Comprehensive Guide to Blood Pressure and JVP Measurement Techniques

 

MEASUREMENT OF BLOOD PRESSURE

Peripheral resistance, stroke volume, and heart rate are multiplied to get blood pressure (BP). Systolic and diastolic levels are the two that exist. There are two common varieties of blood pressure monitors, or sphygmomanometers, in use. When the cuff is inflated and deflated, a mercury column in a vertical glass tube that has been calibrated goes up and down in the Mercury Sphygmomanometer. A spring-loaded needle in an aneroid sphygmomanometer moves on a dial to indicate pressure in response to variations in the cuff's pressure. This is not as reliable, and it is best to compare it often with a mercury sphygmomanometer. Blood pressure is displayed on a screen in a digital blood pressure monitor. Low-cost variants are unreliable.

Technique

The patient should be lying down or sitting comfortably. Position the manometer on the patient's arm at the same level as the cuff (if aneroid type of sphygmomanometer is used, this is not necessary). It should be possible for the cuff to cover roughly two thirds of the arm length. When using a tiny cuff, a higher reading is achieved. Approximately 80% of the limb's circumference should be the length of the cuff, and 40% should be the width. The typical adult cuff has a width of 12.5 cm. Smaller handcuffs are used on children. Take off everything that is on the upper arm. Closely fit the cuff around the upper arm such that the tubing is on the medial side and its lower edge is at least 2.5 cm (1") above the cubital fossa.  Cuff placement on the arm; the minimum distance from the cubital fossa should be one inch

Palpatory Technique

Sensate your radial pulse. The cuff should be progressively deflated after being inflated to a pressure higher than the point at which the radial pulse becomes impalpable. The systolic pressure is determined by measuring the point at which the radial pulse is once again palpable. It is a few millibars lower than the auscultatory method's systolic pressure measurement. Fully deflate the cuff.

Method of Auscultation

Examine the brachial artery, which is located on the biceps tendon's medial side. Gently place the stethoscope over it. and blow up the cuff over the palpatory method's calculated systolic level. One 2 mmHg drop at a time should be made in the cuff pressure. The systolic pressure is the point at which the Krotokoff noises become audible. To the closest 2 mmHg, note the reading. It is incorrect to round up to the nearest zero or five. As the pressure drops even further, the Krotokoff noises get louder until they abruptly become faint (phase IV) and then vanish (phase V). The diastolic pressure is the point at which sounds stop. Even in some circumstances of high cardiac output, the sounds can still be heard at very low volumes. The diastolic level in these cases is determined by taking the sound phase IV threshold at which fainting occurs. Two limbs may have different blood pressure values. Measure the blood pressure in both arms when making a judgment regarding hypertension, and take the reading that is higher to represent the patient's actual blood pressure.

Typical Blood Pressure

With age, it changes. 140/90 or more indicates hypertension in adults, 130-139/85-89 is high normal, and less than 130/85 is normal. Blood pressure is greater in the elderly and lower in women and children.

Pressure at the pulse

It is the variation in pressure between the diastolic and systolic values. 30 to 60 mmHg is the typical range.
Diastolic pressure + one-third of pulse pressure equals mean arterial pressure.

Quiet Space

Typically, Krotokoff noises only become heard during the diastolic pressure after first becoming noticeable during the systolic pressure. These sounds may go away in hypertension patients between the systolic and diastolic pressures. We refer to this as the quiet gap. Its importance is unknown, however there is a chance that the auscultation method will record a high diastolic level if auscultation is not continued until the diastolic level falls below normal, or a low systolic level if the systolic pressure is not assessed using a palpatory method before auscultatory method.

Neck Veins

An essential indicator of cardiovascular health is the central venous pressure, often known as the right atrial pressure. A catheter is inserted by the internal jugular or subclavian vein into the right atrium to measure it. Clinically, the upper limit of venous pulsations in the neck can be observed, and its distance from the sternal angle can be used to estimate the right atrial pressure with virtually clinical accuracy (see below). Then, it's referred to as JVP, or jugular vein pressure. The right atrium and neck veins are continuous. When loaded with blood, they swell; otherwise, they collapse. A normal right atrial pressure of 5 mmHg is the same as a blood column that is 7 cm high. The proximal 78 centimeters of veins, as measured from the right atrial center, continue to enlarge when the patient is upright.

Measuring Jugular Venous Pressure Accurately

The clavicle and sternum conceal the site at which swollen and collapsed veins meet. The transition point is directly behind the clavicle if the patient is inclining at a 45° angle. if the right atrial pressure is rising or the patient is more inclined. As the top limit of venous pulsations, the transition point will become visible in the neck above the clavicle. It has become customary to utilize the manubriosternal angle, also known as the angle of Louis, as a reference point for measuring the venous pressure because attempting to estimate the location of the right atrial center can lead to misinterpretation. Its position remains relatively constant with changes in posture, being 5 cm above the right atrial center. Since the right atrium's normal mean blood pressure is between 7 and 8 cm, a JVP greater than 7–5 cm, or 2–3 cm above the sternal angle, is abnormal.

