Archive for the ‘Cystic Fibrosis’ Category

With a level of significance of 0.05 (type 1 error), a typical power of 0.85 (type 2 error), an inherent variability of 15 percent and a difference of 10 percent between treatments to be regarded as clinically significant—using paried t tests—the sample size required would be 23 subjects. Increasing the power to 0.95 in this case would require a sample size of 32 subjects (SigmaStat, Jan-del Scientific; San Raphael, Calif). Sample size therefore is an essential consideration in evaluating the reliability and power of statistical analysis.

Most studies evaluating CPT treatments in CF patients fail to indicate the statistical power of the study or the size of the change required to be statistically significant and most have sample sizes of less than 20. Hence, the literature becomes even more difficult to interpret in view of sample size and statistical power, particularly those studies where no significant difference was shown between modalities.
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Chest Physiotherapy and Cystic Fibrosis: Within-Subject Variability and Statistical PowerSubjects with CF vary not only from each other in terms of disease manifestations, but also they vary from day to day in their ability to reproduce pulmonary function tests. In CF subjects, the inherent variability in performing PFTs has been estimated to be as high as 15%; however, the individual’s variability has been shown to be very consistent. Cooper et al (1990) suggest that significant changes in pulmonary function data would be more accurately analyzed by incorporating predetermined variability for each individual rather than using group mean data.
Closely correlated with this variability is the need to consider the statistical power of a study, which is the probability of detecting a difference between therapies or groups, if a true difference exists. For example, a power of 70% indicates that there is a 70% chance of detecting a difference between therapies if a difference truly exists and a 30% chance of missing a difference. In addition, errors can be made with statistical analyses and investigators need to determine the level of acceptable errors or level of significance. natural inhalers for asthma

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Physical therapy is only one part of CF management. Thus, it should not be viewed in isolation from the effects of nutrition, medication such as antibiotics, and overall care. Many studies seeking to quantify the effect of CPT on CF, measure the results in terms of changes in pulmonary function, arterial blood gas values, oxygen saturation, and the volume of sputum expectorated in treatment. These measurements will reflect the general state of a CF patient. Changes in these measurements particularly in longitudinal studies cannot be attributed wholly to CPT intervention. natural inhalers for asthma

Cystic fibrosis is a chronic disease resulting in significant anatomic and mechanical distortions of the respiratory system. While measurements such as PFTs and arterial blood gas values will specifically indicate the severity of the disease process, these measurements may be unable to discriminate small and transient changes produced by CPT. More specific measurements, such as pulmonary gas mixing or respiratory muscle oxygen uptake, may be required to assess the effects of CPT.
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Chest Physiotherapy and Cystic Fibrosis: ExerciseExercise tolerance is limited in CF patients by a number of factors including obstruction of the peripheral airways leading to increased residual volume and increased physiologic dead space, hypoxemia, intolerable dyspnea, and uncontrollable coughing. However, certain factors that limit resting expiratory flow rates in children with CF are alleviated during exercise.
At rest, airway instability in expiration may result in airway collapse and resultant secretion and air trapping. Exercise results in alterations in bronchial smooth muscle tone leading to bronchodilation. Subsequent secretion clearance may improve the patency of airways and ventilation of the lungs. This may result in improved expiratory flow rates, increased secretion production, and reduced residual volume in exercise as compared with rest this

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Chest Physiotherapy and Cystic Fibrosis: Compliance With Chest Physical TherapyCompliance with daily CPT has been shown to slow pulmonary deterioration in patients with CF. A variety of studies indicate that while daily treatment might be advised, most patients do not comply. In general, CPT has the lowest compliance rate of any aspect of CF management, patient rate of compliance ranging from 26 to 47%. Davids and Heneley (1990) and Fong et al (1988) found that 52.7 and 74%, respectively, of patients performed physiotherapy only once or twice a week.
Given the poor compliance rates, the studies of CPT conducted over months or years may need to be reassessed, and in particular, those studies that compare unsupervised techniques including exercise. Reisman et al (1988) concluded from their 3-year study of FET vs conventional CPT (including PD and percussion) that conventional CPT should remain a standard component of CPT, since the FET group showed increased rates of pulmonary deterioration. The group performing conventional CPT may have been assisted or under supervision, thus leading to a greater compliance and efficacy of treatment. This factor alone may account for the superiority of this form of treatment over FET. this

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The appropriateness of CPT treatment and the selection of specific techniques provide yet another confounding variable. Studies resulting in poor performance for CPT often include conditions which would not clinically be treated. For example, the association between CPT and decreases in oxygenation has been noted by several authors. Connors et al (1980) studied the effects of percussion and PD on a group of acutely ill adults with conditions such as acute pneumonia and pulmonary edema. It was found that CPT treatment resulted in significant decreases in oxygen levels, which were particularly evident in patients with little or no sputum retention. Since that study, CPT has been shown to have no advantageous effect on the recovery from acute pneumonia or pulmonary edema. The techniques of percussion and PD are indicated for use in patients with conditions in which secretion retention is evident; therefore, it is not surprising that falls in oxygen occur in patients who do not have secretions. further

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Chest Physiotherapy and Cystic Fibrosis: Definition of TechniquesThe rationale for this support includes the inability of severely compromised patients to undertake exercise at the levels required, problems with compliance, acute exacerbation necessitating altered physical activity, and the concern that as the disease progresses, exercise may add another stress to an already stressed system. Given the beneficial effects of exercise on physiologic and psychological parameters, it would appear that in CF patients in whom the respiratory component of the disease is mild or moderate (in both “stable” and acute respiratory infections), exercise should have a place as an adjunct and in some cases as an alternative to daily CPT. Compliance with exercise programs should be monitored and assured on a regular basis. buy zyrtec online

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