Cardiac Device Apnea Compensation via Hemodynamic Feedback
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Solution Overview
Problem
Current active implantable medical devices lack a reliable method to determine whether to increase heart rate in response to apnea or hypopnea, as they cannot easily and permanently measure oxygen saturation, leading to inadequate treatment for some patients.
Innovation Solution
Incorporating a hemodynamic sensor to estimate myocardial contractility variations, allowing the device to conditionally modify its operating parameters, such as stimulation frequency, in response to detected respiratory anomalies, ensuring appropriate compensation for oxygen desaturation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a direct measurement of oxygen saturation is implemented, then the accuracy of treatment decision-making is improved, but the device complexity and difficulty of implementation increase significantly
Solution Approach 1:
The patent uses hemodynamic parameters (cardiac output, systemic vascular resistance) as intermediary indicators to indirectly assess oxygen saturation status. Instead of directly measuring oxygen saturation, the system monitors hemodynamic changes that reflect the body's compensatory responses to hypoxemia, thereby avoiding the need for complex direct oxygen saturation sensors while still enabling accurate treatment decisions.
Solution Approach 2:
The patent replaces the need for direct oxygen saturation measurement (which would require complex optical or chemical sensors) with hemodynamic monitoring using electrical impedance and pressure sensors already present in the device. This substitution leverages existing mechanical and electrical measurement capabilities to achieve the same clinical objective with simpler technology.
2Reliability
If the device systematically increases heart rate in response to apnea or hypopnea detection, then oxygen desaturation is compensated, but patients with adrenergic reactions experience excessive tachycardia and hypertension
Solution Approach 1:
The patent implements a feedback mechanism where the device continuously monitors hemodynamic parameters (cardiac output, systemic vascular resistance, blood pressure) to assess the patient's actual physiological response to respiratory events. Treatment is adjusted based on this feedback: if hemodynamic compensation is adequate, no pacing is applied; if compensation is insufficient, pacing is initiated. This feedback loop prevents excessive tachycardia in patients who already mount appropriate adrenergic responses.
Solution Approach 2:
The patent transitions from a static, predetermined response (systematically increasing heart rate for all apnea/hypopnea events) to a dynamic, adaptive response that adjusts treatment based on real-time hemodynamic assessment. The device evaluates whether the patient's natural compensatory mechanisms are sufficient and only intervenes when necessary, thereby adapting the treatment intensity to each patient's specific physiological state.
3Object-affected harmful factors
If no treatment is applied and the patient's natural compensatory mechanisms are relied upon, then excessive tachycardia is avoided, but oxygen desaturation may persist in patients with insufficient myocardial adaptation
Solution Approach 1:
The patent uses hemodynamic feedback to distinguish between patients with adequate and inadequate natural compensation. By monitoring cardiac output and systemic vascular resistance, the device can identify when myocardial adaptation is insufficient to maintain oxygen saturation, triggering appropriate pacing intervention only in those cases while leaving other patients untreated.
Solution Approach 2:
The patent allows patients with adequate natural compensatory mechanisms to self-regulate their own oxygen saturation without device intervention. The system trusts the patient's own physiological response (adrenergic reaction and myocardial adaptation) to maintain oxygenation, intervening only when this self-service mechanism proves insufficient, thereby minimizing unnecessary treatment while ensuring adequate protection.
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
The solution enables targeted and adaptive responses to apnea or hypopnea, improving oxygen saturation by adjusting stimulation parameters based on myocardial contractility, thereby enhancing treatment efficacy for patients with respiratory disorders.
Implementation Method 1
the device comprises means for detecting an occurrence of apnea or of hypopnea by an analysis of the respiration rate of the patient during his sleep, this rate/rhythm being given by the evolution over the course of the time of the minute ventilation signal (signal MV)
Implementation Method 2
The signal MV provides a continuous indication of the respiration rate and the respiratory flow volume of the patient. The signal MV is a parameter with physiological preponderance (i.e., predominantly physiological in nature) that is obtained by a measurement of intrathoracic (or intracardiac) impedance.
Data Source
AI summary
Improved management of respiratory pauses (apnea) or hypopnea in an active implantable medical device of the cardiac pacemaker, cardiovertor and defibrillator types including multisite devices. This device operates to analyze the patient's respiratory activity, detect the occurrence of respiratory pauses (apnea) or diminutions (hypopnea), analyze the contractility of the myocardium, for example, by measurement of the intracardiac impedance or the endocardial acceleration, and detect the occurrence of a variation of the hemodynamic state. In the event of a significant variation of the hemodynamic state (i.e., contractility) detected in relation to the detection of an apnea or of an hypopnea, the device modifies conditionally and temporarily an operating parameter of the device, for example, the frequency of stimulation, the atrio-ventricular delay or to trigger a multistate stimulation to compensate.