842, USM Original File-1.1 - Parks Medwhich is in collapsible tubes. Refilling from bulk is much...

Operating Manual

Model 842Pocket Doppler

Medical Electronics, Inc.

Parks Medical Electronics, Inc. Aloha, Oregon U.S.A. 1-800-547-6427

DOPPLERMODEL 842

Before You Begin,

Please Read This!

Information contained in this operating manual is provided to help

the user operate the instrument controls. In no way must a

diagnosis be made on the basis of information provided in the manual.

We provide generalized examples of procedures which we believe to

be in current usage. However, the procedure to be used and the

diagnosis of an individual patient must be determined by the

attending physician from information in scientific literature and from

other medical sources.

MODEL 842 POCKET DOPPLER


Parks Medical Electronics, Inc. Model 842 Ver 1.1

SPECIAL INSTRUCTIONSThis instrument is similar to our Model 841/841-A Doppler but has the additional featureof providing an output signal for a graphic recorder. Flow-velocity curves can be recorded.

CONNECTING TO THE ELECTROCARDIOGRAPH:

The dc inputs of most single-channel and some multi-channel ECG machines arecompatible with this Doppler and all others we make. The input characteristics of therecorder should be dc, high impedance (100K or more), and provide a stylus deflectionof 1 cm. with 50 mv. of signal. This requirement is met by almost all single-channelelectrocardiographs of American manufacture. The connector used to plug into theDoppler is a miniature type (1/8 inch diameter Switchcraft 780).

MAKING A RECORDING:

There is one factory preset control in the Doppler which is a threshold control. If it is set toolow or if your battery is weak, the recording will have flat spots on the bottom as shownbelow. We advise you to keep the speaker volume low to conserve battery power andmaintain the proper setting of the input-level (threshold) control. Recorded wave height isset by means of a screwdriver adjustment on the front panel. It need not be adjusted foreach recording because the useful information is in the shape of the wave, and not itsheight. Find a setting which provides a suitable recording size for the majority of your work.

TOO LOW (too far clockwise) CORRECT

BATTERY LIFE:The life of the battery is determined by the quality of battery you use and how loudly youdrive the speaker. For maximum battery life never use a mercury battery, only use analkaline battery and keep volume low. When the sound gets weak or distorted, thebattery should be replaced.TURN OFF WHEN NOT IN USE!

BATTERY REPLACEMENT:Refer to the battery sheet in the back of this manual for instructions on how to replacethe battery.SERVICE:Most failures of the Doppler are related to the probe in some way. Should you suspect theprobe, a replacement is available from the factory. It should be replaced with the samefrequency that is engraved on the body of the original probe. Should you not haveaccess to a biomed department to replace the probe, it is best to return the instrumentto the factory if there is a sensitivity problem. But don’t do so without first calling us.We can handle many service problems over the phone and we are glad to do so.

THE COUPLING GEL ____________________________________________________________

YOU MUST USE GEL IN FRONT OF THE PROBE.We recommend you use a coupling gel made especially for ultrasound. Don’t use agel that is too runny. You can use sterile jellies internally.Ultrasound coupling gels are available from us, or will usually be available from oneof your surgical supply dealers. These gels are available in bulk, sterile packets andbottles. Gel in a semi-rigid tube with a small extended tip is easier to use than thatwhich is in collapsible tubes. Refilling from bulk is much less expensive than buyingmore bottles or packets. Some tubes can be autoclaved.

PLEASE DO NOT USE ECG PASTE OR CREAM.

THE RED PROTECTIVE COVER MUST BE REMOVED FROM THE PROBE BEFORE USE.

WARNING: THIS DOPPLER IS INTENDED FOR USE BY HEALTHCAREPROFESSIONALS ONLY. This Doppler may cause radio interference or may disruptthe operation of nearby equipment. It may be necessary to take mitigation measures,such as reorienting or relocating the Doppler, or shielding the location.

PHYSIOLOGICAL EFFECTS OF ULTRASOUND _______________________________

IMPLANTED DEVICES

Implanted devices such as cardiac pacemakers should be avoided due to the possibilityof affecting their operation. Also some plastics used in replacement surgery may beaffected by absorption of ultrasound energy. Metal implants may lead to reflections andas a precaution, avoid using ultrasound close to these.

STUDIES NEAR SENSITIVE TISSUES

Extreme care should be taken when treating areas near the eye because of the dangerof damage to the retina. Similarly, extreme care should be taken near other sensitivenervous tissue.

Based on experimental and epidemiological data, there is presently no identified riskassociated with diagnostic ultrasound. However, a prudent and conservative approachis recommended in which diagnostic ultrasound should be used only for medical benefitand with minimal exposure.



OPERATING INSTRUCTIONS

USE OF THE PENCIL PROBE IN THE DIAGNOSIS OF ARTERIAL DISEASE IN THE LIMBS

1. THE PROBE. The probe consists of two crystals; one for transmitting the ultrasoundwaves and the other for receiving the reflected waves. If either crystal is damaged, theprobe will not work properly or will not work at all. The crystals are covered by amaterial that is vulnerable to attack by heat, alcohol and ECG paste or cream. Therefore,DO NOT use ECG paste as the contact medium between the skin and the probe. UseAQUASONIC or any gel made for ultrasonic physical therapy equipment. In an emergencyuse any surgical jelly or lubricant, even petroleum jelly or mineral oil. Remove the gelafter use with a soft tissue. If you should find the probe with dried gel on it, wash it offunder running water. Do NOT scrape off the gel because you may damage the coatingover the crystals.

2. POSITION OF THE PROBE: Invariably, people not accustomed to our probeuse it incorrectly. The probe we furnish is different from that of the othermanufacturers and is used differently. If you hand someone the probe and say“Here, try it for yourself”, they will almost always put it over their radial artery andplace the probe perpendicular to the artery—and perhaps with no coupling gel.Many people have tried to compare our Doppler with other makes by this method.Keep in mind that you are not buying a Doppler for use on the radial artery, but foruse on vessels you cannot feel. The best testing ground is therefore in yourparticular area of interest. We believe our instruments will permit you to find thevessels easier, let you hear the venous sounds easier and follow the vesselsbetter than any other device on the market, regardless of price. But it takes somepractice in order to be able to do this. We believe the arm is a good and mostconvenient limb for you to learn on—to learn how to hold the probe depending onthe depth of the artery and vein. The area about 6 inches each side of the elbowis a good place to start.

First, put some gel on the tip of the probe. The gel squeeze-bottle must be shakendownward and then gently squeezed to get the gel to come out. Pile up about aquarter of an inch of gel on the probe, making certain there are no large airbubbles in the pile because ultrasound does not go readily through air. It needs acontinuous conducting medium, and the gel is ideal.

Turn the VOLUME control fully down (counter clockwise) and turn the instrumenton. Gradually turn up the volume. You should hear a rumbling sound if you areholding the probe. This is caused by the vibration of the gel due to tremor in yourarm. Now place the probe over an artery in the arm about half way between theelbow and the wrist. Tilt the back of the probe toward the hand at an angle ofabout 45 degrees, making certain there is gel in the pathway between the probeand the skin. Move the probe and the skin sideways to try to find the center of theartery and the hissing noise at heart rate, which is the Doppler sound for an artery.If the sounds you hear are more or less continuous, that is simply the backgroundnoise of the instrument and it means that you are not over the artery. The mainenergy of the beam is only about as wide as the crystals in the probe, so thereisn’t much room for error in aiming the probe. For this reason you must alwayssearch the area of the artery and tilt the probe for best Doppler sounds.


