Devices and methods for controlling patient temperature
Inventors
Kulstad, Erik • Caherty, Hugh Patrick
Assignees
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Publication Number
US-9301871-B2
Publication Date
2016-04-05
Expiration Date
Abstract
Relatively non-invasive devices and methods for heating or cooling a patient's body are disclosed. Devices and methods for treating ischemic conditions by inducing therapeutic hypothermia are disclosed. Devices and methods for inducing therapeutic hypothermia through esophageal cooling are disclosed. Devices and methods for operative temperature management are disclosed.
Core Innovation
The disclosure relates to relatively non-invasive patient temperature control using an esophageal heat transfer device that includes an input port and a lumen for flow of a heat transfer medium to an inflatable heat transfer region. Upon inflation, the inflatable heat transfer region is configured for contacting the patient’s esophageal epithelium while the heat transfer device provides a fluid path through the lumen. The disclosed concept supports therapeutic hypothermia and other core body temperature targets by controlling the heat transfer medium flow to and from the esophageal heat transfer region.
A central aspect is inflating the esophageal inflatable heat transfer region to perform esophageal heat transfer, and then deflating the inflatable heat transfer region to permit gastric ventilation. The device and system are described with a microprocessor coupled to an external source that regulates flow of the heat transfer medium to inflate the heat transfer region and subsequently deflate it, with the option to re-inflate. Additional sensor concepts include pressure sensing associated with gastric pressure and/or esophageal pressure or intra-abdominal pressure, with signals provided to the microprocessor for control.
The disclosure further describes control logic in which the microprocessor regulates the heat transfer medium flow based on pressure information, including proportional-integrated-differential responses. Comparative and experimental results are described as showing faster cooling and warming and higher heat extraction rates versus prior art, including steady-state temperature control with minimal deviation from a target temperature and minimal shivering in animal experiments (swine). Device structure features described include multi-lumen tubing and configurations that allow gastric access, including helical/C-shaped configurations and additional components for gastric access such as a gastric tube or probe for decompression/alimentation.
Claims Coverage
The partial content identifies three independent claims (device system for core temperature control, a first method for reducing core body temperature with inflation/deflation cycles, and a second method that also includes maintaining gastric access and inserting a gastric tube). Across these independent claims, the inventive concept centers on an esophageal inflatable heat transfer region supplied via a lumen, with periodic deflation to permit gastric ventilation and optional pressure-based control features.
Esophageal inflatable heat transfer region with fluid-path lumen and inflating/deflating control
A system for controlling core body temperature comprising a heat transfer device with an input port, a lumen connected to the input port, and an inflatable heat transfer region configured for contacting the patient’s esophageal epithelium upon inflation, wherein the lumen provides a fluid path for flow of the heat transfer medium to the inflatable heat transfer region, and a microprocessor coupled to the external source that regulates the flow of the heat transfer medium to inflate the heat transfer region and subsequently deflate the heat transfer region to permit gastric ventilation.
Inflatable esophageal heat transfer device cycles to reduce core body temperature with gastric ventilation and re-inflation
A method for reducing core body temperature comprising nasally or orally inserting an esophageal heat transfer device having an input port, a lumen connected to the input port, and an inflatable heat transfer region configured for contacting a patient’s esophageal epithelium upon inflation, advancing the inflatable heat transfer region into the patient’s esophagus, initiating flow of a heat transfer medium along the fluid path to inflate the inflatable heat transfer region, deflating the inflatable heat transfer region to permit gastric ventilation, and re-inflating the inflatable heat transfer region.
Maintain gastric access during esophageal inflation and insert gastric tube
A method for reducing core body temperature comprising nasally or orally inserting an esophageal heat transfer device having one or more lumens configured to provide a fluid path to an inflatable heat transfer region configured for contacting a patient’s esophageal epithelium upon inflation, advancing the inflatable heat transfer region into the patient’s esophagus, initiating flow of a heat transfer medium along the fluid path to inflate the inflatable heat transfer region wherein gastric access is maintained upon inflation of the inflatable heat transfer region, and nasally or orally inserting a gastric tube into the patient.
The independent claims collectively cover a core temperature control system using an esophageal inflatable heat transfer region supplied by a lumen and controlled to inflate/deflate for gastric ventilation, and methods that implement the inflation/deflation cycling by nasally or orally inserting the esophageal heat transfer device, with a further method variant that maintains gastric access during inflation and includes inserting a gastric tube.
Stated Advantages
Relatively non-invasive patient temperature control.
Permits gastric ventilation by deflating the inflatable heat transfer region.
Enables control of therapeutic hypothermia and core body temperature targets.
Faster cooling/warming and higher heat extraction rates versus prior art (as described in the disclosure).
Minimal shivering and minimal deviation from target temperature during steady state (as described in the disclosure).
Documented Applications
Treating ischemic conditions, including ischemia-reperfusion injury, myocardial infarction, stroke, and traumatic brain injury (as described in the disclosure).
Cardiac and respiratory-related use cases described include cardiac arrest and cardiopulmonary resuscitation (CPR), and ARDS (as described in the disclosure).
Therapeutic hypothermia / core body temperature control for maintaining target temperatures such as below about 34°C and around 37°C (as described in the disclosure).
Animal experiments (swine) for temperature control/modulation performance (as described in the disclosure).
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