Exercise as it relates to Disease/Inspiratory muscle training in patients with cystic fibrosis

What is the background to the research?

'Inspiratory Muscle Training In Patients With Cystic Fibrosis' will be the article reviewed in this piece. Cystic fibrosis is a multi-faceted disease that affects multiple organ systems within the body which in turn affects the patients pulmonary functions, exercise capacity and nutritional status. As there was little information and research about the effects of inspiratory muscle training for patients suffering this disease, this study was carried out by five learned experts to evaluate the effects of inspiratory-threshold loading on CF patients concentrating on the strength and endurance of the inspiratory muscles, pulmonary function, exercise capacity, dyspnoea and fatigue . There were two groups to be evaluated on with eight patients in both the training group and the control group.

Where is the research from?

The research was conducted by five well recognised experts that work at the University Hospital in Groningen, Netherlands. The researchers were W De Jong and C.P Van Der Schans, specialists in the Department of Rehabilitation. J Kraan and G.H Koeter, who practise in the Department of Pulmonary Disease and finally, W.M.C Van Aalderen, from the Department of Paediatric Pulmonary . These findings from the authors are reputable and have to ability for the relevance in Australia. A few of these authors also have researched and investigated many other facets relating to health and disease and therefore highlights no bias or preconceived thoughts. However this suggests their willingness to expand further in their knowledge on other topics to enhance the understanding for the ever-changing future for CF sufferers.

What kind of research was this?

The research consisted of a clinical parallel randomised study of two groups, a training group and a control group. A statistical analysis was utilised where the values were presented as means (SD). The differences between the two groups at baseline level in recorded variables were then analysed using the t-test for unpaired samples. The data collected was used to compare pre and post-training values for each group. After the intervention, both the training and sham group individuals were analysed. This was from absolute change from baseline and then estimated with all variables involved.

What did the research involve?

Participants with CF were recruited based on their willingness to take part and ranged from the ages of 10-25yrs. The study involved the sixteen patients being assigned to 1 of 2 groups by the 5 factors that affect a patient being:

• Gender
• Age
• Force Expiratory Volume (FEV1)
• Forced Vital Capacity (FVC)
• Body Mass Index

8 patients trained at inspiratory threshold loads up to 40% of maximal static inspiratory pressure (Pimax) (training group) and the other 8 patients got ‘sham’ training at a load of 10% of Pimax (control group). The training group began their resistance at 20% of their Pimax for 1 week, increasing to 30% of Pimax in the second week and to 40% of Pimax for the last four weeks. This was conducted for 20 minutes a day for five days across a six-week period. Patients were also asked to continue their normal life-style during this period. The methods are described below :

	Equipment	Method	Results
Pulmonary Function	Inspiratory vital capacity FVC and FEV were measured using body plethysmography	Equipment was used to measure the volumes of gases in the body	Residual volume and total lung capacity were measured at baseline only
Exercise Capacity	Exercise capacity was measured during continuous ECG recording using an automatic electromagnetically bicycle	Each subject exercised continuously from the initial starting point of 0 Watts for 1 min, then increasing every minute by 10 Watts. Was terminated when exhaustion hit	HR, BF, VE, VO2 and VCO2 were recorded for 5 min at baseline and throughout the exercise test
Inspiratory Muscles - Strength	Assessed by measuring Pimax at RV with a portable Pimax Monitor	Was repeated until a pressure plateau was seen	The highest recorded pressure maintained for 1 sec was taken for analysis
Inspiratory Muscles - Endurance	Threshold-loading device was used during an incremental loading procedure	Patients started inspiring from a threshold-loading device set at 30% of Pimax for 2 min. The threshold load was then increased every 2 min in increments of 10% of Pimax	The maximal load was defined as the highest load that could be reached and maintained for at least 1 min
Inspiratory Muscles - Questionnaires	A series of questions	Patients to complete a questionnaire at baseline at the end of the day
Inspiratory Muscles -Fatigue	The MFI-20 contains 20 positive- and negative- directed statements	Patients are asked to rate their condition according to the last days	A score is calculated by summation of the scores for each question. A higher score implies more severe fatigue
Inspiratory Muscles - MRC dyspnoea	Dyspnoea scale was used to rate limitation in function due to dyspnoea	To grade dyspnoea with the MRC scale, patients were asked questions concerning their symptoms

The methodology approach was well documented however limitations existed with the sample size of the population. Due to the small sample size, the results may not be an indicator of the broader spectrum of CF patients and therefore to develop more reliable results a larger population is needed.

What were the basic results?

There had been no substantial differences between the training group and the control group before starting the training program. All but one patient in the training group who complained of earache, completed the program. After the six-week study, the mean inspiratory-muscle endurance (%Pimax), in the control group had increased from 50% to 54% in and in the training group it had been boosted significantly from 49% to 66%, which highlights how exercise training assists with inspiratory muscle endurance. The researchers interpreted that low intensity inspiratory-threshold loading at 40% of Pimax enhanced CF patients inspiratory-muscle endurance .

What conclusions can we take from this research?

This study concluded that inspiratory-threshold loading as carried out between the two groups had produced results of improvement for inspiratory-muscle endurance. However, it had little impact on the inspiratory-muscle strength, pulmonary function, exercise capacity, dyspnoea and fatigue of the CF participants. The authors mentioned another study in comparison with theirs as it related to “the effects of inspiratory muscle training in patients with Cystic Fibrosis” in 1982. This study was conducted under higher Pimax values which enabled a greater improvement of inspiratory muscle strength as compared to the recent study. Based on the results of this comprehensive study, the authors have concluded that further study is required to include a larger number of CF patients to determine the specific and transfer effects of inspiratory-muscle training for CF patients.

Practical advice

This study has produced relative data however is only applicable to people aged 10–25yrs. This provides a valuable starting point, although further high-quality studies with greater sample sizes and longer follow up should be conducted. This would result in further data and specific recommendations being obtained that could be used for evaluating the effects of inspiratory-threshold loading on CF patients that could increase and improve their strength and endurance for the many physiological functions that they suffer from.

Further information/resources

Cystic Fibrosis Federation Australia

The Effects of Inspiratory Muscle Training In Patients With Cystic Fibrosis Paper 1982

Inspiratory Muscle Training In Patients With Cystic Fibrosis - Paper Reviewed 2001