Method and apparatus for controlling a ventilator
First Claim
1. An apparatus for automatically controlling a ventilator comprising:
- first means for processing data indicative of at least a measured oxygen level of a patient, and for providing output data indicative of;
required concentration of oxygen in inspiratory gas of the patient (FIO2) and positive end-expiratory pressure (PEEP) for a next breath of the patient;
wherein FIO2 is determined to reduce the difference between the measured oxygen level of the patient and a desired value;
wherein PEEP is determined to keep a ratio of PEEP/FIO2 within a prescribed range and, while keeping the ratio within the prescribed range, to keep the measured oxygen level of the patient above a predefined value; and
second means, operatively coupled to the first means, for providing control signals, based on the output data provided by the first means, to the ventilator;
wherein the control signals provided to the ventilator automatically control PEEP, and FIO2, for a next breath of the patient.
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Abstract
Method and apparatus for controlling a ventilator are described. The invention can be used to control mechanical ventilators as well as respiratory assist devices such as CPAP machines. The apparatus receives input data indicative of patient'"'"'s oxygen level. A controller determines PEEP, or CPAP, and FIO2, on the basis of data indicative of the patient'"'"'s oxygen level. In an alternative embodiment, the apparatus further receives input data indicative of patient'"'"'s carbon dioxide levels, respiratory elastance and airway resistance, and barometric pressure. The controller further utilizes the said input data to determine the optimal values of tidal volume and breathing frequency for a next breath of the patient, and uses the respiratory elastance and airway resistance data to determine any necessary adjustments in the I:E ratio. The controller also applies safety rules, detects and corrects artifacts, and generates warning signals when needed.
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Citations
79 Claims
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1. An apparatus for automatically controlling a ventilator comprising:
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first means for processing data indicative of at least a measured oxygen level of a patient, and for providing output data indicative of;
required concentration of oxygen in inspiratory gas of the patient (FIO2) and positive end-expiratory pressure (PEEP) for a next breath of the patient;
wherein FIO2 is determined to reduce the difference between the measured oxygen level of the patient and a desired value;
wherein PEEP is determined to keep a ratio of PEEP/FIO2 within a prescribed range and, while keeping the ratio within the prescribed range, to keep the measured oxygen level of the patient above a predefined value; and
second means, operatively coupled to the first means, for providing control signals, based on the output data provided by the first means, to the ventilator;
wherein the control signals provided to the ventilator automatically control PEEP, and FIO2, for a next breath of the patient. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for automatically controlling a ventilator comprising the steps of:
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(a) measuring an oxygen level of a patient and providing a data signal indicative of the measured oxygen level;
(b) determining;
(i) required concentration of oxygen in an inspiratory gas of the patient, FIO2, based on the data signal indicative of the measured oxygen level of the patient and to reduce the difference between the measured oxygen level of the patient and a desired value;
(ii) required positive end-expiratory pressure, PEEP, wherein a ratio of PEEP/FIO2 is maintained within a prescribed range, and to keep the measured oxygen level of the patient above a predefined value; and
(c) providing data signals indicative of the required FIO2 and the required PEEP based upon the determining of step (b), for automatically controlling FIO2 and PEEP for a next breath of the patient. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45)
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46. A method for automatically controlling a ventilator comprising the steps of:
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(a) measuring an oxygen level, of a patient, and providing data indicative of the measured oxygen level of the patient;
(b) measuring a carbon dioxide level of the patient and providing data indicative of the measured carbon dioxide level of the patient;
(c) providing data indicative of respiratory elastance, respiratory airway resistance of the patient, and barometric pressure;
(d) determining, from the data indicative of the measured oxygen level of the patient provided in (a), a required concentration of oxygen in an inspiratory gas of the patient, FIO2, to reduce a difference between the measured oxygen level of the patient and a desired value, and providing a data signal indicative of the required FIO2;
(e) determining a required positive end-expiratory pressure, PEEP, and providing a data signal indicative of the required PEEP, wherein the required PEEP maintains a ratio of PEEP/FIO2 within a prescribed range, and while the ratio is maintained within the prescribed range, to keep the measured oxygen level of the patient above a predefined value;
(f) determining, based upon the data provided in (a), (b), and (c), an optimal breathing frequency, a required ventilation, and a required adjustment in inspiration to expiration time ratio, I;
E, for a next breath of the patient, and providing data signals indicative of the same; and
,(g) providing to the ventilator, based upon the data signals provided in (d), (e) and (f), final data signals for automatically controlling;
(i) the required FIO2, (ii) the required PEEP, (iii) the optimal breathing frequency, (iv) the required ventilation, (v) the required adjustment in I;
E ratio, for a next breath of the patient. - View Dependent Claims (47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79)
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Specification