ARMI News - Part 4

Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties: Testing Protocol

Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties: Testing ProtocolPulmonary and systemic arterial pressures and the right atrial pressure (RAP) were continuously recorded, and the pulmonary artery occlusion pressure (PAOP) was recorded intermittently. The cardiac output (CO) was assessed by thermodilution (Cardiac Output Computer; Baxter/Edwards). The cardiac index (CI) was calculated as CO divided by the body surface area. PVR and systemic vascular resistance (SVR) were calculated according to the following standard formulas: PVR = (MPAP — PAOP) X 80/ CO); and SVR = (MAP — RAP) X 80/CO). The PP was calculated as the difference between systolic and diastolic pressure, and the fractional PP was calculated by dividing PP by MPAP. Arterial and mixed-venous blood samples were drawn simultaneously and were analyzed for arterial oxygen saturation (Sao2) with a blood gas analyzer (model 865; Chiron; Emeryville, CA) that was automatically calibrated every hour. buy glucophage
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Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties: Patient Population

Thirty-five patients with PAH and 22 patients with CTEPH were included in the study after obtaining written informed consent. The study was approved by the local ethics committee. PAH was diagnosed as idiopathic (n = 25) if the evaluation performed before catheterization did not reveal any other causes of elevated pulmonary pressure and was associated with other conditions such as congenital heart disease (n = 6), connective tissue disease (n = 2), and HIV (n = 2) that were diagnosed by medical history, echocardiography, antibody screening, rheuma-tologic examination, blood analyses, and additional tests if required according to best clinical practice (eg, pulmonary function tests, blood gas assessment, thoracic CT scan, and coronary angiography). CTEPH was diagnosed if both the radioisotope ventilation-perfusion scan showed more than two areas with perfusion defects and pulmonary angiography showed clear evidence of chronic major-vessel thromboembolic disease with disruption or changes in vessel caliber, arterial wall irregularities, transversal bands tethering the arterial lumen, and/or the absence of segmental or lobar arterial branches.

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Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties

Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity PropertiesStructural and functional changes in the vascular wall and thrombus formation are the main factors responsible for increased pulmonary vascular resistance (PVR) in patients with pulmonary hypertension (PH). The contribution of each of these factors is thought to be different among the variables underlying the causes of PH, thereby accounting for the varying responses to treatment with vasodilata-tive and antiproliferative agents in patients with PH of different etiology. Accordingly, pulmonary vasodilator agents have been used primarily for the treatment of patients with pulmonary arterial hypertension (PAH) and to a lesser extent in those patients with chronic thromboembolic PH (CTEPH) because of the notion that the fibrous organization of thrombotic material in the proximal vessel wall would block the vasodilator effect.

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Technical and Functional Assessment of 10 Office Spirometers: Comment

Technical and Functional Assessment of 10 Office Spirometers: CommentAt variance with standard spirometers, the majority of the office spirometers were not calibrated during the study (Table 1). This may seen somewhat surprising in a laboratory study, but we wanted to respect the instructions of the vendors/manufacturers also in terms of calibration. We must keep in mind that these devices are devoted for the use by GPs and not for laboratory purposes.
The limits of precision of the office spirometers reported in this study refer to short-term repeatability. In real circumstances, the repeatability may decrease after several months if the users do not check regularly the spirometers, especially with screen-type pneumotachographs that commonly become clogged with secretions. buy glucophage online
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Technical and Functional Assessment of 10 Office Spirometers: Recommendation

We did not compare the quality and the cost of the mouthpieces, nor the facility of disinfecting the parts in contact with the exhaled air. We do not have any information on the long-term solidity of the devices, nor on their resistance to shocks during transportation, and to changes in humidity and temperature. We did not make any price/quality assessment. Last but not least, we have no feedback about the aftersales service of the different spirometer representatives. This could be of major importance in real-world circumstances.
Other limitations of the study should also be considered. Of course, all the office spirometers available on the market could not be tested during this study. However, we included office spirometers coming from Europe and the United States, showing different technical characteristics, and our sample was sufficiently diversified. It is noticeable that some of these devices (both hardware and software) are frequently upgraded or changed, so that the same brands sold now may differ from the devices tested. The devices tested were those available in Belgium in 2002. comments
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Technical and Functional Assessment of 10 Office Spirometers: Conclusion

