Patent Application
20070272239
Sleep disordered breathing is common throughout the population. Some sleep disorders may be attributable to disorders of the respiratory tract. Sleep apnea may be a disorder where a person temporarily stops breathing during sleep. A hypopnea may be a period of time where a person's breathing becomes abnormally slow or shallow. In some cases, a hypopnea precedes an apnea event.
Although hypopneas and apneas may have multiple causes, one trigger for these type events may be full or partial blockages in the respiratory tract. In particular, in some patients the larynx may collapse due to forces of gravity and/or due to forces associated with lower pressure in the larynx than outside the body. A collapse of the pharynx, larynx, upper airway or other soft tissue in the respiratory tract may thus cause a full or partial blockage, which may lead to a hypopnea or apnea event.
One method to counter collapse of the larynx may be the application of positive airway pressure, possibly by using a continuous positive airway pressure (CPAP) machine. This may be accomplished in the related art by placing a mask over at least the patient's nose, and providing within the mask a pressure communicated to the pharynx, larynx, or upper airway. The pressure within the pharynx, larynx, or upper airway may be greater than the pressure outside the body, thus splinting the airway open. However, forcing air through a patient's nose may cause drying and thus discomfort.
Some positive airway pressure devices individually control the airway pressure applied to each naris, which may cause dryness and/or discomfort of differing levels in each naris. To address the dryness and/or discomfort, embodiments of the invention are directed to a dual chamber humidifier, one chamber each for each naris. Having dual chambers enables individually controlling the amount of moisture imparted to the air for each naris. Thus, at least some of the illustrative embodiments are a humidifier system comprising an outer housing defining an internal volume, a dividing member within the internal volume that divides the internal the internal volume into a first chamber and a second chamber (the first and second chambers fluidly independent of each other), a first inlet port and first outlet port (the first inlet and outlet ports in fluid communication with the first chamber), and second inlet port and a second outlet port (the second inlet and outlet ports in fluid communication with the second chamber).
Other illustrative embodiments are a system comprising a positive airway pressure device and a humidifier. The positive airway pressure device comprises a first outlet port that provides positive airway pressure to a first naris of a patient, and a second outlet port that provides positive airway pressure to a second naris of a patient. The positive airway pressure supplied to each naris is individually controlled. The humidifier comprises a first water contact chamber (the first water contact chamber in fluid communication with the first outlet port), and a second water contact chamber (the second water contact chamber fluidly independent of the first contact chamber). The first water contact chamber is configured to fluidly couple to a first naris of a patient, and the second water contact chamber is configured to fluidly couple to a second naris of a patient.
The disclosed devices and methods comprise a combination of features and advantages which enable it to overcome the deficiencies of the prior art devices. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description, and by referring to the accompanying drawings.
For a detailed description of the preferred embodiments of the invention, reference will now be made to the accompanying drawings in which:
Certain terms are used throughout the following description and claims to refer to particular system components. This document does not intend to distinguish between components that differ in name but not function.
In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections.
The individually controlled pressures are coupled to a patient's nares by way of a nasal mask. For example,
The heat control circuit 26 may take many forms. In some embodiments, the heat control circuit 26 is a microcontroller executing software programs to perform the heat control in accordance with embodiments of the invention. In alternative embodiments, the heat control circuit 26 may be an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or a programmable logic device (PLD). In yet still further embodiments, the control implemented by the heat control circuit 26 may be implemented way of discrete electronic devices. Regardless of the precise nature of the heat control circuit 26, the circuit 26 sends heat control commands to the heat control device 30A across signal line 34. Likewise, the heater control circuit 26 sends heat control commands to the heat control device 30B across signal line 36. The precise nature of the signals propagated across signal lines 34 and 36 is dependant upon the nature of the heat control devices 30. In some embodiments, the 120 volt alternating current (AC) signal available at a wall outlet is applied to the resistive heater elements 32. In order to control the heat generated, however, the heat control devices 30 are selectively activated to only allow portions of the AC signal to be applied to the resistive heater elements 32. In alternative embodiments, direct current (DC) voltages may be applied to the resistive heater elements 32, and in these embodiments the heat control devices 30 control the DC voltage applied to each of the resistive heater elements 32. Other heat control devices may be equivalently used.
Regardless of the precise nature of the heat control devices 30, each resistive heater element 32 also has associated therewith a temperature sensing device 38. The temperature sensing devices 38 may be thermocouples, resistive thermal devices, (e.g. thermistors), or any device capable of measuring temperature in the ranges expected. In some embodiments, each resistive heater element 32 is sandwiched between layers of rubber, with the temperature sensing devices couple to one of the upper or lower rubber members. Other arrangements may be equivalently used.
In accordance with embodiments of the invention, the heater control circuit 26 applies sufficient power to the resistive heater elements 32 (by way of the heat control devices 30) to maintain a predetermined temperature of water in the chambers 20, 22 as sensed by the temperature sensing devices 38. In accordance with at least some embodiments, the heater control circuit 26 attempts to maintain a water or fluid temperature within the reservoir of approximately 140° degrees F. Higher or lower temperatures may be equivalently used. Although a positive airway pressure device 10 may attempt to equalize airflow as between the nares of a patient, in situations where one naris carries significantly less airflow, the individual control of heat within the chamber 20, 22 for that naris keeps the water from overheating, lessens the likelihood of significant condensation forming in the tube supplying air to that naris, and saves energy.
Still referring to
In yet still further embodiments, the heater control circuit 26 is also capable of sensing when a particular water chamber 20, 22 no longer contains any water. In particular, when all the water from a water chamber 20, 22 has evaporated, the amount of power required to maintain the predetermined temperature (as sensed by the temperature sensor 38) drops significantly from that required to maintain temperature when water is present (whether or not there is airflow through the water chamber 20, 22). In these embodiments, the heater control circuit 26 may cease providing power to the heating element 32 of the water chamber 20, 22 in which all the water has been evaporated. Again, however, the second water chamber 20, 22 may still contain water, thus the heater control circuit 26 may continue to provide power to heat the water in that the remaining water chamber 20, 22.
The reservoir 18 mechanically couples to the base unit 40. In some embodiments, the reservoir 18 slides into mating relationship with the base unit 40, but other mechanical coupling arrangements may be equivalently used. Thus, in some embodiments the base unit 40 orients the outlet ports 42, 44 of the bilateral positive airway pressure device 10 such that they couple to the inlet ports 46, 48 of the reservoir.
The water chambers 20 and 22 comprise a bottom portion 58 and 60 respectively. In accordance with at least some embodiments, the bottom portions 58 and 60 are metallic, while the outer housing 54 may be formed of a plastic material. The bottom member 58 and 60 are, in at least some embodiments, separate metallic plates such that the power and heat generated by one resistive heater element is not applied in any significant form to the water and the adjacent water chamber.
The above discussion is meant to be illustrative of the principles and various embodiments of the present invention. Numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.
