Abstract: An oxygen concentrator comprises a plurality of adsorbent columns, each having an inlet, an outlet and abed of adsorbent material. The oxygen concentrator also includes a vacuum pump for removing separated nitrogen rich gas from the column inlets, a control valve for controlling flow of fluids in and out of the columns, and a breakthrough sensor for signaling the position of a mass transfer zone (MTZ), the breakthrough sensor controlling operation of the control valve as a function of the breakthrough sensor signal. An electric control module (ECM) receives the signal from the breakthrough sensor, and adjusts the control valve based on the signal.

Abstract: A device for delivering a breathing gas to an on-demand breathing mask (23) comprises—an Onboard Oxygen Generator (1) comprising an oxygen-rich gas outlet end; —compressor means (7) comprising inlet means (6) and outlet means (12), said inlet means being connected to oxygen-rich gas outlet end of said Onboard Oxygen Generator (1) for receiving said gas, said compressor means being operable to increase the pressure of said gas for delivery from said outlet means to the on-demand breathing mask. The device further comprises a connecting means (17) to connect said compressor outlet means (12) to said compressor inlet means (6) so that oxygen-rich gas in excess at the outlet means is redirected to the inlet means.

Abstract: The invention relates to a gas-supply system for patients receiving artificial respiration or breathing spontaneously, in which one or several gases (for example NO, oxygen) are added to the respiration gas at varying proportions (continuously or intermittently) by means of a control device (program control, sensor control or combined program/sensor control). This gas-supply system allows for adaptive dosing of the gas to suit individual patients.

Abstract: In one embodiment, the invention provides a device for decreasing intracranial or intraocular pressures. The device comprises a housing having an inlet opening and an outlet opening that is adapted to be interfaced with a person's airway. The device further includes a valve system that is operable to regulate respiratory gas flows through the housing and into the person's lungs during spontaneous or artificial inspiration. The valve system assists in lowering intrathoracic pressures during each inspiration to repetitively lower pressures in the venous blood vessels that transport blood out of the head to thereby reduce intracranial or intraocular pressures.

Abstract: A portable oxygen concentrator includes a reservoir adapted to store oxygen-enriched gas, a delivery valve adapted to communicate with the reservoir, a pressure sensor adapted to measure a reservoir pressure within the reservoir and to measure a pressure drop across the delivery valve, and an input device adapted to receive a pulse does setting. A controller coupled to the pressure sensor and monitors the reservoir pressure and the pressure drop across the delivery valve. The controller is also coupled to the delivery valve to selectively open the delivery valve for pulse durations based on the pulse dose setting to deliver pulses of gas from the reservoir to a user. The controller further adjusts the pulse durations based at least partially upon the reservoir pressure and the pressure drop across the delivery valve.

Abstract: A pressure support system and method of treating disordered breathing that optimizes the pressure delivered to the patient to treat the disordered breathing while minimizing the delivered pressure for patient comfort. The controller in the pressure support system operates as a set of prioritized control layers, wherein each control layer competes for control of the pressure generating system to implement a unique pressure control process. The pressure support system also controls the pressure provided to the patient based on the variability of the monitored data and a trend analysis of this data, including an indication of the skewness of the patient's inspiratory waveform.

Abstract: Described herein are nasal respiratory devices, in particular, nasal respiratory devices configured to achieve positive end-expiratory pressure (PEEP) in a subject wearing the device. PEEP devices may have a threshold pressure for opening during expiration. In some variations, these devices have a threshold pressure for closing during expiration.

Abstract: Methods and apparatus for determining the occurrence of an apnea, patency and/or partial obstruction of the airway are disclosed. Respiratory air flow from a patient is measured to give an air flow signal. The determination of an apnea is performed by calculating the variance of the air flow signal over a moving time window and comparing the variance with a threshold value. One determination of partial obstruction of the airway is performed by detecting the inspiratory part of the air flow signal, scaling it to unity duration and area and calculating an index value of the amplitude of the scaled signal over a mid-portion. Alternatively, the index value is a measure of the flatness of the air flow signal over the mid-portion.

