Systems and methods for endotracheal delivery of frozen particles

Abstract

A treatment system delivers a breathing gas and frozen ice or other particles (FSP) to a bronchus of a lung of a patient in order to induce hypothermia. The breathing gas and the FSP are usually delivered through separate lumens. Clogging of an FSP lumen can be inhibited by heating and/or cooling of the lumen. The temperature of exhaled gases or a body temperature may be measured, and a controller can adjust the duration or rate at which the ice particles are delivered in order to control the patient's core temperature based on the measured temperature.

What is claimed is: 
     
         1 . A system for lowering a core body temperature of a patient to be used in combination with an external ventilator configured to deliver a breathing gas to a bronchus of a lung of the patient, said system comprising:
 a tubular device configured for advancement through the patient's trachea to the bronchus, said tubular device having a breathing lumen and a frozen particle (FSP) lumen isolated from the breathing lumen;   an external FSP source configured to deliver FSP to the FSP lumen of the tubular device; and   a controller configured to adjust the amount or rate of delivery of FSP from the external FSP source through the at least one FSP lumen, whereby a target core temperature of the patient can be achieved and maintained by adjusting the amount or rate of delivery of the FSP; and   means for inhibiting clogging of the FSP lumen resulting from melting and refreezing of the FSP in the lumen.   
     
     
         2 . A system as in  claim 1 , wherein the means for inhibiting clogging of the FSP lumen comprises a heater configured to heat the FSP lumen to inhibit clogging of the FSP lumen resulting from melting and refreezing of the FSP in the lumen. 
     
     
         3 . A system as in  claim 2 , wherein the heater comprises electrical tracing positioned over at least a portion of the FSP lumen. 
     
     
         4 . A system as in  claim 1 , wherein the means for inhibiting clogging of the FSP lumen comprises a cooler configured to cool the FSP lumen to inhibit clogging of the FSP lumen resulting from melting and refreezing of the FSP in the lumen. 
     
     
         5 . A system as in  claim 1 , further comprising a sensor configured to measure a temperature of an exhaled gas or body temperature, wherein the controller adjusts the amount or rate of delivery of FSP through the FSP lumen in response to changes in the measured temperature. 
     
     
         6 . A system as in  claim 1 , wherein the controller is configured to automatically control the delivery amount or rate of FSP in response to the measured temperature according to a feedback control algorithm. 
     
     
         7 . A system as in  claim 4 , wherein the controller is configured to allow a user to manually control the delivery amount or rate of FSP delivery in response to the measured temperature. 
     
     
         8 . A system as in  claim 1 , wherein the external FSP source comprises a means for providing a bolus of FSP and flowing a volume of carrier gas through the bolus to entrain the FSP in the flowing carrier gas to produce an FSP-entrained flowing carrier gas stream. 
     
     
         9 . A system as in  claim 8 , wherein the external FSP source further comprises a means for venting a portion of the carrier gas from the FSP-entrained flowing carrier gas stream to produce a gas reduced FSP-entrained flowing carrier gas stream, wherein said gas reduced FSP-entrained flowing carrier gas stream is delivered to the FSP lumen. 
     
     
         10 . A system as in  claim 9 , wherein the controller is configured to control venting of the carrier gas to produce a tidal volume of total breathing gas delivered to the patient in the range from 150 ml to 1000 ml per inhalation cycle. 
     
     
         11 . A system as in  claim 10 , wherein the controller is configured to vent at least 50% of the gas originally present in the FSP-entrained flowing carrier gas stream to produce the gas reduced FSP-entrained flowing carrier gas stream.