News about Health (Part 8)

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects: Results

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects: ResultsThe absolute threshold for breathlessness was taken as the X variables accompanying the first time the black bar on the screen matched or surpassed the No. 0.5 (“just noticeable”) on the Borg scale. Starting with values beyond the absolute threshold, we computed a series of “change” thresholds considered as justnoticeable differences (JNDs) in breathlessness with the continuous method. A change in breathlessness was indicated whenever the bar was moved to a higher position on the scale and was stationary for at least 1 s. The scale value present after such change was treated as a single rating obtained by the continuous method. This definition of a rating was more conservative than the one used in our previous study, and resulted in a much smaller number of total ratings over the duration of exercise. An Ekman fraction was calculated as the ratio of the breathlessness JND on the Borg scale to the previous breathlessness rating. When multiplied by 100, this measure indicates the percentage of change in breathlessness associated with each physiologic or work JND starting from the absolute threshold to the rating just prior to peak breathlessness. http://cfm-online-shop.com/

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects: Breathlessness

The subjects were told that they could use the entire scale including values between integers.
For the continuous method, the subject adjusted the vertical length of a black bar (0.7 cm wide) on the screen by changing the location of the mouse (in a direction toward or away from the body) to express the perceived level of breathlessness. No verbal cues were given as to when ratings were to be made. The subjects read the following written instructions before performing the exercise test:
This is a scale for rating breathlessness. The No. 0 represents no breathlessness. The No. 10 represents the strongest or greatest breathlessness that you have ever experienced. You should adjust the length of the solid black bar to represent your perceived level of breathlessness by moving the position of the mouse. Use the written descriptions to the right of the numbers to help guide your selection. You should adjust the length of the bar (up or down) at any time during the exercise when you experience a change in your breathlessness. review

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects:

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects: Cardiopulmonary exercise testing was conducted while the subject was seated on the electronically braked cycle ergometer (Ergo-Metrics 800S; SensorMedics; Yorba Linda, CA) and breathing ambient air through a mouthpiece. Expired gas was analyzed for Ve and Vo2 with every breath, using a metabolic measurement system (Medgraphics Cardiorespiratory Diagnostic Systems; St. Paul, MN). After a 1-min equilibration period, the subject pedaled at a speed of 50 revolutions per minute at zero resistance for 1 min. Then the resistance of the cycle ergometer was electronically increased in 15 W/min increments using a ramp protocol until the subject stopped because of symptom limitation.

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects: Materials and Methods

Our specific hypotheses were as follows: (1) the continuous method provides high test-retest reliability that is at least comparable to the discrete method, (2) the slopes of the linear regressions for power production, oxygen consumption (Vo2), and minute ventilation (Ve) as independent variables and breathlessness as the dependent variable are higher in patients with COPD than in healthy subjects, and (3) the x-intercepts and absolute thresholds are lower for patients with COPD compared with healthy subjects.

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal Subjects

Comparison of Continuous and Discrete Measurements of Dyspnea During Exercise in Patients With COPD and Normal SubjectsExercise testing provides a direct approach to examine an individual’s perception of breathlessness based on the principles of psychophysics. The traditional approach has been to ask the patient at specific time intervals (eg, each minute of an incremental or ramp exercise test) to select a rating on the Borg scale or on a visual analog scale that matches severity of breathlessness. However, there are at least two major limitations of this methodology. First, if the patient can only exercise for 3 to 4 min because of severe respiratory disease, only a few ratings of dyspnea are obtained. Second, the subject is asked “on cue” each minute to provide a rating. Although this discrete method for measuring breathlessness is convenient from the physician’s perspective, it is completely arbitrary for the patient because the experience of breathlessness can change continuously during the exercise test. Due to these limitations, valuable information may be lost about the progressive nature of dyspnea throughout exercise. this

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: Conclusion

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: ConclusionOur study suggests that in some individuals with PLCH, extensive RB/ DIP-like changes may be the lesion responsible for the majority of physiologic and clinical abnormalities, rather than the lesions of PLCH. Irrespective of how one defines the final pathologic lesion, it is clear that the entire spectrum of smoking-related interstitial lung injury may be sometimes seen in the same patient, albeit to different degrees (Fig 3).
Several studies have illustrated the utility of HRCT in the diagnostic workup of PLCH. This study and others illustrate the overlap between different radiologic patterns of smoking-induced interstitial patterns of injury, and the need for caution in establishing a diagnosis of these diseases without lung biopsy. We report the occurrence of ground-glass attenuation on HRCT, which may be indicative of significant associated RB/DIP. The only other study describing the presence of ground-glass attenuation in patients with PLCH is the one by Brauner et al, who reported the occurrence of ground-glass attenuation in 4 of 18 patients with PLCH. Reading here

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: PLCH biopsy specimens

Whereas RB is an extremely common lesion that refers to the universal inflammatory reaction found in the respiratory bronchioles of cigarette smokers, RB-ILD is an uncommon ILD that occurs in a small proportion of smokers. In analogy to DIP, the diagnosis of RB-ILD can only be made following careful exclusion of other histologic entities that may explain the presence of ILD.
What then is the clinical significance of determining RB/DIP-like changes on PLCH biopsy specimens? website

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: Discussion

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: DiscussionNo correlation was found between the degree of RB/DIP-like changes and pulmonary function parameters, including TLC (r = — 0.22, p = 0.45), Dlco (r = — 0.42, p = 0.13), or FEV1 (r = 0.11, p = 0.71). Although both index patients had restrictive impairment on lung function testing, the extent of RB/DIP-like changes on biopsy did not correlate with the presence or absence of restrictive physiology in the whole group (Table 1).

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: Radiographic

Cystic change was identified as the sole HRCT abnormality in three cases. Ground-glass attenuation was detected on HRCT in three patients (Table 2). Emphysema was detected in two cases on HRCT (14%). Mild sub-carinal and pretracheal adenopathy (1 to 2 cm) was detected on the CT in three cases (21%).
Radiographic, Histologic, and Functional Correlates of RB/DIP in PLCH in the Study Population
All biopsy specimens showed diagnostic lesions of PLCH. Histopathologic evidence of RB/DIP-like changes were identified in all biopsy specimens (Table 1), with the extent of involvement ranging from 10 to 80% of the biopsy specimen.

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: Clinical and Radiographic Characteristics

The Overlap Between Respiratory Bronchiolitis and Desquamative Interstitial Pneumonia: Clinical and Radiographic CharacteristicsThe second patient (patient 2 in Tables 1, 2) was a 48-year-old white man with a 30-pack-year smoking history referred for evaluation of progressive dyspnea. Although claiming to have quit smoking several months prior to evaluation, arterial blood gas analysis revealed a carbon monoxide concentration of 2%. The pulmonary examination revealed scattered bilateral basal crackles, and pulmonary function testing revealed a restrictive process with a plethysmographically measured TLC of 70% predicted and a Dlco of 55% predicted. HRCT of the chest demonstrated patchy areas of ground-glass attenuation in both lungs, believed to be most consistent with a diagnosis of hypersensitivity pneumonitis or RB-ILD. Link

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