Abstract: A portable oxygen concentrator includes a pair of sieve beds, a compressor for delivering air to the sieve beds, a reservoir receiving oxygen-enriched gas from the sieve beds, and an air manifold attached to the first ends of the sieve beds. A set of valves operate under the control of a controller for selectively opening and closing the valves to alternately charge and purge the sieve beds to deliver oxygen-enriched gas into the reservoir. In addition, an exhaust passage communicates with the plurality of sieve beds to deliver a flow of nitrogen evacuated from the sieve beds such that the flow of the nitrogen is directed at or across the controller to cool the controller.

Abstract: An emergency oxygen supply system for use on aircraft in the event of a loss in cabin pressure is configured for delivering allotments of oxygen and timing the delivery such allotments to each passenger so as maximize the efficiency of the transfer of such oxygen into the passenger's bloodstream. The delivery of each allotment is selected so that the entire allotment is available for inhalation into the region of the lung most efficient at oxygen transfer while the volume of the allotment is selected to substantially coincide with the volume of such region of the lung.

Abstract: A substance delivery apparatus for use with a system for supplying breathable gas to a human or animal includes a sensor to measure the pressure of the supplied breathable gas and to detect inhalation by the human or animal; and a reservoir, a conduit, a pump, and a diaphragm to deliver the substance to the human or animal during inhalation at a pressure higher than the supplied pressure of the breathable gas.

Abstract: A method and a CPAP apparatus for characterizing a plurality of different mask systems, e.g., masks and hoses, are provided. The CPAP apparatus can be calibrated for different mask systems and hoses by including sensors configured to measure flow and pressure at a flow generator of the CPAP apparatus. When the flow generator is fitted to a new mask system, or any changes are made to an existing mask system, mask or patient interface and/or hose, a method for calibrating the flow generator for the new mask system, mask and/or hose is provided.

Abstract: A flow sensor for a medical ventilator system is disclosed herein. The flow sensor includes a valve assembly having a valve seat, and a valve flap attached to the valve seat. The valve flap is composed of an elastomeric material configured to generate a pre-load that biases the valve flap into engagement with the valve seat such that the valve assembly remains closed in the absence of an externally applied force. The flow sensor also includes a pressure transducer configure to measure a first pressure level at an upstream position relative to the valve assembly, and a second pressure level at a downstream position relative the valve assembly. The flow sensor also includes a processor configured to estimate the flow rate of a fluid passing through a medical ventilator system based on the first and second pressure levels.

Abstract: A multiple lumen nasal cannula that can be used to delivery two separate supplies of gases to a patient. The multiple lumen nasal cannula includes a first lumen for delivering a first gas and a second lumen for delivering a second gas. The first lumen includes support structure that reduces the tendency of the cannula to kink and lock the delivery of gas to a patient. The cannula assembly includes a mixing chamber positioned near the patient such that the two supplies of gas are not mixed until a location approximate to delivery to the patient. The nasal cannula assembly includes a connecting device that allows the two separate supplies of gas to be correctly delivered to the two different lumens of the nasal cannula.

Abstract: Signals may be generated in a drug delivering apparatus through which a person inhales to generate a inhaled airstream to signal to the person to cease inhalation after a pre-set period of time has elapsed from detection of the commencement breathing by that person. The pre-set period of time for subsequent inhalations is adjusted depending on the time the person takes to stop inhaling after being signalled.

Abstract: A face mask (10) mechanically coupled to a lung demand valve (LDV) (12). The face mask (10) comprises a main mask and an inner mask (15) which fits over the wearer's mouth and nose. The interior of the inner mask (15) is in fluidic communication with the interior of the main mask (10) by means of non-return valves (16). The interior of the main mask is in fluidic communication with an inlet port (18) which is mechanically and fluidically coupled to a supply port (20) of an LDV. The LDV (12) includes a diaphragm and a cover (44) which comprises three parts (44a, 44b) and (44c). Exhaled air is used to flush the space around the diaphragm. Thus, any toxic or undesirable gas in the vicinity of the diaphragm is pushed out to atmosphere by the exhaled air flowing past and around the diaphragm.

