPD that could be sustained for 5 min was 1 mph (range, 0.6 to 3.5 mph ). Maltais et a}37 examined the ability of 42 patients with COPD to train at an inten sity of 80% of maximal power output on the cycle ergometer for 25 to 30 min over a 12-week program . Although the training intensity for each session averaged 60±23% of maximal power output at week 12, there was a significant improvem ent in exercise capacity and a concomitant reduction in exercise ventilation and arterial lactic acid concentration with training. Based on these collective data , a reasonabl e approach is that the physician or exercise specialist select the initial training intensity based on the individu al patient's daily activity level, results of the cardiopulmonary exercise test , and a discussion with the patient regarding his/h er specific goals. Another important conside ration is, "How should patients monitor the training intensity?" Th e traditional method in health y individu als has been to use CHEST / 113 /4 / APRIL, 1998 SUPPLEMENT
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a target heart rate to regulate/monitor the intensity/" Yet , patients with COPD are limited by the mechanics of breathing, oxygen desaturation, and/or dyspnea rath er than cardiovascular factors . An alternative approach is to use dyspnea ratin gs as a target , just as ratings of perceived exertion have been used as a guide for intensity of effort in health y persons and in those with cardiac diseas e .P" Horowitz et aP9 have shown that dyspnea ratin gs on the 0 to 10 categoryratio scale obtained from an increm ental exercise test can be used to achieve a desired intensity; however , the accuracy was better at a higher exercise level (approximately 80% of peak \102) compared with a lower intensity (approximately 50% of peak \10 2 ) , Practice sessions may also be required for some patients to learn and to receive feedb ack to improve their ability to use the scale.
logical distress are low self-esteem , poor body image, loneliness, and reduced social support. Many pulmonary rehabilitation programs incorporate psychosocial and behavioral _~omponents in addition to upp er and lower extremity exercise training. Strategies include evaluation and possible treatment of anxiety and/or depression, teaching relaxation skills, discussion of family and sexual relations , and providing emotional support. Specific behavioral interventions are smoking cessation, nutritional support, and compliance with the exercise program. Although the scientific evidence to support psychosocial and behavioral interventions is weak, many patient s and staff associated with programs believe that patients with COPD experience such benefits from their participation in pulmonary rehabilitation. Certainly, randomized controll ed trials are necessary to examine these components.
Upper Extremity Exercise Trainin g
Many patients with severe COPD experience breathl essness when using their upp er extremities to perform activities (eg, lifting or carrying objects). By anchoring the arms , muscles of the shoulder girdle (eg, pectoralis muscles ) can pull on the rib cage and contribute to ventilation. Upp er extre mity exercise training can augment the strength and endurance of these muscles, and thereby enhance inspiration. The ben efits of upp er extre mity exercise training are an increase in the ability to perform ann work and decreased \10 2 for the same amount of work. 40 ,4l Although anecdotal reports by patients indicate improvements in dyspnea and functional outcomes with upp er extremity exercise training, to my knowledge, there are no randomized controlled trials that demonstrate such ben efits in these measures. Th e two most common methods to train the uppe r extre mities are arm e rgome try (cycle with th e arms at 50 rpm with resistance loads added as tolerated for a 20- to 30-min duration ) and resistan ce training (l to 2 sets of 8 to 12 repetitions for each major muscle group against gravity or using 1- to 2-kg weights ). Patients should be instructed to coordinate breathing with movem ent of the arm s (entrainment) . Usuall y, expiration occurs with exte nsion of the upper extre mities . Tol erance of upper extre mity exe rcise training is based on arm discomfort and/ or dyspn ea. Psychosocial and Behavioral Comp onents
Anxiety and depression are common in patients with COPD . Such psychological distr ess can contribute to restricted activities of daily living and may be more predictive of functional capacity than physiologic factors are .42,43 Oth er manifestations of psycho2665
CONCLUSIONS
