Pulmonary Rehabilitation in COPD Patients with Elevated P_CO2

Abstract

Exercise programs are a mainstay of pulmonary rehabilitation for COPD. COPD patients with elevated PCO2 are severely impaired and might benefit from rehabilitation more than other patients. However, there is no systematic data to indicate that hypercapnic COPD patients benefit from intensive rehabilitation. Indeed, in patients with hypercapnia, increased exercise might overtax respiratory muscles, which are weak relative to those of eucapnic patients. To investigate this issue, we reviewed all COPD patients admitted to our pulmonary inpatient program from 1983 to 1986 (n = 317). The program includes multiple daily sessions of upper and lower extremity exercise to tolerance. We assessed admission and discharge pulmonary function tests, arterial blood gases (room air), and functional status. Ambulation distance on a 6-min walk test was used as an objective measure of functional status. Patients were grouped according to the results of their admission room air PCO2. We found that eucapnic patients (n = 197) significantly increased ambulation (admission to discharge) from 409 to 816 feet (p less than 0.001). Hypercapnic patients improved as well. Patients with moderate hypercapnia (PCO2, 45 to 54 mm Hg; n = 86) increased their ambulation from 330 to 663 feet (p less than 0.0001). Patients with severe hypercapnia (PCO2 greater than 54 mm Hg; n = 34) increased their ambulation from 336 to 597 feet (p less than 0.0001). We found a small but significant improvement in discharge pulmonary function and arterial blood gas results. We conclude that COPD patients with hypercapnia, despite severe ventilatory impairment and weak respiratory muscles, tolerate exercise well and benefit significantly from intensive inpatient pulmonary rehabilitation.

Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease

“…Later, lactic acid production was seen as a prerequisite to achieve an appropriate training response (34), as reductions in lactic acid were coupled to significant reductions of minute ventilation for a given work rate and oxygen consumption. However, more recent studies in which high-intensity training stimuli were applied clearly showed that patients with FEV 1 below 40% of the predicted values or those with hypercapnia (GOLD Stage IV) should not be excluded from exercise training (37,37,157,262,263). In a large study by Berry and coworkers (166), patients with mild, moderate, and severe COPD showed the same proportional improvement in exercise tolerance after pulmonary rehabilitation.…”

“…The variance explained by the proposed model, however, is too low to allow for appropriate patient selection. Older age (267), severe lung function impairment (166), the presence of hypercapnia (262), and current smoking (268) seem not to be valid exclusion criteria for pulmonary rehabilitation.…”

Effects of Rehabilitation in Patients with Cardiac Disease

“…Whilst these two tests have provided useful information for patients with heart failure and chronic obstructive pulmonary disease, (Foster and Thomas 1990;Foster et al 1988;Guyatt et al 1989) the increase in heart rate obtained with both forms of walk test was only moderate with early MI patients, and the exercise prescription equivalent to 40% peak oxygen uptake was less than the resting heart rate.…”

Respiratory rehabilitation in chronic obstructive pulmonary disease: summary of a systematic overview of the literature

“…69,70 Foster et al 69 found that patients with an elevated pCO 2 at rest will tolerate exercise training and can improve their functional status to an extent that approaches the improvement reported among eucapnic patients. Furthermore, the results of a nonrandomized concurrent cohort study, 70 in which the effect of rehabilitation in patients 75 years of age or older was compared with younger patients, supported the benefits of rehabilitation among the older population.…”