Arterial Pulses and Pressures

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METHOD OF ARM PALPATION

1. Why is palpating both brachial and radial arteries simultaneously an efficient method of palpating the arm pulses, besides speeding up the palpation of the pulses? ANS: It allows you to estimate the systolic blood pressure without a stethoscope or blood pressure cuff. This procedure is described later in this chapter.

Since the brachial artery is a medial vessel, it should be approached medially. The radial artery is a lateral vessel and therefore should be approached laterally.

2. Where are brachial arteries best sought (a) in the young patient and (b) in the older patient?

ANS: a. In the young patient the brachial artery may be hidden just under the biceps.

b. In the older patient brachial tortuosity tends to displace the artery medially away from the biceps.

3. What questions must you answer as you palpate a peripheral pulse?

ANS: a. Is the rate of rise slow, normal, or fast?

b. Is there a shoulder on the upstroke or a midsystolic dip, shoulder, or thrill?

c. Is the pulse volume or pressure small, normal, or large?

d. Is the vessel hard, i.e., does it roll too easily under the fingers?

e. What is the blood pressure? (For the method of estimating blood pressure by palpation, see p. 39.)

RATES OF RISE AND PULSE VOLUME_

1. How can you recognize a normal rate of rise and volume of a carotid or brachial pulse?

ANS: It feels like a gentle tap against the finger tips.

Note: In subjects over age 45, the tap is often followed by a slower rise. The initial tap is caused by a rapid rise to a peak known as the percussion wave. The slower rise following it is called a tidal wave. The tidal wave results from waves reflected from areas where arteries divide. The fusion of reflected and percussion waves forms the tidal waves.

2. What is the shoulder produced by the change in slope of the carotid upstroke seen in elderly subjects called?

ANS: The anacrotic shoulder

Note: Since pulse rises become more rapid as you palpate more peripherally, the shoulder may disappear by the time the pulse reaches the brachials or even high in the neck in comparison with low in the neck.

The normal percussion wave (first peak) is felt as a shaip tap. In the older age groups an anacrotic shoulder occurs, resulting in a late tidal wave that is felt as further outward motion after the initial tap. More peripherally, the shoulder to a higher tidal wave disappears. A shoulder on the upstroke of a percussion wave feels like a "tap and push" effect.

Age >45

Tidal wave

Tidal wave

Brisk Carotid Upstroke Definition
Peripheral changes

Age >45

External brachial

Slow Rate of Rise

1. What is the sensation to the fingers when there is a slow rate of rise? Why?

ANS: The first indication that the rise is slow is the absence of a tap. Then you may notice that the sensation is one of a caressing lift, a gentle push, or a nudge. If you feel a tap followed by a push, then you may be feeling an anacrotic shoulder followed by a late slow-rising tidal wave.

The normal rise is a tap; the slow rise is a caress.

2. What is the significance of a slow rate of rise in the carotid pulse?

ANS: It tells you that there is probably aortic stenosis (AS) due to fixed obstruction to aortic flow.

3. On which side of the neck is the carotid murmur of AS more likely to be palpated?

ANS: A thrill may be palpated more often over the left carotid than on the right.

Note: A lag between the onset of the apical impulse and the carotid impulse predicts a valve area of less than 1 cm2 (100% specific).

If an almost normal tap is followed by a sustained thrill, this is the plateau pulse of AS. In the above figure L2 = lead 2, and 2 RIS means that the microphone was in the second right interspace.

Severity of Aortic Stenosis by Rates of Rise

1. How does the peripheral increase of rate of rise affect an anacrotic shoulder or slow rise of mild AS?

ANS: The anacrotic shoulder and a slow rise in the carotid may become a normal rate of rise in the brachials. However, if myocardial function is decreased, the slow rise of even mild AS may be transmitted to the brachials.

The normal rise is a tap; the slow rise is a caress.

Boldface type indicates that the term is explained in the glossary.

Anacrotic Shoulder
Carotid and brachial pulse contours in a patient with mild AS. By the time the pulse wave reached the brachials, it had become normal.

2. How does the rigid aorta of severe arteriosclerosis in the elderly affect the carotid rate of rise in the presence of AS?

ANS: There may be a normal rate of rise in the carotids. This phenomenon is presumably due to the inability of a noncompliant aorta to expand slowly [1].