The scientific basis for pulmonary rehabilitation has developed substantially over the past decade." Exercise training has been recognized as an essential component of pulmonary rehabilitation, and accepted outcome measures have been established to evaluate potenti al improvements . An increased number of patients with chronic respirato ry disease, the eme rgence of lung volume reduction surgery and lung transplantation as possible treatment modalities, and a focus on the cost of health-care resources should expand the present role of pulmonary rehabilitation programs. Certainly , extended exercise pro grams will be important for patients to maintain short-ter m gains. Future efforts will likely be directed at understanding/improving adherenc e to exercise reconditioning and at developing home- or community-based programs for patient convenience and cost containment.vv'" ApPENDIX
Guidelines for Exercise Prescription for Patients With Chronic Respiratory Disease A. Flexibility Exercises- stretching of th e major muscle gro ups of both upp er and lower extre mitie s. Flexibility/ str etching should be incorporated as part of th e warmup be fore ae robic tr aining and as part of the coo ldown after aero bic training. B. Aerobic Exercises 1. Mode-should incorpo rate large muscle groups that can be continuous and rhythm ic in nature. Types of exercise includ e walking, cycling, rowing, swimming, etc. An indoor exercise activity is an important option for most patients with respiratory disease in case of inclem ent weath er. 2. Frequ ency- recomm end ed minim al frequ ency of train ing Mechanisms and Management of COPD
is th ree to five times per week. An alternate-day schedu le approximates this goal. Eventually, exercise should become part of a daily routine . 3. Intensity Minimal intensity-50% of peak V0 2 Another approac h is to exercise at "maximum limits tolerated hy symptoms ." For example, patien ts should walk as fast as tolerated for 5 min on the treadmill or in a corridor, and then duration can be increased grad ually. 4. Duration-minimal recom mended duration is 20 to 30 min of continuous exercise. Repetitive exercise-rest may be necessary for some patients at the initial session (eg, walk for 5 min, rest for 2 min; then walk again for 5 min, rest for 2 min). It may take weeks to months for some patients to achieve 20 min of continuous aetivitv. 5. Use of supplem ental oxygen. Oxyge~ should be prescribed based on standard criteria (ie, Pa02 0:;55% or arteria l oxygen saturation 0:;88%). The appropriate flow rate for O2 shou ld be adjusted to maintain arterial oxygen saturation :2:90% as monitored by oximetry. This mate rial was adapt ed from references 4 through 7, 35, and 38. REFERENCES 1 American Thoracic Society. Pulmonary rehabili tation. Am Rev Respir D is 1981; 124:663-66 2 Maltais F, Simard A, Simard C, et al. Oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in norma l subjects and in patients with COPD. Am 1 Respir Crit Care Med 1996; 153:288-93 3 Cooper JD, Trulock EP , Triantafillou AN, et aI. Bilateral pneumonectomy (volume reduction) for chronic obstructive pulmonary disease. 1 Thorac Cardiovasc Surg 1995; 109: 106-19 4 Ries AL. Position paper of the American Association of Cardiovascular and Pulmonary Reha bilitation: scientific basis of pulmonary rehabilitation . J Cardiop ulm Rehabil 1990; 10:418-41 5 Casaburi R, Petty TL. Principl es and practice of pulmonary rehabilitation . Philadelphia: Saunders , 1993 6 Hodgkin JE, Connors GL, Bell CWo Pulmonary rehabilitation: guidelines to success. 2nd ed. Philade lphia: IB Lippincott, 1993 7 Fishman AP, ed. Pulmonary rehabilitation: lung biology in hea lth and disease (vol 91). New York: Marcel Dekker, 1996 8 Fishman A. Pulmonary rehabilitation research. Am J Respir Crit Care Med 1994; 149:825-33 9 American Thoracic Society. Statement: stand ards for the diagnosis and eare of patien ts with chronic obstructive pulmonary disease . Am J Respir Crit Care Med 1995; 152:S77120 10 Mahler DA, Harvel' A. Dyspnea. In: Fishman AP, ed. Pulmonary reha bilitation: lung biology in health and disease (vol 91). New York: Marcel Dekker, 1996; 97-116 11 Curtis JR. Assessing health-related quality of life in chronic pu lmonary disease. In: Fishman AP, ed. Pulmonary reh abilitation: lung biology in health and disease (vol 91). New York: Marcel Dekker, 1996; 329-53 12 Pashkow P, Ades PA, Emery CF, et al. (Outcomes Comm ittee of the AACVPR). Outcome measur em ent in cardiac and pu lmonary reha bilitation. J Cardiopulm Rehabil 1995; 15: 394-405 13 Mahler DA, Wein be rg D H, Wells CK, et al. The measurement of dyspnea : cont ents , interobs erver agreement, and physiologic correlations of two new clinical inde xes. Chest 1984; 85:751-58
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Mechanisms and Management of COPO