MODEL 842

When you are looking for deep arteries, or for small or obstructed arteries, you willhave to turn the VOLUME control near maximum. This also means that every time youmove the head of the probe you are going to get some pretty big thumping noises in theearphones. Therefore you want to avoid moving the head of the probe with respect tothe skin as much as possible. That is why you place the probe over the area where youthink the artery is and then you search for the exact point by moving the skin with theprobe and changing the angle of the probe with respect to the skin. You might wonderwhy these big transient noises can’t be filtered. We do limit their intensity, but we donot filter. The reason is that in the search for low-velocity blood flow, such as inoccluded arteries and in the veins, the pitch of the Doppler sounds associated with theblood flow are very low. Any filtering to eliminate or minimize the sounds accompanyingmovement of the probe would also reduce the response to low-velocity blood flowsounds, and of course this is undesirable.

3. DIAGNOSIS OF ARTERIAL DISEASE: The Doppler method of diagnosing arterialdisease of the limbs is only one of several good methods. It is probably the mostconvenient and least expensive of the better methods. It is only qualitative but can bemade semi-quantitative by permitting you to make systolic blood pressure measurementsalong the leg with the aid of a proper cuff and manometer.

The great sensitivity of the transcutaneous Doppler can cause a doctor or technician toconclude improperly that an arterial pathway is open when it isn’t. Collateral flowaround an obstruction can be well-developed, especially in the thigh, and causepulsatile blood to flow in the distal arteries. Or a major artery may be narrowed, causingpulsatile flow distally. These mistakes in diagnosis can be avoided almost entirely bysimple means and a little bit of experience. An experienced user of the Doppler canrecognize the characteristic sounds of open and obstructed arteries. Remember thatDoppler sounds vary in pitch (frequency) with the velocity of blood flow. When you hearthe Doppler sound on a normal artery and compare it with a normal arterial pulse-pressure wave, you will recognize the sound of the dicrotic notch, the very fast rise timeof the wave and perhaps a third sound just before the onset of a new pulse wave. Whilethe origin of these second and third waves in the descending branch of a pulse wavemay be in dispute, their absence in vessels distal to an obstruction is not disputed. Soa diagnostic rule is that whenever you hear the second and perhaps third sounds of apulse wave of a major artery, you can be sure the artery is open proximal to the probe.Plethysmographic studies also show a delayed crest to the wave, associated with aslower rise time to the wave when there is an obstruction proximally. Though theDoppler is permitting you to hear velocity changes rather than true volume changes,the correlation is good enough to be quite valuable diagnostically.

Now the opposite is not necessarily true—that when you can’t hear second andperhaps third sounds the artery is obstructed proximally to the probe. In the digits andsmaller vessels the pulse wave is smoothed out more, especially when there is somevasoconstriction. Now of course there are cases that are in doubt. If you cannot clearlyhear the second and third sounds (the third sound is frequently missing), compare withthe same artery on the other limb. If you find a radical difference in the sound of theDoppler, both in pitch and in amplitude, you are justified in being quite suspicious of thepatency of the artery of the first limb you studied provided you are now fairly skilled atoptimizing the sounds.



MODEL 842

Another thing you listen for is the relative clarity of the arterial wave. How well it standsout from the background noise of the instrument and perhaps the venous flow adjacentto the artery. Move the probe a little to each side of the artery to make this estimation.In a normal person you will find that you can make the arterial pulse wave almostcompletely separate from the venous sounds by positioning of the probe.

The way you really come to a final conclusion that the artery is obstructed proximal tothe probe is by measuring the systolic pressure at the ankle with an ordinary arm cuff.If you want to measure pressure at other places on the leg you will need a special cuff,the bladder of which encircles the limb. We sell such cuffs. The method is as follows:

Wrap the cuff around the ankle or slightly above it so you can get the probe on theposterior tibial and hear the arterial sounds adequately. Inflate the cuff to a pressurewell above the patient’s arm pressure or at least 30 points above the pressure at whichthe Doppler sounds disappear. Gradually reduce cuff pressure until you hear bloodflow, though the sound won’t be normal. At that point read the pressure to obtainsystolic pressure at the ankle. If you have doubts, center the probe on the artery andinflate the cuff again. You can observe at what cuff pressure the blood flow stops andagain where it starts. Where it starts is normally used.

This procedure is very similar to taking pressure on the arm using a stethoscope. Thereyou are using sounds of turbulence or wall motion. Here we are sensing the flow ofblood under the cuff with a much more sensitive device. You can get a clear indicationof systolic pressures as low as 30 mm. of Hg. The only problem is keeping the proberight on the center of the artery while you are inflating and deflating the cuff. An aneroidmanometer mounted on the inflation bulb of the cuff is preferable. Tycos makes sucha device and perhaps others do too.

The possibility of misdiagnosing is greatly reduced by this method provided you maketwo or more measurements and you are skilled at holding the probe in the right placeand at the right angle. A low pressure reading is quite reliable. On diabetics you mayget readings of 300 mm. Hg. or more, even though they have ulcers on their toes.These people with end-artery disease studied plethysmographically with the mercury-in-silastic strain gage, which we also make, will have quite large and normal lookingpulsations in the toes. Their arterial walls are sclerosed so badly sometimes that theywill not compress with cuff pressure.

The normal pressure in the ankles should be about the same as the systolic pressurein the arm, or a little higher. If the ankle pressure is 30 mm or more lower than the armpressure, an obstruction is almost certainly present. Normally one finds that peoplewith arterial obstructions have pressures of 100 or less.

If you have a proper cuff you can take pressures in the same manner (with the probe atthe posterior tibial) just below the knee, just above it and at the top of the thigh. Bymeasuring systolic pressure (the pressure measurement is always where the cuff is, notwhere the probe is) you will find radical differences between measuring sites if theobstruction is between them or you will find that pressures at corresponding points on thetwo legs are quite different. An exception is bilateral obstruction of the bifurcation of theabdominal aorta which may give you fairly symmetrical pressures on both legs. Unfortunatelyyou cannot use the Doppler above the top of the thigh. The pressure measurements madeon the thigh with a narrow cuff will be clinically useful, though not accurate.



MODEL 842

Once you have determined that there is an obstruction it is often desirable to determinejust where it is. It is permissible to check at certain points provided you are quitefamiliar with normal sounds—second and perhaps third sounds. Start at the top of thethigh and listen for the normal arterial sounds. A little to one side you should hearvenous flow varying with respiration. The adjacent venous flow assures you that youare indeed listening to a major artery. This is important because you can get beautifulsounds from a collateral that is aimed toward your probe and giving a tremendousDoppler effect. But a collateral follows a tortuous path and the venous sounds will notbe found adjacent to it. If you have a little problem hearing the vein (and you shouldn’tover big veins) give the leg a slight squeeze distal to the probe to increase the velocityof the venous blood and make its pitch higher. As you follow the superficial femoralartery down toward the knee you will lose the sound, even on normals, in some partsof the path because of tendons or other anatomical obstructions between the probeand the artery. You should be able to pick it up again easily in the popliteal region. Yourear and concentration make a filter to extract wanted information from backgroundnoise that exceeds anything that can be done electronically. You can follow these smallarteries distal to the knee and in some cases they can be followed all the way to theankle and beyond. Keep in mind that some people don’t have a dorsalis pedis artery.If you are working on arteries in the foot, make sure they are dilated by immersing thefoot in a bucket of warm water for a few minutes. Some people are vasoconstrictedmost of the time. They usually will dilate for a while after the immersion and in a fewminutes be constricted again. Also they usually do not have arterial disease.

