Respirator having a trigger sensitivity dependent on the patient gas flow
First Claim
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1. A respirator comprising:
- an inspiration line and an expiration line each adapted for connection to the respiratory path of a patient, and said inspiration line connected to a source of respiratory gas;
first valve means disposed in said inspiration line for setting gas flow through said inspiration line;
second valve means disposed in said expiration line for setting gas flow through said expiration line, said expiration line having a pressure therein;
control means for operating said first and second valve means for producing a respiratory cycle having an inspiration phase and an expiration phase, including maintaining said first valve means open during said expiration phase to an extent for producing an adjustable bypass gas flow in said inspiration line;
pressure sensor means for identifying the pressure in said expiration line;
means for setting a pressure trigger limit;
trigger means, connected to said pressure sensor means and to said control means, for triggering a new inspiration phase when the pressure, measured by said pressure sensor means, in said expiration line during said expiration phase falls below said pressure trigger limit;
flow meter means, connected to said trigger means and to said control means, for identifying patient gas flow; and
means in said control means for automatically changing said pressure trigger limit dependent on said patient gas flow identified by said flow meter means.
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Abstract
A respirator has a bypass gas flow and respective valves in the inspiration and expiration lines for setting the gas flow through these lines. A control unit actuates the valves so that a respiratory cycle is produced and such that the bypass gas flow is maintained during expiration. The expiration pressure is identified by a pressure sensor. When this expiration pressure falls below a prescribed value, a new inspiration phase is triggered. To improve this triggering, the patient gas flow is identified by a flow meter, and the prescribed pressure value is varied dependent on the identified patient gas flow.
138 Citations
13 Claims
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1. A respirator comprising:
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an inspiration line and an expiration line each adapted for connection to the respiratory path of a patient, and said inspiration line connected to a source of respiratory gas; first valve means disposed in said inspiration line for setting gas flow through said inspiration line; second valve means disposed in said expiration line for setting gas flow through said expiration line, said expiration line having a pressure therein; control means for operating said first and second valve means for producing a respiratory cycle having an inspiration phase and an expiration phase, including maintaining said first valve means open during said expiration phase to an extent for producing an adjustable bypass gas flow in said inspiration line; pressure sensor means for identifying the pressure in said expiration line; means for setting a pressure trigger limit; trigger means, connected to said pressure sensor means and to said control means, for triggering a new inspiration phase when the pressure, measured by said pressure sensor means, in said expiration line during said expiration phase falls below said pressure trigger limit; flow meter means, connected to said trigger means and to said control means, for identifying patient gas flow; and means in said control means for automatically changing said pressure trigger limit dependent on said patient gas flow identified by said flow meter means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for operating a respirator having an inspiration line and an expiration line each adapted for connection to the respiratory path of a patient, and said inspiration line connected to a source of respiratory gas, said method comprising the steps of:
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providing a first value disposed in said inspiration line and a second valve disposed in said expiration line; setting gas flow through said inspiration line by operating said first valve disposed in said inspiration line;
setting gas flow through said expiration line by operating said second valve disposed in said expiration line;operating said first and second valves to produce a respiratory cycle having an inspiration phase and an expiration phase and maintaining said first valve open during said expiration phase to an extent for producing an adjustable bypass gas flow in said inspiration line; providing a pressure sensor in said expiration line and sensing the pressure in said expiration line using said pressure sensor; setting a pressure trigger limit; triggering a new inspiration phase when the pressure sensed in said expiration line by said pressure sensor during said expiration phase falls below said pressure trigger limit; identifying patient gas flow; and automatically changing said pressure trigger limit dependent on said patient gas flow. - View Dependent Claims (12, 13)
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Specification