Abstract: A ventilation system is controlled by detecting the resistance and elastance of the patient's respiratory system and adjusting the flow supplied by the ventilator accordingly. In one embodiment, the resistance is detected by controlling the ventilator to superimpose at least one forced single oscillation on the flow and observing the reaction of the respiratory system. In another embodiment, the elastance is detected by controlling the ventilator to supply a pressure which has the effect of temporarily occluding the respiratory system, waiting until the respiratory system has reached equilibrium, and observing the resulting state of the respiratory system. The detection techniques of these two embodiments can be used together.

Abstract: A monitoring catheter that inserts into the patient's esophagus alone or in combination with an existing catheter, such as a feeding or aspiration tube. The monitoring catheter includes a pair of EMG electrodes on an exposed surface that contact the patient's esophageal wall to measure the activity of the diaphragm and/or a pair of pressure detecting mechanisms that measure the pressures within the patient at separate locations. The electrodes are sized and spaced from one another so as to maximize detection of diaphragm muscle activity while minimizing detection of noise. The pressure detecting mechanisms are sized and spaced apart to measure the patient's esophageal and gastric pressures, for example. If necessary, an attaching mechanism secures at least a portion of the monitoring catheter to the existing catheter so that the monitoring catheter uses the existing catheter as a tracking guide.

Abstract: A gas insufflation and suction apparatus is provided for communication with a patient's trachea. The apparatus includes a gas catheter and a suction catheter. When supplying a suitable gas having a desired oxygen concentration to the patient, an output end of the gas catheter is moved past a Y-connector through a T-member into the patient's trachea. After removal of the gas catheter from the patient 's trachea, mucus or other substances can be removed from the patient using the suction catheter. With the gas catheter in its standby position, the suction catheter is moved past the Y-connector through the T-member and located in a desired position in the patient's trachea.

Abstract: An intraoral electromuscular stimulation device and method to treat a breathing disorder. The stimulation device includes a first electrode, a first support member that maintains the first electrode in a sublingual location posterior to a frenulum and proximate to one of a first molar, a second molar and a third molar of a patient. A second electrode is maintained in a sublingual position posterior relative to the first electrode by a second support member. A further embodiment of the stimulation device includes a sensor that detects a respiratory parameter of a patient and outputs a signal indicative thereof. A control unit receives the signal from the sensor, distinguishes between inspiration and expiration, and initiates an electrical stimulation at a stimulation time prior to onset of inspiration and continues stimulation through a portion of inspiration at a level sufficient to induce muscle contraction without pain.

Abstract: A humidity regulating unit including a heating element housed inside a covering that has a porous retaining wall through which water does not pass but steam or gas passes. In one embodiment, the covering has several bulges along the circumference of the heating element that protrudes outward from the outer surface of heating element to form several water routes along the outer surface of heating element. The covering and the outer surface of heating element are bonded between adjacent water routes so that the outer surface of heating element is used as part of the wall of the water routes. As a result, the size of heating element does not restrict making the cross section of each water route as small as possible, and even if the covering breaks, the amount of water leaking from the humidity regulating unit is minimized.

Abstract: An apparatus for diagnosing a breathing disorder of a patient that includes a first sensing system that determines a dimension, such as cross-sectional area, of a portion of the patient's airway and a second sensing system that determines an internal load on the airway. A processing system receives the output from the first and second sensing systems and determines a compliance curve that corresponds to a relationship between the measured dimension and a plurality of internal loads on the patient's airway. The processing system also determines at least one characteristic associated with the compliance curve. This characteristic is indicative of a likelihood that the patient suffers from a breathing disorder.

Abstract: An oxygen mixing arrangement for or in a pressure support ventilator, in which a modular oxygen-providing assembly is selectively insertable into a greater respiration apparatus. Mixing accuracy and controllability is maintained by using gas supplies that have a wide range of pressures. Further, oxygen leakage is minimized by connecting the modular oxygen-providing assembly at a point of the respiration circuit of the greater respiration apparatus that is downstream from a valving arrangement normally used for venting patient exhaust flow and for controlling system pressure by venting excess gas flow to the ambient atmosphere.

Abstract: A system including methods and apparatus for treatment of a medical disorder such as obstructive sleep apnea or congestive heart failure. The system involves applying separate and independent gains to flow rates of pressurized gas delivered to a patient during inspiratory and expiratory phases of a respiratory cycle to deliver the pressurized gas in proportion to the respective gains during inspiration and expiration. A base pressure may be applied in addition to the gain-modified pressures and an elevated pressure profile may be employed to assist or control inspiration. The system may be fully automated responsive to feedback provided by a flow sensor that determines the estimated patient flow rate. A leak computer can be included to instantaneously calculate gas leakage from the system. The system may be utilized in connection with conventional continuous positive airway pressure (bi-level PAP) equipment to effect various beneficial treatment applications.

