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A method and apparatus for determining suitable settings for a servo-ventilator to be used during sleep. Respiratory characteristics of a patient are measured during an awake learning period. With these measured characteristics, a target ventilation setting may be calculated by alternative methods.

A method and apparatus for determining suitable settings for a servo-ventilator to be used during sleep. Respiratory characteristics of a patient are measured during an awake learning period. With these measured characteristics, a target ventilation setting may be calculated by alternative methods. The calculated setting may then be used for enforcing a minimum ventilation during a treatment period where ventilatory support is provided with a servo-controlled ventilator.

대표청구항 ▼

A method and apparatus for determining suitable settings for a servo-ventilator to be used during sleep. Respiratory characteristics of a patient are measured during an awake learning period. With these measured characteristics, a target ventilation setting may be calculated by alternative methods.

A method and apparatus for determining suitable settings for a servo-ventilator to be used during sleep. Respiratory characteristics of a patient are measured during an awake learning period. With these measured characteristics, a target ventilation setting may be calculated by alternative methods. The calculated setting may then be used for enforcing a minimum ventilation during a treatment period where ventilatory support is provided with a servo-controlled ventilator. said first end thereof; said membrane being fixed on said cylinder in the region of said first end and projecting in said transfer channel up to in front of said opening; said membrane being movable between a closed position wherein said opening is closed and an open position wherein said fuel-free gas can flow through said opening and into said transfer channel; said membrane valve assembly further including an essentially stiff membrane carrier for supporting said membrane in said open position thereof; and, said membrane carrier projecting beyond said opening of said bypass channel and said membrane carrier having a break-through opening formed therein at the elevation of said opening of said bypass chamber. 4. The two-stroke engine of claim 3, wherein said membrane is held on said membrane carrier. 5. The two-stroke engine of claim 4, wherein said membrane is clamped between the wall of said transfer channel and said membrane carrier. 6. The two-stroke engine of claim 5, said membrane valve assembly further comprising attachment means for fixing said membrane carrier; and, said attachment means engaging through said cylinder wall from the outside. 7. The two-stroke engine of claim 6, said attachment means being an attachment screw threadably engaging said membrane carrier. 8. A two-stroke engine including a two-stroke engine in a portable handheld work apparatus, the two-stroke engine comprising: a crankcase; a cylinder connected to said crankcase; said cylinder having a cylinder wall defining a cylinder bore open to said crankcase; a piston displaceably mounted in said cylinder bore and said piston and said cylinder conjointly defining a combustion chamber; a crankshaft rotatably mounted in said crankcase; said piston being operatively connected to said crankshaft for driving said crankshaft; a mixture inlet in said crankcase; a transfer channel for flow connecting said crankcase to said combustion chamber and said transfer channel having a first end open to said crankcase and a second end communicating with said combustion chamber; a bypass channel for conducting an essentially fuel-free gas; said bypass channel having an opening into said transfer channel at a location between said first and second ends thereof; said transfer channel being configured as a closed channel over the length thereof in said cylinder wall; a membrane valve assembly including a membrane axially inserted into said transfer channel through said first end thereof; said membrane being fixed on said cylinder in the region of said first end and projecting in said transfer channel up to in front of said opening; said membrane being movable between a closed position wherein said opening is closed and an open position wherein said fuel-free gas can flow through said opening and into said transfer channel; said membrane valve assembly further including an essentially stiff membrane carrier for supporting said membrane in said open position thereof; and, said membrane valve assembly further including: a finished insert part separate from said cylinder; a seal seat formed on said insert part for said membrane when in said closed position; said insert part being inserted into said transfer channel through said first end thereof; and, means for fixing said insert part to said cylinder in said transfer channel. 9. The two-stroke engine of claim 8, wherein said insert part extends in said transfer channel beyond said opening of said bypass channel; said insert part has a flow opening formed therein connecting said opening of said bypass channel to said transfer channel; and, said flow opening delimiting said seal seat on the side of said insert part facing toward said membrane. 10. The two-stroke engine of claim 8, wherein said insert part is fixed approximately seal tight to the inner wall of said transfer channel. 11. The two-stroke engine of claim 8, wherein said cylinder has an assembly slot formed therein; said insert part is a plate configured longer than said membrane and said plate having an end engaging in said assembly slot; and, said fixing means fixing said plate to the cylinder at the other end of said plate. 12. The two-stroke engine of claim 11, said membrane valve assembly further comprising additional fixing means for fixing said insert part in said assembly slot. 13. The two-stroke engine of claim 12, wherein said insert part, said membrane and said membrane carrier conjointly define a component which can be preassembled outside of said cylinder. 14. The two-stroke engine of claim 13, wherein said cylinder has a recess formed therein; and, said membrane carrier has an end portion facing toward said crankcase and has a projection formed thereon at said end portion for engaging said recess. 15. The two-stroke engine of claim 14, wherein said projection is configured to prevent said membrane carrier from rotating in said transfer channel. 16. The two-stroke engine of claim 14, wherein said projection is configured to be of assistance during assembly of said membrane valve assembly in said transfer channel. 17. The two-stroke engine of claim 16, wherein said membrane valve assembly includes an attachment screw for threadably engaging said projection. 18. The two-stroke engine of claim 17, wherein said recess is a through bore and said projection is configured as cylindrical bushing for fitting with accuracy into said through bore. 19. The two-stroke engine of claim 16, wherein said insert part is guided onto said projection. 20. The two-stroke engine of claim 15, wherein said projection is configured as an angled lug of said membrane carrier. 21. A two-stroke engine including a two-stroke engine in a portable handheld work apparatus, the two-stroke engine comprising: a crankcase; a cylinder connected to said crankcase; said cylinder having a cylinder wall defining a cylinder bore open to said crankcase; a piston displaceably mounted in said cylinder bore and said piston and said cylinder conjointly defining a combustion chamber; a crankshaft rotatably mounted in said crankcase; said piston being operatively connected to said crankshaft for driving said crankshaft; a mixture inlet in said crankcase; a transfer channel for flow connecting said crankcase to said combustion chamber and said transfer channel having a first end open to said crankcase and a second end communicating with said combustion chamber; a bypass channel for conducting an essentially fuel-free gas; said bypass channel having an opening into said transfer channel at a location between said first and second ends thereof; said transfer channel being configured as a closed channel over the length thereof in said cylinder wall; a membrane valve assembly including a membrane axially inserted into said transfer channel through said first end thereof; said membrane being fixed on said cylinder in the region of said first end and projecting in said transfer channel up to in front of said opening; said cylinder including a connecting stub formed thereon as one piece with said cylinder and said connecting stub communicates with said transfer channel; and, said bypass channel being connected to said transfer channel via said connecting stub. 22. A two-stroke engine including a two-stroke engine in a portable handheld work apparatus, the two-stroke engine comprising: a crankcase; a cylinder connected to said crankcase; said cylinder having a cylinder wall defining a cylinder bore open to said crankcase; a piston displaceably mounted in said cylinder bore and said piston and said cylinder conjointly defining a combustion chamber; a crankshaft rotatably mounted in said crankcase; said piston being operatively connected to said crankshaft for driving said crankshaft; a mixture inlet in said crankcase; a transfer channel for flow connecting said crankcase to said combustion chamber and said transfer channel having a first end open to said crankcase and a se