If you want to quickly determine the efficiency of flow in the arterial system of the leg,pick up the posterior tibial and listen for 2nd and perhaps 3rd sounds. If you hear them,and you are sure you know the difference between normal and abnormal, go no further.If they do not sound normal or there is doubt, make a blood pressure measurement andcompare it with systolic pressure on the other ankle and on the arm. To find thelocation of the obstruction you can listen with the Doppler, or using a special cuff youcan make blood pressure readings farther up the leg. If the obstruction is in the iliacsyou can note it by the Doppler sound distal to the obstruction or by a much lower thannormal blood pressure at the top of the thigh as measured with the cuff and theDoppler.

PRE-OPERATIVE AND POSTOPERATIVE use of the Doppler is very important. Whenthe patient is on the table, measure systolic pressure at both ankles and record it. Afterblood is again permitted to flow measure both pressures again. The pressure on theoperated leg should be UP compared to the pressure in the other leg, the control. If itisn’t, then it is pretty safe to assume something is wrong. On rare occasions a limb willhave such a high degree of reactive hyperemia that pressure will not be up and mayeven be lower, but the leg will be hot. A large percentage of patients are blocked tosome degree before they get off the table. Blood-pressure measurements will give youan objective evaluation of the surgery. Some surgeons use the pencil probe directly onthe artery (using sterile jelly for coupling) just distal to the repair. The characteristic ofthe flow sound is important. If the runoff is inadequate an experienced ear can detectit and often correct the cause on the table. You can also use Doppler and pressuremeasurements for follow up, comparing pressures at both ankles with systolic pressureat the arm, measured either with a Doppler or stethoscope.



MODEL 842

USING THE DOPPLER ON DIGITS


MODEL 842

Line up the long way of the crystals and the pencil probe body with the length of theartery for best separation of arteries and veins at the ankle and best efficiency on thedigital arteries. Whenever you try to pick up arterial flow from the digits you mustconsider digit temperature. It is often difficult to get a digital pulse when feet are coldor cool. The digits can be so vasoconstricted that blood only oozes through, which issufficient to nourish but does not give a good recording or sound on any device. Thisoccurs in perfectly healthy digits under normal conditions. It also occurs after surgerywhen severe vasospasm may occur.

In order to get a good sound, blood pressure measurement or recording under theseconditions you must cause vasodilatation to take place. One method is to warm theextremity by immersing it in warm water, not hot water. Within a few minutes you willbe able to evaluate the condition of the flow when the limb is at heart level or slightlyabove.

Another method used to dilate peripheral vessels is to occlude all flow at the ankle orforearm with an ordinary arm cuff infrated to well above systolic pressure. This is notnormally painful, especially when vascular disease is present in the arterial system. Iftoo much discomfort is apparent, a different procedure could be tried. Five minutes isusually enough time. On release of cuff pressure a reactive hyperemia will take placeand last for a short time at least. There should be enough time to make an evaluation ofarterial patency. Diabetics may have incompressible arteries so this technique maynot work with them.

When there are two sounds to the arterial pulse wave, the first caused by the filling ofthe vessel with systole and the second being either forward or reverse flow in the diastolicphase, vessels are usually patent. However, blockage of major proximal arteries maybe present with good collateral flow around them.

When there is only one sound with each cardiac cycle and the sound is not brisk, aproximal stenosis or occlusion may be present.

PROPER PROBE PLACEMENT AND PROPER USE OF GEL ARE VERY IMPORTANT!

The pencil probe body should be in line with the artery, not crosswise to it, and shouldbe at about a 45 degree angle. You must be very careful about probe pressure, becausea slight amount of pressure against the skin will occlude the artery. You must use a dabof gel in front of the probe.

You may find it impossible to make blood pressure measurements on the digits with aDoppler, especially the toes. It is better to use our photoplethysmograph for that purpose.Doppler sounds from digital arteries will be very helpful once you become familiar withnormal and pathological sounds. Making digital pressure measurements on the toes isnot a very popular procedure.

Refer to your medical literature for diagnostic procedures. This information is primarilymeant to be a simplified guide to the use of the instruments and the probe.

TECHNIQUES FOR BETTER DOPPLER RECORDINGSMODEL 842


A few hints on use of the probe will probably help you to get better recordings than youotherwise would. Basically, they involve the angle of the probe, how much gel to use,how much pressure to use, and how to orient the crystals in the end of the probe.

The angle of the probe to the vessel is important and there are two opposing factorswhich you must balance. If you are studying a vessel near the surface, holding theprobe almost tangent to the vessel, or at least 30 degrees off tangency, will give you agood recording with minimum filtering. You want to use minimum filtering because itgives you a truer picture of velocity changes occurring during the cardiac cycle whichis an important part of diagnosis. So whenever you are studying digital vessels,supraorbitals dorsalis pedis, etc., try to make your angle to the skin less than 45 degrees.Use no more filtering than is necessary to get an acceptable recording, if you cantolerate the raggedness. The reason this works better is that the shift in frequency bythe Doppler effect is a function of the angle of the incident ultrasound to the blood flow.The pitch of the sound is higher, and with higher pitched sounds you need lesssmoothing. Smoothing introduces distortion into the true velocity picture, so minimalsmoothing gives you more realistic picture of flow velocity changes. Of course youmay choose to use more smoothing to have a better looking graph.

A problem with small vessels is that it is difficult or impossible to separate the arteryfrom an adjacent vein. Venous flow is low velocity, and when the beam of ultrasoundhits the vein, low-pitched sounds will be mixed in with the higher-pitched arterial sounds.They will contaminate the recording. About the only thing you can do to minimizevenous contamination is to orient the crystals in the end of the probe so they are verticalwith respect to the skin. The size of the ultrasound beam sent into the skin, near thecrystal at least, is approximately the size of the crystal. This means that if artery andvein are lying side by side, vertical crystals will give you a narrow beam and a betterchance of insonating the desired vessel.

In the case of making blood pressure measurements at the ankle, you are really notthat interested in getting a pure arterial signal. You would prefer a wider beam so thatslight movements of the foot during inflation or deflation of the cuff don’t cause you tomove the beam off the vessel. Therefore you would want the crystals on the probe tobe parallel to the skin, utilizing the full width of the crystal. Furthermore, in order to geta good signal, you may have to tolerate a wider angle between the probe and the skin.In fact, the deeper the vessel the more the probe has to be aligned toward perpendicular,which is the worst possible position from a Doppler shift standpoint. The reason youhave to go more vertical is because of the power loss of the ultrasound energy as itpasses through the tissue. When vessels are deep and you want a good recording,align the crystals in the probe along the length of the artery so that as much ultrasoundas possible is hitting the target artery. This means you will possibly have to use morefiltering to get an acceptable recording, but that is the trade off. If your sound is weakand there is considerable background noise, the recording is not going to be goodanyway. You must get the best signal-to-noise ratio you can, and you do that by acombination of crystal alignment, angle, and how close you can get to the artery. Don’thesitate to use pressure on deep vessels. If you use pressure on shallow ones suchas the digits and dorsalis pedis, the edge of the probe will shut off the flow.