Abstract: The portable ventilator of the present invention provides a hands-free ventilatory support device in critical care, emergency, and resource-limited environments. The portable ventilator utilizes ambient air and includes a two dual head compressor system to provide a consistent air supply to the patient. The ventilator device is battery operated and is capable of providing up to 60 minutes of care. In a preferred embodiment, the portable ventilator of the present invention also includes a pneumatic subsystem, a control subsystem, a power subsystem and an alarm subsystem. The portable ventilator of the preferred embodiment includes a dual head and single head compressor system that operates alternatively, to provide a consistent and continuous inhalation and exhalation cycle. A portable ventilator of a second preferred embodiment includes a sole dual-head compressor that operates to provide a consistent and continuous inhalation and exhalation cycle.

Abstract: A medical ventilator system that allows the use of pulse flow of oxygen to gain higher FIO2 values and/or conserve oxygen is described. In one embodiment, the ventilator system includes an oxygen concentrator, a medical ventilator and a breathing circuit between the ventilator and a patient. In one embodiment, the oxygen concentrator includes a controller module that is configured to generate a trigger signal to initiate the distribution of one or more pulses of oxygen from the oxygen concentrator to the patient circuit at the onset of a ventilator supplied breath. A small flow of oxygen can be added in between pulses to aid in gaining higher FIO2.

Abstract: An inhalation device for transpulmonary administration comprises: a chamber (16) for containing a pharmaceutical composition which is pulverized into fine particles by an air-generated impact for dispersal in air; an air inlet flow path (2) for introducing to the chamber (16) outside air to apply the air-generated impact to the pharmaceutical composition and for injecting the outside air toward the pharmaceutical composition; an inhalation flow path (1) for inhaling the pulverized pharmaceutical composition; a housing (9) for accommodating the chamber (16), the air inlet flow path (2), and the inhalation flow path (1); a mouthpiece (10) provided at one end of the housing (9), the mouthpiece (9) being provided with a mouth-side flow path (11) which communicates with the inhalation flow path (1), and an auxiliary flow path (12).

Abstract: A gas regulator includes a delivery valve assembly having a delivery outlet and a delivery valve member engageable with the delivery outlet for controlling flow of a gas from a gas source. A timing gas chamber receives gas from the gas source. Gas pressure within the timing gas chamber controls the operation of the delivery valve member. An adjustment system controls the amount of time required for the gas to fill the timing gas chamber so as to control the length of time that the delivery valve assembly is opened to conserve gas. In other embodiments, a capacity adjustment system can adjust the capacity of a gas reservoir system.

Abstract: A process, system and device are provided for automatically recording pressure-vs.-volume curves during artificial respiration with a respirator. The inspiration pressure is increased during the supply of a breathing gas volume flow under the control of a control unit. The resulting breathing gas volume flow rate is detected and the volume is determined from the latter by integration. The control unit compares the breathing gas volume flow detected during the phase of expiration with a preselected set point and acts on an expiration valve (12) in the expiration line (8) by means of a controller in case of deviation from the set point in order to return the breathing gas volume flow to the set point.

Abstract: Disclosed is an apparatus and method for operating powered air-purifying respirators safely in explosive atmospheres. The apparatus and method utilize a current control means for sensing a current flow from a battery to a motor, and stopping the current flow when the current flow exceeds a threshold value for a predetermined amount of time. Upon sensing that the current flow has exceeded the threshold value for the predetermined amount of time, the current control means immediately stops the current flow. The apparatus and method provides sufficient power to properly start and operate the motor by providing a soft start to the motor by limiting the duration of higher than threshold operating current to intervals shorter than the predetermined amount of time. Pulse width modulation is used to ramp-up the motor to speed by supplying pulses of energy to the motor that will not cause the current control means to stop the current flow.

