Method for inducing hypothermia

Abstract

Systems for phase-change particulate slurry cooling equipment and methods to induce hypothermia in a patient through internal and external cooling are provided. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.

Description

RELATED APPLICATIONS[0001]This application is a continuation of U.S. patent application Ser. No. 11 / 124,958 filed May 9, 2005, now U.S. Pat. No. 7,422,601, issued Sep. 9, 2008, which is a continuation of U.S. patent application Ser. No. 10 / 162,442, filed Jun. 3, 2003, by Lance B. Becker et al., entitled “Method for Inducing Hypothermia,” now U.S. Pat. No. 6,962,601 issued Nov. 8, 2005, which is a continuation-in-part of U.S. patent application Ser. No. 09 / 586,576, filed Jun. 2, 2000, by Kenneth E. Kasza, entitled “Method And Apparatus For Producing Phase Change Ice Particulate Saline Slurries,” now U.S. Pat. No. 6,413,444 issued Jul. 2, 2002, and U.S. patent application Ser. No. 09 / 632,195, filed Aug. 2, 2000, by Lance B. Becker, Terry Vanden Hoek, and Kenneth E. Kasza, entitled “Method For Inducing Hypothermia,” now U.S. Pat. No. 6,547,811 issued Apr. 15, 2003, each of which claims the benefit of priority under 35 U.S.C. § 119(3) to U.S. Provisional Application No. 60 / 146,753, file...

AI Technical Summary

Benefits of technology

[0011]The present invention provides for the application of phase-change particulate slurry cooling systems, equipment, and methods designed for cooling patients rapidly and safely. Subcutaneous, intravascular, intraperitoneal, gastrointestinal, and lung methods of cooling are carried out using saline ice slurries or other phase-change slurries compatible with human tissue. Perfluorocarbon slurries or other slurry types compatible with human tissue are used for pulmonary cooling. And traditional external cooling methods are improved by utilizing phase-change slurry materials in cooling caps and torso blankets.

[0012]Since cardiac arrest represents a no or low blood flow state (low blood flow is achieved, for example, with chest compressions) in which cells begin to die within minutes, the rapid induction of moderate to profound hypothermia during cardiac arrest can serve a highly protective function. The use of high fluidity phase-change slurry materials with the capacity for effective internal cooling of such patients makes it possible to cool a victim of cardiac arrest within minutes. Rapid induction of hypothermia during cardiac arrest in a pre-hospital setting can significantly improve a patient's outcome by protecting cells of the brain and heart until blood flow can be reestablished at the hospital using existing cardiac bypass technology.

Problems solved by technology

It is well known that hypothermia can postpone damage to tissues caused by inadequate blood flow and oxygen deprivation.

Despite widespread use of basic life support and advanced cardiac life support by paramedics, survival of cardiac arrest patients is usually less than 2-4%, in large part because cells of the brain and the heart begin to die within minutes following global ischemia, or inadequate blood flow.

However, rapid and significant cooling (within 10 minutes, and to a temperature of 34° C. or less) of a patient without blood flow in a pre-hospital setting has been unachievable.

External cooling methods have not been found effective in achieving the desired rates of cooling.

Several studies by the applicants highlight the fact that current techniques of surface cooling alone are not effective for the rapid induction of hypothermia.

This results in a cooling rate of less than 6° C. per hour, not rapid enough for protective use during cardiac arrest.

), achieving a nearly maximally effective surface heat transfer coefficient, the lack of blood flow during cardiac arrest prevents achieving the desired protective core cooling rates.

The physics of thermal heat-transfer creates a formidable challenge to rapid cooling of a human with little or no circulation.

This is particularly problematic since the brain and heart are the targets of the cooling process.

The difficulty is that without a pulse or adequate perfusion, there is very little transfer of heat from the deeper tissues to the superficial tissues.

Unfortunately, the speed of cooling with these techniques is too slow to avoid a lethal outcome due to ischemic reperfusion injury to vital organs, including the heart and brain.

Images