3. Why does supravalvular AS have both rate of rise and blood pressure greater on the right carotid and subclavian than on the left?

ANS: Because there is streaming of the jet straight up along the ascending aorta toward the innominate, right carotid, and right subclavian arteries.

Supravalvular obstruction caused the blood in the aorta to take a relatively shaip turn before it can exit through the left carotid and subclavian arteries.

Rapid Rates of Rise (Brisk Pulse) with Normal Pulse Pressures

1. When will a large volume ejected from the left ventricle (LV) have a normal pulse pressure?

ANS: If there are two outlet orifices for ejection, as in mitral regurgitation (MR) or ventricular septal defect (VSD).

2. Why is there an increase in volume in the LV in MR and VSD?

ANS: In MR and VSD the LV receives two sources of blood in diastole. In MR, the LV receives the normal amount from the left atrium plus the blood it regurgitated in the previous systole. In VSD, the LV receives, in addition to the normal left atrial blood, the blood it shunted into the RV and pulmonary circuit in the previous systole.

This depicts the extra diastolic flow through the mitral valve that takes place when MR occurs during the previous ventricular systole. In MR, the normal pulmonary venous return to the LV is added to the returning regurgitant flow to increase the volume in the LV beyond normal. Thus, in MR, the left artrium is volume-overloaded during ventricular systole and the LV is volume-overloaded during ventricular diastole.

Note that the arrows representing ejection into the aorta are equal, i.e., the forward stroke volume in MR is not reduced unless the MR is very severe or there is cardiac damage.

3. Why is the pulse rise brisk in MR and VSD volume overloads?

ANS: The increased volume produces a Starling effect on the LV.

4. Why is there a brisk rate of rise with hypertrophic obstructive cardiomyopathy (HOCM)?

ANS: In HOCM there is no obstruction until the outflow tract contracts and approximates the thickened septum to a mitral leaflet. Because of a catecholamine effect on the hypertrophied muscle, the LV ejects as much as 80% of its blood before the obstruction occurs. The rate of rise in HOCM is among the fastest in cardiology.

Phonocardiogram Trace

This is a phonocardiogram and pulse tracing from a 34-year-old woman with HOCM. The outflow gradient was 70 mmHg. Some mitral regurgitation was present. There was a large LV on X-ray. Note the rapid rate of rise to a high percussion wave and the midsystolic dip that produce the "pointed-finger" carotid pulse contour.

5. What is the Brockenbrough effect?

ANS: In normal subjects the postextrasystolic pulse after a long pause is larger than normal. In HOCM it appears to stay the same because of the increase in obstruction due to the Starling effect, the postextrasystolic potentiation effect and the decrease in afterload, all causing an increase in contractility.

Arterial Tracings Water Hammer Pulse
A B

The Brockenbrough effect is seen in the postextrasystolic beat B because the pulse pressure decreased to 40 mmHg from 55 mmHg during sinus rhythm at A.

Rapid Rates of Rise with Increased Pulse Pressure

1. What name is given to describe a rapidly rising pulse with an increased pulse volume or pulse pressure?

ANS: Bounding

2. What are the most common cardiac causes of a bounding pulse?

ANS: Aortic regurgitation (AR), persistent ductus arteriosus, and coarctation.

3. What are the most common noncardiac causes of a rapid rise with increased pulse pressure?

ANS: Thyrotoxicosis, pregnancy, and severe anemia.

4. Why is the pulse of AR bounding?

ANS: a. There is a high systolic pressure because a large volume is ejected.

The large volume is from two sources: the diastolic AR flow plus the mitral diastolic flow. The Starling effect caused by stretching the LV creates the rapid rise. b. There is a low diastolic pressure.

5. What causes the decreased diastolic pressure in AR?

ANS: The lower diastolic pressure in AR is only partly due to backflow into the LV during systole. It is mostly due to the reflex decrease in peripheral resistance caused by the large stroke volume stretching the carotid and aortic sinuses. Although gross AR will generally have a diastolic pressure of about 50 mmHg or less, if the patient goes into heart failure the resultant reflex increase in peripheral resistance caused by low output may raise the diastolic pressure to normal values.

This illustration represents ventricular diastole in a patient with AR. The reason for the large volume in diastole in AR is obvious, since the LV fills from two sources. As long as the LV is healthy, it will eject the usual 60-75% of its increased end-diastolic volume, i.e., its ejection fraction will remain normal. Thus, the aorta will receive a large stroke volume with each systole.

