Inhalation-based control of medical gas

Apparatus for administering medical gas from a source thereof to the respiratory tract of a patient in the course of a cycle of inhalation and exhalation and in correspondence with a select application rate, comprising:

• a medical gas circuit connectable with said source and having a gas application valve actuable for a pulse forming interval to apply said medical gas to said patient through an application conduit conveying an inhalation and expiration pressure condition of said patient;
• a pressure sensor coupled with said medical gas circuit and having a sensing output in response to the said presence of a said inhalation pressure condition through said application conduit for said cycle;
• an amplifier responsive to said sensing output for deriving an amplified sensing signal;
• a comparator responsive to a threshold input of predetermined level and to said amplified sensing signal for deriving a triggering output in correspondence with said inhalation pressure condition;
• a pulse timer responsive to said triggering output for deriving a pulse output of select duration for effecting said actuation of said gas application valve for said select duration;
• and
• next pulse timing means responsive to said pulse output for effecting the derivation of said triggering output a predetermined interval subsequent to said pulse output in the continued and uninterrupted presence of said sensing output representing said inhalation during said cycle.

Apparatus for administering medical gas from a source thereof at source pressure to the respiratory tract of a patient comprising:

• a solenoid valve having a winding energizable to assume a gas transfer orientation from a closed orientation;
• a first gas transfer path connectable with said source and in gas transfer relationship with said solenoid valve;
• a bypass valve manually adjustable from a closed position to provide select gas flow rates;
• a second gas transfer path connectable with said source and in gas transfer relationship with said bypass valve;
• a third gas path connected in gas transfer relationship to said bypass valve and said solenoid valve and operably associated with said patient respiratory tract;
• a variable area gas flow meter including a transparent tubular housing, a ball therein responsive in gas buoyancy to fluid flow through said housing, and gas flow rate indicia upon said housing, coupled within said second gas transfer path;
• and
• control means for selectively energizing said solenoid winding.

The method for supplying medical gas to the respiratory system of a patient during the course of inhalation and exhalation comprising the steps of:

• providing a supply of said gas under regulated pressure;
• providing a gas conduit input positionable upon said patient and responsive to the instantaneous pressures of said patient respiratory system to exhibit a negatively categorized pressure upon said inhalation;
• detecting the commencement of said negatively categorized pressure;
• providing a first pulse supply of predetermined duration of said gas to said patient in a quantity corresponding with a select gas application rate, substantially at said detected commencement of negatively categorized pressure;
• and
• providing a second pulse supply of predetermined duration of said gas to said patient in the presence of said negatively categorized pressure and following a first predetermined delay interval of about 0.6 second.

The method for supplying medical gas to the respiratory system of a patient during the course of inhalation and exhalation comprising the steps of:

• providing a supply of said gas under regulated pressure;
• providing a gas conduit input positionable upon said patient and responsive to the instantaneous pressures of said patient respiratory system to exhibit a negatively categorized pressure upon said inhalation;
• detecting the commencement of said negatively categorized pressure;
• providing a first pulse supply of predetermined duration of said gas to said patient in a quantity corresponding with a select gas application rate, substantially at said detected commencement of negatively categorized pressure;
• providing a second pulse supply of predetermined duration of said gas to said patient in the presence of said negatively categorized pressure and following a first predetermined delay interval;
• and
• providing a third pulse supply of said gas of predetermined duration to said patient in the presence of said negatively categorized pressure and following a second interval of about 0.6 second subsequent to said first predetermined interval.

Apparatus for administering medical gas from a source thereof to the respiratory tract of a patient in correspondence with a select application rate, comprising:

• a medical gas circuit connectable with said source and having a gas application valve actuable for a pulse forming interval to apply said medical gas to said patient through an application conduit conveying an inhalation and expiration pressure condition of said patient;
• a pressure sensor coupled with said medical gas circuit and having a sensing output in response to the said presence of a said inhalation pressure condition through said application conduit;
• an amplifier responsive to said sensing output for deriving an amplified sensing signal;
• a comparator responsive to a threshold input of predetermined level and to said amplified sensing signal for deriving a triggering output in correspondence with said inhalation pressure condition;
• a pulse timer responsive to said triggering output for deriving a pulse output of select duration for effecting said actuation of said gas application valve for said select duration;
• and
• next pulse timing means responsive to said pulse output for effecting the derivation of said triggering output an interval of about 0.6 seconds subsequent to said pulse output in the presence of said sensing output.

Apparatus for administering medical gas from a source thereof to the respiratory tract of a patient in correspondence with a select application rate, comprising:

• a medical gas circuit connectable with said source and having a gas application valve actuable for a pulse forming interval to apply said medical gas to said patient through an application conduit conveying an inhalation and expiration pressure condition of said patient;
• a pressure sensor coupled with said medical gas circuit and having a sensing output in response to the said presence of a said inhalation pressure condition through said application conduit;
• said medical gas circuit including a conduit path extending from said application conduit to said pressure sensor;
• said gas application valve being operatively associated with said conduit path between said pressure sensor and said patient;
• a check valve within said conduit path between said gas application valve and said pressure sensor and configured for restricting response of said pressure sensor to only negative inhalation gas pressures;
• an amplifier responsive to said sensing output for deriving an amplified sensing signal;
• a comparator responsive to a threshold input of predetermined level and to said amplified sensing signal for deriving a triggering output in correspondence with said inhalation pressure condition;
• a pulse timer responsive to said triggering output for deriving a pulse output of select duration for effecting said actuation of said gas application valve for said select duration;
• and
• next pulse timing means responsive to said pulse output for effecting the derivation of said triggering output a predetermined interval subsequent to said pulse output in the presence of said sensing output.

Apparatus for administering medical gas from a source thereof at source pressure to the respiratory tract of a patient comprising:

• a solenoid valve having a winding energizable to assure a gas transfer orientation from a closed orientation;
• a first gas transfer path connectable with said source and in gas transfer relationship with said valve;
• a bypass valve manually adjustable to provide select gas flow rates;
• a second gas transfer path connectable with said source and in gas transfer relationship with said bypass valve;
• a third gas path connected in gas transfer relationship to said bypass valve and said solenoid valve and operably associated with said patient respiratory tract;
• a check valve within said third gas transfer path for effecting conveyance of said negative pressures to said gas pressure sensor and blocking conveyance of positive gas pressures thereto;
• a variable area gas flow meter including a transparent tubular housing, a ball therein responsive in gas buoyancy to fluid flow through said housing, and gas flow rate indicia upon said housing, coupled within said second gas transfer path;
• and
• control mean for selective energizing said solenoid winding and including a gas pressure sensor coupled with said third gas transfer path and responsive to negative pressures therein to effect energization of said solenoid winding.