Compensation for unmeasurable inspiratory flow in a critical care ventilator

摘要

A system and method for operating a ventilator to compensate for external gas flow reaching a patient from an external device, such as a nebulizer. A control unit of the ventilator monitors the gas flow rate from the ventilator and compares the gas flow rate from the ventilator to an expired gas flow rate from the patient. The difference between the inspired flow rate and the expired flow rate is due to the external device. The control unit modifies the operation of the ventilator to compensate for the external gas flow rate such that the flow of gas reaching the patient is maintained at a desired level.

主权项

1. A method of operating a ventilator to provide an inspiratory gas flow to a patient including an external gas flow from a medical device that operates separately and independently from the operation of the ventilator and without communication with the ventilator, the method comprising the steps of:
setting a desired inspiratory flow rate in a control unit of the ventilator; monitoring a flow of gas from only the ventilator in the control unit of the ventilator utilizing an inspiratory sensor of the ventilator; monitoring an expiratory flow of gas from the patient in the control unit of the ventilator utilizing an expiratory sensor of the ventilator; determining an external flow rate from the medical device in the control unit of the ventilator based on the difference between the expiratory flow rate and the ventilator flow rate; and operating the control unit of the ventilator to reduce the ventilator flow rate based upon the determined external flow rate such that the combination of the reduced ventilator flow rate and the external flow rate provides the desired inspiratory flow rate to the patient.