6. How can you exaggerate the rapid rate of rise and increased pulse pressure in AR?

ANS: Elevate the patient's arm as you feel the radial artery with the distal palmar surface of your hand. You will find that a larger pulse volume occurs only if the patient has significant AR.

Note: If the diastolic pressure as measured by the arm elevated vertically is over 15 mm lower than that measured by the arm in the conventional position, aortic regurgitation is probably present.

7. What is Corrigan's pulse?

ANS: It is the bounding carotid seen by eye.

Note: a. The large volume and rapidly rising pulse of AR detected by palpation is often called a water-hammer pulse. A water hammer, a Victorian toy, consists of a vacuum tube partly filled with water. When the tube is inverted, the water drops like a rock due to unopposed gravity and strikes the bottom of the tube with a loud noise. b. The loud sounds heard when the stethoscope is placed over the rapidly rising large pulsations of the femoral artery are called Traube's sign, or pistol-shot sounds.

8. What is Duroziez' double murmur?

ANS: Duroziez' double murmur consists of two murmurs: the first is the systolic murmur heard by gradually compressing the femoral artery with a finger proximal to the stethoscope chest piece; the second is a diastolic murmur produced by gradually compressing the artery distal to the stethoscope. This latter murmur is due to backflow as the blood in all the large arteries flows backward toward the aortic valve in diastole.

Note: Traub's sign and Duroziez' double murmurs are more of historical than practical interest because no more information is gained from them than by palpating the pulses or taking a blood pressure.

Summary of Quick Diagnoses Possible from the Carotid Pulse

1. Feel for a gentle tap. This means you are feeling a carotid with a normal amplitude and rate of rise. (Feel your own carotid with light to moderate finger pressure to learn what a normal pulse volume with a normal rate of rise feels like.)

2. If you feel no tap but only a "push" you should assume that aortic stenosis is probably present.

3. If you feel a sharp tap (brisk pulse) due to a rapid rate of rise, consider MR, VSD, or HCM if the pulse volume or pressure is normal. If the pulse amplitude is increased, consider AR, PDA, or coarctation.

PULSUS BISFERIENS

1. What is meant by a bisferiens pulse?

ANS: Bis means "twice" andferiens means "beating." Therefore, a bisferiens pulse is a twice-beating pulse. Actually it is a double-peaked arterial pulse so that there is a midsystolic dip in systole.

2. What is the physiological significance of a bisferiens pulse?

ANS: It is always associated with the ejection of a rapid jet of blood through the aortic valve. At the peak of flow, a Bernoulli effect (suction effect of rapid flow over a surface) on the walls of the ascending aorta causes a sudden decrease in lateral pressure on the inner aspect of the wall.

3. What causes the most marked bisferiens pulse?

ANS: A combination of moderate AS and severe AR [2].

4. When can AS cause a bisferiens pulse in the absence of AR? ANS: Severe HOCM can have a bisferiens pulse. (See p. 38) Note: a. A carotid shudder describes a short vibration effect when AS and

AR produces a slight bisferiens effect, and suggests that there is no significant myocardial depression. Pure severe AR can produce either a carotid thrill or bisferiens pulse.

b. A double-peaked systolic wave is sometimes more easily felt in the brachial or radial artery than in the carotid.

c. A bisferiens pulse is more likely in younger patients, perhaps because the arterial tree is more distensible.

The fall in lateral wall pressure during peak velocity requires a high velocity of ejection. This implies the presence of a relatively healthy myocardium.

High-velocity jet

Stenotic valve

Bernoulli effect

Bisferiens Pulse

Bisferiens pulse in a patient with severe AR. (EDM = early diastolic murmur of AR at left sternal border; MDM = mid-diastolic murmur at apex [Austin Flint murmur]).

The Palpable Dicrotic Wave

1. What is a dicrotic wave?

ANS: A dicrotic wave is a small wave that follows the dicrotic notch in an external carotid pressure tracing. On auscultation, S2 separates the two components of the dicrotic pulse.

Note: The dicrotic notch is the notch on a carotid pulse tracing at the time of aortic valve closure. The same notch in an aortic pressure tracing is called the incisura.

