ESA Dose Calculation for Hemoglobin Stability

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Solution Overview

Problem

Current methods for determining the dose of erythropoiesis-stimulating agents (ESAs) in patients with renal anemia fail to maintain hemoglobin concentration within a stable target range, leading to excessive fluctuations and increased risks of death due to either excessive or insufficient ESA doses.

Innovation Solution

A method that calculates the target hemoglobin production rate and corresponding ESA concentration to stabilize hemoglobin levels by determining the ESA dose based on the relationship between hemoglobin production rate and ESA concentration, using formulas to calculate the required ESA dose to maintain the target hemoglobin concentration within a 90-day red-blood-cell lifespan.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the ESA dose is determined based on doctor's experience, then the dosing process is simple, but the hemoglobin concentration fluctuates excessively above or below the target value

Engineering Contradiction:

Improvedosing process simplicityVSAvoidhemoglobin concentration stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent implements a feedback control system where the ESA dose for the next measurement period is determined based on the difference between the target hemoglobin concentration and the actually measured value. The algorithm calculates the dose adjustment proportionally to the concentration difference, creating a closed-loop control that automatically corrects deviations from the target value, thereby stabilizing hemoglobin concentration while maintaining operational simplicity.

Inventive Principle:

Principle #23Feedback

2Quantity of substance

If the ESA dose is increased to raise hemoglobin concentration, then the hemoglobin level increases, but the risk of death increases due to excessive concentration

Engineering Contradiction:

Improvehemoglobin concentrationVSAvoidrisk of death

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The feedback algorithm prevents excessive hemoglobin concentration by calculating the next ESA dose based on the actual measured value and target difference. When the measured concentration approaches or exceeds the target, the algorithm automatically reduces or stops dose increases, thereby preventing harmful supranormal concentrations while still achieving adequate hemoglobin levels.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies partial action by using a proportional dose adjustment rather than maximum dose increases. The ESA dose is increased by an amount proportional to the concentration difference, not by a fixed maximum amount, allowing gradual approach to the target concentration without overshooting into harmful ranges.

Inventive Principle:

Principle #16Partial or excessive action

3Quantity of substance

If the ESA dose is decreased to reduce hemoglobin concentration, then the hemoglobin level decreases, but the risk of death increases due to insufficient concentration

Engineering Contradiction:

Improvehemoglobin concentrationVSAvoidrisk of death

Core Design Contradiction:

Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The feedback control system prevents excessive dose reduction by calculating the next ESA dose based on the actual measured hemoglobin concentration and target difference. When the measured concentration is below the target, the algorithm automatically increases the dose proportionally to the deficit, preventing harmful subnormal concentrations while avoiding unnecessary dose increases when the target is already achieved.

Inventive Principle:

Principle #23Feedback

4Loss of time

If the hemoglobin concentration is measured once per month, then the measurement frequency is low and treatment cost is reduced, but the range of fluctuation of hemoglobin concentration cannot be sufficiently decreased

Engineering Contradiction:

Improvemeasurement frequencyVSAvoidhemoglobin concentration stability

Core Design Contradiction:

Loss of timeVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by calculating the ESA dose for the entire next measurement period in advance, based on the current measured concentration and target difference. This predetermined dose adjustment compensates for the low measurement frequency, ensuring that hemoglobin concentration remains stable throughout the month even though measurements are only performed monthly.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS10496794B2Method of determining dose of erythropoiesis-stimulating agent

Publication Date: 2019.12.03 NIPRO CORP

AI summary

A method of determining an ESA dose, which allows a hemoglobin concentration in the blood to be stably maintained at a target value, and which can decrease a range of fluctuation of the hemoglobin concentration with respect to the target value. The method comprises the steps of: setting the target value of the hemoglobin concentration in the blood; calculating a target value of a hemoglobin production rate which allows the hemoglobin concentration to reach the target value; calculating a serum ESA concentration which allows the hemoglobin production rate to reach the target value, from a relationship between the hemoglobin production rate and the ESA concentration; and calculating an amount of administration of an ESA which gives the serum ESA concentration, from a relationship between the ESA concentration and the amount of administration of the ESA, to determine an ESA dose which allows the hemoglobin concentration to reach the target value.