Patent ID: 8312879

Claim:
A method for determining the resistance of an endotracheal tube that is connected to a mechanical ventilator operated by a controller to provide respiratory support to a patient, the method comprising the steps of: receiving with the controller a first pressure from a ventilator end of the endotracheal tube wherein the first pressure is an airway pressure; measuring a second pressure from a patient end of the endotracheal tube, wherein the second pressure is a bronchial pressure; receiving with the controller a flow rate into the endotracheal tube; deriving with the controller an airway resistance from the airway pressure and the flow rate; deriving with the controller a bronchial resistance from the bronchial pressure and the flow rate; deriving with the controller an endotracheal tube resistance from the airway pressure, bronchial pressure, and flow rate; monitoring the airway resistance; and when an increase in airway resistance is detected, further comparing a change in endotracheal tube resistance to a change in the bronchial resistance to determine a location of an airway obstruction; wherein if the change in endotracheal tube resistance is greater than the change in bronchial resistance, the controller determines that the endotracheal tube is obstructed.