Symptoms, lactate and exercise limitation at peak cycle ergometry in adults with cystic fibrosis

The purpose of this study was to investigate symptoms, lactate accumulation and limiting factors at peak exercise in cystic fibrosis (CF) patients. In total, 104 CF adults attending an adult CF centre and 27 controls performed progressive cycle ergometry to a symptom-limited maximum. Measurements taken at peak exercise included: heart rate, ventilation, oxygen uptake, carbon dioxide output, oxygen saturation and blood lactate. Symptom scores of perceived breathlessness and muscle effort were recorded using Borg scales. The CF subjects had a lower mean body mass index, forced expiratory volume in one second (FEV(1)) and peak oxygen uptake than controls. Peak lactate concentrations were very similar to controls (mean+/-sd 6.8+/-2.0 mmol x L(-1) versus 7.4+/-1.0 mmol x L(-1)). Symptom scores were no different to controls for either breathlessness (4.5+/-2.0 versus 4.3+/-1.0) or perceived muscle effort (6.1+/-2.0 versus 6.5+/-1.0), with higher scores for muscle effort than breathlessness in both groups. In addition, peak ventilation was lower than the predicted maximum, and high peak heart rates were recorded supporting nonpulmonary factors as important in limiting peak exercise. Peak oxygen uptake was correlated with FEV(1). Comparison of CF subjects with mild or moderate pulmonary disease and controls revealed similar exercise responses. In contrast, those CF patients with severe lung disease (FEV(1) <40% predicted) had significantly higher breathlessness, lower muscle effort scores, lower peak lactate, lower peak heart rate and a mean ventilation exceeding predicted, thus confirming that ventilation was the major factor limiting exercise. In conclusion, cystic fibrosis subjects have a reduced peak exercise capacity, but their exercise response is similar to controls in generating high blood-lactate concentrations and symptoms of muscle effort in excess of dyspnoea. Nonpulmonary factors influence peak performance more in those without severe disease.

Individualised unsupervised exercise training in adults with cystic fibrosis: a 1 year randomised controlled trial

BACKGROUND

Short term studies of exercise training have shown benefits in cystic fibrosis. Transferring exercise programmes to the community and sustaining them long term is a challenge for the patient. The effectiveness of an individualised unsupervised home based exercise programme was examined in adults with cystic fibrosis over a 1 year period.

METHODS

Subjects were randomised to undertake three sessions per week of upper and lower body exercise based on individualised preferences (n = 30) or to a control group (n = 18). They were evaluated at baseline and at 12 months. The primary outcome measure was improved fitness as assessed by change in blood lactate concentration at the end of an identical constant work rate for both arm and leg ergometric testing. Secondary outcome measurements were heart rate and pulmonary function.

RESULTS

For leg exercise, significant differences were seen at 12 months between the active and control groups in the mean (SE) change in blood lactate levels (-0.38 (0.23) mmol/l v 0.45 (0.25) mmol/l, p<0.05) and heart rate (-4.8 (2.5) bpm v 3.4 (2.5) bpm, p<0.05), confirming a training effect. For arm ergometry there was no change in lactate levels at 12 months but there was a significant difference in forced vital capacity (46 (72) ml v -167 (68) ml, p<0.05).

CONCLUSIONS

A training effect, as measured by a reduction in lactate levels and heart rate, can be achieved with unsupervised individualised home exercise in adults with cystic fibrosis. A benefit to pulmonary function was observed and together these findings suggest that exercise programmes should be encouraged as an important component of care in cystic fibrosis.

Acute anaphylaxis following midline catheterisation in a patient with cystic fibrosis

A 16 year old male with cystic fibrosis experienced an acute life threatening anaphylactic reaction following the insertion of an Ohmeda Hydrocath(TM) midline peripheral venous catheter. The catheter was immediately withdrawn and treatment with intravenous adrenaline, hydrocortisone, chlorpheniramine, and colloid over a 24 hour period resulted in a gradual resolution of symptoms.

Exercise limitations and training for patients with cystic fibrosis

Exercise has much to offer to cystic fibrosis patients. Overcoming the limits of decreased pulmonary function by increasing fitness has a considerable potential to improve patients' quality of life; decreased breathlessness allows greater mobility and participation with peers in social and sporting activities, improves confidence and self-esteem and creates a greater pleasure in life for the individual patient. There are also immediate therapeutic gains and potentially long-term gains with improved survival. Above all, cystic fibrosis patients enjoy and prefer exercise as a therapeutic option to most other forms of therapy.

Effect of tonicity of nebulised colistin on chest tightness and pulmonary function in adults with cystic fibrosis

BACKGROUND

Inhalation of hypertonic nebulised colistin causes chest tightness and is a reason for discontinuing the treatment. This study examines the relationship of chest tightness and change in lung function in response to the inhalation of a range of tonicities of nebulised colistin and their influence on patients' preference.

