Method and apparatus for controlling a patient's body temperature by in situ blood temperature modification

Abstract

The present invention provides a method and apparatus for controlling the internal body temperature of a patient. According to the present invention, a catheter is inserted through an incision into a large blood vessel of a patient. By selectively heating or cooling a portion of the catheter lying within the blood vessel, heat may be transferred to or from blood flowing within the vessel and the patient's body temperature may thereby be increased or decreased as desired. The invention will find use in treating undesirable conditions of hypothermia and hyperthermia, or for inducing a condition of artificial hypothermia when desired. The method and system further provide for the cooling of initially hypothermic patients whose blood or body temperature has been warmed above the desired target level and the warming of initially hyperthermic patients whose blood or body temperature has been cooled below the desired target temperature.

Description

RELATED APPLICATIONS[0001]This patent application is a continuation of copending U.S. patent application Ser. No. 11 / 044,997 filed Jan. 26, 2005, which is a continuation of U.S. patent application Ser. No. 10 / 643,321 filed Aug. 19, 2003 and now issued as U.S. Pat. No. 6,849,083, which is a continuation of U.S. patent application Ser. No. 10 / 004,579 filed Dec. 4, 2001 and now issued as U.S. Pat. No. 6,635,076 which is a continuation of U.S. patent application Ser. No. 09 / 522,135 filed on Mar. 9, 2000 and now issued as U.S. Pat. No. 6,436,131 which is a continuation of U.S. patent application Ser. No. 09 / 131,081 filed Aug. 7, 1998 and now issued as U.S. Pat. No. 6,149,676 which is a division of Ser. No. 08 / 584,013 filed Jan. 8, 1996 and now issued as U.S. Pat. No. 5,837,033, the entire disclosures of which are incorporated herein by reference. This application does not claim priority prior to Jan. 8, 1996.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present inve...

AI Technical Summary

Benefits of technology

The present invention provides a system and method for restoring normal body temperature in patients who are initially hypothermic or hyperthermic. The system includes an intravascular catheter with heating and cooling capabilities, a control unit, and a temperature sensor. The method involves selectively heating or cooling the patient's blood flow to achieve the desired target temperature. The system can be used in both hypothermic and hyperthermic patients, and the method can be performed using the same intravascular catheter or an external control unit. The invention allows for the safe and effective restoration of normal body temperature in patients without causing further damage or discomfort.

Problems solved by technology

Accidental hypothermia results when heat loss to the environment exceeds the body's ability to produce heat internally.

In many cases, thermoregulation and heat production are normal but the patient becomes hypothermic due to overwhelming environmental cold stress.

Hypothermia of either type is a dangerous condition which can have serious medical consequences.

In particular, hypothermia interferes with the ability of the heart to pump blood.

Hypothermia may be fatal for this reason alone.

Additionally, low body temperature seriously interferes with the enzymatic reactions necessary for blood clotting.

This sometimes results in bleeding that is very difficult to control, even when normal clotting factor levels are present.

These effects and other adverse consequences of hypothermia lead to drastically increased mortality rates both among victims of trauma and in patients undergoing surgery.

While the direct heating of patient blood can be highly effective, even in treating severe and profound cases of hypothermia, it has been observed by the inventor herein that the excess transfer of heat can cause the patient's temperature to rise above normal body temperature, resulting in hyperthermia.

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