Light-scattering instrument to detect thromboemboli in blood

Solen, Kenneth A.; Sukavaneshvar, Sivaprasad; Zheng, Yuanyi; Hanrahan, Brian; Hall, Matthew W.; Goodman, P.; Goodman, Benjamin T.; Mohammad, Fazal

doi:10.1117/1.1527934

Cited by 12 publications

(6 citation statements)

References 37 publications

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“…39 The LSMD directed laser light (830 nm) through the tubing wall into the flowing blood, and the resulting light-scattering signal was monitored by photodetectors 90 • from, but at the same axial position as, the light source. The detected signal was directed into a computer, where customized software "counted" the disruptions (peaks) in the scattering pattern associated with emboli passing through the LSMD.…”

Section: Experimental Modelmentioning

confidence: 99%

Computational Model of Device-Induced Thrombosis and Thromboembolism

et al. 2005

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A numerical model of thrombosis/thromboembolism (T/TE) is presented that predicts the progression of thrombus growth and thromboembolization in low-shear devices (hemodialyzers, oxygenators, etc.). Coupled convection-diffusion-reaction equations were solved to predict velocities, platelet agonist (ADP, thromboxane A2, and thrombin) concentrations, agonist-induced and shear-induced platelet activation, and platelet transport and adhesion to biomaterial surfaces and adherent platelets (hence, thrombus growth). Single-platelet and thrombus embolization were predicted from shear forces and surface adhesion strengths. Values for the platelet-biomaterial reaction constant and the platelet adhesion strength were measured in specific experiments, but all other parameter values were obtained from published sources. The model generated solutions for sequential time steps, while adjusting velocity patterns to accommodate growing surface thrombi. Heparinized human blood was perfused (0.75 ml/min) through 580 microm-ID polyethylene flow cells with flow contractions (280 microm-ID). Thrombus initiation, growth, and embolization were observed with videomicroscopy, while embolization was confirmed by light scattering, and platelet adhesion was determined by scanning electron microscopy. Numerical predictions and experimental observations were similar in indicating: 1) the same three thrombotic locations in the flow cell and the relative order of thrombus development in those locations, 2) equal thrombus growth rates on polyethylene and silicon rubber (in spite of differing overall T/TE), and 3) similar effects of flow rate (1.5 ml/min versus 0.75 ml/min) on platelet adhesion and thrombosis patterns.

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Section: Experimental Modelmentioning

confidence: 99%

Computational Model of Device-Induced Thrombosis and Thromboembolism

et al. 2005

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“…In 1994, Solen et al developed a light scattering microemboli detection (LSMD) system using light at wavelengths of 624 and 828 nm transmitted through the outflow cannula of a left ventricular assist device . Other researchers have also developed LSMD methods . These simple optical techniques using LEDs, optical fibers, and photodiodes are significantly more cost‐effective compared with ultrasound techniques .…”

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confidence: 99%

“…Other researchers have also developed LSMD methods . These simple optical techniques using LEDs, optical fibers, and photodiodes are significantly more cost‐effective compared with ultrasound techniques . However, these methods are not able to detect early‐stage thrombus formation within the pumps.…”

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confidence: 99%

Development of an Optical Detector of Thrombus Formation on the Pivot Bearing of a Rotary Blood Pump

et al. 2016

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Continuous optical monitoring of thrombus formation in extracorporeal mechanical circulatory support (EMCS) devices will contribute to safe, long-term EMCS. A clinically applicable optical detector must be able to distinguish among the optical characteristics of oxygen saturation (SaO2 ), hematocrit (Hct), and thrombus formation. In vitro studies of spectral changes at wavelengths from 400 to 900 nm associated with SaO2 , Hct, and thrombus formed around the top pivot bearing of a Gyro C1E3 pump were conducted. Fresh porcine blood anticoagulated with sodium citrate was circulated in a mock circuit using the pump. The SaO2 , Hct, and anticoagulation activity were altered using an oxygenator, autologous plasma, and calcium chlorite injection, respectively. Light from a xenon lamp was guided by an incident fiber perpendicularly fixed on the top bearing. This light was scattered by blood pooled between the male and female pivots. The detection fiber was perpendicularly fixed against the incident fiber, and the side-scattered light was detected and guided to a spectrophotometer. As a result, light at two different wavelengths, 420 and 810 nm, was identified as suitable for thrombus detection because it was negligibly influenced by SaO2 and was able to detect the optical characteristics of fibrin. The light at these two wavelengths responded more quickly to thrombus formation than the inlet or outlet pressure, and flow rate change. The optical changes showed the changes in Hct around the top pivot bearing, which is caused by the reduction in density of fibrin-trapped red blood cells (RBCs) due to the RBCs being swept away by the surrounding blood flow. The proposed method was also able to detect fibrin production by extracting subtle differences in the optical characteristics between the Hct and thrombus formation.

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“…Therefore, the light can be used to obtain information from blood and deeper tissues. Light‐scattering microemboli detectors (LSMDs), which apply a near‐infrared laser or a light‐emitting diode at wavelengths of 624 , 632 , 805 , 810 , or 830 nm, can detect microthrombi flowing in the extracorporeal circuit. However, no spectroscopic analytical method has been investigated.…”

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confidence: 99%

Feasibility of the Optical Imaging of Thrombus Formation in a Rotary Blood Pump by Near-Infrared Light

et al. 2014

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Blood coagulation is one of the primary concerns when using mechanical circulatory support devices such as blood pumps. Noninvasive detection and imaging of thrombus formation is useful not only for the development of more hemocompatible devices but also for the management of blood coagulation to avoid risk of infarction. The objective of this study is to investigate the use of near-infrared light for imaging of thrombus formation in a rotary blood pump. The optical properties of a thrombus at wavelengths ranging from 600 to 750 nm were analyzed using a hyperspectral imaging (HSI) system. A specially designed hydrodynamically levitated centrifugal blood pump with a visible bottom area was used. In vitro antithrombogenic testing was conducted five times with the pump using bovine whole blood in which the activated blood clotting time was adjusted to 200 s prior to the experiment. Two halogen lights were used for the light sources. The forward scattering through the pump and backward scattering on the pump bottom area were imaged using the HSI system. HSI showed an increase in forward scattering at wavelengths ranging from 670 to 750 nm in the location of thrombus formation. The time at which the thrombus began to form in the impeller rotating at 2780 rpm could be detected. The spectral difference between the whole blood and the thrombus was utilized to image thrombus formation. The results indicate the feasibility of dynamically detecting and imaging thrombus formation in a rotary blood pump.

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Light-scattering instrument to detect thromboemboli in blood

Cited by 12 publications

References 37 publications

Computational Model of Device-Induced Thrombosis and Thromboembolism

Computational Model of Device-Induced Thrombosis and Thromboembolism

Development of an Optical Detector of Thrombus Formation on the Pivot Bearing of a Rotary Blood Pump

Feasibility of the Optical Imaging of Thrombus Formation in a Rotary Blood Pump by Near-Infrared Light

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