Noninvasive measurement of total hemoglobin and hemoglobin derivatives using multiwavelength pulse spectrophotometry -In vitro study with a mock circulatory system

2006 ◽  
Author(s):  
Hironori Suzaki ◽  
Naoki Kobayashi ◽  
Takashi Nagaoka ◽  
Kiyotaka Iwasaki ◽  
Mitsuo Umezu ◽  
...  
Keyword(s):  
Circulatory System ◽  
In Vitro Study ◽  
Vitro Study ◽  
Noninvasive Measurement ◽  
Mock Circulatory System ◽  
Total Hemoglobin ◽  
Hemoglobin Derivatives

In Vitro Study of Flow Regulation for Pulmonary Insufficiency Using Diode Valves

2007 ◽  
Author(s):  
Tiffany A. Camp ◽  
Stephanie Hequembourg ◽  
Richard S. Figliola ◽  
Tim McQuinn
Keyword(s):  
Pulmonary Valve ◽  
Pulmonary Regurgitation ◽  
Circulatory System ◽  
In Vitro Study ◽  
Pulmonary Insufficiency ◽  
Pressure Gradients ◽  
Right Heart ◽  
Mock Circulatory System ◽  
The Right

The operating pressures in the right heart are significantly lower than those of the left heart and with marked differences in the circulation impedances. The pulmonary circulation shows a tolerance for mild regurgitation and pressure gradient [1]. Pulmonary regurgitation fractions on the order of 20% and transvalvular pressure gradients of less than 25mm Hg are considered mild [4]. Given this tolerance, we examine the concept of using a motionless valve to regulate flow in the pulmonary position. In a previous study, the use of fluid diodes was shown to be a promising concept for use as a pulmonary valve [2]. In this study, we test two different diode designs. For each diode valve, flow performance was documented as a function of pulmonary vascular resistance (PVR) and compliance. Tests were done using a pulmonary mock circulatory system [3] over the normal adult range of PVR and compliance settings.

scholarly journals The Influence of Aortic Wall Elasticity on the False Lumen in Aortic Dissection: An In Vitro Study

2020 ◽  
Vol 54 (7) ◽  
pp. 592-597
Author(s):  
Hugo T. C. Veger ◽  
Erik H. Pasveer ◽  
Jos J. M. Westenberg ◽  
Jan J. Wever ◽  
Randolph G. Statius van Eps
Keyword(s):  
Aortic Dissection ◽  
Aortic Wall ◽  
Ex Vivo ◽  
False Lumen ◽  
Circulatory System ◽  
In Vitro Study ◽  
Vitro Study ◽  
Major Influence ◽  
Distal Location

Background: Hemodynamics, dissection morphology, and aortic wall elasticity have a major influence on the pressure in the false lumen. In contrast to aortic wall elasticity, the influence of hemodynamics and dissection morphology have been investigated often in multiple in vitro and ex vivo studies. The purpose of this study was to evaluate the influence of aortic wall elasticity on the diameter and pressure of the false lumen in aortic dissection. Methods: An artificial dissection was created in 3 ex vivo porcine aortas. The aorta models were consecutively positioned in a validated in vitro circulatory system with physiological pulsatile flow. Each model was imaged with ultrasound on 4 positions along the aorta and the dissection. At these 4 locations, pressure measurement was also performed in the true and false lumen with an arterial catheter. After baseline experiments, the aortic wall elasticity was adjusted with silicon and the experiments were repeated. Results: The aortic wall elasticity was decreased in all 3 models after siliconizing. In all 3 siliconized models, the diameters of the true and false lumen increased at proximal, mid, and distal location, while the mean arterial pressure did not significantly change. Conclusions: In this in vitro study, we showed that aortic wall elasticity is an important parameter altering the false lumen. An aortic wall with reduced elasticity results in an increased false lumen diameter in the mid and distal part of the false lumen. These results can only be transferred to corresponding clinical situations to a limited extent.

scholarly journals In Vitro Study of Flow Regulation for Pulmonary Insufficiency

2006 ◽  
Vol 129 (2) ◽  
pp. 284-288 ◽  
Author(s):  
T. A. Camp ◽  
K. C. Stewart ◽  
R. S. Figliola ◽  
T. McQuinn
Keyword(s):  
Pulmonary Circulation ◽  
Circulatory System ◽  
In Vitro Study ◽  
Mechanical Valve ◽  
Pulmonary Insufficiency ◽  
Regurgitant Fraction ◽  
Mock Circulatory System ◽  
Mechanical Valves ◽  
The Right

Given the tolerance of the right heart circulation to mild regurgitation and gradient, we study the potential of using motionless devices to regulate the pulmonary circulation. In addition, we document the flow performance of two mechanical valves. A motionless diode, a nozzle, a mechanical bileaflet valve, and a tilting disk valve were tested in a pulmonary mock circulatory system over the normal human range of pulmonary vascular resistance (PVR). For the mechanical valves, regurgitant fractions (RFs) and transvalvular pressure gradients were found to be weak functions of PVR. On the low end of normal PVR, the bileaflet and tilting disk valves fluttered and would not fully close. Despite this anomaly, the regurgitant fraction of either valve did not change significantly. The values for RF and transvalvular gradient measured varied from 4 to 7% and 4to7mmHg, respectively, at 5lpm for all tests. The diode valve was able to regulate flow with mild regurgitant fraction and trivial gradient but with values higher than either mechanical valve tested. Regurgitant fraction ranged from 2 to 17% in tests extending from PVR values of 1to4.5mmHg∕lpm at 5lpm and with concomitant increases in gradient up to 17mmHg. The regurgitant fraction for the nozzle increased from 2 to 23% over the range of PVR with gradients increasing to 18mmHg. The significant findings were: (1) the mechanical valves controlled regurgitation at normal physiological cardiac output and PVR even though they failed to close at some normal values of PVR and showed leaflet flutter; and (2) it may be possible to regulate the pulmonary circulation to tolerable levels using a motionless pulmonary valve device.

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