Technical and Functional Assessment of 10 Office Spirometers: ConclusionWe devised a new questionnaire about the user friendliness of office spirometers. The results of this small and informative survey suggest large similarities among the majority of the spirometers. Almost all of them have an interface with a personal computer, can be connected to a printer, and have correct help functions. An important issue is the automated quality assessment. Most of the devices check the reproducibility and the acceptability of the spirometric maneuvers. Many spirometers display immediately messages about the quality of the “blow.” The software offers mostly a large choice of reference tables and provides an automated interpretation. According to some authors,” this feature is not without danger of misinterpretation for uninformed users. Large differences were encountered for the facility to use during home visits. Some devices are readily excluded by their large size. Some spirometers display a flow-volume curve on a small screen on the device itself. The need for calibration of the spirometers is a controversial aspect. read more

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Technical and Functional Assessment of 10 Office Spirometers: Discussion

The tests done with the computer-controlled mechanical syringe indicate that the spirometers working under ideal laboratory conditions, at least at ambient conditions, are reliable, but they do not guarantee that the same performances will be obtained in real-life conditions, as patients are tested throughout the day, as it was the case in our study. Therefore, we and other groups propose that the spirometers should be tested both with waveform generators (on a bench) and with real patients.
The precision of FEV1 measured by the office spirometers was comparable to that of the standard spirometers. Only one device showed unacceptable limits of precision (> 200 mL) for FEV1 (± 0.295 L for the Simplicity).
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Technical and Functional Assessment of 10 Office Spirometers: Research

Technical and Functional Assessment of 10 Office Spirometers: ResearchThe use of the 24 ATS standard waveforms for FVC and FEV1 is recommended, but the recent ATS/ERS statement does not require that these tests must be performed by an independent laboratory, such as the laboratory at LDS Hospital for example. We requested the results of these tests from the manufacturers of the office spirometers. Datospir models 70 and 120, Simplicity, OneFlow, Pneumotrac, and SpiroStar (Medikro; Kuopio, Finland) devices were tested by their manufacturers using 24 ATS standard waveforms, and the other devices were tested at LDS Hospital. All the spirometers tested at LDS Hospital using the 24 standard ATS waveforms had fewer than three accuracy errors and repeatability errors for FVC or FEVj at ambient testing conditions. http://www.naturalbreastenhancementpill.com/

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Technical and Functional Assessment of 10 Office Spirometers: User-Friendliness Assessment

Some office spirometers showed an apparent good agreement with the standard spirometers (low bias), but the visual inspection of the Bland and Altman plot revealed a proportional difference. In other words, there was a significant relationship between the mean difference and the average values, as indicated in Table 3 by a statistically significant coefficient of correlation. In the example of Figure 2, FEV1 was underestimated for small values and overestimated for larger values. As shown in Tables 3 and 4, a proportional difference was observed in one device for FVC, in four devices for FEV1, and in two devices for FEV1/FVC. fully
The pooled results of this survey are shown in the on-line supplementary material. The overall user friendliness of the tested devices was judged to be good. The information provided by the spirometers was in general very complete. The clusters of questions with strongly favorable answers were those about the general properties of the software, the completeness of the displayed information, and the automated tests of quality assurance. We noted intermediate positive answers for the following clusters: patient administrative data facilities, comparison of successive spirometrics and facilities for use at home visits. Rather unfavorable scores were given to the functions for export of data.
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Technical and Functional Assessment of 10 Office Spirometers: Results

Technical and Functional Assessment of 10 Office Spirometers: ResultsA total of 399 different subjects (age range, 25 to 87 years; mean ± SD, 61.2 ± 14.6 years; 128 women) were studied in the three centers. The distribution of the 300 COPD patients according to the GOLD classification was as follows: stage 1, 10.3%; stage 2, 20.4%; stage 3, 59.0%; and stage 4, 6.3%. The nine ETs (three women) all had normal spirometric data (FVC, 4.68 ± 1.04 L; FEV1, 3.80 ± 0.90 L). paxil 40 mg
Table 2 presents the precision of the standard diagnostic spirometers and each model of office spirometer. The precision was measured in ETs from the three centers (n = 9). The precision of FEV1 was comparable between the standard and office spirometers, except for one device (Simplicity; Puritan Bennett; Pleasanton, CA), in which the limits of precision were > 200 mL. Three models—OneFlow (Clement Clarke International; Harlow, Essex, UK), EasyOne (NDD; Zurich, Switzerland), and Simplicity—showed precision limits > 200 mL for FVC.
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