Systems for anesthetic agent vaporization

Abstract

Methods and systems are provided for delivering anesthetic agent to a patient. In one embodiment, a liquid anesthetic agent container includes a base region, an interior of the base region configured to hold liquid anesthetic agent and a capillary force vaporizer (CFV). The CFV can be configured to couple to a vapor reservoir of a patient breathing circuit to supply vaporized anesthetic agent vaporized by the CFV to a patient, the CFV comprising a heating element, a temperature of the heating element controllable by a driver of the patient breathing circuit based at least in part on a pressure of the vapor reservoir as measured by a pressure sensor coupled to the vapor reservoir.

What is claimed is: 
     
         1 . A liquid anesthetic agent container, comprising:
 a base region, an interior of the base region holding liquid anesthetic agent; and   a capillary force vaporizer (CFV) housed in an adapter region, the adapter region configured to couple to a vapor reservoir of a patient breathing circuit to supply vaporized anesthetic agent vaporized by the CFV to a patient, the CFV comprising a heating element, a temperature of the heating element controllable by a driver of the patient breathing circuit based at least in part on a pressure of the vapor reservoir as measured by a pressure sensor coupled to the vapor reservoir.   
     
     
         2 . The liquid anesthetic agent container of  claim 1 , wherein the adapter region comprises a coupling end that includes a fastener configured to couple to a complementary fastener of the patient breathing circuit. 
     
     
         3 . The liquid anesthetic agent container of  claim 2 , wherein the patient breathing circuit includes an anesthesia machine including the vapor reservoir, wherein the complementary fastener comprises a port of the anesthesia machine, and wherein when the adapter region is coupled to the vapor reservoir via the port, the anesthetic agent vaporized by the CFV is configured to flow to a gas passage of the anesthesia machine. 
     
     
         4 . The liquid anesthetic agent container of  claim 3 , wherein the adapter region includes an electrical connection configured to electrically couple the heating element of the CFV to the driver, and wherein a concentration of the vaporized anesthetic agent is estimated from the pressure of the vapor reservoir and based on a mass flow of fresh gas in the gas passage and one or more of a temperature of the vapor reservoir, a temperature of the CFV, and a position of a multi-outlet valve positioned upstream of the vapor reservoir. 
     
     
         5 . The liquid anesthetic agent container of  claim 4 , wherein the CFV comprises a wick, the wick extending into an interior of the liquid anesthetic agent container. 
     
     
         6 . The liquid anesthetic agent container of  claim 5 , wherein the driver is positioned at a bottom of the vapor reservoir. 
     
     
         7 . The liquid anesthetic agent container of  claim 1 , wherein the adapter region forms a neck of the liquid anesthetic agent container. 
     
     
         8 . The liquid anesthetic agent container of  claim 5 , wherein the liquid anesthetic agent travels along the wick via capillary action. 
     
     
         9 . The liquid anesthetic agent container of  claim 8 , wherein the wick supplies the liquid anesthetic agent to the heating element, wherein the heating element generates the vaporized anesthetic agent. 
     
     
         10 . A system, comprising:
 a liquid anesthetic agent container configured to hold liquid anesthetic agent and a capillary force vaporizer (CFV); and   a patient gas machine including a port configured to couple to the liquid anesthetic agent container, the port of the patient gas machine coupled to a vapor reservoir and wherein vaporized anesthetic agent is configured to flow to the patient gas machine via the port, the patient gas machine further comprising a controller and a proportional valve positioned downstream of the vapor reservoir and configured to control an amount of the vaporized anesthetic agent supplied to a patient, the controller storing instructions executable to adjust an amount of power supplied to a heating element of the CFV and adjust a position of the proportional valve based on the amount of power supplied to the heating element.   
     
     
         11 . The system of  claim 10 , wherein the patient gas machine comprises an anesthesia machine. 
     
     
         12 . The system of  claim 10 , wherein the patient gas machine comprises a ventilator. 
     
     
         13 . The system of  claim 10 , wherein the patient gas machine comprises a gas passage configured to flow fresh gas and adapted to fluidically couple to an outlet of the CFV, the patient gas machine further including at least one sensor coupled to the gas passage. 
     
     
         14 . The system of  claim 12 , wherein the controller stores instructions executable to adjust the amount of power supplied to the heating element to adjust a temperature of the heating element based on output from the at least one sensor. 
     
     
         15 . The system of  claim 14 , wherein the at least one sensor comprises a mass flow sensor, and wherein the instructions are executable to adjust the temperature of the heating element responsive to an estimated concentration of vaporized anesthetic agent differing from a setpoint concentration, the estimated concentration of vaporized anesthetic agent determined at least in part from output of the mass flow sensor. 
     
     
         16 . The system of  claim 14 , wherein the at least one sensor comprises a concentration sensor, and wherein the instructions are executable to adjust the temperature of the heating element responsive to a measured concentration of vaporized anesthetic agent differing from a setpoint concentration. 
     
     
         17 . A system, comprising:
 a liquid anesthetic agent container configured to hold liquid anesthetic agent;   a capillary force vaporizer (CFV) comprising a heating element;   a gas passage configured to flow fresh gas, the gas passage fluidically coupled to a vapor reservoir at a first junction;   a proportional valve positioned in an outflow passage coupled to the vapor reservoir and the gas passage at a second junction, downstream of the first junction;   at least one sensor coupled to the gas passage downstream of the second junction; and   a controller storing non-transitory instructions executable to:
 determine a concentration of vaporized anesthetic agent in the gas passage downstream of the vapor reservoir based on output from the at least one sensor; 
 adjust a temperature of the heating element based on a difference between the determined concentration and a setpoint concentration; and 
 adjust a position of the proportional valve based at least in part on the temperature of the heating element, a pressure of the vapor reservoir, or a combination thereof. 
   
     
     
         18 . The system of  claim 17 , wherein the at least one sensor comprises a concentration sensor positioned in the gas passage downstream of the vapor reservoir, and wherein adjusting the position of the proportional valve based on user input, the temperature of the heating element, and/or the pressure of the vapor reservoir comprises adjusting the position of the proportional valve based on the pressure of the vapor reservoir to maintain the pressure of the vapor reservoir below a maximum pressure above which condensation of the vaporized anesthetic agent occurs. 
     
     
         19 . The system of  claim 17 , wherein the at least one sensor comprises a first ultrasonic sensor positioned in the gas passage upstream of the vapor reservoir and a second ultrasonic sensor positioned in the gas passage downstream of the vapor reservoir. 
     
     
         20 . The system of  claim 19 , wherein the instructions are executable to determine the concentration of the vaporized anesthetic agent by:
 determining a first speed of sound in the gas passage upstream of the vapor reservoir based on output from the first ultrasonic sensor;   determining a second speed of sound in the gas passage downstream of the vapor reservoir based on output from the second ultrasonic sensor; and   determining the concentration of the vaporized anesthetic agent based on a difference between the first speed of sound and the second speed of sound.