Pulse Oximetry Splitter Cable Isolation Against Ground Loops
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Solution Overview
Problem
Existing patient monitoring devices face the risk of electric shock due to the formation of ground loops when multiple sensors are connected, particularly when using splitter cables, which can be hazardous to patients and damage equipment.
Innovation Solution
Incorporating decoupling circuits in medical cable assemblies, including splitter cables and individual cables, to electrically decouple sensors from the monitor, preventing the formation of ground loops and reducing the risk of electric shock.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors are connected to a monitor using splitter cables, then the monitoring capability is improved, but ground loops form causing electric shock hazard
Solution Approach 1:
The patent introduces an intermediary device (isolation amplifier or galvanic isolator) between the sensors and monitor that blocks ground loop currents while allowing physiological signals to pass through. This mediator prevents the harmful electrical connection without interfering with the monitoring function.
Solution Approach 2:
The patent segments the electrical connection into isolated sections using multiple ground references at different electrical potentials. By dividing the ground path into separate, isolated segments rather than a continuous path, ground loop currents are prevented from forming while maintaining signal integrity.
2Device complexity
If splitter cables are used to connect multiple sensors, then the device complexity is reduced, but ground loops form causing equipment damage
Solution Approach 1:
The isolation amplifier acts as a mediator in the cable system that prevents ground loop formation without requiring complex cable management. This simple intermediary component maintains equipment safety while preserving the ease of splitter cable configuration.
Solution Approach 2:
The patent changes the electrical parameters of the cable system by introducing galvanic isolation that blocks DC ground potential differences while allowing AC physiological signals to pass. This parameter change prevents ground loops without affecting the cable configuration simplicity.
3Object-affected harmful factors
If ground loops are prevented using traditional methods, then patient safety is improved, but costly upgrades to monitoring equipment are required
Solution Approach 1:
The patent employs relatively inexpensive isolation amplifier modules or isolator components that can be added to existing monitors without major upgrades. These cost-effective components provide ground loop protection without requiring expensive equipment replacement.
Solution Approach 2:
The isolation amplifier serves as an affordable intermediary addition to existing monitoring equipment that provides ground loop protection. Rather than requiring complete system upgrades, this mediator component can be integrated into existing monitors to improve patient safety.
Data Source
AI summary
A pulse oximetry system for reducing the risk of electric shock to a medical patient can include physiological sensors, at least one of which has a light emitter that can impinge light on body tissue of a living patient and a detector responsive to the light after attenuation by the body tissue. The detector can generate a signal indicative of a physiological characteristic of the living patient. The pulse oximetry system may also include a splitter cable that can connect the physiological sensors to a physiological monitor. The splitter cable may have a plurality of cable sections each including one or more electrical conductors that can interface with one of the physiological sensors. One or more decoupling circuits may be disposed in the splitter cable, which can be in communication with selected ones of the electrical conductors. The one or more decoupling circuits can electrically decouple the physiological sensors.