EP0671180A1
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Device for determining an opening pressure in a lung
Assignee: Siemens Elema AB
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Filing: 1994-12-15
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Granted: —
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Expires: 2014-12-15
Abstract
Abstract Most alveoli could collapse in different illnesses and injuries to a lung. A relatively high positive pressure, which could in itself damage the lung or impede its healing, is required to open the alveoli. A positive pressure is often applied at the end of the expiratory phase in order to keep the alveoli open throughout entire respiratory cycles. With a ventilator according to the invention, an opening pressure (58, 66) for the lung can be determined from measurement values for the pressure and the volume of air supplied to the lung. The ventilator registers the measurement values and determines the opening pressure (58, 66) from the relationship between measurement values for pressure and for volume. The determined opening pressure (58, 66) can then be used by a physician for setting an appropriate end expiratory pressure (PEEP) for the respiratory phase or be used by a control unit in the ventilator for automatic setting of an appropriate end expiratory pressure.
Inventors
- 👤 Ulf Sjöstrand
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 04:32
CPC Classifications
A; A61; A61M; A61M16/00; A61M16/021; A61M16/022; A61M16/024; A61M16/026; A61M16/0003; A61M2016/0027; A61M2016/003; A61M2016/0033; A61M2016/0039
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
139 words
A ventilator/respirator (2) for regulating the flow of air to and the pressure of air in a lung, comprising a pressure gauge (26) for determining the pressure of air in the lung and a volume-determining device (12A, 12B, 12C, 42) for determining the volume of air supplied to the lung, characterized by a registration unit (40), connected to the pressure gauge (26) and the volume-determining device (12A, 12B, 12C, 42) for registering the determined air pressure and the determined air volume during at least part of an inspiratory phase, and a calculation unit (46), connected to the registration unit (40) in order to determine, from the relationship between registered pressure measurement values and volume measurement values, an opening pressure (58, 66) in the lung at which opening pressure (58, 66) several of the alveoli in the lung are inflated.
Claim 2
Dependent Claim
32 words
A ventilator/respirator according to claim 1, characterized by a display unit (38), preferably a digital display or a monitor, connected to the calculation unit (46) for displaying the opening pressure (58, 66).
Claim 3
Dependent Claim
70 words
A ventilator/respirator according to claim 1 or 2, characterized by a control unit (48) connected to the calculation unit (46) and to an expiratory valve (34) for automatic regulation of the expiratory valve (34) depending on the opening pressure (58, 66) determined by the calculation unit (46) so a positive end expiratory pressure (PEEP), greater than ambient pressure, is maintained in the lung at the end of an expiratory phase.
Claim 4
Dependent Claim
37 words
A ventilator/respirator according to claim 3, characterized in that the control unit (48) sets the lowest end pressure in the lung at a specific percent of the opening pressure, preferably 60-100% of the opening pressure (58, 66).
Claim 5
Dependent Claim
95 words
A ventilator/respirator according to claim 3 or 4, characterized in that the ventilator/respirator supplies a predetermined volume of air to the lung during the inspiratory phase of every respiratory cycle, the registration unit (40) registers pressure in the lung at the end of the inspiratory phase of every respiratory cycle, and the calculation unit (46) determines the relative increase in pressure occurring in the lung when the predetermined volume of air is supplied to the lung and determines, over a specific number of respiratory cycles, whether the relative pressure increase is declining, increasing or unchanged.
Claim 6
Dependent Claim
28 words
A ventilator/respirator according to claim 5, characterized in that the control unit (48) strives to maintain the determined increase in pressure by varying the positive end expiratory pressure.
Claim 7
Dependent Claim
25 words
A ventilator/respirator according to any of the above claims, characterized in that the calculation unit (46) determines the opening pressure (58, 66) at specific intervals.
Claim 8
Dependent Claim
38 words
A ventilator/respirator according to any of the above claims, characterized in that the calculation unit (46) sets the opening pressure (58) at the pressure at which the registered volume of supplied air exceeds a specific threshold value (56).
Claim 9
Dependent Claim
38 words
A ventilator/respirator according to claims 1-7, characterized in that the calculation unit (46) sets the opening pressure at the pressure at which a specific increase in pressure causes an increase in volume which exceeds a specific volume value.
Claim 10
Dependent Claim
77 words
A ventilator/respirator according to any of claims 1-7, characterized in that the calculation unit (46) establishes a curve (64) which, within a specific interval of the inspiratory phase, preferably between a minimum volume value (60) and a maximum volume value (62), is optimally fitted to the registered values for air pressure and air volume and sets the opening pressure (66) at the pressure at which the fitted curve intersects a specific volume value, preferable a zero value.
Claim 11
Dependent Claim
28 words
A ventilator/respirator according to claims 10, characterized in that the calculation unit (46) establishes the fitted curve (64), in the selected interval, according to the least squares method.
Claim 12
Dependent Claim
19 words
A ventilator/respirator according to claims 10 or 11, characterized in that the calculation unit fits a linear curve (64).
Claim 13
Dependent Claim
19 words
A ventilator/respirator according to claims 10 or 11, characterized in that the calculation unit fits a non-linear curve (64).
References Cited (Backward Citations)
GB2121292A
Cited
SE500447C2
Cited
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