Insufflator Pressure-Volume Transition Detection
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Solution Overview
Problem
Current medical insufflators rely on heuristic methods to determine insufflating pressure for laparoscopic procedures, which can lead to inadequate or excessive pressure in the peritoneal cavity, causing clinical risks such as post-operative pain and reduced venous return, as the pressure required varies significantly with patient body composition and position.
Innovation Solution
An insufflator equipped with a pressure sensor, flow sensor, and signal processor that determines the optimum maximum pressure by analyzing the pressure-volume relationship, transitioning from a first to a second relationship to ensure the lowest safe pressure for adequate working volume, preventing over-pressurization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If higher insufflating pressure is used to achieve adequate working volume in subjects with high body fat, then working volume is improved, but clinical risks such as post-operative pain and reduced venous return increase
Solution Approach 1:
The system dynamically adjusts the insufflating pressure parameter based on real-time monitoring of pressure-volume relationship, transitioning from fixed heuristic pressure values to adaptive parameter control that optimizes working volume while minimizing clinical risks
Solution Approach 2:
The system implements feedback control by continuously monitoring cavity pressure and volume, using sensors to detect the transition point where further pressure increase yields diminishing volume returns, and automatically adjusting pressure to maintain optimal working conditions without exceeding safe limits
2Ease of operation
If fixed heuristic pressure values from literature are used, then ease of operation is improved, but measurement precision of optimal pressure deteriorates
Solution Approach 1:
The system performs self-calibration by automatically determining the optimal pressure-volume relationship for each individual patient through real-time monitoring, eliminating the need for surgeons to manually reference literature values while achieving personalized precision
Solution Approach 2:
The system conducts preliminary measurement during the setup phase to establish the patient-specific pressure-volume curve before the actual surgical procedure, enabling both ease of operation during surgery and high measurement precision through pre-determined optimal parameters
3Volume of moving object
If pressure is increased beyond the transition point, then working volume gain diminishes, but pressure continues to rise significantly
Solution Approach 1:
The system dynamically identifies the transition point in the pressure-volume relationship where compliance changes, and adapts the insufflation strategy to operate optimally below this point, preventing unnecessary pressure elevation while maintaining adequate working volume
Solution Approach 2:
The system applies partial action by delivering just enough insufflating gas to reach the optimal working volume at the transition point, avoiding excessive gas delivery that would cause disproportionate pressure increases with minimal volume gain
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
This solution allows for the precise determination of the optimum maximum pressure, minimizing clinical risks by maintaining the lowest necessary pressure for effective visualization and reducing complications like post-operative pain and venous return.
Implementation Method 1
a pressure sensor for producing a signal indicative of the pressure in the cavity
Implementation Method 2
a flow sensor for monitoring flow of insufflating gas being delivered to the cavity and for producing a signal indicative of the cumulative volume of insufflating gas delivered to the cavity
Data Source
AI summary
An insufflator (1) operable in a set-up mode and a normal insufflating mode comprises a housing (10) for receiving pressurised insufflating gas from an external source (11) thereof. A microprocessor (13) controls a flow controller (16) in response to signals read from a pressure monitoring device (21) and a flow sensor (20) to maintain the peritoneal cavity (3) of a subject insufflated at a selectable working pressure. In the set-up mode, an optimum maximum pressure value is determined, beyond which the cavity (3) should ideally not be insufflated, since beyond the optimum maximum pressure there is minimal gain in working volume in the cavity (3), while the pressure in the cavity (3) increases significantly for each unit volume of insufflating gas delivered to the cavity (3). The optimum maximum pressure is determined as being the pressure in the cavity at the point of inflection (39) on a line (35) representing the pressure/volume relationship between the pressure in the cavity and the cumulative volume of insufflating gas delivered to the cavity (3) where a first linear relationship transitions to a second linear relationship. The point of inflection (39) is determined from a smoothed version (37) of the line (35) where the portions of the smoothed line (37) representing the first and second pressure/volume relationships intersect at (39).