Venous Jugular Pulse

Two waves, 'a' and 'v', and two descents, 'x' and 'y', are present. The right atrial contraction and the 'a' wave occur at the same time. One reason for the 'x' fall is the relaxation of the right atrium. The 'c' wave, a minor wave observed during the 'x' fall of venous pulsations, is believed to be an artifact resulting from carotid pulsations. The 'v' wave shows how venous return causes the right atrium to fill. The right atrium empties into the right ventricle during ventricular diastole, which causes the "y" descent.

Technique

A 45° angle should be used to support up the patient. Venous pulsations in the neck at this angle will be seen if there is a modest rise in the right atrial pressure. The head needs to be in line with the trunk, properly supported, and slightly slanted to the left. There need to be adequate lighting. Although the external jugular vein is more readily seen, it is unreliable for two reasons, which is why the internal jugular vein is recommended. A valve exists at the point where it joins the superior vena cava, making it unable to accurately reflect right atrial pressure. Because it is shallow, variations in local pressure can easily impact it.

To examine the veins in the neck, raise the patient's head end to a 45° angle.
Because the right internal jugular is better aligned with the superior vena cava than the left, the right side is favored. The internal jugular vein is invisible and located deep alongside the carotid artery. However, venous pulsations are visible along the sternomastoid's anterior border if they exist. When viewed from the side (in profile) as opposed to the front (en face), they are easier to see.

Distinction Between Venous and Arterial Pulsations in the Neck

Venous pulsations must be distinguished from arterial pulsations, which are frequently seen in the neck. The information below will be beneficial:

1. The upper limit of venous pulsations indicates the vein's transition from a distended to a collapsed state. It is impacted by:
2. Posture shifts, rising to a recumbent and falling to an upright position.
3. Breathing; it subsides during inspiration.
4. Variation in intraabdominal pressure: the abdomen will rise in response to a sudden pressure (abdominojugular reflux).
5. These characteristics are not present in arterial pulsations.
6. There is greater outward movement in arterial pulsations and more inward movement in venous pulsations.
7. Every arterial pulse is accompanied by two venous pulsations. Examine the patient's left carotid artery and compare its pulse to those that are visible on the right.
8. Venous pulsations stop when little pressure is given at the base of the neck, while arterial pulsations continue.
9. Arterial pulsations are easily perceptible but venous pulsations are not palpable (except from in tricuspid regurgitation)
   Wavy venous pulsations.
10. The examiner is looking for venous pulsations on the patient's right side while standing on the left side and palpating his left carotid.
11. Pulsatile displacement of the ear lobule may arise from extremely high venous pressure; arterial pulsations are not the origin of this phenomenon.

Note: In certain cases, the venous pressure might be so high that the patient's veins stay enlarged until they are raised much above the head, or the veins pulsate only while the patient is upright.

Jvp Measurement

The two pencil method is used to assess JVP after the upper limit of venous pulsations has been established. Put one pencil at the neck's upper limit of venous pulsations (the place where a distended and collapsed vein transitions), which is vertical to the ground, and another pencil at the sternal angle, which is horizontal to the ground. Calculate the vertical pencil's length (in centimeters) from the sternal angle to the point where the horizontal pencil crosses it. Up to 3 cm, it is JVP and typical.

Reasons For Elevated Jvp

• Failure of the right ventricle
• Pericarditis with constriction
• Emboli around the heart
• Disease of the tricuspid valve

Unusual Wave Form

Comparing the venous pulsations with the carotid pulsations, which indicate systole, allows one to distinguish between the two types of venous waves: 'a' wave is presystolic, meaning it occurs immediately before the carotid pulsation, while 'v' wave is late systolic, meaning it occurs near the conclusion of the carotid pulsation. 'X' decline is typically more noticeable.
Right atrial and right ventricular hypertrophy (due to pulmonary hypertension or pulmonary stenosis) and tricuspid stenosis are conditions that are associated with prominent "a" waves.

Cannon waves

When the right atrium contracts against a closed tricuspid valve, an incredibly huge "a" wave is created. These can be observed in cases of intact retrograde conduction and total cardiac block with ventricular pacing.

Ventricularization of the venous circulation

Tricuspid regurgitation results in a noticeable early systolic wave. It manifests as a perceptible 'v' wave that happens early.

Kussmaul Sign

During inspiration, the JVP increases rather than falls in constrictive pericarditis, which occurs less frequently with tamponade. The right atrium cannot expand because of the stiff pericardium, and the JVP rises as a result of the diaphragm's downward migration during inspiration compressing the enlarged liver and increasing the venous return.