METHODS

Twenty seven adult patients with cystic fibrosis and a mean forced expiratory volume in one second (FEV1) of 54% predicted (range 24-98) were studied. They inhaled a nebulised solution of hypertonic, isotonic, and hypotonic colistin over three consecutive days in random order in a double blind fashion. Measurements of chest tightness, using a visual analogue scale (VAS), and FEV1 were recorded before and 0, 15, 30, 60, and 90 minutes following inhalation. The solution preferred by each patient was determined at the end of the three days.

RESULTS

All tonicities caused a significant fall in FEV1 % predicted and an increase in chest tightness, with no differences between the solutions. However, the mean (SE) time to the maximum fall in FEV1 % predicted was significantly different between the solutions (hypertonic 7.8 (2.1) min, isotonic 19.2 (5.5) min, and hypotonic 34.2 (5.9) min) with a mean difference (95% CI) between hypotonic and hypertonic solutions of 28.04 (14.6 to 41.5) min, between isotonic and hypertonic solutions of 12.0 (-0.1 to 24.1) min, and between hypotonic and isotonic solutions of 15.6 (1.8 to 29.4) min. Positive correlations existed for the maximum fall in FEV1 % predicted between the hypertonic and isotonic solutions (r = 0.62, p < 0.001) and between the hypotonic and isotonic solutions (r = 0.64, p < 0.001). There was no correlation between the objective and subjective measurements for any solution. The patients' preference varied.

CONCLUSIONS

All tonicities of colistin caused equal symptoms of chest tightness and reduction in pulmonary function. It is recommended that the patient is challenged with nebulised colistin before prescription of the drug and that the challenge is preceded by an inhaled bronchodilator. Most of the patients preferred the isotonic or hypotonic solutions. The isotonic solution reflects a fall in FEV1 representative of all the solutions. The fall in FEV1 to the hypotonic solution occurred over a longer period and may be better tolerated by some patients.

Exercise testing and prognosis in adult cystic fibrosis

BACKGROUND

The assessment of prognosis is an important issue in cystic fibrosis. The prognostic value of exercise testing in comparison with other predictors of mortality was examined.

METHODS

Ninety two adult patients with cystic fibrosis performed progressive maximal exercise tests and outcome was assessed at five years. The results of exercise testing were examined along with spirometric values, age, sex, body mass index (BMI), and sputum culture.

RESULTS

Twenty two subjects died during the five year follow up period and 67 survived. Five subjects received a lung transplant and were excluded from the analysis. There were significant differences between those who survived and those who died: mean (SE) forced expiratory volume in one second (FEV1) 68.9 (2.7) versus 39.7 (3.5)% predicted, BMI 19.0 (0.3) versus 17.1 (0.4) kg/m2, peak oxygen uptake (VO2 peak) 66.6 (2.2) versus (53.7) (3.7)% predicted, peak work rate (Wpeak) 89.4 (3.8) versus 71.2 (5.5)% predicted, peak minute ventilation (VEpeak) 51.3 (2.0) versus 43.3 (3.1) 1/min, and ventilatory equivalent for oxygen (VE/VO2) 32.4 (0.6) versus 38.7 (1.7). Age, sex, oxygen saturation and Burkholderia cepacia colonisation were not found to be significant predictors of mortality. When significant independent factors were entered into a multivariate logistic regression model only FEV1 was found to be a significant correlate of mortality. A cutoff for FEV1 of 55% predicted gave the best combination of specificity and sensitivity with 54% of those below this value dying within five years and 96% of those above it surviving.

CONCLUSIONS

The results of maximal exercise testing are correlated with survival but they are not better than the FEV1 as prognostic indicators.

Long-term change in exercise capacity, body mass, and pulmonary function in adults with cystic fibrosis

STUDY OBJECTIVES

Cross-sectional studies in patients with cystic fibrosis (CF) have shown that exercise capacity is correlated with pulmonary function and body mass. We have examined whether the same relationships are seen longitudinally in adults with CF.

DESIGN

Subjects who first performed progressive maximal cycle ergometry between 1986 and 1989 were retested using an identical protocol a mean of 6.3 years later.

PARTICIPANTS AND SETTING

Adults with CF attending a regional center.

MEASUREMENTS AND RESULTS

The principal exercise measures were peak oxygen uptake (VO2peak), ventilation (VEpeak), oxygen saturation, and heart rate. Spirometry, weight, and height were also recorded at each time point. At baseline, subjects had a mean age of 19.8 years, body mass index (BMI) of 19.0, FEV1 of 69% predicted, VO2peak of 1.56 L/min, and VEpeak of 48.9 L/min. At repeated testing after a mean interval of 6.3 years, the FEV1 had fallen significantly to 54% predicted (p < 0.001) and the BMI had risen significantly to a mean of 20.9 (p < 0.001). There were no significant differences in VO2peak or VEpeak, although VEpeak was a significantly higher proportion (72% vs 61%) of predicted maximal voluntary ventilation.

CONCLUSIONS

Adults with mild to moderate pulmonary dysfunction were able to increase body mass and maintain VO2peak despite a declining FEV1. VO2peak was not reduced by the decrease in FEV1 because VEpeak was unaffected. Improved nutrition may have contributed to maintaining fitness.