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Results for “Closing Volume”

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At least 127 records · Page 7Linked to original sources
PubMed1979

Influence of expiratory flow rate on "closing volume" measurement.

The influence of expiratory flow rate (VE) on the onset of phase IV was studied in 15 normal subjects. VE was controlled voluntarily and varied between 0.2 and 2.5 l/s. All subjects showed significantly higher values for CV/VC, % at expiratory flow rate of 1.0 and 1.5 l/s, compared to those estimated at 0.2 l/s. The correlation between CV and volume of flow limitation (VFL) was also studied. For most of the subjects a considerable disagreement between the two values at very low VE was found. At higher flows, however, CV and VFL agreed well. Our results indicate that CV measurement is markedly influenced by VE in the range 0.2--1.5 l/s. This finding gives further support to the hypothesis that CV is determined in part by dynamic flow-limiting properties of the lung as well as by true airway closure.

Closing Volume↗
PubMed1981

[Comparing investigations of the valence of acetylcholine test and the closing volume for the early detection of non-specific lung diseases (author's transl)].

Investigations in 77 healthy persons and 94 patients with a manifest obstructive lung disease have led to the result that not only the central but also the peripheral part of the bronchial system are influenced by the bronchial reactivity. Accordingly the examination of the bronchial reactivity (0.01% acetylcholine solution as ultrasonic aerosol) enable in healthy persons a certain differentiation between smokers and non-smokers if the single breath test by means of the slope index are used. Therefore the method of investigation may be recommended for the early detection of functional disorders of persons with inhalatory exposure to noxious substances.

Acetylcholine↗
PubMed2005

Demonstration and operative influence of low prime volume closed pump.

Various improvements have been made in cardiopulmonary bypass (CPB) in the past few decades. We designed a new type of CPB to reduce the secretion of systemic inflammatory markers. We used a low prime volume pump (LPVP), completely closed CPB circuit and examined coagulant factors and inflammatory cytokines. In this study, we demonstrate the efficacy of LPVP using molecular biological data. Fourteen patients were randomized prospectively into two groups: Group L patients underwent LPVP (n = 8) and Group N patients underwent normal prime volume CPB (n = 6). We measured thrombin-antithrombin III complex (TAT), complement factor (C3a), and interleukin (IL)-10 levels at four time points. TAT (66.1 +/- 15.1 ng.mL(-1)), C3a (1895 +/- 282 ng.mL(-1)) and IL-10 (486 +/- 114 pg.mL(-1)) levels in Group N were significantly higher than in Group L (TAT, 19.5 +/- 4.4 ng.mL(-1); IL-10, 105 +/- 24.6 pg.mL(-1); C3a, 1349 +/- 369 ng.mL(-1)) immediately following CPB. LPVP demonstrated a lower systemic inflammatory response compared to normal prime volume CPB, as assessed using a molecular biological approach.

Aged↗
PubMedDate not supplied

Color flow Doppler mapping studies of "physiologic" pulmonary and tricuspid regurgitation: evidence for true regurgitation as opposed to a valve closing volume.

Color flow Doppler mapping using either an Aloka 880 or a Toshiba SSH65A system was performed in 39 normal subjects (aged 13 to 45 years) and 43 patients (aged 13 to 82 years) with pathologic tricuspid or pulmonary regurgitation to evaluate the incidence of "physiologic" regurgitation of right heart valves and to determine the differentiating characteristics in the spatial distribution and velocity encoding of "normal" and "pathologic" regurgitant jets. In the normal subjects, tricuspid and pulmonary regurgitation were documented in 32 (83%) and 36 (93%), respectively, and were unrelated to the system being used. Flow acceleration and aliasing were imaged on the right ventricular side of the tricuspid regurgitant orifice and on the pulmonary artery side of the pulmonary valve (in both normal subjects and patients), and indicated flow convergence for true regurgitation through an orifice as opposed to blood being driven retrogradely by the closing valve. Such proximal acceleration was documented in all patients with pathologic tricuspid regurgitation, in 31/32 of the normal subjects with tricuspid regurgitation, and was also observed in 12/15 (80%) of the patients and 4/12 (33%) of normal subjects with pulmonary regurgitation who were examined with the Toshiba system. The dimensions (mean +/- SD) of tricuspid regurgitant jets (length [JL] and area [JA]) were consistently larger in the patients than in the normal subjects [JL: 3.4 +/- 0.9 vs 1.2 +/- 0.5 cm, p less than 0.001; and JA: 5.7 +/- 2.0 vs 1.4 +/- 0.7 cm2, p less than 0.001) as were the pulmonary regurgitation jet dimensions (JL: 1.8 +/- 0.4 vs 0.9 +/- 0.08 cm, p less than 0.001; JA: 1.8 +/- 0.7 vs 0.3 +/- 0.08 cm2, p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