Doppler Red Blood Cell Backscatter Monitoring for Real-time Assessment of Adequacy of Anticoagulation in an Extracorporeal Circuit: In-Vitro Study
Presented During:
Friday, September 20, 2024: 5:00PM - 6:30PM
Omni King Edward Hotel
Abstract No:
10111
Submission Type:
Abstract Submission
Authors:
Syed Peer (1), Teri Ulferts (2), Satoshi Miyairi (1), Pranava Sinha (1)
Institutions:
(1) University of Minnesota, Masonic Children's Hospital, Minneapolis, MN, (2) Experimental Surgical Services, University of Minnesota, Minneapolis, MN
Submitting Author:
Syed Peer
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University of Minnesota, Masonic Children's Hospital
University of Minnesota, Masonic Children's Hospital
Co-Author(s):
Teri Ulferts
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Experimental Surgical Services, University of Minnesota
Experimental Surgical Services, University of Minnesota
Satoshi Miyairi
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University of Minnesota, Masonic Children's Hospital
University of Minnesota, Masonic Children's Hospital
*Pranava Sinha
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University of Minnesota, Masonic Children's Hospital
University of Minnesota, Masonic Children's Hospital
Presenting Author:
Syed Peer
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University of Minnesota
University of Minnesota
Abstract:
Doppler Red Blood Cell Backscatter Monitoring for Real-time Assessment of Adequacy of Anticoagulation in an Extracorporeal Circuit: In-Vitro Study
Objective: Red blood cells (RBCs) are primarily responsible for the ultrasound backscatter generated by blood. The ultrasound RBC backscatter is known to be related to the level of RBC aggregation. Increased RBC aggregation can be a precursor for intravascular thrombosis. This study investigates the association between blood ultrasound backscatter signal in an in-vitro extracorporeal membrane oxygenation circuit (ECMO) and the intensity of anticoagulation.
Methods: A mock pediatric extracorporeal membrane oxygenation circuit (ECMO) consisting of a 500 ml venous reservoir, 3/8-inch cardiopulmonary bypass (CPB) tubing, roller pump and an oxygenator was primed with fresh heparinized ovine blood. Activated clotting time (ACT) of >200 secs was achieved and flow of 400 ml/min was maintained. A pulse Doppler probe (GAMPT BCC 100) mounted on the circuit tubing (post-oxygenator) was used to measure the mean ultrasound backscatter signal (volts/second) in the circuit. Blood samples for baseline activated clotting time and complete blood count were drawn. At 60 minutes protamine reversal was given to normalize the ACT. The ultrasound backscatter was monitored in real-time and recorded for analysis.
Results: The anticoagulated (ACT>200 secs) mock ECMO circuits (n=3) produced constant baseline backscatter of 1.1 volts/sec; 1.5 volts/sec; 1.6 volts/1 sec at a hematocrit of 9.6%; 12.2% and 13% respectively. Protamine reversal (ACT <200 secs) led to a steady increase in the baseline ultrasound backscatter signal over 1-2 minutes followed by circuit thrombosis (Figure 1.)
Conclusions: Reversal of anticoagulation in an in-vitro ECMO circuit is associated with a sustained increase in the measured mean ultrasound backscatter signal followed by circuit thrombosis. Doppler RBC backscattering monitoring can potentially be used for the real-time assessment of adequacy of anticoagulation in an extracorporeal circuit.
Objective: Red blood cells (RBCs) are primarily responsible for the ultrasound backscatter generated by blood. The ultrasound RBC backscatter is known to be related to the level of RBC aggregation. Increased RBC aggregation can be a precursor for intravascular thrombosis. This study investigates the association between blood ultrasound backscatter signal in an in-vitro extracorporeal membrane oxygenation circuit (ECMO) and the intensity of anticoagulation.
Methods: A mock pediatric extracorporeal membrane oxygenation circuit (ECMO) consisting of a 500 ml venous reservoir, 3/8-inch cardiopulmonary bypass (CPB) tubing, roller pump and an oxygenator was primed with fresh heparinized ovine blood. Activated clotting time (ACT) of >200 secs was achieved and flow of 400 ml/min was maintained. A pulse Doppler probe (GAMPT BCC 100) mounted on the circuit tubing (post-oxygenator) was used to measure the mean ultrasound backscatter signal (volts/second) in the circuit. Blood samples for baseline activated clotting time and complete blood count were drawn. At 60 minutes protamine reversal was given to normalize the ACT. The ultrasound backscatter was monitored in real-time and recorded for analysis.
Results: The anticoagulated (ACT>200 secs) mock ECMO circuits (n=3) produced constant baseline backscatter of 1.1 volts/sec; 1.5 volts/sec; 1.6 volts/1 sec at a hematocrit of 9.6%; 12.2% and 13% respectively. Protamine reversal (ACT <200 secs) led to a steady increase in the baseline ultrasound backscatter signal over 1-2 minutes followed by circuit thrombosis (Figure 1.)
Conclusions: Reversal of anticoagulation in an in-vitro ECMO circuit is associated with a sustained increase in the measured mean ultrasound backscatter signal followed by circuit thrombosis. Doppler RBC backscattering monitoring can potentially be used for the real-time assessment of adequacy of anticoagulation in an extracorporeal circuit.
Mechanical Support and Thoracic Transplantation Summit:
ECMO/Mechanical Support
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