Systems and methods for monitoring blood flow using a dynamic optical phantom
Systems and methods are provided for monitoring of blood flow using a dynamic phantom that incorporates optical properties and mechanical properties of the tissue surrounding an artery (e.g., the radial artery at the wrist). The phantom can include: a body with optical properties representative of surrounding skin layers; a vessel chamber with mechanical properties representative of the artery; and a pulsatile pump that cycles a blood-mimicking fluid (BMF) to maintain physiologically accurate pressure fluctuations typically seen at the artery. The phantom can be fabricated through the combination of rapid prototyping using both stereolithography (SLA) and fused deposition modeling (FDM) methods to develop mold casting to control geometric properties. Photoplethysmography (PPG) signals for different properties representing varying skin tone and obesity can be collected using a pulse oximeter device.
1 . A system for monitoring blood flow, the system comprising:
a phantom body part model that mimics compliance and elasticity of human skin;
tubing, a first portion of which is embedded in the phantom body part model;
a blood-mimicking fluid (BMF) disposed in the tubing;
a pressurized bulb pump flow mechanism in operable communication with the phantom body part model and configured to drive pulsatile flow of the BMF through the tubing to mimic arterial pulse behavior;
a motor in operable communication with the pressurized bulb pump flow mechanism and configured to cause the pressurized bulb pump flow mechanism to compress;
an optical sensor disposed proximate to the phantom body part model and configured to optically sense photoplethysmography (PPG) waveforms of the BMF in the first portion of the tubing embedded in the phantom body part model during operation of the system; and
an outlet pressure choke disposed on the tubing and configured to dynamically control and manipulate the PPG waveforms sensed by the optical sensor.
2 . The system according to claim 1 , further comprising a cam disposed on the motor and a shaft disposed between the cam and the pressurized bulb pump flow mechanism,
the shaft being in direct physical contact with the cam and the pressurized bulb pump flow mechanism, and
the motor being configured to cause the cam to turn and thereby push the shaft into the pressurized bulb pump flow mechanism and compress the pressurized bulb pump flow mechanism at predetermined intervals.
3 . The system according to claim 1 , the tubing comprising the first portion, a second portion connecting the pressurized bulb pump flow mechanism to the first portion, a third portion connecting the first portion to a fluid reservoir, and a fourth portion connecting the fluid reservoir to the pressurized bulb pump flow mechanism.
4 . The system according to claim 3 , further comprising a first one-way valve disposed on the second portion of the tubing and configured to allow the BMF to flow from the pressurized bulb pump flow mechanism to the first portion of the tubing embedded in the phantom body part model.
5 . The system according to claim 4 , further comprising:
a second one-way valve disposed on the third portion of the tubing and configured to allow the BMF to flow from the first portion of the tubing embedded in the phantom body part model to the fluid reservoir; and
a third one-way valve disposed on the fourth portion of the tubing and configured to allow the BMF to flow from the fluid reservoir to the pressurized bulb pump flow mechanism.
6 . The system according to claim 4 , the outlet pressure choke being disposed on the third portion of the tubing.
7 . The system according to claim 1 , the BMF comprising deionized water and India ink.
8 . The system according to claim 1 , the phantom body part model comprising a silicone material.
9 . A method for monitoring blood flow, the method comprising:
providing the system according to claim 1 ;
operating the motor to cause the pressurized bulb pump flow mechanism to compress at predetermined intervals to mimic arterial pulse behavior;
utilizing the optical sensor to sense PPG waveforms of the BMF in the first portion of the tubing embedded in the phantom body part model; and
using the outlet pressure choke to dynamically control and manipulate the PPG waveforms sensed by the optical sensor.
10 . The method according to claim 9 , the system further comprising a cam disposed on the motor and a shaft disposed between the cam and the pressurized bulb pump flow mechanism,
the shaft being in direct physical contact with the cam and the pressurized bulb pump flow mechanism, and
the motor being configured to cause the cam to turn and thereby push the shaft into the pressurized bulb pump flow mechanism and compress the pressurized bulb pump flow mechanism at predetermined intervals.
