Blood pressure is always taken before any drops are placed in the patient's eyes. You must know the patient's blood pressure in case they were to faint, have a reaction, or pass out during a procedure. Accordingly, if a patient faints, has a reaction, or passes out it's very important you know their initial blood pressure.
Diagnosis of high or low blood pressure is not made based on one day's findings. At least three measurements must be performed on different days to confirm the findings as abnormally high or low. Therefore, you would normally have the patient return several times to confirm your diagnosis. There are occasions when blood pressure and other ocular findings confirm the patient must be referred immediately.
The following values are meant to serve as guidelines. There will always be circumstances when you have to use common sense.
Recorded:
Example
mmHg
ACCEPTED NORMAL ADULT RANGE
100 To 119mmHg
60 To 79mmHg
120/80mmHg is now considered prehypertensive!!
NORMAL & UPPER RANGES FOR VARIOUS AGE GROUPS
NEWBORNS:
mmHg
14 YEARS:
mmHg
25 YEARS AND OLDER:< 120mmHg/< 80mmHg
Cardiac output = C.O. Stroke Volume = S.V. Heart Rate = H.R.
- 2.) Weight: (Increases systolic and diastolic blood pressure)
- 3.) Race: (African-Americans 2 times more than Caucasians)
- 4.) Meals: (Blood pressure increases slightly after meals)
5.) Sleep: (Normal blood pressure drops followed by a slow increase)
Normal: Drops approximately 20 mmHg during sleep
Hypertensive: Drops approximately 60 mmHg during sleep
In elderly patients we see an increase in the systolic blood pressure with a fairly constant disastolic pressure (or at least one hopes). This is in part due to loss of the elasticity of the vessels and a decrease in the cross section area of the vessels in cases of arteriosclerosis.
Blood pressure is measured indirectly at the brachial artery of the right arm, however, this may vary at different offices or hospitals. Blood pressure measurements which are slightly over 140/90 must be considered stage 1 hypertensive and evaluated again in at least two weeks. Blood pressure findings 160/100 and over must be considered elevated. It would be prudent in such cases to contact the patient's family physcian.
Classifying Hypertension: 2003 National Institute of Health recommendations. The following stages are based on two or more readings taken on at least two separate visits. The measurements are in mmHg and apply too adutls age eighteen years of age or older. Should the diastolic and systolic findings fall into different categories use the higher measurement to classify the patient's blood pressure. In patients over 50 the high systolic pressures are more important than low diastolic.
|
Category
|
Systolic
|
Diastolic
|
Recommended follow-up
|
|
Normal
|
< 120
|
< 80
|
Recheck in two years |
|
High-normal
|
120-139
|
80-89
|
Recheck in one year |
|
Stage 1
|
140-159
|
90-99
|
Confirm within two weeks |
|
Stage 2
|
160-179
|
100-109
|
Evaluate or refer for additional care |
|
Stage 3
|
= to or >180
|
= to or >110
|
Evaluate or refer for additional care immediately |
Source: The seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Modified for use within Optometric offices and clinical settings.
If a patient's blood pressure is abnormally low or high check the pressure in both arms. If the measurements are substantial asymmetric between the two arms the cause could be:
1.) STENOSIS OF THE BRACHIOCEPHALIC ARTERY
2.) STENOSIS OF THE SUBCLAVIAN ARTERY
The side of the body with the lower pressure is the affected side. A 5 to 10 mmHg difference between the right and left arm is considered to be normal.
The (FRAMINGHAM HEART STUDY) determined 5 major risk factors that contributed to the development of coronary vascular disease. They are:
1.) HIGH BLOOD PRESSURE (HBP)-Typical retinal findings are flame shaped hemorrhages of the nerve fiber layer, decreased A/V ratio, crossing phenomenons, increase ALR and with severe hypertension papilledema and macular star.
