The MSBC was adapted from the four-minute test described by Freedman (1970). It was determined by asking the patients to breathe humidified air as rapidly and as deeply as possible for three minutes via a low resistance two-way valve and minute ventilation was recorded. Eucapnea was maintained by adding carbon dioxide to the inspired gas at a rate adjusted to maintain the end-tidal level at 5 percent. The patient was informed of the passing of each 30-second interval but was given no other encouragement. Read the rest of this entry »
The valve characteristics were studied by connecting it to an electric blower and measuring flow at the air intake by means of a pneumotachograph, pressure at the mouthpiece, and plunger mass on electronic scales.
For any given mass there is a threshold opening pressure. At pressures less negative than threshold, the valve is completely closed (this occurs at flows less than 0.05 L/s). Once the inspiratory pressure reaches threshold, the valve opens and thereafter pressure changes by less than 1 cm HtO/L/s for flows up to 3.0 L/s. http://antimicrobialmed.com/
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Patients with CAO attending the Department of Thoracic Medicine were invited to take part in an inspiratory muscle training program if they fulfilled the following criteria:
1. Poor exercise tolerance that had led to curtailment of usual activities.
2. The ratio of FEV, to VC was less than 40 percent, and the FEV, was less than 50 percent of predicted normal.
3. The baseline FEV, altered by less than 0.2 L after the administration of200 pig of aerosol salbutamol.
4. The CAO was demonstrated to be stable as shown by clinical assessment, FEV/VC measurement and blood gas analysis on at least two occasions four weeks apart. Read the rest of this entry »
In recent years, a number of studies have examined the role of IMT in patients with CAO. Some of these studies have suggested that IMT has a beneficial effect on exercise tolerance, whereas other studies have failed to demonstrate such an effect. One factor influencing the outcome of these various studies has been identified by Belman et al, who showed that patients can be coached to minimize the work of breathing through resistive orifices by reducing inspiratory flow and frequency. Read the rest of this entry »
In: COPD17 Oct 2014
However, similar changes in skeletal muscle have been found with aging, disuse and malnutrition and may not be peculiar to patients with COPD. Whatever, the determinants of RM endurance are more complex than the determinants of RM strength.
For the respiratory muscles, four factors could reduce the endurance time: low basal energy stores, low rate of energy supply, reduced efficiency, and an increased external power of breathing.
The diaphragm and intercostal muscle of COPD patients have reduced energy stores, which possibly could lead to a reduction of RM endurance. Measurement of energy stores would require muscle biopsies which we did not do in this study. Read the rest of this entry »
In: COPD16 Oct 2014
In the endurance test of Nickerson and Keens, mean SIP/MIP percent was 68 ±3 percent. Our normal elderly subjects had a Ppk/MIP of 79 ±19 percent which was similar to the SIP max/MIP of 77 ± 6 percent found in normal younger subjects by Martyn et al. This suggests that learning occurs during the first 2-min incremental test with no significant change in results on repeated visits. In our patients with COPD, mean Ppk/MIP was 48 ± 16 percent (61 percent of the mean Ppk/MIP of the normal elderly group). read more
However, Belman and Mittman found MSVC/MW in ten COPD patients prior to training to be 79 ± 22 percent. This is very similar to the value noted before for normal subjects by Leith and Bradley. Read the rest of this entry »
In: COPD15 Oct 2014
The MIP increased on subsequent visits in the normal elderly subjects, primarily from visit 1 to visit 2. Since the tests were spaced one week apart and only took 30 min to complete, there should not have been a training effect. Therefore, the increase in MIP suggests a learning effect. This was seen only in the normal subjects who had no experience with any lung function testing. Although the COPD group had not undergone RM endurance testing previously, they were familiar with other pulmonary function tests. Nickerson and Keens found a 10 percent increase in MIP when 12 normal younger subjects were retested after two weeks. A third test on four subjects did not show further improvement. Read the rest of this entry »
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