11 . The method according to claim 9 , the tubing comprising the first portion, a second portion connecting the pressurized bulb pump flow mechanism to the first portion, a third portion connecting the first portion to a fluid reservoir, and a fourth portion connecting the fluid reservoir to the pressurized bulb pump flow mechanism, and
the operating of the motor to cause the pressurized bulb pump flow mechanism to compress at predetermined intervals comprising the BMF flowing from the pressurized bulb pump flow mechanism through the second portion to the first portion, then to the third portion, then to the fluid reservoir, then to the fourth portion, and then back to the pressurized bulb pump flow mechanism.
12 . The method according to claim 11 , the system further comprising a first one-way valve disposed on the second portion of the tubing, and
the operating of the motor to cause the pressurized bulb pump flow mechanism to compress at predetermined intervals comprising the BMF flowing one way in the second portion of the tubing from the pressurized bulb pump flow mechanism to the first portion of the tubing embedded in the phantom body part model.
13 . The method according to claim 12 , the system further comprising:
a second one-way valve disposed on the third portion of the tubing; and
a third one-way valve disposed on the fourth portion of the tubing,
the operating of the motor to cause the pressurized bulb pump flow mechanism to compress at predetermined intervals comprising the BMF flowing one way in the third portion of the tubing from the first portion of the tubing embedded in the phantom body part model to the fluid reservoir, and
the operating of the motor to cause the pressurized bulb pump flow mechanism to compress at predetermined intervals comprising the BMF flowing one way in the fourth portion of the tubing from the fluid reservoir to the pressurized bulb pump flow mechanism.
14 . The method according to claim 9 , the BMF comprising deionized water and India ink.
15 . The method according to claim 9 , the phantom body part model comprising a silicone material.
16 . A system for monitoring blood flow, the system comprising:
a phantom body part model that mimics compliance and elasticity of human skin;
tubing, a first portion of which is embedded in the phantom body part model;
a blood-mimicking fluid (BMF) disposed in the tubing;
a pressurized bulb pump flow mechanism in operable communication with the phantom body part model and configured to drive pulsatile flow of the BMF through the tubing to mimic arterial pulse behavior;
a motor in operable communication with the pressurized bulb pump flow mechanism and configured to cause the pressurized bulb pump flow mechanism to compress;
a cam disposed on the motor and a shaft disposed between the cam and the pressurized bulb pump flow mechanism; and
an optical sensor disposed proximate to the phantom body part model and configured to optically sense photoplethysmography (PPG) waveforms of the BMF in the first portion of the tubing embedded in the phantom body part model during operation of the system,
the shaft being in direct physical contact with the cam and the pressurized bulb pump flow mechanism,
the motor being configured to cause the cam to turn and thereby push the shaft into the pressurized bulb pump flow mechanism and compress the pressurized bulb pump flow mechanism at predetermined intervals,
the tubing comprising the first portion, a second portion connecting the pressurized bulb pump flow mechanism to the first portion, a third portion connecting the first portion to a fluid reservoir, and a fourth portion connecting the fluid reservoir to the pressurized bulb pump flow mechanism, and
the system further comprising:
an outlet pressure choke disposed on the third portion of the tubing, the outlet pressure choke being configured to dynamically control and manipulate the PPG waveforms sensed by the optical sensor;
a first one-way valve disposed on the second portion of the tubing and configured to allow the BMF to flow from the pressurized bulb pump flow mechanism to the first portion of the tubing embedded in the phantom body part model;
a second one-way valve disposed on the third portion of the tubing and configured to allow the BMF to flow from the first portion of the tubing embedded in the phantom body part model to the fluid reservoir; and
a third one-way valve disposed on the fourth portion of the tubing and configured to allow the BMF to flow from the fluid reservoir to the pressurized bulb pump flow mechanism.
17 . The system according to claim 16 , the BMF comprising deionized water and India ink,
the phantom body part model being a phantom wrist model, and
the material of the phantom body part model being a silicone material.