Syncope Prevention via Posture-Aware NMES
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Solution Overview
Problem
Current methods for preventing syncope, such as graduated compression stockings and cardiac pacing, are either uncomfortable, poorly tolerated, or show mixed results due to the complexity of syncope mechanisms, particularly in cases without significant heart rate drops or venous return issues.
Innovation Solution
A monitoring system incorporating biomechanical and physiological sensors that detect posture changes, heart rate, and leg activity to predict syncope types like orthostatic hypotension, neurocardiogenic, and postural orthostatic tachycardia syndrome, using neuromuscular electrical stimulation (NMES) to prevent venous pooling through muscle contractions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If graduated compression stockings are used to prevent syncope, then venous pooling is reduced, but comfort and ease of operation deteriorate
Solution Approach 1:
The patent replaces the mechanical compression system of graduated compression stockings with an electrical stimulation system (NMES). Instead of using continuous mechanical compression through fabric, the system uses electrical impulses to trigger muscle contractions that mechanically pump blood back to the heart, thereby eliminating the discomfort of tight stockings while achieving the same hemodynamic effect.
Solution Approach 2:
The system employs the patient's own muscle pump mechanism to prevent venous pooling. By stimulating the patient's calf muscles to contract, the system utilizes the body's natural physiological mechanism for venous return, rather than imposing an external mechanical constraint like compression stockings. This self-service approach improves comfort while maintaining effectiveness.
2Reliability
If cardiac pacing is used to increase heart rate and blood pressure, then syncope prevention is improved, but device complexity and mixed results increase due to varying syncope mechanisms
Solution Approach 1:
The patent extracts the specific function needed for syncope prevention (venous return enhancement) from the broader cardiac pacing system. Instead of using a full cardiac pacemaker that controls heart rate and rhythm, the invention isolates and applies only the necessary intervention (lower limb muscle stimulation) to address venous pooling, thereby reducing device complexity while targeting the specific pathological mechanism.
Solution Approach 2:
The system applies stimulation locally to the lower limb muscles rather than globally affecting the entire cardiovascular system through cardiac pacing. By targeting specifically the calf muscle pump mechanism, the system addresses the local hemodynamic problem of venous pooling in the lower extremities without the need for complex whole-body cardiac rhythm control.
3Reliability
If drugs are prescribed to increase systemic vascular resistance or expand blood volume, then syncope prevention is improved, but safety deteriorates due to unsafe blood pressure rise when lying down
Solution Approach 1:
The system applies muscle stimulation preemptively during posture transitions (from lying to standing) before syncope can occur. By activating the muscle pump in advance during the critical transition period, the system prevents venous pooling before it causes hemodynamic instability, rather than using drugs that continuously increase blood pressure and may cause unsafe rises when the patient is lying down.
Solution Approach 2:
The system uses intermittent, periodic muscle stimulation rather than continuous drug administration. Electrical impulses are delivered in cycles that mimic natural muscle activity patterns, activating the venous pump only when needed during posture maintenance or transition, thereby avoiding the continuous systemic effects and safety concerns associated with pharmacological agents.
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 system effectively minimizes syncope risk by providing real-time NMES to prevent venous pooling, improving venous return, and reducing the risk of falls-related injuries, with high usability and minimal patient intervention.
Implementation Method 1
delivering electrical stimulation to muscles to prevent venous pooling and improve venous return
Data Source
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AI summary
A monitoring system has biomechanical sensors (206), physiological sensors (205) and a controller (102, 204) which receive sensory inputs from the sensors (101 ) to provide output signals for the output device, and it detects from the sensory inputs risk of a syncopal event The bio-mechanical sensors include sensors (206, 207) arranged to allow the processor to detect a user postures and posture transitions. The processor operates a finite state machine, in which there is a state corresponding to each of a plurality of user physical postures and to each of a plurality of transitions between said postures, and the processor determines a relevant state depending on the sensory inputs. A device output may be muscle stimulation to prevent syncope, and there are stimulation permissions associated with the finite state machine states.