Abstract: Method for the constant automatic monitoring of the regularity of the breathing of a diver during scuba dives, characterized in that it involves measuring pressure variations in the air supplied by the regulator first stage which reduces the pressure of the compressed air delivered by the compressed-air bottles to the pneumatic stabilizer jacket and/or to the demand valve caused by the amplitude and frequency of the breathing acts of the diver.

Abstract: A breathable air safety system and method having a fill station are disclosed. In one aspect, a method of safety of a building structure is described. A prescribed pressure of an emergency support system is ensured to be maintained within a threshold range of the prescribed pressure by including a valve of the emergency support system to prevent leakage of breathable air from the emergency support system. A filling process of a breathable air apparatus is safeguarded by enclosing the breathable air apparatus in a secure chamber of a fill site of the emergency support system of the building structure. The prescribed pressure of the emergency support system is designated based on a municipality code that specifies a pressure rating of the breathable air apparatus. The prescribed pressure of the emergency support system is maintained such that a system pressure is compatible with the breathable air apparatus.

Abstract: A breathable air safety system and method having at least one fill site is disclosed. In one aspect, a method of safety of a tunnel structure is disclosed. A prescribed pressure of an emergency support system is ensured to be within a threshold range of the prescribed pressure by including a valve of the emergency support system to prevent leakage of breathable air from the emergency support system. The prescribed pressure of the emergency support system is designated based on an authority agency that specifies a pressure rating of the breathable air apparatus. An air extraction process is expedited from the emergency support system by including a RIC (rapid interventions company/crew)/UAC (universal air connection) fitting to a fill panel to fill a breathable air apparatus.

Abstract: Methods and apparatus for determining leak and respiratory airflow are disclosed. A pressure sensor (34) and a differential pressure sensor (32) have connection with a pneumotach (24) to derive instantaneous mask pressure and airflow respectively. A microcontroller (38) estimates a non-linear conductance of any leak path occurring at a mask (12) as being the low pass filtered instantaneous airflow divided by the low pass filtered square root of the instantaneous pressure. The instantaneous leak flow is then the conductance multiplied by the square root of the instantaneous pressure, and the respiratory airflow is calculated as being the instantaneous airflow minus the instantaneous leak flow. The time constants for the low pass filtering performed by the microcontroller (38) can be dynamically adjusted dependent upon sudden changes in the instantaneous leak flow.

Abstract: A powered air-purifying respirator that includes an enclosure, defining a single contiguous enclosed interior, an inlet duct, including an inlet and a distribution portion, that guides ambient air to the interior of the enclosure, a plurality of filter canisters disposed within the interior of the enclosure, and a blower that forces air through the at least one inlet, into the interior of the enclosure and through the plurality of filter canisters to produce filtered air suitable for breathing. A valve controls the flow of ambient air through the inlet duct. A fluid dam, disposed in an air path between the inlet and the filter canisters prevents liquids from reaching the filter canisters. The enclosure is reinforced and is adapted to provide protection for the filter canister from flame and heat while the filter canister is in use. A recirculation valve recycles previously-filtered air back into the enclosure.

Abstract: The system of the present invention reduces hydrostatic imbalances acting on the diaphragm of a diver's open-circuit breathing apparatus' regulator. In general, the system applies a flexing force to the diaphragm based on the position of the diver's head relative to gravity when the mouthpiece is in the diver's mouth. The system can be realized by a simple mechanical pendulum assembly attached to the regulator.

Abstract: An alarm system and method for use with a breathing apparatus that provides a source of breathable air to a user/diver. A tactile signal is generated in response to a signal representing at least one parameter corresponding to the breathing apparatus status, and the tactile signal can be both felt and heard by the user. The tactile signal may be generated in combination with a visual and/or an additional audible alarm. The tactile signal may be a vibration. The alarm may be worn on the face, either on the mask or on the mouthpiece. The vibrator serves two functions, one as a tactile alarm that the diver can feel during operation, and a second as an auditory alarm through bone-conduction of sound. The tactile alarm indicates to the user/diver that his particular unit is the one transmitting an alarm signal, and cannot be mistaken for any other device.