2.) SERUM CHOLESTEROL LEVELS-With arcus of the cornea might want to order a complete lipid profile or complete blood chemistry (CBC).
Arcus juvenilis or arcus senilis if they form a complete circle (Annulus) within the cornea is also called "Anterior Embrotoxins". Once the cholesterol deposits are in the cornea they will always remain. Therefore, one cannot say a person's cholesterol is high, but it has been high or is presently high. In young patients it will most likely be high and a complete blood chemistry CBC or a least a lipid profile needs to be ordered.
3.) CIGARETTE SMOKING-Has also been linked to increase risk of cataract development and macular degeneration as well as high blood pressure.
4.) GLUCOSE INTOLERANCE (DIABETES)--Increased development of cataracts, glaucoma, retinal detachments and resulting blindness. Typical retinal findings are blot and dot hemorrhages, hard and soft exudates, neovascularization of the nerve head and engorged veins.
5.) ELECTROCARDIOGRAPHIC (EKG) EVIDENCE OF LEFT VENTRICULAR HYPERTROPHY
OTHER CONTRIBUTING FACTORS INCLUDE
1.) FAMILY HISTORY OF CORONARY VASCULAR DISEASE
2.) OBESITY
3.) ELEVATED TRIGLYCERIDES
4.)URIC ACID PROBLEMS (E.G., GOUT)
HIGH BLOOD PRESSURE PRIMARILY CAUSES:
1.) HEART FAILURE
2.) KIDNEY FAILURE
3.) STROKE
THE PATHOPHYSIOLOGY OF HYPERTENSION (HTN) HAS FIVE FACTORS THAT DETERMINE BLOOD PRESSURE.
1.) EJECTION VOLUME FROM THE HEART
2.) ELASTICITY OF THE ARTERIOLES
3.) ACTUAL BLOOD VOLUME
4.) VISCOSITY OF THE BLOOD
5.) PERIPHERAL RESISTANCE (PR)
In about 90% of hypertensives no cause of the hypertension can be easily established. These individuals are called primary hypertensives or individuals with essential hypertension. These individuals whose blood pressure is elevated and it is essential that their blood pressure be elevated (apparently) in order for profusion of blood to get to their kidneys, brain and other body organs. This is how the term essential hypertension was classically derived. However, though this elevated blood pressure is helpful in some ways, it is very dangerous.
CHOLESTEROL LEVEL: (ONE OF THE FIVE MAJOR RISK FACTORS)
The total cholesterol value is quite important, but it alone is not considered sufficient in evaluating the risk of coronary heart disease (CHD). One must evaluate the triglycerides level (TRIG). The high density lipids (HDL) level,"good cholesterol," and then calculate the low density lipids (LDL), "bad cholesterol." All the following findings and tests are run with the patient fasting. Nothing by mouth for 10 - 16 hours.
"Cholesterol Guidelines Regardless Of Sex Or Age"
|
Levels Of Concern
|
Total Cholesterol
|
Calculated LDL
|
|
Desirable
|
< 200 mg/dl
|
< 100 mg/dl
|
|
Borderline
|
201 To 239 mg/dl
|
131 To 159 mg/dl
|
|
High
|
> 240 mg/dl
|
> 160 mg/dl
|
Like to see: HDL > 50 mg/dl or mg/100ml
LDL < 100 mg/dl or mg/100ml
"Triglycerides"
|
Levels Of Concern
|
Expected Values
|
|
Normal
|
= To Or < 150 mg/dl Or mg/100ml
|
|
Borderline
|
150 To 199 mg/dl Or mg/100ml
|
|
Abnormal
|
200 To 499 mg/dl Or mg/100ml
|
"HDL - Reference Ranges"
|
Males
|
22 To 68 mg/dl Or mg/100ml
|
|
Females
|
30 To 80 mg/dl Or mg/100ml
|
LDL is calculated after the TRIG and HDL are precipitated out. Most of the triglycerides are in the "Very Low Density Lipids" VLDL and it is *assumed you can divide the triglycerides by 5 to get a value for the cholesterol in the VLDL. The following will help you better understand your test results and the validity of the laboritory.
