Blood Purification Device Calcium Flow Control
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Solution Overview
Problem
Existing blood purification apparatuses using citric acid as an anticoagulant face challenges in accurately determining the calcium flow rate to be supplied to patients, leading to potential calcium concentration imbalances due to citric acid's interaction with blood calcium, necessitating a more precise method for calcium replenishment.
Innovation Solution
A blood purification apparatus that calculates the total calcium flow rate from the total calcium concentration and waste liquid flow rate in the waste liquid circuit, determining the calcium solution supply flow rate using a formula incorporating a coefficient derived from the sieving coefficient and calcium ion concentrations, allowing for accurate calcium replenishment without directly sampling patient blood.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If citric acid is used as an anticoagulant, then blood coagulation is prevented, but calcium concentration in blood is significantly lowered
Solution Approach 1:
The system continuously monitors calcium concentration in the blood circuit and automatically adjusts the calcium solution supply flow rate based on real-time measurements. The control unit receives calcium concentration data from sensors and dynamically modifies the calcium supplementation to maintain target calcium levels, creating a closed-loop feedback system that resolves the calcium depletion caused by citric acid anticoagulation
Solution Approach 2:
The system changes the supply flow rate parameter of calcium solution based on measured calcium concentration levels. By dynamically adjusting this parameter in response to varying calcium concentrations in the blood circuit, the system maintains calcium homeostasis despite the calcium-chelating effect of citric acid anticoagulant
2Quantity of substance
If calcium solution supply flow rate is increased to compensate for calcium loss, then calcium concentration is maintained, but device complexity increases
Solution Approach 1:
The system performs self-regulation by automatically measuring calcium concentration and adjusting calcium solution supply without requiring external intervention. The control unit autonomously processes sensor data and modifies pump operation to maintain target calcium levels, enabling the system to self-correct calcium imbalances caused by citric acid anticoagulation
Solution Approach 2:
The control unit integrates multiple functions including calcium concentration monitoring, flow rate calculation, and pump control into a single device. This multi-functional approach consolidates what could be separate complex subsystems into one unified control mechanism, maintaining calcium homeostasis while minimizing overall device complexity
3Measurement precision
If direct blood sampling is used to measure calcium concentration, then measurement accuracy is improved, but patient safety risks increase
Solution Approach 1:
The system uses an intermediary substance (calcium indicator dye) that binds to calcium ions in the blood, creating a fluorescent complex whose intensity correlates with calcium concentration. This indirect measurement method allows accurate calcium level assessment without direct blood sampling, eliminating needle stick risks while maintaining measurement precision through optical detection
Solution Approach 2:
The system replaces mechanical blood sampling (needle insertion and manual collection) with an optical measurement system. Fluorescence sensors detect calcium concentration non-invasively through optical signals, substituting the mechanical sampling process with a safer, contactless detection method that maintains measurement accuracy while eliminating patient safety risks
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 simple and accurate determination of the calcium flow rate supplied to patients, effectively maintaining appropriate calcium concentrations by adjusting the calcium solution supply based on real-time measurements, thereby preventing calcium imbalances and ensuring patient safety.
Implementation Method 1
a blood purifier and a blood circuit that sends blood collected from a patient to the blood purifier and returns blood purified in the blood purifier to the patient
Implementation Method 2
an amount of ionized calcium in blood is reduced due to the action of citric acid, and an amount of Ci-Ca conjugates (a type of calcium complex) increases
Data Source
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AI summary
A blood purification apparatus includes a blood circuit, a waste liquid circuit, citric acid solution supply means, and calcium solution supply means. The blood purification apparatus is configured to calculate a total calcium flow rate of a waste liquid from a total calcium concentration in the waste liquid in the waste liquid circuit when a citric acid solution is supplied from the citric acid solution supply means and a waste liquid flow rate in the waste liquid circuit, and determine a supply flow rate of a calcium solution in the calcium solution supply means from the total calcium flow rate in the waste liquid.