Abstract: An insufflation system that includes a first tube that inserts into a patient's airway for providing a primary flow of breathing gas to such a patient. At least one insufflation catheter is provided in or within the first tube for delivering a flow of insufflation gas to the patient. In one embodiment, the flow of insufflation gas is delivered in a first direction generally toward the patient's lungs and in a second direction generally opposite the first direction so that the flow in the second direction creates a negative stagnation pressure that substantially cancels out the positive stagnation pressure generated by flow in the first direction. In second embodiment, an exhaust vent is provided in the first tube for exhausting a flow of gas from the first tube at a rate that is equivalent to the rate at which the flow of insufflation gas is being delivered to the patient's airway, thereby preventing over-inflation of the patient's respiratory system.

Abstract: An apparatus for transferring two frequencies of electromagnetic energy to and from a portion of a living body for the purpose of blood oxygen saturation measurements. The two frequencies of electromagnetic energy are transferred to the portion of the living body through a single optical fiber cable (which could be a bundle) to a coupler and then through a short section of optical cable to an optical element adjacent to the portion of the living body. After the two frequencies of electromagnetic energy are transmitted through the portion of the living body they are received by another optical element and transported away from the portion of the living body to a coupler through a short section of optical cable where they may be converted to electrical signals. Alternatively, the two frequencies of electromagnetic energy are carried away from the coupler.

Abstract: A method and device for controlling sleep disorder breathing utilizes variable multiple level pressures. A pressure source supplies compressed breathable gas at a relatively low pressure to the user's airway. Pressure transducers monitor pressures and convert them into electrical signals. The electrical signals are filtered and processed to extract specific features such as duration and energy levels. If these features exceed selected threshold values for duration and energy level over a minimum period of time, then the microprocessor declares the presence of sleep disorder breathing. If a selected number of these events occur within a selected time period, then the microprocessor adjusts the pressure delivered by the pressure source. If sleep disorder breathing is not detected within a certain time period, then the microprocessor lowers the pressure level gradually. The device and method disclosed in this patent is capable of detecting apnea, hypopnea, and pharyngeal wall vibration.

Abstract: A method of detecting changes in a person's respiration between inspiration and expiration by monitoring of gas flow characteristics.

Abstract: A method and apparatus for transferring two frequencies of electromagnetic energy to and from a portion of a living body for the purpose of blood oxygen saturation measurements. The two frequencies of electromagnetic energy are transferred to the portion of the living body through a single optical fiber cable (which could be a bundle) to a coupler and then through a short section of optical cable to an optical element adjacent to the portion of the living body. After the two frequencies of electromagnetic energy are transmitted through the portion of the living body they are received by another optical element and transported away from the portion of the living body to a coupler through a short section of optical cable where they may be converted to electrical signals. Alternatively, the two frequencies of electromagnetic energy are carried away from the coupler.

Abstract: A patient monitoring apparatus for monitoring and/or measuring a physiological characteristic of said patient. A user interface having an interior portion communicates with an airway of a user such that substantially all gas inhaled and exhaled by the user enters the interior portion of the user interface. At least one vent element is associated with the user interface and communicates the interior portion of the user interface with an ambient atmosphere outside the user interface. The vent element and user interface define a flow element across which a pressure differential is created during inhalation and exhalation. The pressure differential is the pressure difference between the pressure within the interior portion of the user interface and the pressure of the ambient atmosphere outside the user interface.

Abstract: Improved methodology and apparatus for the clinical study and treatment of sleep apnea which incorporates one or more of the following features: (1) application of mono-level, alternating high and low level, or variable positive airway pressure generally within the airway of the patient with the mono-level, high and low level, or variable airway pressure generally being coordinated with and/or responsive to the spontaneous respiration of the patient, (2) usage of adjustably programmable pressure ramp circuitry capable of producing multiple pressure ramp cycles of predetermined duration and pattern whereby the ramp cycles may be customized to accommodate the specific needs of an individual sleep apnea patient so as to ease the patient's transition from wakefulness to sleep, (3) remote control or patient-sensed operation of the apparatus, (4) employment of safety circuitry, reset circuitry and minimum system leak assurance circuitry, controls and methods, and (5) utilization of clinical control circuitry whereb

Abstract: Apparatus for delivering pressurized gas to the airway of a patient including: a gas flow generator for providing a flow of gas, a breathing appliance for sealingly communicating with the airway of the patient, and a conduit for delivery of the gas flow to the airway of the patient, the conduit having a first end connected to the gas flow generator and a second end connected to the breathing appliance. The apparatus further includes at least one sensor in fluid communication with the conduit and located substantially at the gas flow generator for detecting conditions corresponding to breathing patterns of the patient and generating signals corresponding to the conditions, and an information processor for receiving the signals and for controlling the output of the gas flow generator responsive to the signals.

Abstract: A swivel exhaust conduit for rotatably connecting a patient mask to the delivery conduit of a positive pressure air supply. The swivel exhaust conduit design provides an exhaust port that utilizes the rotating bearing of the swivel conduit's rotating two-piece design for permitting and directing exhaust of CO.sub.2 laden air. A baffle chamber formed in the clearance of the two pieces provides an area where noise is reduced. As CO.sub.2 laden exhaust exits the swivel exhaust conduit, it is directed away from the patient mask and down the outside of the delivery conduit via a slit pattern on the swivel conduit.

Abstract: A flow regulating system including a valve and a method for maintaining a constant gas flow rate at varying gas pressure by means of differential gas pressure applied to opposed sides of a valve diaphragm.