Abstract: A ventilator device delivers ventilatory support to a patient in a back up timed mode when patient respiration is not detected or a spontaneous mode when patient respiration is detected. The timing threshold governing the back-up mode is chosen to deviate from normal expected respiration time for the patient to promote patient initiated ventilation in the spontaneous mode but permit back-up ventilation in the event of apnea. Automated adjustments to the timing threshold during the timed mode are made from the less vigilant timing threshold to a more vigilant threshold at or near a timing of normal expected breathing of the patient. Such adjustments may be made from a minimum to a maximum vigilance timing settings or incrementally there between as a function of time in the timed mode which is preferably the number of delivered machine breaths.

Abstract: A breathing regulator having a non-linear positive pressure spring is provided for use in an air supplied respirator. The regulator includes a housing formed from a regulator body and a cover sub-assembly, a diaphragm assembly, and the non-linear spring. The spring holds the diaphragm assembly closed and resists the force applied by air pressure during exhalation by the user, but collapses once a sufficient amount of force has been applied, thereby permitting the user to exhale freely.

Abstract: A scuba mask purging apparatus and method providing selective introduction of pressurized air into a scuba mask to initiate purging, pressure balancing, and de-fogging. An inlet valve, typically positioned conveniently on the top or the side of the mask may control the release of pressurized air into the mask. A pressure-sensitive outlet valve releases the pressurized air to force water from the mask. The outlet valve may be positioned on the lower portion of the mask or at a location where water is likely to collect.

Abstract: A breathable air safety system and method having at least one fill site is disclosed. In one aspect, a method of safety of a structure is disclosed. A prescribed pressure of an emergency support system is ensured to be within a threshold range of the prescribed pressure by including a valve of the emergency support system to prevent leakage of breathable air from the emergency support system. The prescribed pressure of the emergency support system is designated based on a municipality code that specifies a pressure rating of the breathable air apparatus that is used in an authority agency of a particular geographic location. An air extraction process is expedited from the emergency support system by including a RIC (rapid interventions company/crew) /UAC (universal air connection) fitting to a fill panel to fill a breathable air apparatus.

Abstract: The invention relates to a nozzle system for a delivery device for liquids, which comprises a nozzle and a device which fixes the nozzle in the delivery device. The device has a liquid reservoir from which a liquid is forced through a nozzle under pressure to deliver the liquid. The nozzle is secured by a holder on the delivery device. This holder may itself be secured by a second holder, e.g. in the form of a check nut, or the check nut itself may be the holder. According to the invention at least part of the outer surface of the holding device is micro- or nanostructured.

Abstract: A closure device of a second-stage regulator for scuba divers, the regulator comprising a regulator body with an inlet conduit for connection to a first-stage regulator which supplies a breathable gaseous mixture at relatively constant pressure, an outlet conduit for connection to a mouthpiece of the users, and an opening closed by a deformable diaphragm. The device comprises a locking frame connected in an articulated manner or jointedly to the regulator body to lock the diaphragm in the opening, and a member for fastening the frame to the regulator body.

Abstract: A ventilator of the present invention includes a housing, a gas flow generator disposed in the housing, a gas outlet port provided on an exterior surface of the housing, and a first conduit coupling the gas flow generator to the gas outlet port. A gas inlet port is also provided on an exterior surface of the housing. A second conduit couples the gas inlet port to a first exhaust valve in the housing that regulates a flow of exhaust gas from the second conduit. A second exhaust valve in the housing is coupled to the first conduit and regulates a flow of exhaust gas from the first conduit. A controller coupled to second exhaust valve causes the second exhaust valve to change a degree of flow restriction based on a respiratory phase of a patient coupled to the ventilator when the ventilator is operating in a single-limb ventilation configuration.

