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The Early Recognition and Management of Chronic Obstructive Pulmonary Disease
Index:
COPD Definitions and Pathogenesis
The National Lung Health Education Program
Maintenance Management of Symptomatic COPD
Treatment of Advanced Disease
Treatment of Advanced Disease
Beyond bronchodilators, corticosteroids, antibiotics and ancillary pharmacologic agents, additional technologically oriented care is appropriate for selected patients with advanced stages of disease. The strategies include pulmonary rehabilitation, long-term home oxygen (LTOT), and surgery.
Pulmonary Rehabilitation
The original definition of pulmonary rehabilitation by the committee of the American College of Chest Physicians 1974 was as follows:"Pulmonary rehabilitation may be defined as an art of medical practice wherein an individually tailored, multi-disciplinary program is formulated, which through accurate diagnosis, therapy, emotional support and education, stabilizes or reverses both the physio and psychopathology of pulmonary diseases and attempts to return the patient to the highest possible functional capacity allowed by the pulmonary handicap and overall life situation."
Since that time, other definitions have been offered, but none have a better foundation than the above. Text books have been written to summarize the technologies and therapeutic approaches to pulmonary rehabilitation, and one is cited in the references at the end of this section.
The components of pulmonary rehabilitation include patient and family education, the strategic use of pharmacologic agents, (which are covered in another section), breathing retraining and breathing exercises, physical reconditioning, oxygen (in selected patients), and patient support groups.
A new publication for COPD patients gives a state of the art review of what is understood of COPD and how to cope with it. It is written for patients and their families in layman’s language. (See Frontline Advice for COPD Patients).
Most experts believe that pulmonary rehabilitation should be considered earlier in the disease process than it has been traditionally thought of (i.e., moderate COPD), not waiting until the patient has severe disease.
Numerous studies have shown that pulmonary rehabilitation increases exercise tolerance, provides a better quality of life, and reduces anxiety and depression. There is a variable effect upon hospitalizations, but, in general, hospitalizations are also reduced.
The systemic nature of advanced COPD has received appropriate emphasis. The spiraling dyspnea and inactivity pathway must be stopped. For some reason, patients with only mild to moderate stages of COPD cannot achieve an age-predicted target heart rate of maximum oxygen consumption. Why this is must have something to do with oxygen delivery or oxygen utilization.
Oxygen
The consequences of hypoxemia in advanced stages of COPD are reactive pulmonary hypertension, increased airflow resistance and expanded red cell mass, reduced tissue oxygen transport and combinations. The scientific basis for oxygen administration for at least 15 hours per day has been established by the nocturnal oxygen therapy trial (NOTT) and the British MRC trial. In both trials, the survival difference was seen between continuous ambulatory oxygen and stationary oxygen, and stationary oxygen versus no oxygen.
Why nearly continuous oxygen therapy in the NOTT study prolonged survival in COPD patients remains unexplained. It could be the duration of oxygen therapy or, more likely, the ability to ambulate with oxygen. The ability to ambulate would improve tissue oxygen transfer, and perhaps restore energy production at the tissue level. Ambulation provides physical reconditioning and has known psychosocial value. The NOTT study showed that continuous oxygen improved brain function more than nocturnal oxygen.
Prescribing Principles
Table 6 lists the USA prescribing criteria for long term oxygen therapy (LTOT). These criteria were used in the NOTT.
Table 6
Prescribing Criteria for Long Term Oxygen Therapy
The prescribing criteria specified by the Medicare program, which must be met in order for the costs of the oxygen to be reimbursed, are as follows:
Qualification on the basis of hypoxemia alone:
- Pa02 55 mmHg, or
- Sa02 88% (breathing room air)
Qualification requiring additional clinical evidence of hypoxia, Pa02 56-59 mmHg or Sa02 89% plus one or more of the following:
- P-pulmonale (P waves 3 mm or more in lead II, III, or a VF of electrocardiogram)
- clinical right-sided heart failure (dependent edema)
- Erythrocytosis
(hematocrit over 55%)
New Developments:
New developments in oxygen therapy include the use of transtracheal oxygen and concealing oxygen cannula in ordinary eye glasses.
New light-weight systems such as the Helios (weighing only 3.75 lbs.) filled with a conserver providing an 8-hour supply of oxygen at 2 liters per minute make ambulation and participation in the full activities of daily living a reality. Light-weight, battery powered oxygen concentrators are on the horizon. One unit weighs less than 10 lbs. and has just been introduced to the marketplace, the Essential Life StyleTM(AirSep).
The mechanisms of improved survival from all LTOT include improved hemodynamics from reduced right ventricular afterload or increased right ventricular function, improved tissue oxygen transport, and improved cellular oxygen utilization.