TECHNIQUES FOR BETTER DOPPLER RECORDINGSMODEL 842


For vessels near the surface, higher frequency probes work best. This is because, intheory at least, the efficiency of reflection of ultrasound varies as the fourth power of thefrequency. This means, in theory, that for near-surface vessels 10 MHz. is 16 times betterthan 5 MHz. In practice there is a noticeable difference but it is nowhere near that great.When it comes to depth, the inverse applies. Many people have the impression that youneed 4 or 5 MHz for veins. You need lower frequencies for an advantage in depth. It hasnothing to do with arteries or veins. In fact, the Doppler shift is twice as much at 10 as it isat 5 so the sounds are easier to hear. Use whatever works best for you and don’t try tostick to anybody’s rules. If lower frequencies were better, why don’t we use 2 MHz.The reason is that the efficiency of reflection off red cells in the smaller vessels is verypoor. The radial artery does not give a good signal, but the highly vascular placentadoes and so does the abdominal aorta. 2 MHz. is used mostly for obstetrics and for thedetection of air emboli in neurosurgery done in the sitting position. In the first casethere is much more blood involved plus the beating fetal heart, and in the second casethe air embolus is much larger than a red cell. So in both cases the targets are bigger.10 MHz. makes a very poor obstetrical Doppler and 5 isn’t much better.We make a smaller probe we call a skinny pencil. Its outside diameter is 1/4" asopposed to the 3/8" diameter of our standard probe. It is a bit easier to manipulatearound digits and its smaller beam separates small arteries and veins better. Somepeople like it especially for the supraorbial arteries.We also make two sizes of flat probes which can be attached to the skin. They aremostly used for blood pressure measurements in the O.R. and in nurseries, butsometimes they are affixed over the dorsalis pedis or posterior tibial during vascularsurgery. There can be a problem of the gel running out and compression of the arteryinadvertently, especially the dorsalis pedis. The posterior tibial at the level of the externalmalleolus may be under quite a bit of tissue and not give a good signal to noise ratioexcept on skinny people. A further complication is that after vascular surgery you mayget vasospasm and need a pencil probe to pick up the signal. If you have spasm orsuspect it, you have to make repeated ankle pressure measurements over a period oftime and see if pressure continues to rise.Knees should be bent to pick up popliteals. The groin crease is an easy place to pickup deep venous flow. With the patient lying down, you should hear considerable variationin venous velocity with respiration.With a special cuff you can measure finger and penile pressures. You can monitor theeffects of warming or drugs on the fingers of people with vasospastic disease with aninfant probe attached with Velcro or tape.You can monitor or record supraorbital flow with a flat probe above the supraorbitalnotch. When you try to get a supraorbital recording, which can be difficult, it is easy toget a nearby artery that feeds the eyelid and flows in the wrong direction. This can beavoided to a large extent by laying the probe flat against the cheek, pointed upward.With older people you may have to stretch the skin above the notch to straighten out atwisted artery. You’ll probably get the best recordings by using the probe from abovethe notch, but be aware of the hazard of getting the wrong artery.Internal carotids can be picked up just below the angle of the jaw and on the anterior pillarof the tonsillar fossa. Internal flow tends to be more continuous and is fairly easilydistinguished from external carotid or common carotid flow. Always know your own flowsounds well so you know what is normal. It takes some time to get familiar with normalsounds, but after a while you will know what the recording would look like just by listening.

The assessment of calf venous disease by Doppler ultrasound may be achieved with anaccuracy of up to 85% compared to venography when one is experienced with thetechnique. The status of the calf veins can be assessed by listening with the Doppler atthe posterior tibial vein at the ankle, the popliteal vein, the superficial femoral vein, andthe common femoral vein. The status of the calf veins is determined by a combinationof augmentation maneuvers when listening at these various points.

Normal Respiration Flow Sounds: The Doppler is initially placed over the posteriortibial vein at the ankle behind the medial malleolus. Generous amounts of acoustic gelmust be used, and one must be careful to avoid undue pressure with the probe whichmight result in obstruction of venous flow. Initially the posterior tibial artery signal iselicited. The probe is then moved slightly to either side of the arterial signal until thewindstorm like venous signal is heard. Normally this signal should wax and wane withrespiration. In the presence of calf vein thrombosis, the signal may be more continuousor there may be no audible signal present. If the feet are vasoconstricted, a venous flowsignal may not be heard until the venous velocity is increased by gentle compression ofthe foot.

Checking Competency of the Valves: Once the optimal venous signal is elicited, thecalf is then compressed with the hand which is not holding the probe. The fingersshould be spread so that much of the calf muscle is compressed. During this procedure,no venous flow should be heard. If venous flow signals are elicited, this is a sign ofdeep venous valvular incompetence, usually secondary to old deep vein thrombosis.

Augmenting Venous Velocity by Compression: Next the calf is released and oneshould normally hear an augmentation of venous flow as blood enters the previouslydecompressed calf veins. The magnitude and duration of the augmented signal can beinfluenced by several factors including the temperature of the foot, the general vasomotortone of the patient and the presence or absence of venous thrombosis in the calf. It isimportant to compare the augmentation signals in each foot. In vasoconstrictedindividuals with cold feet, the posterior tibial venous augmentation may be very minimalbut it should be symmetrical. If there is good augmentation in one leg and pooraugmentation in the other, the latter leg is usually the site of venous thrombosis. Next,the common femoral and then the superficial femoral veins are examined and the signalsassessed for augmentation upon calf compression. Calf-vein thrombosis will result in adecreased augmentation of the venous signals at these sites. Similarly the poplitealvein should be examined. In general, the most sensitive indicator of calf-vein thrombosisis a relative decrease in augmentation upon release of calf compression with the probepositioned over the posterior tibial vein at the ankle. There are certain conditions whichwill imitate calf-vein thrombosis. Such problems as subfascial hematoma, a rupturedBaker’s cyst, extensive edema, or other conditions which cause increased pressure onthe calf veins may result in a decreased augmentation of flow during the aforementionedmaneuvers. Such conditions can be best diagnosed by a venogram if the diagnosis isin question.

TECHNIQUE OF EVALUATING CALF VENOUS DISEASE


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STRANGE NOISES FROM THE DOPPLER

On occasion there are noises you might not expect from the Doppler when in fact theDoppler is working fine. The following are some common concerns and their causes.

Concern:

Popping scratchynoises sounds whenthe probe is firstplaced on the skin.

Static when the dryprobe is movedthrough the air.

High pitched tone.

Buzzing noise thatalmost obliterates theDoppler signal.

Howling noise whenprobe is held or laidon a table with gel onit.

Cause:

Air bubbles in the gel aremoving and/or popping.Hair movement can alsocause these noises.

Possibly loose connectorsinternally, where the probeconnects to the instrument.

Radio interference from amobile service, police stationnearby, even another Dopplerworking close by. Usuallyoccurs near large openwindows, rarely in the centerof the building.

Electrocautery or othersparking device, badfluorescent light fixture orneon signs nearby.

Probe is acting as amicrophone and you aregetting acoustic feedback.

Remedy:

Use a new dab of gel thatlooks clear, push the probedown enough so hair isimmobilized, and wait a fewseconds for everything tosettle. If the noise is notthere when the probe isclean (no gel) andsuspended in the air, theDoppler and/or probe areprobably working fine.

There is normally some staticgenerated when the instrumentis moved through the airwithout gel on the probe, but itisn’t severe. Have the probereplaced or contact the factoryif the problem persists.

Move the Doppler to anotherlocation away from windowsand toward the center of thebuilding. If the problempersists contact the factory.

Move the Doppler to anotherlocation away from theinterference. If the problempersists contact the factory.

Wipe gel from probe, If thenoise does not occur withoutgel on the probe, it isprobably working fine.


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ADDITIONAL TESTS:1. Try using earphones if you have a howling noise. If there is no howl using earphones

but there is with a speaker, it is acoustic feedback.2. Should you have access to a biomed department, try a different probe, even if it

is the wrong frequency it will let you know if the problem is noisy connectors insidethe instrument or frayed shielding near the probe body.