PALPATION OF THE LEG PULSES_

1. What are some of the points to help you feel difficult popliteals with the patient supine?

ANS: a. Popliteals are never directly palpable. You should only attempt to feel their transmitted pulsations.

b. Maintain similar sensations of skin to skin on all parts of the palms of both hands by having the palms in complete contact with the patient's skin, i.e., there should be no air separating any of your hand from the patient's skin.

c. Squeeze with the entire hand, i.e., with the thumbs as well as with the fingers.

2. How can you best feel a faint posterior tibial or dorsalis pedis pulse?

ANS: Try various degrees of dorsiflexion of the foot in order to separate the extensor retinaculum of the ankle from the arteries.

3. Where is the usual site to find a palpable dorsalis pedis?

ANS: Between the great and index toes.

Note: a. The dorsalis pedis may be absent in as many as 10% of normal adults.

b. The main purpose of palpating the foot pulses routinely is to document the foot pulses as a basis for future follow-up of peripheral vascular problems.

c. If the skin of the foot is colder than expected and the leg pulses smaller than expected, elevate each leg passively. This intensifies the pallor in the ischemic limb, with little effect on the limb with normal arterial circulation.

It will not be necessary to place the patient in the prone position if you remember that the key to popliteal palpation is to feel for an area of transmitted pulsation.

ESTIMATING SYSTOLIC BLOOD PRESSURE

BY PALPATION ALONE_

1. If it takes only gentle pressure on a brachial artery to obliterate the ipsilateral radial that you are palpating simultaneously, what is the systolic pressure?

ANS: Almost certainly normal, i.e., about 120 ± 20 mmHg. This assumes that the pulse volume in the radials is not so small that they already are almost impalpable.

2. What is the systolic pressure if it takes (a) moderate or (b) marked pressure on the brachials to obliterate the radials?

ANS: a. The blood pressure is probably between 130 and 160 mmHg. b. The blood pressure may be over 160 mmHg.

Note: a. A reliable estimation can only be made when gentle pressure eliminates the radials, because there are too many factors to consider if it takes more than slight pressure to obliterate the radials. b. You can eliminate the confusing effect of pushing a brachial into a groove by carrying out the procedure on the opposite arm.

ACCURATE BLOOD PRESSURE MEASUREMENT

1. How do the heart and blood vessels control arterial systolic and diastolic pressure levels?

ANS: Systolic blood pressure (the highest pressure reached by the arteries) is controlled by the stroke volume of the heart and the stiffness of the arterial vessels that receive the stroke volume. Diastolic blood pressure (lowest pressure found in the aorta and its branches after maximal runoff into the periphery) is controlled primarily by peripheral resistance.

2. What is normal systolic and diastolic blood pressure?

ANS: In an adult the upper limit of normal blood pressure should probably be considered to be 140/90 mmHg.

Note: A rough rule of thumb for systolic pressure in infants and children is:

3. What arterial abnormality can cause a rise in systolic blood pressure and leave diastolic blood pressure normal?

ANS: A stiff aorta, secondary to atherosclerosis in elderly patients.

Note: It used to be taught that an elevated diastolic pressure is more associated with a poor cardiovascular prognosis than an elevated systolic pressure. It is now known that an elevated systolic pressure has the same or a worse prognosis than an increase in diastolic pressure, because of the harmful effects of an increase in pulse pressure.

4. In what percentage of patients is there a difference of 10 mmHg or more in systolic blood pressure between the arms if the pressure in both arms is taken separately?

ANS: If hypertensives are included, 25% of patients will have at least a 10-mmHg difference in systolic blood pressure [3]. If only normotensive patients are studied, only about 1% will have a 10-mmHg difference.

5. If a patient has a history of presyncope or syncope on standing (orthostatic hypotension), how long should the patient stand before checking for a fall in blood pressure?

ANS: If the blood pressure does not fall immediately, you should recheck after 3-5 min of standing.

Note: A drop of more than 15 mmHg in systolic pressure or any fall in diastolic pressure suggests hypovolemia or autonomic dysfunction.

KOROTKOFF SOUNDS_

1. What is meant by Korotkoff sounds?

ANS: these are sounds produced by the pulsations of an artery under a partially constricting blood pressure cuff (described by the Russian physician N. S. Korotkoff in 1905).

