Dual-Lumen Catheter ACT Monitoring With Impedance Clot Sensing
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Solution Overview
Problem
Existing ACT measurement methods require larger blood samples obtained through venipuncture, are cumbersome, time-consuming, and prone to temperature changes affecting accuracy, leading to potential patient harm and complications.
Innovation Solution
An apparatus and method for real-time ACT testing using a catheter with two lumens to collect microliter blood samples from an indwelling venous catheter, combined with an impedance sensor and microfluidic cartridge for continuous monitoring, maintaining blood temperature and providing immediate results on a digital display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional venipuncture methods are used to obtain blood samples for ACT testing, then sufficient blood volume can be obtained, but the process becomes cumbersome, time-consuming, and causes patient discomfort
Solution Approach 1:
The patent extracts the blood sampling function from traditional venipuncture and integrates it directly into the catheter system. The catheter includes a lumen that allows blood to be drawn directly from the patient's vascular system without requiring separate venipuncture procedures, thereby eliminating the cumbersome manual collection process while maintaining adequate sampling capability.
Solution Approach 2:
The patent merges the blood sampling function with the catheter structure itself. The catheter combines the functions of vascular access, blood sampling, and temperature maintenance into a single integrated device. The sampling lumen is built into the catheter assembly, allowing blood to be drawn directly through the catheter structure rather than requiring separate collection procedures.
2Measurement precision
If manual transfer of blood samples to testing devices is performed, then testing can be conducted, but temperature changes occur affecting ACT measurement accuracy
Solution Approach 1:
The patent applies preliminary temperature control by maintaining the blood sample at physiological temperature (37°C) within the catheter before testing begins. The catheter includes a heating element that pre-warms the blood sample to the correct temperature, ensuring that when the sample is transferred to the testing device, temperature changes do not occur and measurement accuracy is maintained.
Solution Approach 2:
The catheter acts as an intermediary between the patient's vascular system and the testing device. It includes a temperature-controlled chamber that maintains the blood sample at a constant physiological temperature during the sampling and transfer process. This intermediary structure prevents temperature fluctuations that would otherwise occur during manual handling and transfer to the testing device.
3Quantity of substance
If larger blood samples are collected for ACT testing, then adequate volume is obtained, but patient discomfort and potential harm increase
Solution Approach 1:
The patent changes the parameter of blood sample volume from milliliters to microliters. The integrated sampling system uses a microliter-scale collection mechanism that requires only minimal blood volume (micro aliquots) to perform accurate ACT testing. This parameter change from larger to smaller volumes eliminates the need for significant blood loss while maintaining adequate sample quantity for testing.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables efficient, accurate, and timely monitoring of ACT, reducing patient discomfort and complications, minimizing blood volume, and decreasing procedure time and medication use.
Implementation Method 1
An impedance sensor in combination with the aspiration catheter then analyzes the micro aliquots of blood so collected to provide in real time ACT results
Implementation Method 2
The collected specimen is collected into a syringe or other tube and immediately transferred into a testing device cartridge or cuvette. The ACT test should be completed no more than 1 to 2 minutes after the blood sample is collected and the blood temperature should be maintained at a constant temperature, normally 37° C.
Data Source
AI summary
An activated clotting time measurement apparatus comprising a catheter having first and second lumens inserted into a vascular vessel of a patient and a sensor module. The first and second lumens are connected to a peristaltic pump whereby aliquots of blood is collected from the patient's vascular vessel and delivered to a sensor cartridge in the sensing module by the first lumen via a control valve and uncollected blood is returned to the patient's vascular vessel in the second lumen. The sensor cartridge has a sensing channel, a pair of electrodes, and a clotting activator whereby the aliquots of blood are clotted. A current generator generates current to the electrodes through the clotted blook aliquots where an impedance measurement device measures the electrical impedance caused by the clotted blood and delivers impedance signals to a processor and display device for processing and display.