SUMMARY: The problem may simply be a probe or it may be peculiar to the environmentin which it is used. If you have tried the tests and remedies mentioned and you stillsuspect a problem contact the factory toll-free at 1-800-547-6427.

CARE OF THE PROBEMODEL 842


The Doppler probes are easily ruined through misunderstanding and neglect. Over 90%of the failures of the Doppler are due to failure of the probe in some way. It will pay youto read what follows and transmit this information to any person using the Doppler.

ABOUT THE PROBE: The active part of the probe consists of two crystals. Onetransmits the ultrasonic waves and the other receives them. Each crystal can serveeither function. The crystals are held in place by a material that protects the crystalsand the tiny wires soldered to them. This material is vulnerable to attack by heat,alcohol and ECG paste. We recommend an ultrasonic gel but in an emergency, useany surgical jelly. DO NOT use ECG paste or cream as a contact medium between theskin and probe.

After use, the probe should be gently wiped clean of the Aquasonic or other acousticalcoupling gel with a soft tissue. If the gel has dried on the probe, put it under warm tapwater to soften the gel and permit you to wipe it off.

Should someone use a sharp instrument to scrape off dried gel, they may also succeedin scraping off the material covering the tiny wires and crystals as well. We speak fromlong experience. Damage such as this will make your probe inoperable.

A replacement probe is available from the factory. When calling, please specify thefrequency that is engraved on the body of the original probe or specified on a labelattached to the cable. DO NOT remove the label attached to the cable, it containsimportant reordering and warranty information. Warranty void if removed. Should younot have access to a biomed department to replace the probe, it is best to return theinstrument to the factory if there is a sensitivity problem.

THE COUPLING GEL which we furnish is cal led Aquasonic, made by ParkerLaboratories. This gel is available from us or a similar ultrasonic gel (not runny) willusually be available from one of your surgical supply dealers. The .25 liter bottles maybe autoclaved. Other makes of gel may work as well, though the dispenser may not beas convenient.

Coupling gel in sterile packets is also available from us. You can also use sterile jelliesinternally such as K-Y or ABCO. Any sterile liquid or gel without excessive bubbles maybe used. Placing the pencil probe directly on wet tissue will also work.

GENERAL MAINTENANCE OF THE DOPPLERMODEL 842


NOTES FOR THE SERVICE TECHNICIAN

In addit ion to true service problems you wi l l f requently encounter “operatortrouble” . Things to watch out for are:

1. The Doppler is tuned to a frequency which is different from that marked on the probe.This occurs in hospitals that have Dopplers and probes of more than one frequency. Theprobes and instruments get mixed up. We try to circumvent this by sending a particularhospital Dopplers and probes of the same frequency. The frequency of the Doppler ismarked on the inside of the instrument and the frequency of the probe is marked on itsconnector. These frequencies should match. A variat ion of .1 MHz is not signif icantat around 5 or 10 MHz, but it is around 2 MHz.

2. The Battery is either the wrong type or was shorted while being installed. The resultis diminished battery life.

3. If you have a problem with the recording being too small it may be caused by incompatibilityof the recorder. The Doppler output is designed to work with the dc input of anelectrocardiograph which has a high input impedance (usually 100k or more) anddeflects the stylus 1 cm for a 50 mV input. Most research recorders are compatiblewith the high-impedance single-ended output of our Doppler, but some require a lowimpedance signal of around .1 volt for a cm of deflection and they will not functionproperly with the Doppler without a pre-amplifier.

4. An attempt is made to feed the signal from the earphone jack on the Doppler to anotherdevice for either amplification or processing and it does not work. The most likelyreason for this is that a tip-ring-sleeve-type (stereo) plug has been used. You mustuse a single ended plug to take off the audio signal.

True service problems can be broken down into the following general categorieswhich are listed in the approximate order of their occurrence.

1. Failure of the probe. This accounts for about 90% of al l the service problems.The user should keep a spare probe of the proper frequency on hand if they dependon the Doppler. Should you not have access to a biomed department to replace theprobe, it is best to return the instrument to the factory if there is a sensitivity problem.

2. Failure of the battery or plastic case because the instrument was dropped. Batteryconnector is sprung so that good contact is not made.

3. A leaking battery has corroded battery connector so that good end contact is not madeor corrosive fluid has penetrated end insulator causing electrical leakage to ground.

4. Component failure, unsoldered joint or poorly soldered joint, wire to battery or connectorbroken (perhaps only internally). Look for broken resistors around the edge of the circuitboard. They may be broken inadvertently during the process of changing the battery.

In general we suggest you return the unit to us for service that might be complicated orthat may require transistors. The reason is that transistors are often selected for lownoise or their dc operating characteristic. Customers in the U.S. can call us toll-free at1-800-547-6427. Our regular business phone is 503-649-7007. Business hours are7:00 am to 3:30 pm, Pacific Time, Monday through Friday.

BATTERY REPLACEMENT


MODEL 842

FOR BETTER PERFORMANCE ALWAYS USE A 9 VOLT ALKALINE BATTERY.

When the sound gets weak or distorted, the battery should be replaced.

CAUTION: Never use mercury batteries!

TO REMOVE BATTERY:Remove three screws on the back of instrument; lift off back; unsnap the batteryby pulling off the snap-on cover.When replacing the battery, be sure the snap-on cover is properly mated to thebattery terminals before applying pressure to snap it into place.

Battery must be recycled or disposed of properly.

THIS DEVICE USES A 9 VOLT BATTERY FOR ITS POWER SOURCE.

Leg distress -- cramps, fatigue, or just vague pain-- often signal the presence of a peripheralvascular disease. It could be arterial -- the firstsign of arteriosclerosis obliterans. Simple officeevaluation, including the patient’s descriptionof leg pain, and an examination of the affectedlimbs, will often give a clear picture of theunderlying vascular problem -- where it is, howextensive it is, which vessels are involved, andhow adequate is the collateral circulation.A typical patient with arteriosclerosisobliterans, the most common of the arterialocclusive diseases, develops pain in one or bothlegs that requires him to stop and rest afterwalking a short distance. He may call it acramp, a charley horse, or it may be just afeeling of tiredness in the limb after walking acertain distance. An elderly patient often admitsto having calf pain for months or sometimesyears with “no reason to mention it since achesand pains are bound to occur as you grow older.”However, where he previously could walk 4-5blocks before the calf pain occurred and madehim stop, he’s concerned because the pain nowoccurs after walking only a block or so.Arterial occlusive disease due to arteriosclerosisobliterans, is insidious in onset and oftenpresent in a patient for many years before anyischernic symptoms occur. Rarely will anyonecomplain of intermittent claudication, the mostcommonest symptom of arterial occlusivedisease, while indoors. However, walkingoutdoors causes the pain to occur. There is atypical pattern to this symptom of limbischemia; exercise -- pain -- rest -- relief.Patients characterize the pain of intermittentclaudication in various ways. One will describeit as a sensation of cramping or tightness, “asif the leg is in a vise”. Another will describeincreasing fatigue eventually forcing the patientto stop walking and rest. However, in all of thesepatients, resting for a few minutes is sufficientto relieve the pain If the need to sit down orelevate the extremity is a feature of a patient’scomplaint, or if it takes more than a few minutesfor the pain to abate, suspect a disease processother than arterial insufficiency as the cause ofthe pain.

