Drug Delivery System And Method For Conscious Sedation/Analgesia

Abstract

Inhalant anesthetics are developed with a number of properties including rapid onset and recovery, controllability, and, ideally, a broad safety profile. The efficacy of these agents is measured by their ability to create anesthesia within the framework of the other desirable properties. The instant invention focuses on the dosage level where analgesia occurs but amnesia or lack of consciousness does not. In addition to identifying the dosage level where pain is sharply reduced or eliminated but awareness remains, a delivery system for safe and effective delivery of the agent is described.

What is claimed is: 
     
         1 . A method for delivery of a mixture to a patient effective to produce analgesia without loss of consciousness in a patient wherein the method comprises:
 a) forming a gaseous mixture of oxygen and a halogenated material selected from the group consisting of halogenated ethers and halothane by mixing oxygen with the halogenated material in a delivery manifold, the manifold having a controller configured to provide a gas having a concentration of the halogenated material that is limited to not more than about 0.636 MAC; and   b) controlling the proportions of oxygen and halogenated material in the gaseous mixture by metering a liquid flow of the halogenated material into a gas containing the oxygen such that the gaseous mixture comprises a ratio of oxygen to halogenated material effective for producing analgesia without loss of consciousness in the patient;   c) delivering said gaseous mixture to the patient to produce analgesia without loss of consciousness in the patient; and   d) performing a medical or dental intervention or procedure during analgesia while the patient is conscious.   
     
     
         2 . The method of  claim 1 , including one or more of the following:
 a. active analgesic agent recovery;   b. monitoring the patient with an EKG, NIBP, SaO2, and/or capnography, or other respiration monitoring; and/or   c. measuring oxygen concentration.   
     
     
         3 . The method of  claim 1  wherein the halogenated material is enflurane. 
     
     
         4 . The method of  claim 1  wherein the halogenated material is isoflurane. 
     
     
         5 . The method of  claim 1  wherein the halogenated material is sevoflurane. 
     
     
         6 . The method of  claim 1  wherein the halogenated material is desflurane. 
     
     
         7 . A system for delivering gas to a patient to produce analgesia without loss of consciousness in the patient comprising:
 a) an oxygen source;   b) a reservoir suitable for storing a liquid phase of an analgesia producing agent, the agent being a halogenated material selected from the group consisting of halogenated ethers and halothane;   c) a delivery manifold having a pair of inputs connected to the oxygen source and to the reservoir, respectively, and having an output, the manifold providing a gaseous mixture of oxygen and the analgesia producing agent by metering a flow of the liquid halogenated material into the oxygen, the manifold having a controller configured to provide the gaseous mixture such that the halogenated material is limited to not more than about 0.636 MAC for producing analgesia without loss of consciousness; and   d) means for conveying the gaseous mixture from the output of the delivery manifold to a patient for producing analgesia without loss of consciousness in the patient while a medical or dental intervention or procedure is carried out.   
     
     
         8 . The gas delivery system of  claim 7 , wherein the delivery manifold comprises a pressure regulator and a flow meter connected in fluid communication, the flow meter being in fluid communication with the output of the delivery manifold. 
     
     
         9 . The gas delivery system of  claim 8 , wherein the pressure regulator is in fluid communication with the input of the delivery manifold connected to the oxygen source and the flow meter is in fluid communication with the input of the delivery manifold connected to the reservoir. 
     
     
         10 . The gas delivery system of  claim 7 , further including heating means operatively associated with the reservoir containing analgesia producing agent and ambient temperature sensing means in controlling relation to a heating means to provide compensation for changes in environmental temperature conditions. 
     
     
         11 . The gas delivery system of  claim 7 , further including an oxygen flush arrangement operatively coupled between the oxygen source and a patient. 
     
     
         12 . The gas delivery system of  claim 7  wherein the oxygen source comprises a cylinder. 
     
     
         13 . The gas delivery system of  claim 7  wherein the reservoir comprises a cylinder. 
     
     
         14 . The gas delivery system of  claim 7  wherein the reservoir has a mated index. 
     
     
         15 . The gas delivery system of  claim 7  wherein the pressure regulator is digital. 
     
     
         16 . The gas delivery system of  claim 7  wherein the pressure regulator is analog. 
     
     
         17 . The gas delivery system of  claim 7  wherein a gas scavenging system is provided. 
     
     
         18 . A drug delivery system having a reservoir to provide halogenated material, the halogenated material being selected from the group consisting of halogenated ethers and halothane, wherein the reservoir is suitable for storing the halogenated material in a liquid phase, and a delivery manifold for providing a gaseous mixture of oxygen and the halogenated material by metering a flow of the liquid halogenated material into the oxygen, the manifold including a controller configured to provide a concentration of the halogenated material in a gas phase that is limited to not more than about 0.636 MAC for producing analgesia without loss of consciousness in a patient that is undergoing a medical or dental intervention or procedure. 
     
     
         19 . The drug delivery system of  claim 18 , wherein the halogenated material is halothane. 
     
     
         20 . The drug delivery system of  claim 18 , wherein the halogenated material is enflurane. 
     
     
         21 . The drug delivery system of  claim 18 , wherein the halogenated material is isoflurane. 
     
     
         22 . The drug delivery system of  claim 18 , wherein the halogenated material is sevoflurane. 
     
     
         23 . The drug delivery system of  claim 18 , wherein the halogenated material is desflurane. 
     
     
         24 . The drug delivery system of  claim 7 , including one or more of the following:
 a. a system for active analgesic agent recovery;   b. a system for monitoring the patient with an EKG, NIBP, SaO2, and/or capnography, or other respiration monitoring;   c. a system for measuring oxygen concentration;   d. a system for confirming the type of analgesic agent, which may include an RFID (Radio Frequency Identification Device), or bar code;   e. a system for collecting, storing and providing data about the operations of the conscious sedation system and/or the patient;   f. a system for holding the bottle that maintains pressure between the bottle and a conduit carrying analgesic agent from the bottle;   g. a system for pressurizing a reservoir that holds liquid analgesic agent;   h. one or more masks for delivering vaporized analgesic agent to a patient;   i. connectors facilitating connection of the drug delivery system to a centralized oxygen and/or scavenging system.