Burn patient resuscitation system
Inventors
Salinas, Jose • Kramer, George C. • Drew, Guy A.
Assignees
University of Texas System • United States Department of the Army
Publication Number
US-8597273-B2
Publication Date
2013-12-03
Expiration Date
2028-03-19
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Abstract
A system for operating a semi-closed loop and/or a closed loop resuscitation of a burn patient in view of patient information and other physiological data gathered by the system. The system in at least one embodiment includes an urine sensor, an infusion pump and a processor that controls the operation of the infusion pump at least in part from a signal received from the urine sensor.
Core Innovation
The invention relates to a semi-closed loop or closed loop system and method for burn patient resuscitation that utilizes a system including a urine sensor, an infusion pump, and a processor. The processor controls the operation of the infusion pump based at least in part on signals received from the urine sensor to maintain a target urinary output range, which serves as a surrogate marker for adequate renal blood flow and cardiovascular function.
The invention addresses the problem of effective resuscitation in burn patients, where traditional fluid resuscitation methods frequently result in over-resuscitation, causing fluid overload and complications such as pulmonary edema, abdominal compartment syndrome, and delayed wound healing. Current practices rely on formulas like the Brooke or Parkland formulas with hourly manual adjustments based on urinary output, but these often lead to infusion volumes exceeding recommended levels and variability in patient outcomes.
The core innovation is a system and method employing a model-based, algorithmic approach that adjusts fluid infusion rates continuously or semi-continuously using measured urinary output and patient-specific variables such as weight, total body surface area burned, and hours post burn. The system can operate in a closed loop to autonomously control infusion or in a semi-closed loop mode providing infusion rate recommendations for clinical approval. The system uses mathematical models, including an exponential decay function of infusion rate constants and Gaussian functions centered on target urinary output, to calculate new infusion rates and aims to optimize fluid therapy, reduce workload on burn experts, and extend burn expertise to less specialized or austere care environments.
Claims Coverage
The patent contains three independent claims describing systems for burn patient resuscitation with varying components and functionalities. The main inventive features involve methods for calculating infusion rates using model-based constants and controlling infusion pumps based on urinary output measurements and patient data.
Infusion rate calculation using model-based constants and urinary output error
A system with a urine sensor, an infusion pump, and a processor that calculates the new infusion rate using an equation incorporating the current infusion rate, current urinary output, and infusion rate model-based constants; the equation includes an exponential decay of the infusion rate constant with hours post burn.
Incorporation of patient-specific modifiers and Gaussian function in infusion rate calculation
The infusion rate calculation further multiplies the urinary output error by modifiers based on patient weight, percentage of total body surface area burned, and a Gaussian function centered on the target urinary output to fine-tune infusion adjustments.
Timing control of infusion rate calculations and semi-closed or closed loop operation
A timer provides periodic triggers for calculating new infusion rates based on elapsed time post burn, and the system includes a selector allowing operation in closed loop (autonomous infusion control) or semi-closed loop (recommendation-based infusion control) modes.
The claims collectively cover a burn resuscitation system integrating continuous or periodic urinary output monitoring with model-based algorithmic infusion rate calculations that include patient-specific factors and time post injury, capable of operating autonomously or with clinician oversight to control infusion pumps and provide decision support for optimal fluid therapy.
Stated Advantages
Provides tighter and more consistent control of urinary output compared to human intervention, potentially lowering total infused volumes and improving fluid balance.
Pushes burn resuscitation expertise into environments lacking specialized personnel, including combat zones and mass casualty situations.
Reduces workload on advanced burn centers by enabling less experienced medical staff to optimize the first 24 to 48 hours of burn care.
Enables continuous monitoring and rapid response to physiological changes, improving patient safety and treatment efficacy.
Offers robust error detection and notification systems to alert medical staff of equipment failures or patient non-responsiveness.
Documented Applications
Use in resuscitating burn patients with moderate to severe burns requiring large volume fluid therapy.
Deployment in initial care facilities, including civilian emergency rooms and forward military medical units, where expert burn care is unavailable.
Use in austere environments such as combat zones or mass casualty situations to extend burn care expertise.
Semi-closed loop mode supports clinical staff by recommending infusion rates while allowing manual oversight and adjustment.
Closed loop mode permits autonomous control of infusion pumps for continuous fluid management during burn resuscitation.
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