2. What are the conventional five phases of Korotkoff sounds, and which ones are the only important ones to remember?

ANS: The five phases are: phase 1, onset of tapping sounds; phase 2, at a pressure of about 10-15 mmHg lower than phase 1, a murmur may be heard after the tap; phase 3, reappearance of only the tapping sound; phase 4, muffling; phase 5, disappearance of sounds. Phases 4 and 5, i.e., muffling and disappearance, are the only phases that are sometimes referred to in the literature by numbers.

3. By how much may blood pressure be wrong if the Korotkoff sounds are soft?

ANS: By as much as 60 mmHg.

4. How can you increase the loudness of Korotkoff sounds?

ANS: a. Increase brachial flow by having the patient open and clench the fist about 10 times. If popliteal or foot pressures are being taken, flexion and extension of the ankle serves the same purpose. This degree of mild exercise does not alter the actual blood pressure.

b. Inflate the cuff quickly.

c. Elevate the arm before inflating the cuff.

Note: Steps a and b above should be done routinely, and step c should be done only if the Korotkoff sounds are still soft.

5. Why will rapid cuff inflation increase loudness of Korotkoff sounds?

ANS: Slow inflation prolongs the low pressure phases of inflation, which acts as a venous tourniquet and traps venous blood in the forearm. The increased blood volume in the forearm will decrease the flow gradient of the arterial blood passing under the cuff during deflation.

6. How can you get an accurate blood pressure without a stethoscope?

ANS: Palpate the brachial artery with a thumb at the cuff edge. The systolic pressure occurs when the pulse returns; the diastolic pressure occurs when an increasingly dynamic pulse suddenly feels normal.

1. Where are Korotkoff sounds loudest? (a) In the center of the cuff, (b) at the edge of the cuff, or (c) a few centimeters distal to the cuff edge? ANS: In the center of the cuff.

2. Are Korotkoff sounds dominantly low or high frequency?

3. If Korotkoff sounds are dominantly low frequency, why is it better to use the diaphragm chest piece, which is designed for high frequency?

ANS: a. A bell chest piece cannot get as close to the center of the cuff as can a diaphragm, because a piece of the diaphragm can be inserted under the cuff.

b. A good air seal is difficult to obtain with a bell on a rounded arm surface unless firm pressure is applied. Heavy pressure with the stethoscope may result in a falsely low diastolic pressure.

4. What is the best position for the patient's arm to locate the brachial artery quickly? ANS: The patient's palm should face upward. In this position the brachial artery is more easily located than with the palm in any other position.

CHEST PIECE PLACEMENT AND CHOICE

Since a stethoscope chest piece cannot be placed completely under a cuff, the best compromise is to slip as much as possible of the diaphragm chest ' e under the distal edge of the cuff.

5. When is a bell chest piece preferable in taking a blood pressure?

ANS: a. When the high frequencies in Korotkoff sounds disappear, as when a patient is in shock. b. When the blood pressure is recorded in the thigh with the chest piece in the popliteal space where the Korotkoff sounds are soft partly because rapid inflation of a thigh cuff is difficult.

EQUIPMENT SOURCES OF ERROR_

1. It used to be taught that a mercury manometer always be used in preference to an aneroid (rotating-needle) type. Is this still true?

ANS: About 15% of hospital aneroid manometers are inaccurate by about 10 mmHg when tested against a mercury manometer. The error can be in the low, middle, or upper pressure range. However, there is now a shift back to using aneroid manometers (with frequent testing against mercury manometers) because of the occasional danger of mercury poisoning should the manometer break.

the effect of a too-narrow cuff on the blood pressure reading?

A too-narrow cuff may require excessive inflation pressure to occlude the brachial artery. As a result, the pressure reading may be as much as 50 mmHg too high.

3. What is considered to be an adequate cuff width relative to the arm diameter or circumference for obtaining an accurate blood pressure?

ANS: The cuff width (not length) should be at least 40% of the arm's circumference.

Note: a. The center of the rubber bladder must be placed over the brachial artery.

b. The error will be less if the cuff is slightly larger than recommended than if the cuff is slightly smaller.

4. How can you overcome the small-cuff problem if a large cuff is not available for a fat arm?

ANS: Place the cuff on the forearm and either auscultate or use a Doppler probe over the radial artery.

5. What error is likely with a loosely applied cuff? ANS: The pressure may be falsely high.

SYSTOLIC PRESSURE MEASUREMENT_

1. Why is it usually taught that you should first inflate the cuff until you feel the radial pulse disappear?

ANS: It is said that this will:

a. Prevent inflating the cuff higher than necessary.

b. Avoid being fooled by the auscultatory gap.