Abstract: Fluid regulators provide a fluid to a cannula for use by a person. Fluid conservers also a fluid to a cannula for use by a person. A fluid conserver may be operational in a continuous flow mode of operation and an intermittent flow mode of operation. The selection of either the continuous flow mode of operation and the intermittent flow mode of operation may be based on a position of a flow selector. A home fill device may operate with a fluid conserver and may include an oxygen concentrator which provides a source of fluid.

Abstract: An oxygen separator for separating oxygen from ambient air utilizing a vacuum swing adsorption process has a mass of less than 2.3 kg. A carrier is mountable on a person to support the oxygen separator for ambulatory use.

Abstract: A bi-directional flow sensor is adapted for reducing pneumatic noise during pressure sensing with a flow passing through the flow sensor. The flow sensor comprises a hollow, tubular member having a throat section disposed between a ventilator end and a patient end. A flow restrictor is disposed in the throat section and is adapted to measure differential pressure in the flow. A baffle is mounted at the ventilator end and is adapted to minimize non-axial flow at pressure taps located on opposing ends of the flow restrictor. The patient end includes a flow obstruction configured to promote uniform velocity across the flow at the pressure taps during exhalation flow from the patient end to the ventilator end. The flow sensor minimizes pneumatic noise to less than 0.1 LPM to allow accurate patient flow measurement and triggering of inhalation and exhalation phases at flow rates of 0.2 LPM.

Abstract: A gas regulator includes a slave valve assembly for receiving and controlling the flow of gas to a desired destination. A timing chamber is positioned adjacent to the slave valve assembly. The timing chamber has an inlet for also receiving the gas. An electronically operated pilot valve assembly is in communication with the timing chamber for operating the slave valve assembly. When the pilot valve assembly is closed, gas pressure within the timing chamber acting on the slave valve assembly closes the slave valve assembly. When the pilot valve assembly is open, gas exits the timing chamber and reduces the gas pressure in the timing chamber, thereby allowing the slave valve assembly to open and deliver the gas to the desired destination.

Abstract: A pressure support system has a motor, a switching element that supplies power to motor windings, and a blower coupled to the motor. Rotation of the blower elevates a pressure of fluid in a patient circuit coupled to an outlet of the blower. A rotational speed controller maintains the motor at a set rotational speed corresponding to a selected pressure for the fluid in the patient circuit. The rotational speed of the motor is maintained by a switching signal provided by a rotational speed controller to the switching element to control the actuation of the switching element. A fluid parameter monitoring portion monitors a parameter associated with the flow of fluid in the patient circuit, such as the magnitude, direction, or volume, based on a characteristic, such as duty cycle, of the switching signal, or based on a characteristic of a control signal that is used to generate the switching signal.

Abstract: An emergency oxygen supply system for use on aircraft in the event of a loss in cabin pressure is configured for delivering allotments of oxygen and timing the delivery such allotments to each passenger so as maximize the efficiency of the transfer of such oxygen into the passenger's bloodstream. The delivery of each allotment is selected so that the entire allotment is available for inhalation into the region of the lung most efficient at oxygen transfer while the volume of the allotment is selected to substantially coincide with the volume of such region of the lung.

Abstract: A mask adapted to be attached to a user's face is disclosed. The mask comprises a body and a gas connection structure. The body is formed with an inner space which is defined along with the user's face. The inner space allows the user to breathe through the nose. The gas connection structure connects to the body so that the inner space is connectable with the ambient air via the gas connection structure. Thereby, the user is capable of breathing through his/her nose to drive the ambient air into the inner space and reduce the moisture formed in the inner space.

