초록 ▼

Inhalation methods and apparatus are provided for performing xenon-enhanced studies or tests. The present invention is useful during computed tomography studies to provide neurologists with accurate yet relatively inexpensive measurements of cerebral blood flow. The apparatus includes a variable vol

Inhalation methods and apparatus are provided for performing xenon-enhanced studies or tests. The present invention is useful during computed tomography studies to provide neurologists with accurate yet relatively inexpensive measurements of cerebral blood flow. The apparatus includes a variable volume xenon/oxygen chamber for obtaining a closed-loop arrangement with the patient, thereby minimizing xenon gas usage during the study. According to the method of the invention, the volume of the xenon/oxygen chamber is reduced during a first phase of the study, while the patient\s lung xenon concentration increases. The second phase is initiated when the variable chamber obtains a selected minimum value, after which exhalation returns to the chamber. During the second phase, oxygen and xenon are added to the closed loop system to maintain the desired concentrations, carbon dioxide is removed, and the chamber volume slowly increases. Apart from xenon inhalation studies, the method and apparatus have utility for a wide range of inhalation procedures, especially those involving relatively expensive inhalation gases.

대표청구항 ▼

Apparatus for conducting xenon-enhanced inhalation of a patient\s lungs during neurological studies, including an oxygen source, a xenon source, and a patient breathing mask for transmitting inhalation gas to said patient, the improvement comprising: a flexible bag defining a variable volume chamber

Apparatus for conducting xenon-enhanced inhalation of a patient\s lungs during neurological studies, including an oxygen source, a xenon source, and a patient breathing mask for transmitting inhalation gas to said patient, the improvement comprising: a flexible bag defining a variable volume chamber for receiving said inhalation gas, said bag having an inhalation port and an exhalation port; conduit means interconnected to said inhalation port, said patient breathing mask, and said exhalation port for series connecting said variable volume chamber and said patient\s lungs in a closed loop; a gas discharge port in fluid communication with said conduit means for releasing gas from said closed loop; oxygen sampling means in fluid communication with said conduit means for detecting oxygen concentration within said closed loop; xenon sampling means in fluid communication with said conduit means for detecting xenon concentration within said closed loop; control means for providing preselected oxygen and xenon concentration values; oxygen input valve means in fluid communication with said conduit means for selectively inputting oxygen from said oxygen source to said closed loop in response to a detected oxygen concentration value from said oxygen sampling means less than said preselected oxygen concentration value from said control means; xenon input valve means in fluid communication with said conduit means for selectively inputting xenon from said xenon source to said closed loop to response to a detected xenon concentration value from said xenon sampling means less than said preselected xenon concentration value from said control means; carbon dioxide removal means in fluid communication with said conduit means for removing carbon dioxide from said inhalation gas within said closed loop; volume indicator means for detecting when said variable volume chamber obtains a predetermined minimum volume; and first valve means responsive to said volume indicator means for closing said gas discharge port and terminating gas discharge from said closed loop when said variable volume chamber obtains said predetermined minimum value; wherein substantially all xenon gas is thereafter repeatedly exhaled from said patient\s lungs to said flexible bag and retained within said closed loop.