As the disease progresses a different type of painoccurs in the toes or heel. Termed rest pain ornight pain, it is an ominous symptom ofadvanced arterial occlusive disease due tomultisegmental blocks in the major limbarteries and an inadequate collateralcirculation around these blocks. This paincharacteristically occurs in the distal portion ofthe foot, the toes, over the dorsum of the foot,in the heel area, or in the region of themetatarsophalangeal joint. The patientdescribes the pain as a severe ache or throbbingwhich often wakes him after several hours ofsleep. Relief is sometimes obtained by rubbingthe affected foot or placing it in a dependentposition over the edge of the bed. Elevating thelimb often increases the pain. In some patients,relief is afforded by sleeping in a chair with theleg in a dependent position.Leg pain and even “pseudoclaudication”, a formof leg pain that can mimic true intermittentclaudication, can occur with a variety ofprocesses other than arteriosclerosis obliteranssuch as degenerative disorders, for example,osteoarthritis of the hip of spondylolysis.Compression of the cauda equina also canproduce claudication-like symptoms. Inthese patients, the typical cycle ofexercise-pain-rest-relief is not present.The presence of normal pulses in the leg and anormal ankle systolic blood pressure aids indistinguishing the pain of pseudoclaudicationfrom arteriosclerosis obliterans.Examination of the affected foot yields a greatdeal of information. Skin color, texture, andconsistency all depend on arterial blood flowand can indicate the presence of an impairedcirculation.If the patient has only mild, generallyasymptornatic occlusive arterial disease, thecolor and nutrition of the leg and foot appearsnormal. As the ischemic process becomesmore severe, the skin appears shiny and smooth,and hair is often absent from the toes and thedorsal region of the foot. Muscle atrophy, loss ofsubcuataneous fat, and pallor all indicate a severedegree of ischernia.

Diagnosis and Treatment of Chronic ArterialInsufficiency of the Lower Extremities

HOWARD C. BARON, M.D., F.A.C.S.*

A fairly simple and accurate clinical test that canmeasure the degree of arterial insufficiency inthe affected leg is the elevation-dependencymaneuver performed while the patient is on theexamining table. With the patient lying on hisback, place his heels in the palms of your handsand elevate both legs 24-36 inches off the table.Hold the legs in this position for at least 45-60seconds. Observe the color of the feet and legs,particularly the soles of the feet. If the arterialcirculation is normal the skin coloration willdecrease only slightly. Skin pallor will developin the affected limb according to the degree ofarterial insufficiency. If pallor occurs in both feetsuspect either an arteriosclerotic block in theabdominal portion of the aorta or similar blocksin the major limb arteries. After the period ofleg elevation, generally no more than severalminutes, have the patient immediately stand up.In a patient with normal arterial circulation inthe legs, color will return to the foot in 10 secondsor less, and the superficial veins in the distalportion of the foot will fill in 10-15 seconds. Ifarterial insufficiency is marked, the normal colormay take 40-60 seconds to return; in severecases more than 2 minutes. Reactionary ruborof the foot (a burgundy red color) may occur afterthe limb becomes dependent; this indicates thepresence of ad-vanced limb ischemia and oftenportends ulceration and “ gangrene of the foot”.An absent or greatly diminished pulse is adiagnostic finding of major importance. Thepresence of a pulse however, does not alwaysindicate a normal arterial flow; its absence isfar more significant.In a patient who complains of intermittentclaudication and has palpable resting pulses,don’t discard the diagnosis of arteriosclerosisobliterans without investigating the“disappearing pulse” phenomenon. Have thepatient exercise until he experiencesclaudication; examination of the ankle pulsesmay then reveal an absent pulse associated withleg pallor. The physiologic explanation issimple: exercise causes a marked dilation of thearteriolar beds within the exercising muscles.During exercise blood is shunted to thesemuscle groups causing a drop in the anklesystolic blood pressure which is distal to thesite of the arterial block. As the ankle systolicblood pressure falls, the distal pulses disappear.Except when life expectancy or surgical risk

contravenes due to other systemic diseases,angiography and surgical revascularization isindicated for all patients with symptomaticarteriosclerosis obliterans exhibiting cutaneousskin changes, such as ischernic ulcers organgrene; the presence of rest pain orintermittent claudication that handicaps thepatient economically or socially.Angiography is necessary to evaluate the extentof the arterial lesion. Typical arterial lesions dueto arteriosclerosis obliterans are segmental,occurring in areas of branching, narrowing, orbifurcation sites of an artery. The commonestoccurring at the bifurcation of the aorta, or theiliac and femoral artery divisions. Anotherfrequent site is the distal superficial femoralartery as it emerges from the adductor canal ofHunter and the distal popliteal artery as itbranches into the anterior and posterior tibialand peroneal arteries.Certain patients are not candidates forangiography; these include the elderly patientwith moderate disability and associated cardiacdisease, and generally any patient with thepresence of another life-threatening disease. Asatisfactory angiographic study provides avisual study of the anatomic lesion, indicatingthe extent of the lesion and to a degree itsseverity.

The angiogram, however, does not yieldinformation regarding the hemodynamicsignificance of the lesion. For this informationthe Doppler flow detector is a useful andaccurate instrument. The importance of theankle/arm systolic blood pressure ratio in thediagnosis and objective assessment of arterialdisease underscores the value of the Dopplerultrasound blood flow detector. Although theauscultatory method with a stethoscope isone of the most common blood pressuremeasurements in clinical medicine, it is seldomused in the lower extremity because it isdifficult to obtain the Korotkoff sounds inthe distal portion of a limb, especially whenarterial occlusive disease is present. TheDoppler flow detector, when used with asphygmomanometer and a pneumaticocclusion cuff, can measure the lowerextremity systolic blood pressure easily andaccurately. Normally, the ankle systolic bloodpressure is slightly higher than the arm systolic

additional collateral circulation. However, thelong period before results can be evaluated isrisky: gangrene may supervene calling foremergency surgical reconstruction of theoccluded vascular bed if amputation is to beavoided.

CONCLUSIONThere are both humanitarian, economic andsocial reasons for mounting a strong effort tosalvage the lower limbs in patients, who areoften elderly, and debilitated, but obviouscandidates for a revascularization procedure.The physical, psychological and economicburdens following amputation preclude auseful or comfortable life in the yearsremaining to them.Limb salvage, the desideratum of any age, isparticularly important in the geriatric patientwhose care then places a heavy burden on aspouse of similar age or another familymember. A patient confined to a wheelchair orbed is unable to attend to even the simplestpersonal needs; he often becomes withdrawnfrom human contacts, psychologically as wellas physically damaged.Partial limb revascularization, by saving theextremely valuable knee joint, is often areasonable alternative, allowing salvage of asmuch as possible of a limb affected byend-stage ischernia.The goal should be treatment of the diseasewithout loss of the lower l imb or, ifamputation becomes necessary, a below-kneeprocedure or even a transmetatarsalamputation, permitting the patient to lead amore normal life.

