Patent Application
20060042627
Not Applicable
Not Applicable
Not Applicable
This invention relates in general to Polysomnogram testing and in particular to a PAP titration apparatus and method.
Many sleep related respiratory conditions are caused by a blockage or partial blockage of the respiratory tract. Snoring, for example, is caused by a partial blockage of the respiratory tract. As the blockage increases, hypopnea or a reduction of air flow to the lungs occurs. Apnea, or a temporary cessation of breathing, can occur when the airway becomes totally blocked. A person suffering from sleep apnea may have difficulty functioning during the day because of insufficient sleep caused by the apnea events. In severe cases, the person also can suffer from problems caused by reduced blood oxygen levels.
One form of treatment for severe snoring, hypopnea and sleep apnea involves the application of a pneumatic splint to the person's respiratory tract while he sleeps. Sufficiently high Positive Airway Pressure (PAP) is applied to the person's airway to prevent its collapse or blockage. The applied positive pressure is usually within a range of three to 20 cm H2O. The positive air pressure is supplied by a PAP device that includes a regulated blower that supplies a flow of air to a face mask via a flexible tube. The face mask is designed to cover the user's nose and/or mouth and forms an air-tight seal with the user's face. Typically, when the PAP device is initially turned on, the device supplies a comfortable lower pressure to the person while he falls asleep. The PAP device then gradually increases the pressure to a prescribed therapeutic level.
A physician who suspects that a person is suffering from one of the above-described sleep disorders will refer the person to a sleep clinic for a sleep study, or Polysomnogram (PSG), to determine the exact nature of the problem and to select the appropriate treatment. A PSG is usually a multi-component test. The first component involves an overnight diagnostic test during which the patient's sleep is monitored. Referring now to
The sensors are connected to a Terminal Box, or “Pin Box” 18 located in the sleeping room 12. The Terminal Box 18 provides connection terminals for the sensor wires and is connected by cables 20 to a remotely located monitoring station 22. The Terminal Box may be temporally disconnected form the cables 20 to allow the subject mobility within the sleeping room 12. The monitoring station 22, which is manned throughout the PSG diagnostic test by a polysonmographic technician, includes a PSG subsystem 24 that receives and records all the data provided by the sensors 14. The subsystem 24 is typically a personal computer and is monitored and controlled by the polysonmographic technician with a keyboard 26 and display monitor 28. Additionally, a printer (not shown) for downloading data and a loudspeaker (not shown) for monitoring the subject 10 may be provided.
If, upon review of the diagnostic test results, the physician determines that the subject is suffering from Obstructive Sleep Apnea (OSA), he will order the second part of the PSG which involves another overnight stay at the sleep clinic to determine an appropriate pressure to overcome the airway obstruction. A schematic diagram of the apparatus for the second part is shown in
During the first part of the night, the polysonmographic technician carries out a PAP titration during which the pressure of the air supplied to the subject 10 by the PAP device 44 is progressively increased. Typically, the pressure is increased in increments of 0.5 cm H2O from an initial starting pressure of three cm H2O. After each incremental increase, the monitored subject data is reviewed for a period of time before applying the next incremental increase. From a comparison of the data, an optimal pressure setting is selected and applied to the subject 10 for the remainder of the night. For ongoing treatment, a PAP apparatus is calibrated with the optimal pressure setting and presented to the subject 10 for his use.
It is apparent from the above description that the polysonmographic technician is very busy during the PAP titration. The technician not only has to continuously evaluate the sensed data, but he also must remember to periodically adjust the pressure of the air being supplied by the PAP apparatus 22. Accordingly, it would be desirable to to simplify the titration process to aid the technician.
This invention relates to an improved PAP titration apparatus and method.
The present invention contemplates a PAP device that is operative to supply a flow of pressurized air at a selected pressure. The invention also includes a programmed controller connected to the PAP device that is operative to increase the pressure of air supplied by the PAP device by a predetermined increment at predetermined time intervals.
The present invention also contemplates a method for titrating a PAP device that includes providing a programmed controller connected to a PAP device that is operative to incrementally increase the pressure of air supplied by the PAP device at predetermined time intervals. The controller is the actuated and the operation of the PAP device is monitored.
Various objects and advantages of this invention will become apparent to those skilled in the art from the following detailed description of the preferred embodiment, when read in light of the accompanying drawings.