2. What is meant by the auscultatory gap?

ANS: It is the silence caused by the disappearance of Korotkoff sounds after the first appearance of the true systolic pressure, and the reappearance of pressure some 10-20 mmHg lower.

3. Why is it unnecessary to feel the radial pulse disappear first before applying the stethoscope?

ANS: a. An auscultatory gap requires venous distention of the forearm and concomitant low flow. If you routinely have the patient clench his or her fist 10 times and inflate the cuff rapidly, you will prevent the auscultatory gap [4], and the extra time required to feel the radial pulse for this purpose will be eliminated. b. It is just as easy to inflate the cuff until the Korotkoff sounds disappear as it is to inflate the cuff until the radial pulse disappears.

Avoiding Technical Errors in Finding Systolic Pressure

1. How high should you inflate the cuff?

ANS: It is not necessary to inflate the cuff more than 10 mmHg above systolic pressure. Unnecessarily higher inflation may cause discomfort that may elevate blood pressure falsely, and it also makes it take longer to deflate to systolic pressure. In adults, you may immediately raise the cuff pressure to 140 mmHg and listen for Korotkoff sounds. If Korotkoff sounds are present, then inflate another 10 mmHg and keep doing this until the Korotkoff sounds disappear. In children it is probably better to inflate immediately to only 120 mmHg. Thus, instead of taking time to feel for disappearance of the radial pulse to note the degree of cuff inflation, with the Korotkoff sound method you will never inflate more than about 10 mm Hg above systolic pressure.

2. How slowly should you deflate the cuff?

ANS: Not more than 5 mmHg per second or per beat, especially when beginning to deflate. This will prevent deflation through the first Korotkoff sounds or through a pulsus alternans (5- to 10-mmHg difference in blood pressure in alternate beats; see below under Pulsus Alternans). Slow deflation also prevents development of a negative pressure above the mercury column.

3. Where should the brachial artery be in relation to heart level when taking blood pressure?

ANS: The brachial artery should be at near heart level; otherwise gravity will add its pressure to the brachial artery pressure.

4. What errors occur if the rubber part of the cuff balloons beyond its covering or if the cuff is so loose that central ballooning occurs?

ANS: Both conditions will require excessive cuff pressure to compress the artery, and the reading will be falsely high.

5. When are Doppler methods a preferable method of recording blood pressure, even though only a systolic pressure can be obtained?

b. In legs, especially when there is arterial occlusive disease, coarctation, or a low output state.

c. In shock states.

d. During cardiopulmonary resuscitation (CPR) to test for effectiveness of blood flow.

Note: The systolic blood pressure obtained by the Doppler method can be accepted as nearly the same as that obtained by a stethoscope.

6. How does taking the blood pressure in an unsupported arm over 30 s affect the blood pressure?

ANS: The diastolic pressure may be 5 mmHg higher.

DIASTOLIC BLOOD PRESSURE RECORDING

1. Which is closer to intra-arterial diastolic pressure, muffling (phase 4) or disappearance (phase 5)?

ANS: Disappearance [5].

Note: It is also easier to get agreement between two examiners on the disappearance point than on the muffling point.

2. When must muffling be used?

ANS: If the disappearance point is 10 mmHg or more below muffling, as in hyperkinetic states with a falsely low disappearing point. If the difference is over 10 mmHg, it is a good idea to record both muffling and disappearance, e.g., 140/70-40.

ACCURACY OF BLOOD PRESSURE RECORDING

1. Why should we round off blood pressure readings to the nearest 5 or zero digit rather than to the nearest 2?

ANS: It is more scientific because blood pressure readings in the same patient fluctuate too much between different physicians and under different circumstances to make the last figure significant to the nearest 2. Also, it is easier to remember a number that ends with a 5 or 0. See p. 48, question 5.

Note: a. Most examiners record blood pressures to the nearest 2 because (1) manometers are graduated in increments of 2; (2) there is a sense of increased accuracy; (3) a definition of hypertension for treatment or insurance purposes is often based on 140/90 mmHg as being the limit of upper normal, so that 140/92 mmHg would require treatment or a change in insurance rating. b. In hypertensives with ambulatory monitoring, readings vary as much as 30 mmHg during a 12-h day.