*If the triglycerides are over 400mg/dl the following formula is no longer valid for calculating a patient's LDL level.
Calculation: LDL = TOTAL CHOLESTEROL (TC) - (TRIG/5 +HDL)
Or: LDL = TC - HDL - (TRIG/ 5)
| TC/HDL = Risk Factor Ratio For Developing CHD |
| Risk |
Males |
Females |
| 1/2 The Average (Low) |
3.4 |
3.3 |
| Average (Normal) |
5.0 |
4.4 |
| 2 Times The Average |
9.6
|
7.1 |
| 3 times The Average |
23.4
|
11.0 |
| LDL/HDL = Risk Factor Ratio For Developing CHD |
| Risk |
Males |
Females |
| 1/2 The Average (Low) |
1 |
1.47 |
| Average (Normal) |
3.55 |
3.22 |
| 2 Times The Average |
6.25
|
5.03 |
| 3 times The Average |
7.99
|
6.14 |
It is important to realize laboratory tests are not always accurate. The "National Institutes of Health"(NIH) and the "Center for Disease Control"(CDC), developed a method of testing called the "Abell-Kendall" method which is the Gold Standard test, also, referred to as the Lipid Research Center method (LRC). The most commonly used methods in hospitals and doctor's offices and many commercial laboratories give results that are 10 to 16 percent higher or lower than the LRC method. The point is both the patient and the doctor should know the testing method being used and not to over treat or be overly alarmed by the results. Example: Cholesterol finding of 230mg/dl by one laboratory (borderline high) could be considered acceptable (193.2mg/dl) by the lipid research center method LRC. Calculation: 230-(230)16% = 193.2mg/dl or it might be 16% higher too. This may not always be the case, but must be considered. Most likely not a good argument. This is why re-testing of patients with elevated cholesterol levels is important.
GLUCOSE LEVEL: (BLOOD SUGAR) ONE OF THE OF THE FIVE RISK FACTORS Fasting blood sugar findings nothing by mouth (NPO) 10 to 16Hrs.
LOW: = To < 60mg/dl or mg/100ml or less
NORMAL: 70 - 99mg/dl or mg/100ml
BORDERLINE: 100 - 125mg/dl or mg/100m (pre-diabetes)l
HIGH: >140mg/dl or mg/100ml "Ketones on Breath"
COMA RISK: >700mg/dl or mg/100ml
Diabetes Mellitus: Signs/Symptoms: Complaints of constant or varying blurry vision. Definite swings in refractive error either in the hyperopic or myopic direction. Increase in normal daily thirst and urination patterns. Retinal blot and dot hemorrhages, soft and hard exudates, plus engorged veins. These retinal signs usually come later in the disease, unless the patient is a know diabetic and their blood sugar level is not being controlled.
When the blood sugar level gets over 200 to 300mg/dl a patients refractive error will show changes that may be either toward myopia or hyperopia one cannot always predict. Always think about this sign when you notice marked refractive changes.
Diabetes Mellitus Diagnostic Criteria:
1.) Signs and/or Symptoms + Fasting blood sugar: equal to or greater than140mg/dl or mg/100ml
2.) Signs and/or Symptoms + None fasting random blood sugar: equal to or greater than 200mg/dl on one occasion
BLOOD PRESSURE PROCEDURE
1.) Patient should avoid consumption of caffeine, smoking and exercising for at least 30 minutes before blood pressure is taken. Doctors at the health center feel the patient should avoid smoking for at least 3 hours on a follow-up visit when monitoring their blood pressure.
2.) Blood pressure can be taken through a thin shirt or blouse rather than having the patient remove it or rolling the sleeve up.
3.) Palpate the brachial artery just below the bend of the elbow with your middle and forefinger.