222 East 19th StreetNew York, New York 10003

*Attending Vascular Surgeon, Cabrini MedicalCenter, New York, N.Y.; Associate Professorof Surgery, New York, University School ofMedicine, New York, N.Y.

blood pressure. Any pressure gradient ordifference that exists between the arm andankle systolic blood pressure provides avaluable, objective hemodynamic assessmentof the arterial lesion. Certainly, the lower theankle systolic blood pressure when comparedto that in the arm, the greater the gradient andtherefore, the more advanced the arterialocclusive lesion in the distal abdominal aortaor lower extremity arteries.Two of the most important aspects of managingpatients with Arteriosclerosis obliterans are theneed to avoid any form of injury to theaffected foot, this includes the avoidance ofany form of home surgery on the feet, and theavoidance of tobacco smoking. A recent studyof ours indicates that 40 percent of majorlower extremity amputations might have beenavoided by taking simple precautions againstinfect ions s temming from mechanical ,thermal, or chemical injuries to the feet.Meticulous, periodic, podiatric care isnecessary for any foot with an impairedcirculation with its known increasedsusceptibility to infection. Even fungalinfections such as athlete’s foot can put theischernic foot at serious risk. Certainover-the-counter pharmaceutical preparationsfor removing corns and calluses that containcaus t ic chemica ls can be harmful tosurrounding tissues, especially when used inthe presence of an impaired circulation andshould be avoided!Thromboendarterectomy of the occluded arteryor the use of bypass grafts are the operativeprocedures most frequently used forrevasculatization of the ischernic limb.Sympathectomy may be helpful in certainpatients, but is rarely considered for patientswho are candidates for arterial surgery and itis not recommended for treatment ofintermittent claudication. However, minorischemic ulcerations may heal and rest painmay occasionally be relieved followingsympathectomy.A limited number of patients with advancedarteriosclerosis obli terans may showimprovement over periods of weeks fromnon-surgical measures including rest, the useof vasodilators, and avoidance of tobaccosmoking, permitting the development of an

Practical Office Technics forPhysiologic Vascular Testing*

COL CLYDE 0. HAGOOD, JR., MC, USAF, LTC DAVID J.MOZERSKY, MC, USAF, and SSGT RANDAL N. TUMBLIN, BS, USAF, †Lackland AFB, Tex

A therosclerosis of the peripheral vessels is ex-tremely common in our society and is respon-sible for significant morbidity and mortality. Itis therefore imperative that the physician whofirst encounters patients with vascular com-plaints recognizes the disease and begins propertreatment. Until recently, the diagnosis of arte-riosclerosis obliterans has been dependent uponthe clinical history and physical examination.As a result, the disease has only been detect-able in a relatively far advanced stage.Since the introduction of the Doppler ultrasonicvelocity detector in 1959, more sensitive andobjective methods of evaluation have beenavailable to the clinician.1-4 The use of thesetechnics, however, has been restricted to arelatively small number of specialists andinvestigators. Although they are extremelysimple to do, these examinations have not beenwidely used by primary care physicians.The purpose of this paper is to familiarizeclinicians with three simple office technics fordetecting atherosclerotic occlusive disease andto present three cases that illustrate theefficiency of these technics.

*Read before the Section on Surgery, SouthernMedical Association, Sixty-seventh Annual ScientificMeeting, San Antonio, Tex.

†From the Department of Surgery, Vascular SurgeryService, W i l f o r d H a l l U S A F M e d i c a l C e n t e r,Lackland Air Force Base , Tex .

R e p r i n t r e q u e s t s t o C M R # 8 , B o x 3 6 9 5 0 1 ,L a c k l a n d A F B , Tex 78236 (Dr. Hagood).

Material and TechnicsThe Doppler ultrasonic velocity detector hasbecome a familiar tool used by obstetricians andvascular surgeons alike.5 The instrument usestwo piezoelectric crystals. One crystal, whenstimulated by an electric voltage, emits acontinuous wave of ultrasonic energy at afrequency of 5 to 10 MHz, which is transmittedthrough the skin. If this sound wave is reflectedback from stationary tissue interfaces, thefrequency of the returned signal received by thesecond crystal will be the same as thetransmitted frequency. If the sound wavestrikes moving red cells, the returned signal willbe a different frequency from the transmittedsignal. The difference is directly proportionalto the velocity of the blood, according to theDoppler principle. The transmitted and receivedfrequencies are compared electronically and thedifference between the two, the Doppler shiftfrequency, is amplified. Since this frequencyis in the audible range, it can be perceived withearphones or a loudspeaker. For most clinicalpurposes, the audible signal is all that isnecessary. Ultrasonic energy transmitted bythese instruments has been tested both in thelaboratory and clinically and has been foundto be non-destructive to tissue.6 Examinationcan thus be carried out at frequent intervalswithout fear of over-exposure. After the routinehistory and physical examination have beencompleted, the peripheral vessels are surveyedwith the Doppler ultrasonic velocity detector.

SOUTHERN MEDICAL JOURNAL, Vol 68, No. 1

Abstract: The development of the Doppler ultrasonic flow velocity detectorhas improved diagnostic accuracy in peripheral arterial occlusive disease.Survey of the peripheral vessels with the Doppler ultrasonic flow velocitydetector, measurement of systolic arterial blood pressure at the ankle andarm, and exercise testing are three easily done tests which may be readilycarried out in the doctor’s office and which provide usefulinformation. Noninvasive vascular testing should be in thearmamentarium of all primary care physicians.

OFFICE TECHNICS FOR VASCULAR TESTING - Hagood et al

The quality of the arterial signals is evaluatedat the common femoral, superficial femoral,popliteal posterior tibial, and dorsalis pedisarteries bilaterally. If the vessels are patent,these signals will be composed of at least two,and often three, distinct sounds. The first ishigh-pitched and is distinctly separated fromthe second (Fig 1, A).

When mild proximal arterial stenosis ispresent, there is a slight decrease in thefrequency of the first sound and the secondsound is no longer detected (Fig 1, B). As thedegree of occlusion becomes progressivelymore severe and collateralization develops, thesignal becomes more monotonous with onlysmall fluctuations with each heart beat (Fig1, C). These changes in the nature of thearterial signal can be detected easily5 aftergaining some experience with the instrument.

An objective and reproducible determinationof the extent of the occlusive disease processcan be made by measuring the systolic arterialpressure at the ankle.7 Standard bloodpressure cuffs are placed around the ankle andthe arterial flow signal is monitored in theposterior tibial or dorsalis pedis artery (Fig2). The cuff is then inflated until the arterialsignal is no longer detected. With the probestill in place, the pressure is graduallylowered in the cuff until flow signals areaudible once again. The point at which flowis re-established is the systolic pressure atthe leve l o f the cuff . Under normalcircumstances, the systolic pressure in theankle should be equal to or above thesystolic pressure in the brachial artery. If theartery is occluded, the pressure will belowered in the vessels distal to the occlusion.


Graph ic r ep resen ta t ion o f aud ib le Dopple r u l t r a son ic f low ve loc i ty s igna l s ob ta ined f rom theposter ior t ibial ar tery of three separate pat ients . A - normal; B - obstructed; C - severely obstructed.

FIG I

NORMAL SCALE - 2 cm = 1 SEC. OBSTRUCTED


FIG 2

Technic of obtaining ankle systolic blood pressure. The angle of the probe in relation to thelong axis of the posterior tibial artery should be optimized to obtain the best signal.

An arm-to-ankle pressure gradient of morethan 20 to 30 mm Hg is suggestive of oc-clusion at more than one level. It has beenfound that the ankle/arm pressure ratio cor-relates well with the severity of the obstruc-tive process.4 When the ratio is one or greater,it is unlikely that significant obstruction ispresent. Similarly, rest pain is rare when theankle/arm pressure ratio is greater than 0.5.There are some patients in whom the ankle pres-sure is normal or nearly normal and whohave significant complaints of claudica-tion. In these patients, exercise testing isan extremely valuable method of evaluation.8

When the blood flow to a limb is increasedby exercise, the pressure gradient between thearm and ankle is accentuated.2 In severe casesof obstructive vascular disease, the ankle sys-tolic pressure may be unobtainable followingexercise. Depending upon the extent and lo-cation of the disease and the type of exer-cise, there may be a period of up to 20 to 30minutes before the ankle pressure returns tonormal levels. The routine vascular exami-nation should include stressing the patientwith some form of exercise and measuringthe arm and ankle pressure immediatelyafter the activity, using the method pre-viously described.

