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The Hospital for Sick Children

George A Volgyesi

Joseph A Fisher

Alex Vesely

Hiroshi Sasano

Janet Tesler

A breath powered positive airway pressure device having an expiratory chamber for receiving expired air from a user. The chamber has at least one resiliently flexible surface that is configured to expand to accommodate the expired air, so that the pressure within the chamber gradually increases during expiration. The device may also include an inspiratory chamber for holding air to be inspired, wherein the at least one resiliently flexible surface forms a flexible partition separating the expiratory chamber from the inspiratory chamber. The flexible partition is configured to expand into the inspiratory chamber during expiration, so that the air that is held within the inspiratory chamber also becomes pressurized during expiration.

Breath powered positive airway pressure device

A gas flow control mechanism for a gas blender comprising: a voltage sensitive orifice defining a passage for each gas to be controlled and having an inlet port in fluid communication with a gas source and an outlet port in fluid communication with a plenum for mixing at least two gases; a gas flow controller placed in a feed back loop to adjust at least a parameter or characteristic of a gas flow exiting from the orifice through the outlet port to preset value; the gas flow controller comprising a gas flow resistor in fluid communication with the gas exiting from the orifice and adapted to generate an output signal based on a gas flow characteristic, and a comparator, responsive to the gas resistor flow signal, to continuously evaluate and monitor the characteristic of the gas exiting from the orifice, compare the same with the preset value and minimize any difference therebetween by adjusting current supplied to the orifice which in turn adjusts the gas flow therethrough to the preset value by adjusting the passage.

Electronic gas blender and gas flow control mechanism therefor

A method of controlling PCO in a patient at a predetermined desired level(s) comprising a breathing circuit which is capable of organizing exhaled gas so as to be preferentially inhaled during re-breathing when necessary by providing alveolar gas for re-breathing in preference to dead space gas.

Rebreathing circuit to set and stabilize end tidal and arterial PCO2 despite varying levels of minute ventilation

An inhalation device for use in delivering a powdered substance to a user, the inhalation device comprises a housing including a holding portion for holding the substance; an air entry passageway sized and configured to direct air entering the inhalation device at the portion and to fluidize the substance upon inhalation by the user; a hold-up chamber in flow communication with the holding portion for receiving the fluidized substance and maintaining the substance in a fluidized state during inhalation by the user; and an air exit passageway in flow communication with the hold-up chamber and adapted to deliver the substance to the user.

Inhalation device

A breath-powered inhalation device includes a hollow cylindrical body having an air inlet at one end and an air outlet at another end. The air outlet is narrowed so that air velocity increases as air moves through the outlet. At the air outlet is positioned a releasing mechanism which preferably has a fibre tip impregnated with a medicament or the like. As the air rushes past the releasing mechanism, the medicament or the like is atomized and carried into the respiratory tract of the user by the air. The breath-powered inhalation device of the present invention provides advantages over conventional inhalation devices using compressed gases as propellants since it is more compact, simpler and does not require synchronization of activation of the device and inhalation by the user.

Breath-powered mist inhaler

A device for monitoring tidal volume in a subject comprising a flexible substrate for attachment to an animal or human whose tidal volume is to be monitored; sensing means attached to the substrate and connectable into an electric circuit which converts changes in tidal volume in the animal or human to a signal output, the sensing means comprising a series of semiconductive sensors and conductive sensors. A method for monitoring tidal volume in a subject using the device is also described.

Device and method for measuring tidal volume

Device and method for testing the accuracy of pulse oximeters used in estimating arterial blood saturation levels. The device is for use in enabling a pulse oximeter to measure the absorption of the radiation emitted by the oximeter by a pulsatile liquid contained within the device, which device comprises the liquid, a resiliently flexible displaceable member adjacent the liquid which in operation is manually made to rhythmically move with a steady frequency and amplitude so as to effect a change in the depth of a volume of the liquid in the direction acted upon by the radiation such that the liquid is operably provided in pulsatile form while under the influence of the radiation. The device provides a cheap and convenient method of testing the accuracy of the pulse oximeters.

Method of testing the accuracy of pulse oximeters and device therefor

Device and method for testing the accuracy of pulse oximeters used in estimating arterial blood saturation levels. The device is for use in enabling a pulse oximeter to measure the absorption of the radiation emitted by the oximeter by a pulsatile liquid contained within the device, which device comprises the liquid, a resiliently flexible displaceable member adjacent the liquid which in operation is made to rhythmically move with a steady frequency and amplitude so as to effect a change in the depth of a volume of liquid in the direction acted upon by the radiation such that the liquid is operably provided in pulsatile form while under the influence of the radiation. The device provides a cheap and convenient method of testing the accuracy of the pulse oximeters.

The invention provides a device capable of monitoring the concentration of anaesthetic gas in a breathing mixture being delivered to a patient to cause narcosis and consists essentially of an electronic transducer which provides an output signal proportional to the concentration of anaesthetic gas in a breathing mixture. The transducer includes a sensor having first and second electrical conductors positioned in proximity to one another and defining a space between the conductors. A substantially non-conductive material fills the space between the conductors and has a molecular structure which permits the absorption of the anaesthetic gas thereby causing variations in the electrical characteristics of the sensor. An electrical circuit is provided which is coupled to the sensor to provide the output signal which is proportional to the variations in the electrical characteristics of the sensor.

Measurement of anaesthetic gas concentration

The invention provides apparatus for measuring the rate of flow of liquid being circulated in a closed loop system by a pump using a bolus of indicator injected suddenly into the system upstream of the pump and a sampling station downstream of the pump. The apparatus includes signal means for location at the sampling station to provide an electrical signal proportional to the indicator passing this station. The electrical signal has an increasing portion, a decaying exponential portion, and a distorted portion caused by recirculation of the indicator in the system. A signal analyzer is coupled to the signal means to receive the electrical signal and includes a wave generator sensitive to the exponential portion and including extrapolation means for providing a portion of the exponential curve lost by interference by recirculation. The signal analyzer provides an output signal corresponding to the increasing portion, the exponential portion, and the portion provided by the extrapolation means. The apparatus also includes signal interruption means operable to discontinue the electrical signal before the curve reaches the distorted portion to avoid interference of this portion in the extrapolation of the exponential portion. Also, integrator means is coupled to the signal analyzer to receive the output signal and to provide a reading of the rate of flow of the liquid.

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Willowdale, Canada

George A Volgyesi