Cooling Tourniquet with Sensor Feedback for Limb Ischemia
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing treatments for acute limb ischemia (ALI) are inadequate in preventing tissue and nerve damage during the critical period before revascularization, leading to high rates of amputation and disability, and existing cooling methods risk frostbite or tissue injury due to low thermal conductivity and body's protective mechanisms.
Innovation Solution
A cooling tourniquet system with a controllable cooling pad and temperature sensors that rapidly cool the limb to 5-15°C without causing frostbite, using a control component to manage temperature based on sensor data and maintain deep limb cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If rapid core limb cooling is attempted by lowering skin temperatures, then cooling speed is improved, but tissue injury risk increases due to frostbite or cold burn
Solution Approach 1:
A thermal control system with temperature sensors and feedback control acts as an intermediary between the cooling source and the limb tissue. The system monitors skin temperature in real-time and adjusts cooling intensity to maintain temperatures within the safe range (5-15°C), preventing frostbite while achieving rapid core cooling.
Solution Approach 2:
The patent implements a closed-loop feedback control system where temperature sensors continuously monitor skin and core limb temperatures, and the cooling system automatically adjusts its output based on these measurements. This feedback mechanism ensures rapid cooling while preventing tissue damage by stopping cooling when safe temperature thresholds are reached.
2Speed
If subzero skin temperatures are applied to achieve rapid cooling, then cooling effectiveness is improved, but blood vessel constriction occurs due to body's protective mechanisms
Solution Approach 1:
The patent changes the temperature parameter from subzero to a controlled range of 5-15°C. This parameter modification maintains the therapeutic benefit of rapid cooling while avoiding the physiological response of blood vessel constriction that occurs at subzero temperatures, thereby improving cooling effectiveness without triggering protective mechanisms.
3Reliability
If therapeutic cooling is provided to prevent ischemic damage, then tissue preservation is improved, but logistical difficulties prevent sustained cooling in situ
Solution Approach 1:
The cooling system is designed as a multi-functional device that can be applied to various limbs and integrated with existing tourniquet protocols. The portable design with self-contained cooling sources and power supply makes it universally applicable in field conditions without requiring complex logistical support, enabling sustained cooling during transport and treatment.
Solution Approach 2:
The system incorporates self-regulating features including temperature sensors, feedback control, and automated adjustment mechanisms that reduce the need for continuous manual intervention. This self-service capability allows the cooling system to maintain therapeutic temperatures autonomously during transport, overcoming logistical challenges of sustained cooling.
4Reliability
If tourniquet use is extended to save lives, then survival rate is improved, but limb loss increases due to ischemic damage
Solution Approach 1:
The patent converts the harmful effect of ischemia into a beneficial outcome by applying therapeutic cooling during tourniquet application. The cooling reduces metabolic rate and protects tissues from ischemic damage, allowing extended tourniquet use for life-saving hemorrhage control without increasing limb loss. The harm of prolonged ischemia is transformed into a protected state through controlled cooling.
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
Rapid deep cooling of the limb prevents nerve and tissue damage, potentially reducing amputation risk and improving outcomes in ALI cases by preserving limb function.
Implementation Method 1
Because of the low thermal conductivities of human tissue, however, rapid core limb cooling can be difficult to achieve
Implementation Method 2
A control component is operably connected to receive the limb temperature data from the at least one temperature sensor
Implementation Method 3
A cover member encloses the cooling pad and includes a tourniquet on a proximal portion of the cover member
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A cooling tourniquet system (100) includes a cooling component (110) with a tourniquet (112) at a proximal end and a control component (130). The cooling component includes a cooling pad (120) configured to be wrapped about an extremity, and a cover (111) that wraps around the cooling pad. An inner surface of the cooling pad includes one or more sensors for detecting the temperature of the extremity. The tourniquet is configured to be applied to the extremity to stop blood flow distally from the tourniquet. The control component receives temperature data from the sensors, and controls the cooling pad based on the received data rapidly cooling the extremity at depth, without causing frostbite tissue damage. In one embodiment the control component circulates a chilled fluid with a time-varying temperature profile through passages in the cooling pad. In an embodiment the cover includes an air bladder that holds the cooling pad in contact against the extremity.