2. What are some factors that can change blood pressure beyond 2 mmHg if the blood pressure is taken by the same physician at two different times?

ANS: a. If the blood pressure is read during inspiration on one day and expiration on another, the readings on expiration will be slightly higher.

b. If blood pressures are read with the antecubital fossa at the level of the fourth parasternal interspace on one day and the xiphoid on another, the blood pressure will be about 5 mmHg higher in the xiphoid area level.

c. If the room is cold on one occasion and warm on another, or if the noise level is higher one time than another, the blood pressure will be slightly higher under the cooler or noisier conditions.

d. If the patient is under stress on one day and not on another, the readings may differ.

e. Because of the patient's circadian rhythm, the patient's blood pressure will be different at different times of the day. Although most patients have a lower blood pressure in the morning than in the late afternoon, by as much as 20 mmHg, individual differences exist. Untreated hypertensive patients have their highest pressures between 9:00 and 11:00 a.m.

3. What are some of the factors that can change blood pressure beyond 2 mmHg in the same patient because two different examiners have taken the blood pressure?

ANS: a. If one physician uses muffling and the other uses disappearance for the diastolic pressure, the readings will be different by as much as 10 mmHg.

b. If one physician presses the chest piece harder than the other, the diastolic reading may be lower, especially if the brachial artery is soft, as in young subjects.

c. If one physician takes the reading with the patient's arm unsupported and the other has the patient rest the arm on a table, the reading may be 5 mmHg higher in the former than in the latter.

d. If one physician uses an aneroid manometer and the other uses a mercury manometer, the reading may be higher or lower by at least 5 mmHg.

e. If one physician applies the cuff more loosely than the other, there may be a difference of as much as 10 mmHg.

f. If one physician routinely inflates the cuff to almost 200 mmHg and the other to only about 20 mmHg above systolic pressure, the discomfort caused by the first physician will cause a higher systolic pressure.

g. If one physician uses a relatively small cuff on a fat arm, and the other uses a large cuff, there may be as much as a 50-mmHg difference in pressure.

h. If one physician's appearance and manner are threatening and the other has a more pleasant and benign personality, the patient's blood pressure may be higher by at least 5 mmHg when taken by the former.

i. If one patient's physician takes the blood pressure with the patient sitting in a comfortable chair and the other with the patient sitting on an examining table with the legs dangling, the former will obtain a lower reading [6].

4. What are some factors that can change blood pressure beyond 2 mmHg when soft Korotkoff sounds are present?

ANS: a. The hearing acuity of one physician may be keener than that of another.

b. The physician who has the patient open and close his or her fist a few times to increase blood flow may hear soft Korotkoff sounds at a higher pressure than the physician who does not do this.

c. The physician who inflates the cuff more rapidly, thus increasing blood flow to the forearm, may hear the first Korotkoff sounds at a higher reading.

d. The physician who places the chest piece partly under the cuff will hear the faint first Korotkoff sounds sooner than one who places it 1 or 2 cm below the cuff.

e. If there is an auscultatory gap due to low flow, the physician who knows how to increase arm flow may hear the first Korotkoff sounds at a considerably higher level than the physician who measures the blood pressure in a routine fashion.

5. What are some of the advantages of being scientific and recording the blood pressure to the nearest 5 or zero?

ANS: a. It is easier to remember and record three rather than six numbers between each 10 mmHg (e.g., 120,125, and 130 rather than 120, 122, 124, 126,128, and 130). b. Estimation to the nearest 5 mmHg is also faster because the slight fluctuations of blood pressure that occur from moment to moment make it difficult and time-consuming to try to determine the pressures to the nearest 2 mmHg.

SUMMARY OF HOW TO TAKE ARM BLOOD PRESSURES BY LISTENING FOR KOROTKOFF SOUNDS_

1. Ask the patient to extend his or her arm with the palm upward to clarify the position of the brachial artery.

2. Be sure that the center of the cuff bladder is over the brachial artery, and if you must use an aneroid manometer, make sure that the indicator needle is in the zero area on the dial before inflating the cuff.

3. Place the diaphragm of your stethoscope partly under the cuff over the brachial artery and press lightly.

4. Ask the patient to open and close the fist about l0 times.

5. Raise the cuff pressure as quickly as possible to 140 mmHg for an adult and 120 mmHg for a child with the arm at heart level, and listen for Korotkoff sounds. If they are present, pump the cuff up another 20 mmHg. Repeat the listening and pumping until no Korotkoff sounds are heard.

