Filtering patient signal also for ventilation artifacts

Abstract

In embodiments, an external medical device is intended to care for a patient. If it receives an input that signifies that ventilation artifact is present in a signal of the patient, it transmits a corrective signal responsive to the received input. In further embodiments, a patient signal is received, which is generated from a patient while the patient is or was receiving chest compressions at a frequency Fc, and also receiving ventilations at frequency Fv. At least one filter mechanism may be applied to the patient signal to substantially remove artifacts at a) frequency Fc, b) a higher harmonic of frequency Fc, and c) a third frequency substantially equaling frequency Fc plus or minus frequency Fv, while substantially passing other frequencies between them. As a result, the patient signal can be cleaner, for diagnosing the patient's state more accurately.

What is claimed: 
     
         1 . An external medical device comprising:
 a housing; and   a processor within the housing configured to:   receive a physiological signal generated from a patient while the patient is receiving ventilations from a ventilator,   detect that an artifact is present in the physiological signal of the patient, the artifact due to ventilations received by the patient; and   take a corrective action responsive to the artifact, wherein the corrective action includes applying a filter to the physiological signal.   
     
     
         2 . The device of  claim 1 , wherein
 the processor is configured to detect the artifact by an automatic analysis of the physiological signal.   
     
     
         3 . The device of  claim 2 , wherein
 the physiological signal is an electrocardiogram (“ECG”) signal of the patient.   
     
     
         4 . The device of  claim 2 , wherein
 the physiological signal is an impedance signal of the patient.   
     
     
         5 . The device of  claim 1 , wherein
 the processor is configured to detect the artifact by a correlation of an airway signal of the patient with another signal of the patient different from the airway signal.   
     
     
         6 . The device of  claim 5 , wherein
 the airway signal is one of a capnography signal, an airway pressure signal, and an airflow signal.   
     
     
         7 . The device of  claim 1 , wherein
 the corrective action includes discontinuing an operation of the ventilator.   
     
     
         8 . The device of  claim 1 , wherein
 the filter includes a comb filter.   
     
     
         9 . The device of  claim 1 , wherein
 the filter includes an augmented filter.   
     
     
         10 . An external medical device comprising:
 a housing; and   a processor within the housing configured to:   receive a physiological signal generated from a patient while the patient is receiving chest compressions from a mechanical chest compression device;   detect that an artifact is present in the physiological signal of the patient, the artifact due to chest compressions received by the patient; and   take a corrective action responsive to the artifact, wherein the corrective action includes applying a filter to the physiological signal.   
     
     
         11 . The device of  claim 10 , wherein
 the processor is configured to detect the artifact by an automatic analysis of the physiological signal.   
     
     
         12 . The device of  claim 11 , wherein
 the physiological signal is an electrocardiogram (“ECG”) signal of the patient.   
     
     
         13 . The device of  claim 11 , wherein
 the physiological signal is an impedance signal of the patient.   
     
     
         14 . The device of  claim 10 , wherein
 the processor is configured to detect the artifact by a correlation of an airway signal of the patient with another signal of the patient different from the airway signal.   
     
     
         15 . The device of  claim 14 , wherein
 the airway signal is one of a capnography signal, an airway pressure signal, and an airflow signal.   
     
     
         16 . The device of  claim 10 , wherein
 the filter includes a comb filter.   
     
     
         17 . The device of  claim 10 , wherein
 the filter includes an augmented filter.   
     
     
         18 . An external medical device comprising:
 a housing; and   a processor within the housing configured to:   receive a patient signal generated from a patient while the patient is receiving chest compressions from a mechanical chest compression device and receiving ventilations from a ventilator;   detect that an artifact is present in the physiological signal of the patient, the artifact due to chest compressions and ventilations received by the patient; and   take a corrective action responsive to the detected artifact, wherein the corrective action includes applying a filter to the physiological signal.   
     
     
         19 . The device of  claim 10 , wherein
 the processor is configured to detect the artifact by an automatic analysis of the physiological signal.   
     
     
         20 . The device of  claim 10 , wherein
 the processor is configured to detect the artifact by a correlation of an airway signal of the patient with another signal of the patient different from the airway signal.