| dc.description.abstract | Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive and life-limiting
condition of unknown cause with no curative treatment. The impact of IPF
on a patient’s quality of life is devastating and palliative treatment such as
pulmonary rehabilitation programmes are used to improve quality of life
among these individuals, yet relatively little attention has been made to access
the effectiveness of rehabilitation programs aimed designed for these patients.
There are large gaps in our knowledge on the cardiorespiratory response to
exercise and rehabilitation among IPF patients and this study aims to fill this
gap in a physiological prospective. We quantified the effects of an eight-week
pulmonary rehabilitation program for IPF patients, conducted at Morriston
Hospital, Swansea. Fifteen individuals (13 with Idiopathic Pulmonary Fibrosis
and two with Pulmonary Fibrosis associated with Rheumatoid Disease) underwent
physical and physiological assessments during a three-day testing protocol:
1) On Day 1, physical function (six-minute walk test) and ventilatory function
(spirometry) were measured; 2) On Day 2, patients’ cardio-respiratory responses
to slowly-increasing, wide-ranging metabolic challenge (using a protocol
consisting of periods of rest, incremental bicycle exercise to maximal
effort, and post-exercise recovery) were assessed via respiratory gas analysis
and ECG recording; 3) On Day 3, patients’ cardio-respiratory responses to
rapid-onset, high-workload metabolic challenge were assessed (using a protocol
including a rapid-onset, constant workload bicycle exercise) by modelling
dynamic respiratory oxygen and heart rate responses. Respiratory gas
analysis was used to measure the rate of oxygen uptake ( V O2 ) and oxygen
uptake efficiency (OUES). All assessments were performed before and after
participants completed the pulmonary rehabilitation programme. A Holter ECG recorder (Pathfinder/Lifecard Digital CF system; Spacelabs Medical
Ltd., UK) provided continuous ECG data throughout each exercise test,
from which heart rate was derived. Following the rehabilitation programme,
heart rate was elevated by 11% - 18% during exercise and recovery states.
Post-rehabilitation V O2 was significantly increased (p = 0.01 - 0.03) during
the first two minutes of heavy-intensity exercise, whilst HR was reduced
(p = 0.04) during this period. OUES and standard measures of respiratory
performance (minute ventilation, peak 2 V O ) were unchanged following rehabilitation,
whilst peak HR and work rates were significantly reduced during
incremental exercise only (p < 10−3). Pulmonary rehabilitation improved the
rate of oxygen uptake during heavy-intensity exercise, despite substantially
lower heart rates. This suggests that the rehabilitation programme increased
systemic arterial-tissue oxygen exchange and/or influenced cardiovascular
function to improve systemic oxygen delivery. We might therefore expect
that individuals with IPF would find it easier to perform the activities of daily
life, including those requiring substantial metabolic demands, following rehabilitation. | en_US |
