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Cardiovascular System: Arterial pressure, Korotkoff sounds, Central venous pressure, Arterial pulse


Measuring central venous pressure
The patient is at a 45-degree angle with the surface, the default zero is the right atrium center.
Whatever the position, Sternum is located just 5 cm from the right atrium center. And corresponds to the level of the midaxillary line so when measuring arterial pressure the device must be at the level of the midaxillary line.
Central pressure CVP normal 8-6 ​​mmHg.

Measure the height of jugular congestion
Jugular column: The point on the jugular vein path where the jugular congestion reaches its peak.
We take from this point a parallel to the line of the midaxillary and measure its height from the line passing from Sternum, then add to this 5 cm height that separates the center of the right atrium and the line passing through Sternum so that the total is CVP

Jugular venous pulse

Jugular_venous_pulse
source: www.youtube.com
Consisting of 3 elevations (A, C, V) representing positive waves and descents (X, Y) representing negative waves
Wave A
  • Mechanism of occurrence: atrial contraction
  • cases that increase their height are: Pulmonary valve stenosis PS - high pulmonary tension PH - Constrictive pericarditis - Tricuspid valve stenosis - Myxoma at right atrium - Complete heart block
  • cases in which the height decreases: Absence in atrial fibrillation

Wave C
  • mechanism of Occurrence: Tricuspid valve closure

Wave V
  • mechanism of Occurrence: Atrial fullness in venous blood with pressure gradients
  • cases that increase their height are: tricuspid insufficiency or atrial septal defect (ASD)

Descent X
  • mechanism of Occurrence: In the ventral contractions fall fibrous ring and thus increase the volume and relaxation of the atria
  • cases that increase their height are: Constrictive pericarditis

Descent Y 
  • mechanism of Occurrence: rapid ventricular fullness at the beginning of diastole
  • cases that increase their height are: Constrictive pericarditis, Tricuspid insufficiency
  • cases in which the height decreases: Tricuspid valve stenosis, atrial myxoma in right atrium.

Abdominojugular reflux (hepatojugular reflux)
The patient is lying 45 degrees and then the doctor puts his hand on the upper right quadrant of the abdomen and then gently press the abdomen for at least 60 seconds:
In the healthy: we see jugular vein congestion for a short time, then congestion disappear, and return the vein of the normal state.
In patients who complain of a disease on the right side "such as the severe right ventricular insufficiency or severe tricuspid insufficiency," the congestion remains and we say that the sign is positive.

Differentiation of the impulses of the carotid and jugular venous pulse

Impulses of the carotid
  • one strong beat "one peak"
  • clearly palpable
  • does not change by standing, breathing or expiration
  • does not go away with pressure

Jugular venous pulse
  • several heights and decreases "has two peaks".
  • It weakens when touched by fingers
  • weakens or misses while standing and inspiratory
  • misses when pressed

Basics in measuring arterial pressure

measuring_arterial_pressure
source: www.quora.com
1. Conditions and method of measuring arterial pressure:
  • Pressure must be measured in the upper and lower extremities.
  • It should be measured in the position of lying and standing
  • Systolic pressure difference between the upper extremities does not exceed 10 mmHg (at the expense of systolic), while in the lower extremities does not exceed 20 mmHg.
  • The diastolic pressure of the upper and lower extremities is equal.
  • The pressure should be measured with a blood pressure gauge, on the following conditions: (the patient is lying or sitting, his arm resting at the level of the heart, and cuff higher than the elbow by 2 cm, in a warm atmosphere without being a smoker, an abuser or eating food in the last half hour)

2. Korotkoff sounds

7-Korotkoff-Sounds-five-phases-14
source: www.researchgate.net
Are the sounds we hear during Stethoscope during the measurement of arterial pressure, consisting of five stages, namely:
  • A. Phase I: Hearing a beat sound: corresponds to systolic pressure
  • B. Phase II: A light puff appears at a distance of 30-40 mmHg
  • C. Phase III (Mean arterial pressure): The puff becomes higher because of increased blood flow through the compressed artery
  • D. Phase IV: Sound starts to fade
  • E. Phase V: completely miss the sound (diastolic pressure)

3. Auscultatory Silent Gap A
A. Definition: The inability to hear the sound in Phase II of Korotkoff sounds, and occurs when some patients have arterial hypertension, and there is no clear explanation yet.
B. The most likely cause: high arterial pressure ---> congestion and enlargement of the veins, fluid flow from the veins ---> fluid pressure on the artery ---> Atelectasis on the artery ---> the absence of blood flow within the artery ---> the silent gap occurs
This phenomenon leads to an erroneous assessment of arterial pressure, where we calculate it less than the true value and therefore to avoid these Phenomena We rely on the absence of the radial artery as an indicator of systolic pressure.

Arterial pulse
The shape and volume of the arterial pulse involve several factors:
  • Beat volume of the left ventricle.
  • The force of ejaculation and its speed.
  • Peripheral resistance (arterioles(
  • Pressure pulse (the difference between the systolic and diastolic blood pressure).
  • Adapting the arterial bed.
  • The dimension between the vessel and the heart.

The things that are investigated during the pulse are:
  • Speed (rhythm(
  • volume (full, weak, thread(
  • Shape (wave type(
  • Symmetry.

The typical natural pulse pattern
The pulse is initially up and up (with ventricular contraction), then slowly drops at the end of the ventricular contraction, then bounces slightly up (due to the closure of the aortic valve S2), then gradually decreases.
  1. Thready pulse, cause: shock, atherosclerosis
  2. Water hammer pulse or collapsing pulse (Corrigan's pulse) (differential pressure is wide): cause: aortic valve regurgitation, PDA, hyperthyroidism, pregnancy, decreased peripheral resistance (peripheral hyperthermia)
  3. Plateaued Pulse: delayed and plateaued peak, decreased amplitude, and gradual downslope (pulsus parvus et tardus), cause: narrowing of the left ventricle exit (Aortic valve stenosis, Subaortic Stenosis)
  4. Bisferious pulse: cause: Hypertrophic obstructive cardiomyopathy (hocm), aortic valve disease (Stenosis and insufficiency(
  5. Pulsus bigeminus: cause: extrasystoles
  6. Mechanical alternans pulse:  cause: left ventricular systolic impairment (Weak beat, heart resting and then strong beat(
  7. Pulsus paradoxus: Cause: constrictive pericarditis, severe cardiac relaxation, asthma

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