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Publication Number
US-8343097-B2
Publication Date
2013-01-01
Expiration Date
Abstract
Methods and systems for infusing a cooled infusate to a target location in a patient are described. A temperature of the blood and infusate admixture upstream of the catheter as well as at other locations along the catheter may be monitored and a feedback system utilized to control the volume, temperature, and/or infusion rate of the infusate so as to achieve a predetermined temperature at the target location. Control may also be based on the patient's native vessel flow rate. The system may monitor or calculate hematocrit upstream of the catheter and adjust infusion so as to provide sufficient oxygenation of the blood and infusate admixture. The system may also monitor reflux of the infusate past a distal end of the catheter and reduce infusion upon the detection of reflux.
Core Innovation
The invention relates to an intravascular cooling catheter system that includes an insertion device adapted to fluidicly communicate with a source of an infusate. A controller controls a temperature of the infusate in accordance with a temperature of a blood and infusate mixture downstream of an infusate exit location while the insertion device is placed in a blood vessel of a patient with a downstream flow of blood for infusion of the infusate.
The controller also controls at least one of an infusion rate of the infusate or a volume of the infusate passing through the insertion device in a downstream direction in accordance with a native vessel flow rate in the blood vessel. The invention further includes sensor-based determination of native vessel flow rate, including monitoring plateauing of the native vessel flow rate, and control of infusate delivery in accordance with that native vessel flow rate.
The invention also calculates a hematocrit of the blood and infusate mixture downstream of an exit location, wherein the hematocrit is calculated downstream the exit location using a dilution factor dF and the relationship Hct*(1−dF). The controller uses infusion rate and a blood-per-unit-time term X represented by equations using multiple temperatures and a core body temperature, to support hematocrit-based control of infusion rate and/or infused volume.
The invention further specifies a multi-sensor architecture and placement that support downstream and near-exit conditioning of control. A device can include a plurality of temperature sensors with a first temperature sensor positioned downstream relative to the infusate exit location, a second temperature sensor to measure the temperature of the infusate at least one of at and adjacent the exit location, a third temperature sensor to measure a temperature outside the insertion device upstream and adjacent the exit location, and a fourth temperature sensor to measure a core body temperature of the patient.
Claims Coverage
The partial set includes six independent claims, with inventive features centered on downstream mixture-temperature control, native vessel flow-rate-based infusion rate/volume control, multi-sensor placement for downstream and near-exit measurements, and downstream hematocrit computation used for infusion control.
Downstream mixture temperature and native flow-rate control of infusion
A device with an insertion device adapted to fluidicly communicate with a source of an infusate and a controller adapted to control a temperature of the infusate in accordance with a temperature of a blood and infusate mixture downstream of an infusate exit location while the insertion device is placed in a blood vessel of a patient with a downstream flow of blood for infusion of the infusate, wherein the controller controls at least one of an infusion rate and a volume of the infusate passing through the insertion device in accordance with a native vessel flow rate in the blood vessel.
Native vessel flow-rate sensor signals to control infusion rate and volume
A device with an insertion device adapted to fluidicly communicate with a source of an infusate, a plurality of sensors, and a controller adapted to receive signals from the sensors indicative of a native vessel flow rate in a blood vessel and to control at least one of an infusion rate of the infusate and a volume of the infusate passing through the insertion device in accordance with the signals from the sensors.
Four temperature sensors including downstream mixture, near-exit infusate, upstream external, and core temperature
A device with an insertion device, a plurality of temperature sensors comprising a first temperature sensor positioned downstream relative to an infusate exit location adapted to measure a temperature of an infusate and blood mixture, a second temperature sensor adapted to measure a temperature of the infusate at least one of at and adjacent the exit location, a third temperature sensor adapted to measure a temperature outside the insertion device upstream and adjacent the exit location, and a fourth temperature sensor adapted to measure a core body temperature of the patient, and a controller adapted to receive signals from the temperature sensors and control a characteristic of the infusate in accordance with signals received from at least one of the plurality of temperature sensors.
Downstream hematocrit computed from dilution factor and temperature terms for infusion control
A device with an insertion device and a controller adapted to control at least one of an infusion rate through the insertion device and a volume passing through the insertion device in accordance with a hematocrit of a blood and infusate mixture downstream of an exit location, wherein hematocrit is calculated downstream the exit location using the equation (Hct)*(1−dF), wherein dF=(infusion rate)/(infusion rate+X), wherein X=(infusion rate*(T1−T2)/(T4−T1)), T1 is a temperature of the blood and infusate mixture downstream the exit location, T2 is a temperature of the infusate at least one of at and adjacent the exit location, T3 is temperature adjacent to and upstream the exit location, and T4 is the core body temperature of the patient.
Downstream hematocrit based on base whole body hematocrit and dilution for infusion rate/volume control
A device with an insertion device and a controller adapted to control at least one of an infusion rate through the insertion device and a volume of infusate passing through the insertion device in accordance with a hematocrit of a blood and infusate mixture downstream of an exit location, wherein hematocrit is calculated using a base whole body hematocrit of the patient (Hct) and dilution of the blood (dF).
The inventive features center on using downstream blood and infusate mixture temperature and/or downstream blood-and-infusate mixture hematocrit, combined with a native vessel flow rate to control infusion rate and/or volume. Additional coverage specifies controller architectures that receive signals from multiple temperature sensors at defined locations relative to the infusate exit, and hematocrit calculation using base whole body hematocrit and dilution or the Hct*(1−dF) formulation with dF and X based on infusion rate and temperature terms.
Stated Advantages
Documented Applications
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