Surgery
Lung transplantation is available for only a select few patients. Although the quality of life is improved through lung transplantation, rejection through bronchiolitis obliterans is a major limiting factor. The length of life in advanced stages of COPD is not greatly increased with lung transplantation as compared with pulmonary rehabilitation therapy alone. The National Emphysema Therapy Trial (NETT), which evaluated lung volume reduction surgery, has recently reported that surgery was superior to ordinary pulmonary rehabilitation. Selection of ideal patients is key. Eliminating patients with an FEV1of less than 20% of predicted, a DCO of less than 20% of predicted, and homogenous distribution of emphysema, seem critical.
New techniques may make lung volume reduction surgery less traumatic and more accessible to selected individuals. The goal of lung volume reduction surgery is to improve elastic recoil and restore the length-tension relationships in the diaphragm. Ventilation profusion distribution is also improved. The clinical counterpart is reduced dyspnea, improved exercise tolerance and improved oxygenation. A limited number of patients can be freed from the use of LTOT, at least for a period of time.
References
Beeh KM, Kornmann O, Lill J, et al: Induced sputum cell profiles in lung transplant recipients with or without chronic rejection: correlation with lung function. Thorax 2001;56:557-560. Increased sputum neutrophils relate to rejection in lung transplant patients.
Butland RJ, Pang J, Gross ER, et al: Two-, six- and 12 minute walking tests in respiratory disease. BMJ 1982;284:1607-1608. The original report that gave evidence that the 6 minute walk test correlated well with the twelve minute walk test.
Casaburi R, Petty TL (eds): Principles and Practice of Pulmonary Rehabilitation. WB Saunders, Philadelphia PA, 1993. A comprehensive text book on pulmonary rehabilitation with a historical perspective.
Christopher KL, Spofford BT, Petrun MD, et al: A program for transtracheal oxygen delivery. Assessment of safety and efficacy. Ann Intern Med 1987;107:802-808. An early report on the advantages of transtracheal oxygen (TTO) delivery in selected patients with COPD.
Continuous or nocturnal oxygen therapy in chronic obstructive lung disease: a clinical trial. Nocturnal Oxygen Therapy Trial Group (Petty TL, Chairman) Ann Intern Med 1980;93:391-398. The original report of the NOTT which showed a significant survival benefit for ambulatory oxygen used for more hours than stationary nocturnal oxygen (17.4 hours versus 11.8 hours).
Good JT Jr., Petty TL: Frontline Advice for COPD Patients. Snowdrift Pulmonary Conference, Inc., Denver CO – 94 p. A comprehensive monograph written for patients.
Heaton RK, Grant I, McSweeny AJ, et al: Psychologic effects of continuous and nocturnal oxygen therapy in hypoxemic chronic obstructive pulmonary disease. Arch Intern med 1983;143:1941-1947. Showed that ambulatory oxygen improved brain function more than in nocturnal stationary oxygen.
Hudson LD, Tyler ML, Petty TL: Hospitalization needs during an outpatient rehabilitation program for severe chronic airways obstruction. Chest 1976;70:606-610. Evidence of reduced hospitalizations following institution of a pulmonary rehabilitation program.
Long-term domiciliary oxygen therapy in chronic hypoxic cor pulmonale complicating chronic bronchitis and emphysema. Report of the Medical Research Council Working Party. Lancet 1981;1:681-686. Showed a survival benefit with oxygen delivered for 15 hours per day compared with no oxygen. Survival effect did not occur until after 500 days of treatment.
Mueller RE, Petty TL, Filley GF: Ventilation and arterial blood gas changes induced by pursed lips breathing. J Appl Physiol 1970;28:784-789. Pursed lips breathing resulted in slower, deeper breathing and improved arterial oxygenation.
Petty TL, Bliss PL: Ambulatory oxygen therapy, exercise, and survival with advanced chronic obstructive pulmonary disease (the Nocturnal Oxygen Therapy Trial revisited). Resp Care 2000;45:204-211. A retrospective analysis of the NOTT study. Survival with ambulatory oxygen was superior to survival with stationary oxygen in persons able to increase their exercise. Hospitalizations also reduced with ambulatory oxygen.
Petty TL: Pulmonary rehabilitation of early COPD. COPD as a systemic disease. Chest 1994;105: 1636-1637. An editorial comment about why COPD must be considered a systemic disease.
Ries AL, Kaplan RM, Limberg TM, et al: Effects of pulmonary rehabilitation on physiologic and psychosocial outcomes in patients with chronic obstructive pulmonary disease. Ann Intern Med 1995;122:823-832. A controlled trial showing advantages of pulmonary rehabilitation over standard care.
The National Emphysema Treatment Trial Group. Rationale and design of the National Emphysema Treatment Trial. J Cardiopulmonary Rehabil 2000;20:24-36. A detailed review of study design and rationale.
The National Emphysema Treatment Trial Group. Patients at high risk of death after lung-volume-reduction surgery. N Engl J Med 2001;345:1075-1083. Evidence of high mortality in patients with extremely poor ventilatory and diffusion function.