Method and signal processing unit for determining a cardiogenic signal

Abstract

Method for determining an estimate (Sig res,est ) for a respiratory signal (Sig res ), where the respiratory signal (Sig res ) correlates with the spontaneous breathing and / or artificial ventilation of a patient (P), wherein the method is assigned a reference heartbeat period (H_Zr ref ) is specified, wherein the method is carried out automatically using a signal processing unit (5), wherein the signal processing unit (5) Receives measured values ​​from at least one sum signal sensor (2.1.1 to 2.2.2) that measures a signal generated in the body of the patient (P), and uses such measured values ​​to generate a sum signal (Sig Sum ), whereby the sum signal (Sig Sum ) an overlay - the respiratory signal to be estimated (Sig res ) and - a cardiogenic signal (Sig kar), which correlates with the patient's cardiac activity (P), includes, using the sum signal (Sig Sum ) - multiple heartbeats and - for each detected heartbeat, a heartbeat period [H_Zr(x)] in which this heartbeat takes place, detected and - by an approximate computational compensation of the influence of cardiac activity on the sum signal (Sig Sum ) an intermediate signal (Sig com ) or - the sum signal (Sig Sum ) as the intermediate signal (Sig com ) used, wherein the signal processing unit (5) calculates at least one attenuation signal [Mod(1), ..., Mod(n)] or determines it by a read access to a data memory (9), where the or each attenuation signal [Mod(1), ..., Mod(n)] is correlated with the average time course of the contribution of the cardiogenic signal (Sigkar ) at the intermediate signal (Sig com ) in the reference heartbeat period (H_Zr ref ) correlates, wherein the signal processing unit (5) for at least one detected heartbeat, preferably for each detected heartbeat, an intermediate signal section [SigA com (x)] as a section of the intermediate signal (Sig com ) in the heartbeat period [H_Zr(x)] of this heartbeat, for at least one, preferably for each sampling time (t) in the heartbeat period [H_Zr(x)] of this heartbeat - the reference time point [τ(t)] in the reference heartbeat period (H_Zr ref ) corresponding to this sampling time (t) and - determines the respective value of the or each damping signal [Mod(1), ..., Mod(n)] at this reference time [τ(t)] and using the attenuation signal values ​​thus determined from the intermediate signal section [SigAcom (x)] an attenuated intermediate signal section [SigA com,d (x)] for the heartbeat period [H_Zr(x)] and wherein the signal processing unit (5) estimates the value (Sig res,est ) for the respiratory signal (Sig res ) using the or each attenuated intermediate signal section [SigA com,d (x)] is generated.

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