Analgesic anaesthetic compositions
AssigneeAberdeen University
InventorsJohn Alexander Strachan Ross, Michael Eric Tunstall, Robert Colin Rodgers
Life of this patent
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Abstract
An analgesic anaesthetic composition comprising up to 50% v.backslash.v nitrous oxide, the balance being oxygen and another respirable gas; characterized by the addition of an analgesically effective amount of an ether-based analgesic anaesthetic disposed in a single container above its pseudo-critical temperature at a pressure of up to 2000 psi, thereby to form and maintain a homogenous analgesic composition.
Claims5
An analgesic anesthetic composition comprising up to 50% v/v nitrous oxide, an analgesically effective amount of an ether-based analgesic anesthetic selected from the group consisting of isoflurane, enflurane, sevoflurane, and desflurane and the balance being oxygen and another respirable gas disposed in a single container above its pseudo-critical temperature at a pressure of up to 2000 psi, thereby to form and maintain an analgesically effective homogenous composition in use.
A method of minimizing fluctuations in the concentration of an analgesic anaesthetic composition administered from a pressurized container via a first stage reduction chamber, said composition comprising up to 50% v/v nitrous oxide, an effective amount of an ether-based analgesic anaesthetic selected from the group consisting of isoflurane, enflurane, sevoflurane, and desflurane and a balance of oxygen or other respirable gas mixture, which method comprises at least one of the following steps:
- (I) maintaining the pressure drop between the container and a first reduction chamber at a value of less than 62 bar;
- or
- (II) arranging a 1 liter/minute gas bleed from the reduction chamber associated with the demand flow control mechanism, or
- (III) mechanically discarding or diluting the first breath after a rest period from the apparatus at the inception of inhalation;
- or
- (IV) using an absorbative system in the breathing system to take up any of said ether-based analgesic anaesthetic which has liquidized.
Dependencies are inferred from the claim text.