Jugular venous pulse (1957) Pt. 1 of 4

[Music] in 192 Sir James McKenzie published his classical work entitled the study of the pulse arterial venus and hepatic and the movements of the heart this superb book can still be obtained and makes exciting reading his investigations were made chiefly by means of the clinical polygraph a cup shaped receipt was placed over the pulsating vein and connected pneumatically by way of a rubber tube to a tamber to the membrane of this a lever was attached in McKenzie's original instrument the lever marked smoke paper covering a revolving drum but in this instrument Modified by Sir Thomas Lewis the lever carries a pen which writes on smooth white paper the polygraph has several drawbacks including time lag due to air transmission overshooting due to the mechanical inertia of amplifying levers and the Primitive method of recording in modern instruments developed from the polygraph the receiver is usually a carbon microphone electrical transmission eliminates time lag thermionic valves provide suitable amplification and the recording systems are similar to those used for electrocardiography the fogam may be timed against a simultaneous arteriogram and electrocardiogram as shown here on the sandborn polyiso as a matter of fact a phonocardiogram probably makes a better reference tracing the jugular pulse consists essentially of four main waves a x v and y a and v being crests reged string high pressure X and Y being troughs or periods of low pressure the a-wave corresponds to right atrial syst a fifth positive wave C May interrupt the X descent the X descent begins with atrial relaxation and is augmented during the earlier part of ventricular syy by displacement of the floor of the atrio ventricular septum towards the apex of the heart creating a negative pressure within the Atria the Venus pressure Rises later during ventricular syy to form the v-wave because at this time Al flow from the Atri is temporarily obstructed the Y descent or the down slope of V begins as soon as the tricuspid valve opens when right atrial and ventricular pressures equalize rapidly and fall together to the truff Y after which they rise again before the onset of the next atrial contraction the nature of the seawave proper is controversial the large seawave recorded in the jugular fogam however is the cortic pulse itself as shown by McKenzie no wave of similar amplitude and timing is seen in right atrial pressure tracings while taking full advantage of modern instrumental techniques it must be emphasized that accurate analysis of the wave form of the jugular pulse and reasonably precise measurement of the amplitude of each individual wave is usually possible at the bedside the patient should be placed supine if the pressure is below sternal angle level or propped up if the pressure is raised the correct position being that which favors maximum jugular of pulsation the most readily inspected pulsation is that of the internal jugular vein with normal Rhythm there are two main waves the a wave of atrial cyly the v-wave of entric cyly and two traps X and Y per cardiac cycle the movement is soft diffuse undulant and normally impalpable when timed against the cored pulse only the first trap X appears to coincide with syy the a wave precedes it the V Peak is appreciably later and Y is clearly diastolic you can see the arterial pulse here clearly By the Light reflection on the red spot the Venus pressure Rises on expiration and falls with inspiration passively following the changes in inter thoracic pressure