6. If the Korotkoff sounds are still very soft, raise the arm before inflating the cuff.

7. Deflate the cuff at a rate of about 5 mmHg per heartbeat or per second until the first Korotkoff sounds of the systolic blood pressure are heard. Record it to the nearest 5 or zero digit.

8. Listen for pulsus alternans. This requires slow cuff deflation when the first Korotkoff sound is detected.

9. Deflate the cuff further until muffling is heard. Then deflate further until the Korotkoff sounds disappear. If the difference between the muffling point and the disappearance point is less than 10 mmHg, report the disappearance point as the diastolic pressure. If, however, the difference is greater than 10 mmHg, report both numbers (to the nearest 5 or zero digit).

10. If the arm is so fat that the cuff width or bladder length is less than 40% of arm circumference, use a thigh cuff. If no thigh cuff is available, use an arm cuff over the radial artery.

PSEUDOHYPERTENSION _

1. What is meant by pseudohypertension?

ANS: Pseudohypertension refers to a misleadingly high systolic, diastolic, or mean blood pressure measured with a cuff compared with the pressure measured directly by intra-arterial needle.

2. How high a blood pressure may be recorded with "pipestem" brachial arteries secondary to medial (Monckeberg's) sclerosis with a normal intra-arterial measurement?

ANS: More than 300 mmHg by cuff measurement, despite a reading of about 130 mmHg by intra-arterial measurement. (The diastolic pressure may also be higher by cuff measurement.)

3. When should you suspect pseudohypertension?

ANS: The suspicion of pseudohypertension is based on the following findings. The patient is elderly and has:

a. A blood pressure that is elevated disproportionately to the clinical findings, i.e., no evidence of LV hypertrophy on the ECG, no cardi-omegaly on X-ray or physical examination, no renal failure, and no hypertensive retinopathy.

b. A palpable radial artery after the radial pulse has been eliminated by inflation of the cuff above the systolic pressure. This is a variation of Osler's maneuver, in which he compressed the radial artery with the index finger and felt for a palpable artery distal to the site of compression.

Note: A positive Osler test is reliable only in patients with severe hypertension.

PULSUS ALTERNANS_

1. What is pulsus alternans?

ANS: Pulsus alternans refers to an alternating fluctuation of pulse pressure, i.e., with every other beat the blood pressure is lower, presumably because of an alternation in either the number or strength of cardiac fibers contributing to each systole.

2. What is the usual etiology of pulsus alternans?

ANS: Pulsus alternans is associated with myocardial damage. The damage is usually severe enough to cause gross heart failure. However, it may be present without heart failure when it is secondary to cardiac hypertrophy and increased afterload, as in hypertension or aortic stenosis, but with the addition of some minor myocardial damage, such as the scar of an old infarction.

3. How much alternation in blood pressure must be present between beats before alternans can be detected by palpation?

ANS: Over 10 mmHg. However, a difference of this magnitude is unusual. Therefore, a blood pressure cuff must be used to detect a pulsus alternans by noting a sudden doubling of the Korotkoff sounds a few millimeters of mercury below the first detectable taps. Pulses alternans is easier to feel by palpation of the radial or femoral arteries than by the carotid. A very light finger pressure is necessary.

Note: a. Palpation of the radial pulse with two fingers may be used. By varying the pressure on the proximal finger, the weaker beats can be eliminated while the stronger ones are preserved, thus effectively halving the pulse rate. b. Alternation of the loudness of the second sound and of any ejection murmur may also be noted.

The heart sounds are shown in the top line. The next line is taken with a microphone over the brachial artery distal to a blood pressure cuff. Note the doubling of the number of Korotkoff sounds when the cuff had been deflated from 140120 mmHg.

4. Is pulsus alternans more or less likely with a high venous pressure? What is its significance?

ANS: Less likely. Therefore it is more likely to be present with the legs dangling or after administration of a diuretic.

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Responses

  • Efrem
    Is there a mmhg rating for arteries?
    7 years ago
  • dinodas
    Why would systolic pressure rise only 10mmHg in normotensive individual?
    7 years ago
  • mario
    Can you feel a distal arterial pulse with an arterial line?
    7 years ago
  • Averardo
    Where to find brachial pulse?
    2 years ago

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