Respiratory system for inducing therapeutic hypothermia
The present invention provides a method and apparatus for controlling a patient's body temperature and in particular for inducing therapeutic hypothermia. Various embodiments of the system are described. The system includes: a source of breathing gas, which may be in the form of a compressed breathing gas mixture; a heat exchanger or other heating and/or cooling device; and a breathing interface, such as a breathing mask or tracheal tube. Optionally, the system may include additional features, such as a mechanical respirator, a nebulizer for introducing medication into the breathing gas, a body temperature probe and a feedback controller. The system can use air or a specialized breathing gas mixture, such as He/O 2 or SF 6 /O 2 to increase the heat transfer rate. In addition, the system may include an ice particle generator for introducing fine ice particles into the flow of breathing gas to further increase the heat transfer rate.
1. Apparatus for inducing therapeutic hypothermia, comprising:
a source of breathing gas;
a heat exchanger configured to exchange heat with a flow of breathing gas from the source;
an ice particle generator configured to introduce fine ice particles into the flow of breathing gas; and
a breathing interface configured to deliver the flow of breathing gas containing the fine ice particles to a patient.
2. The apparatus of claim 1 , wherein the source of breathing gas comprises a mechanical ventilator.
3. The apparatus of claim 1 , wherein the source of breathing gas comprises a mechanical ventilator configured to deliver ambient air to the apparatus.
4. The apparatus of claim 1 , wherein the source of breathing gas comprises a supply of compressed breathing gas.
5. The apparatus of claim 4 , wherein the compressed breathing gas comprises a mixture containing oxygen and helium.
6. The apparatus of claim 4 , wherein the compressed breathing gas comprises a mixture containing oxygen and sulfur hexafluoride.
7. The apparatus of claim 1 , wherein the ice particle generator includes a source of water and an atomizer for introducing fine droplets of water into the flow of breathing gas.
8. The apparatus of claim 1 , wherein the ice particle generator includes a source of saline solution and an atomizer for introducing fine droplets of saline solution into the flow of breathing gas.
9. The apparatus of claim 7 , wherein the atomizer is an ultrasonic atomizer.
10. The apparatus of claim 7 , wherein the ice particle generator includes a chiller for cooling the water prior to atomization.
11. The apparatus of claim 1 , wherein the heat exchanger is configured to selectively cool or heat the flow of breathing gas from the source.
12. The apparatus of claim 1 , further comprising a temperature sensor for measuring body temperature of the patient.
13. The apparatus of claim 11 , further comprising a feedback controller for controlling operation of the apparatus based on the measured body temperature of the patient.