Abstract: A method of generating an oxygen-enriched gas for a user via an oxygen generating system is disclosed herein. The oxygen generating system includes at least one sieve bed having a nitrogen-adsorption material disposed therein, the nitrogen-adsorption material being configured to adsorb nitrogen from a feed gas introduced thereto, thereby generating the oxygen-enriched gas therefrom. The at least one sieve bed has an internal gas pressure within a volume defined by the at least one sieve bed. The method includes measuring the internal sieve bed pressure, measuring an ambient atmospheric parameter, and detecting inhalation of the user. The method further includes selectively controlling, substantially in real time, delivery of the oxygen-enriched gas to the user based on at least one of the internal sieve bed gas pressure measurement, the ambient atmospheric parameter measurement, the inhalation detection, or combinations thereof.

Abstract: A compressed air respirator has prolonged operating time due to a rebreathing feature. The respirator has a compressed air reserve (1) with a connected demand air supply valve (2), wherein the demand air supply valve (2) is connected with a reversible breathing gas reservoir (4) with adjustable volume. A rebreathing line (25) for the user of the apparatus has an expiration valve (88), wherein the rebreathing line (25) is connected with the breathing gas reservoir (4).

Abstract: Systems and methods for configuring the operation of an alternating pressure ventilation mode are provided. According to one embodiment a configuration method includes monitoring gas flow between a patient and a ventilation system. Based on the monitoring, a peak expiratory flow rate (PEFR) is determined Information indicative of values of parameters of the ventilation mode are received, including a higher pressure setting, a lower pressure setting and a duration of the higher pressure setting. User input is also received indicative of a target percentage of PEFR at which the ventilation system should cycle from the lower pressure setting to the higher pressure setting. Based on the target percentage, a duration of the lower pressure setting is programmatically determined. Finally, the ventilation system is configured to automatically cycle between the higher and lower pressure setting at a predetermined flow based on the parameters and the duration of the lower pressure setting.

Abstract: A gas mask for normal pressure operation and overpressure operation allows changeover of the expiration valve (4) from normal pressure operation to overpressure operation is made possible in a simple manner. The pretension of the valve spring (7) of the expiration valve (4) is adjusted by an angle lever (10) pivotable about an axis of rotation (13).

Abstract: The invention provides, in one aspect, a head up display unit for a re-circulating gas self-contained breathing apparatus of the type having at least one sensor for determining the oxygen partial pressure of the re-circulating gas. At least one optical fiber (32) is provided for transmitting a light signal or signals from a respective light emitter, positioned outside the wearer's field of view and electrically connected to the at least one sensor, to a display (26) in the wearer's field of view to provide the wearer with a visual indication of the light emitter signal or signals.

Abstract: An entrainment-based mechanical ventilator may be initially set to approximate the patient's spontaneous respiratory frequency, enabling the patient to entrain to the ventilator if the ventilator frequency matches the patient's spontaneous breathing frequency or is within a reasonable range from it. If the preset frequency of the ventilator is set too high or too low from the spontaneous frequency, the patient will fall out of phase and “fight” the ventilator. The ventilator phase relative to the patient's breathing effort indicates the difference between the ventilator frequency and spontaneous frequency. Based on the phase difference, a closed-loop control mechanism may continuously adjust the ventilator frequency to match the patient breathing frequency until the phase shift is within a preset limit. Patient-ventilator entrainment will occur when the ventilator frequency is within a certain range from the patient breathing frequency.

Abstract: The present invention describes a method and apparatus for non-invasive prediction of the “intrinsic positive end-expiratory pressure” (PEEPi) which is secondary to a trapping of gas, over and above that which is normal in the lungs; the presence of PEEPi imposes an additional workload upon the spontaneously breathing patient. Several indicators or markers are presented to detect and quantify PEEPi non-invasively The markers may include an expiratory air flow versus expiratory air volume trajectory, an expiratory carbon dioxide flow versus expiratory air volume trajectory, an expiratory carbon dioxide volume to expiratory air volume ratio, an expiratory air flow at onset of inhalation, a model of an expiratory waveform, a peak to mid-exhalation airflow ratio, duration of reduced exhaled airflow, and a Capnograph waveform shape.