Anesthesia Shunt Bypasses Gas Leak to Maintain Tidal Volume
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Solution Overview
Problem
Anesthesia machines face challenges in maintaining adequate tidal volume and ventilation due to gas leakage from the patient side, which can lead to inadequate lung inflation, hypoxemia, and potentially lethal conditions like asphyxia, requiring continuous manual attention and interrupting the workflow of trained attendants.
Innovation Solution
A rebreathing device with a shunt mechanism that bypasses gas from the actuating side to the patient side when the partition is maximally displaced, incorporating a vaporizer and CO2 scrubber, and featuring a check valve and flow alarm to ensure continuous anesthesia delivery and alert the attendant to leaks, thereby compensating for volume loss and maintaining sedation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If manual bleeding of supplemental fresh gas is performed to compensate for leaks, then gas volume loss is compensated, but the attendant's workflow is interrupted and continuous presence is required
Solution Approach 1:
The system automatically detects gas leaks through the flow sensor and activates the supplemental fresh gas inlet valve without requiring manual intervention. The controller monitors flow rate deviations and autonomously adjusts gas delivery to compensate for leaks, allowing the attendant to perform other tasks while maintaining adequate gas volume in the patient circuit.
Solution Approach 2:
The flow sensor continuously monitors the flow rate of gas through the patient circuit and provides feedback to the controller. When a leak is detected (flow rate falls outside expected range), the controller activates the supplemental fresh gas inlet valve to compensate. This closed-loop feedback system maintains gas volume automatically throughout the anesthesia procedure.
2Reliability
If continuous manual monitoring and intervention is performed to protect against adverse effects, then patient safety is maintained, but the attendant cannot perform other work tasks
Solution Approach 1:
The anesthesia machine performs self-monitoring and self-correction by automatically detecting gas leaks and activating supplemental fresh gas delivery. The flow sensor continuously monitors circuit conditions, and the controller autonomously adjusts gas flow to maintain patient safety without requiring constant attendant intervention.
Solution Approach 2:
The manual mechanical process of continuously monitoring and manually adjusting gas flow is replaced by an automated electronic system. The flow sensor and controller work together to detect and compensate for leaks automatically, substituting the attendant's manual skills and continuous presence with an automated detection and correction system.
3Reliability
If the flow sensor and controller are added to automatically compensate for leaks, then continuous anesthesia delivery is ensured, but device complexity increases
Solution Approach 1:
The flow sensor and controller are integrated into the existing anesthesia machine architecture, serving multiple functions: monitoring gas flow rates, detecting leaks, controlling the supplemental fresh gas inlet valve, and providing alerts to the attendant. By making these components multi-functional, the system achieves reliable continuous anesthesia delivery without proportionally increasing complexity.
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 ensures continuous and adequate anesthesia delivery by automatically compensating for gas leaks, reducing the need for constant manual intervention and minimizing the risk of adverse respiratory outcomes, allowing for more efficient operation in intensive care units.
Implementation Method 1
A shunt defines a bypass flow path from the actuating side to the patient side when the moveable partition is at a maximal displacement towards the patient side
Implementation Method 2
A vaporizer is disposed in the bypass flow path of the shunt
Implementation Method 3
a scrubber may be used to absorb carbon dioxide from the patient exhaled gas
Implementation Method 4
The shunt may include a check valve disposed in the bypass flow path
Data Source
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AI summary
The disclosure provides a way to supplement the tidal volume delivered to the patient by a leaking re-breather when the delivered volume becomes less than that set by the ventilator (in either pressure-regulated or volume modes). This may be accomplished with a shunt — a gas conduit joining the non-patient side of the re-breather to the patient side. A low-resistance, plenum or a draw-over vaporizer may also be incorporated into the gas pathway. Such a device may include a housing with a movable partition separating an actuating side from a patient side. The housing includes a ventilator orifice for pneumatic communication between a ventilator and the actuating side and a patient orifice for pneumatic communication between the patient side and a patient. A shunt defines a bypass flow path from the actuating side and to the patient side when the moveable partition is at a maximal displacement towards the patient side.