Referring again to the drawings, there is illustrated in
The PDA 50, also commonly referred to as a hand-held computer, is a handheld device that typically combines computing, telephone/fax, internet and networking features. Most PDA's use a stylus instead of a keyboard for input. Thus, the PDA 50 is actuated with either a stylus or its keyboard, depending upon the specific device. The invention also contemplates that the PDA 50 may be hardwired or connected by a wireless method to the PSG subsystem 24. In this case, the technician could use the keyboard 26 to actuate the PDA 50. In the preferred embodiment, any one of a number of hand held computers may be utilized, such as, for example, Hand Spring, Palm, Visor or Clié; however, the invention also may be practiced with other PDA's than those named.
The invention contemplates that the polysonmographic technician programs the PDA 50 with a “titrate assist” convenience feature by setting incremental pressure changes, time intervals and a maximum pressure. When the titrate assist feature is activated, the PDA 50 first verifies that it is actually connected to an ABOB 45. Typically, only sleep clinics are equipped with ABOB's. The titrate assist continues only upon verification that the PDA 50 is connected to a ABOB 45. Thus, the verification confirms that the PDA is being used for its intended function. Following verification of the presence of the ABOB 45, the PDA 50 is operative to place the PAP device 44 in the PAP mode. Then a PDA based algorithm that is stored in the PDA 50 begins sending step-wise incremental pressure increase commands to the PAP device 44 at the preset set time intervals. The PDA 50 continues to increase the pressure until the predetermined maximum pressure limit is sent. Thus, the PDA 50 becomes a timer and provider of pressure set signals to the PAP device 44. When the PDA 50 determines that it has sent the maximum permitted pressure set signal, it ceases sending signals. As indicated above, the starting pressure, pressure increments, time intervals and the maximum pressure limit are pre-set by the polysonmographic technician before the start of the test.
In the preferred embodiment, the incremental pressure step increases can vary from 0.5 cm H2O to 5 cm H2O in 0.5 cm H2O pressure adjustment increments; however, the invention also may be practiced with other sizes of pressure step increases and pressure adjustment increments. Additionally, in the preferred embodiment, the time interval between pressure step changes can vary from one minute to 30 minutes in one minute time adjustment increments. Again, the invention also may be practiced with other time period intervals and time adjustment increments.
The present invention also contemplates a method for operation of the PDA 50 that is described by the PDA algorithm. A flow chart for the PDA algorithm is shown in
The invention also contemplates that the PDA 50 may include pause and stop features that allow the polysonmographic technician to hold the current pressure for the duration of the pause or to stop the process. The flow chart shown in
In decision block 66, the PAUSE FLAG status is checked. If the PAUSE FLAG is set, the algorithm transfers to point 56 and continues operation, leaving the PAP device 44 supplying air at the current pressure setting. If the PAUSE FLAG is not set in decision block 66, the algorithm transfers to decision block 54 and continues as described above. Thus, as shown in the flow chart, the algorithm will remain in a loop until the PAUSE FLAG is reset. By checking the status of the STOP FLAG before checking the status of the PAUSE FLAG, the algorithm allows a system interrupt during a pause.
The invention also contemplates that the PDA 50 may include a pressure reduction feature that would allow the polysonmographic technician to incrementally reduce the pressure of the air supplied by the PAP device 44. Such a function may be desirable to allow the technician to “fine tune” the pressure supplied to the subject 10. The flow chart shown in
Also shown in
It will be appreciated that, while a button is described above for actuating the stop, pause and decrease features, depending upon the specific PDA 50 used, a stylus may be used in place of a button.
The titration method described above is an open loop process, in that it provides input signals for pressure change to the PAP device 44 on a timed basis. The PDA 50 makes no therapy changes as a result of observing the response of the subject to the changed pressure. Additionally, the PDA 50 does not interpret any resulting subject data. These functions remain under the control of the polysonmographic technician or other sleep clinic personnel. Furthermore, the PDA 50, as illustrated does not change any portion of the PAP device 44. Additionally, it will be appreciated that the flow charts shown in
While the preferred embodiment of the invention has been described and illustrated as including a PDA 50, it will be appreciated that the invention also may be practiced with other devices, such as, for example, a microprocessor that has been programmed with one of the algorithms described above. Alternately, the personal computer included in the monitoring station 22 may be programmed with one of the algorithms described above to incrementally increase the pressure supplied by the PAP apparatus 44 at predetermined time increments. Additionally, as described above, the invention contemplates that communication between the various devices may be either hardwired or use wireless technology.
In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been explained and illustrated in its preferred embodiment. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.
