Hello,my name is Eric Morgan and this is J Schmidt,and today we're going to be talking about collecting cardiac impedance.The cardiac impedance signal also described as Z naught and its first derivative DZDT are used in conjunction with the electrocardiogram or ECG.To calculate statistics such as projection period stroke volume and cardiac output.Since cardiac impedance is typically used along with ECG.The subject has already been prepped for collecting ECG.First let's take inventory of the necessary supplies for collecting cardiac impedance.To collect cardiac impedance we need four ECG medical sensors or electrodes with four lead wires attached.alcohol prep pads,and micropore tape.Cardiac impedance is measured with four electrodes two on the front and two on the back of the subject.The signal is generated by passing a constant current through two CCS electrodes on the back.and sensing the resulting voltage from the front SNS electrodes.The voltage is modulated by the volume of blood in the chest.I'm going to start by placing the positive sense electrode,this electrode should be placed on the jugular notch just above where the collar bones meet.When to use an alcohol prep pad locate the area where the collar bones meet and clean the site directly above it.Next I'm going to take an electrode from the strip with the white lead wire attached.and I'm going to place it on the site which I've just cleaned.Finally I'm going to take a piece of micropore tape,and make a service loop next to the sensor.We can see when I tug on the wire the tension is applied to the service loop as opposed to the electrode.allowing it to maintain contact with the skin.I'm going to ask my subject to drop the lead wire down the shirt as it's generally more comfortable for the subject to have the lead wire through the shirt as opposed to up and out of the collar .If your task involves a subject speaking you may experience a lot of movement noise on the impedance Channel.If the electrode is placed on the neck.you can always move the electrode lower so that it's on the bone or to either side,The negative sense lead goes just below the sternum on the xiphoid process I'll ask our subject to lift their shirt above their stomach.This time I'm going to use my fingers to locate where the ribs come together and clean just below it with the alcohol prep pad.I'm going to take another electrodeagain with a white lead wire attached,and place it the site I've just cleaned.Finally once again I'm going to take a piece of micropore tape and make a service loop next to the electrode.Since the subject already has their shirt lifted up I'll go ahead and place the negative CCS lead which goes on the lower back.The placement of this electrode depends on the location of the negative sense lead on the chest.So I'm going to have the subject turn so their side is facing .Going to place my finger on the negative sense lead and estimate about an inch and a half down from it on the lower back.and clean that site with the alcohol prep pad.Next I'll take another electrode this time with a red lead wire attached,and place it on the site I've just cleaned.Finally,I'll take my micropore tape and make a service loop.Finally I'll place the positive CCS lead this lead again goes on the subjects spine but roughly one and a half inches above the positive sense lead on the chest.Using the same technique as before I'll locate the site by putting my fingers on the positive sense lead.and estimating about an inch and a half above it on the back.I'll clean that site with the alcohol prep pad.I'm going to take another electrode again with the red lead wire attached and place it firmly on the site I've just cleaned .Finally I'll make a service loop using my micropore tape and I'll ask the subject to pass the lead wire down their shirt for comfort.Once the electrodes have been placed the leads can be plugged into the data acquisition device such as the MindWare.You can see the color of the leads corresponds with the color of the channel.It's important for certain statistical analysis of cardiac impedance to know the distance between the sense electrodes on the subjects chest.I'm going to take my measuring tape and measure between the center of the sense electrodes.and I'm going to record this value for future use in the impedance analysis application.Thanks for watching and be sure to check out our other videos on our YouTube page.