- A.) The patient should be sitting comfortably, legs uncrossed, and the palm of their hand facing up. Their arm resting relaxed at the level of the fourth intercostal space . If the arm is too high the blood pressure will be artificially low and if it is too low the pressure will be artificially high.
- B.) Wrap the blood pressure cuff snugly, but not too tightly around the upper arm. Two fingers should easly slide up under the cuff. The lower edge of the cuff should be about one inch above the bend of the elbow. Place the diaphragm of the stethoscope directly over the brachial artery.
- C.) Locate the patients radial artery at the wrist and palpate it using your middle and forefinger not your thumb.
- D.) Inflate the cuff quickly about 20 mmHg above the level at which the radial pulse ceases, always over 140 mmHg, and make a mental note of that reading. This reading will be a close estimate of the systolic pressure and will help keep you from missing the auscultatory gap. This is the silence between the true systolic and its reappearance at a pressure 15 - 20 mmHg lower, thus, giving you a false systolic finding.
- E.) Deflate the cuff slowly at first then at a rate of about 5-10 mmHg/sec
-
Phases of the Korotkoff sounds
I. This is the first clear tapping sound and will last for 10 - 15 mmHg and corresponds with the systolic reading. Make a mental note of the reading that will be recorded later.
II. This is a tap and murmur which lasts about 20mmHg.
III. Here the sound becomes sharp and louder.
IV. Here the sound becomes muffled.
- V. Here the sound stops and corresponds to the diastolic.
- F.) Record your findings to the nearest even number, which arm was used, time of day and if the patient was sitting (example) "150/100 mmHg L.A., Sit @ 8:00am."
-
If the cuff is too wide for a patient your findings will be artificially low. If the cuff is too narrow for a patient your findings will be artificially high. This is the reasons Dr. Meetz suggested you have the three different size cuffs. The cuff width should be about 40 % the arm circumference. If the patient's arm is too high this will cause the measurements to be low. If the patient's arm is too low this will cause the measurements to be high.
Carotid Artery Auscultation
This is not something you will perform on every patient. In cases where there are symptoms or signs of possible vascular disease (normally in the elderly) you should be knowledgeable about performing the procedure. This is a convenient time to review and learn the procedure.
You will be listening for a rushing sound "Bruits" (noises) caused by turbulent blood flowing through a narrowed or partially obstructed artery with a stethoscope. Bruits are not commonly heard in asymptomatic patients. Hence, patients with amaurosis fugax (transient monocular blindness), transient ischemic attacks (TIA) [transient blurring of vision or loss of hemispheric visual fields which returns within approximately 5 minutes, though, may last longer], Hollenhorst plaques (plaques of cholesterol lodged in retinal arteries, usually at a bifurcation).
Have the patient comfortably seated and chin slightly elevated and tured to the side. Palpate to locate the common carotid artery with your middle and index finger Using the bell side of the stethoscope, place it over the common carotid artery about and inch above the clavicle. Have the patient hold their breath and listen for bruits for about 10 seconds. Have the patient breath and reposition the bell further up the artery, repeat the procedure 3 - 4 times along the length of the common carotid artery. The presence of a bruit is the sound of a whooshing, blowing or roaring each time the heart beats as the blood rushes through the narrowed artery. In young adults or children, because of the vessel elasticity, bruits may be heard and they are benign. Elderly or middle age patients are the most commonly affected and there has to be at least a 50% reduction before bruits are heard and are much easier heard at 70%.
Ophthalmodynamometry (ODM) is a quick in office technique for screening patients with possible insufficient carotid artery openings. However, today if you suspected an insufficient carotid artery problem a more diagnostic test is a Doppler ultrasonography, often called "duplex," of the carotid system. It is basically an ultrasound of the carotid artery system with a pictorial read-out showing the extent of blockage of the carotid artery system. For more information see page 68 in Primary Care of the Posterior Segment by Dr. Larry Alexander.
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