The form of exercise which is selected willdepend upon the interest, requirements, andresources of the physician. In our clinic, allpatients have been exercised on a level,motorized treadmill at 3 mph to the point ofclaudication, or a distance of 1,000 yards.This is an indication of how far the subjectcan walk at a marching pace on flat groundand is an object ive assessment of hiscomplaints of claudication. Strandness andBell3 have found that by angl ing thetreadmill at 120/, grade and at a speed of 2mph the amount of work involved isincreased and pressure gradients areaccentuated. Normal subjects can walk fiveminutes with no difficulty and no drop inankle pressure. A patient propelled treadmillmay also be used with a metronome. Thepatient is instructed to step each time themetronome beats and, in this inexpensiveway, the functional and provocative test ofthe pat ient ’s exerc ise capaci ty can becarried out.

Two less elaborate methods of exercisingpatients are available and may be usedin office practice. Carter8 has recently usedactive plantar and dorsiflexion of the footaga ins t a resistance provided by theattendant’s hand. Alternatively, the patientcan be instructed to rapidly perform toe liftsuntil fatigue or calf pain develops.



These methods are less standardized thantreadmill exercise, but they have the advan-tage of requiring no special equipment.If the initial ankle systolic pressure after exer-cise is equal to or higher than pre-exercise val-ues, then the test is normal and no further mea-surements are required. If the initial ankle pres-sure is low, the measurements are repeated ev-ery minute for the next ten minutes. It shouldbe emphasized that the Doppler survey, anklepressure measurements, and exercise testingcan be done in less than 20 minutes by para-medical office personnel.The following cases are presented to illustratethe usefulness of vascular testing methods inthe clinical situation.

Case ReportsCase 1 . A 52-year-old man came to themedicine clinic complaining of pain involv-ing the right leg, thigh, and buttock. The painwas precipitated by walking one block and re-lieved by rest. Physical examination of the rightleg showed 2+ femoral and dorsalis pedispulses and a weakly palpable posterior tibialpulse. No trophic changes or temperature dif-ferences between the two legs were observed. Itwas the physician’s initial impression that theslightly diminished pulses probably were notresponsible for the symptoms, but the patientwas referred to the vascular surgery clinic forfurther studies at that time. The survey withthe Doppler ultrasonic velocity detector re-vealed abnormal signals at the right femoral,popliteal, dorsalis pedis, and posterior tibialareas. The brachial systolic pressure was 112turn Hg. The right ankle systolic pressure was86 mm. Hg. The patient was able to walk 115yards at 3 mph on the treadmill.These studies suggested the presence of severeocclusive atherosclerosis of the right iliac ar-tery. Angiography confirmed a high-grade steno-sis of the entire right common iliac artery andits bifurcation. An aortoiliac endarterectomywas done subsequently. Postoperatively the pa-tient was completely asymptomatic. Survey withthe ultrasonic velocity detector showed normalflow in both lower extremities. The brachialsystolic pressure was 140 mm Hg. The anklesystolic pressures were 137 turn Hg on the rightand 140 mm Hg on the left.

Comment. At the time the patient was initiallyseen in the general medicine clinic, hiscomplaints were suggestive of severe occlusivearterial disease. The fact that pulses werepalpable in all areas, however, was confusingto the physicians who first saw him. When hewas examined in the vascular laboratory usingthe Doppler ultrasonic velocity detector thelesion was quickly localized to the right iliacartery. The 34 turn Hg arm/ankle gradientdemonstrated the severity of the problem, andthe functional disability was confirmed by hisperformance on the treadmill. Since the patient’sjob required a great deal of walking he wasessentially disabled by his condition. On thebasis of the objective tests, proper, diagnosisand treatment were begun.Doppler survey and ankle pressuremeasurements not only suggested the correctdiagnosis preoperatively, but also confirmedthe salutory effect of the surgical procedurepost-operatively. Patients with symptomssuggestive of claudication and intact pulsesmay be mistakenly treated for arthritis,neuritis, or emotional problems. As was shownin this case, the correct diagnosis can bequickly and accurately made, using simpletesting procedures.Case 2. A 62-year-old man with many com-plicated medical problems came to our clinicwith complaints of pain in the right calf andnight pain. Pain in the calf was precipitatedby walking less than 100 ft and relieved byrest. Physical examination of the right legshowed a normal pulse in the groin. No otherpulses were palpable. The right brachial sys-tolic blood pressure was 206 mm. Hg. The rightankle systolic pressure was 78 turn Hg. Sur-vey with the Doppler ultrasonic velocity de-tector showed a slightly abnormal flow signalhigh in the right groin. This signal becamehigh-pitched and continuous at a point abouttwo inches below the inguinal ligament, andlow-pitched, monotonous signals were noticeddistal to that level. He walked for 108 yardson the flat treadmill at 3 mph. There was a66.5% decrease in ankle systolic pressure af-ter exercise. An arteriogram done by theSeldinger technic showed minimal decrease inthe aorta and the right iliac artery. The super-ficial femoral artery was occluded in Hunter’scanal. Close inspection of the bifurcation ofthe common femoral artery suggested signifi-cant occlusive disease,


involving the origin of the deep femoral artery.Due to the patient’s poor state of generalhealth, the right groin was explored underlocal anesthesia. A large occlusive plaque waslocated in the common femoral artery and atight stenosis of the deep femoral orifice wasobserved. A common femoral and deep femo-ral endarterectomy were done. The patient wasexamined in the laboratory three months afteroperation. Brachial systolic pressure was 132mm. Hg. The right ankle systolic pressure was70 mm. Hg. He walked 1,000 yards on theflat treadmill at 3 mph with a 61% decreasein ankle pressure after exercise.Comment. The history and physical findingswere not compatible with an isolated,superficial femoral artery obstruction.Disabling claudication and night pain areusually indicative of multiple arterialocclusions. The 128 mm Hg pressuregradient between the arm and anklesuggested that this was the case. Since a fullfemoral pulse was palpated, and only aslightly abnormal Doppler flow signal washeard in the upper common femoral artery, itwas thought that the obstructed arterieswere located in the thigh or calf or both.The presence of arterial signals in thepopliteal artery indicated its patency.Doppler examination of the dorsalis pedisand posterior tibial arteries showed arterialflow signals similar to those obtained in thepopliteal artery. This suggested no signifi-cant obstructive lesion between these levels.On the basis of these findings, theobstructive lesions could be localized to thesuperficial and deep femoral arteries.Results of angiography confirmed thesuperficial femoral artery obstruction andsuggested severe stenosis of the deep femoralorifice (Fig 3). Since the hemodynamicallysignificant lesions were confined to thethigh, it seemed logical to increase thecollateral circulation distal to the occludedsuperficial femoral artery. Therefore, anendarterectomy of the distal commonfemoral artery and deep femoral arteryorifice was done.It is significant to note that there were nochanges i n t he pa t i en t ’s phys i ca lexamination after operation and, withoutvascular testing, only his testimony could



be used to indicate a beneficial result.The pre-operative ankle/arm ratio was0.38. After operation, it rose to 0.53. Inaddition, the patient’s exercise toleranceincreased nearly tenfold. These concrete datashould be used as the criteria for success orfailure.

FIG 3

Angiogram showing a large plaque in the commonfemoral artery involving the orifice of the profunda.

Case 3. A 54-year-old dentist was seen oneyear after bypass graft for severe aortoiliacocclusive disease. Three months af teroperation, he was evaluated in the laboratory.Brachial systolic pressure was 108 mm Hg.Ankle systolic pressures were 114 mm Hgon the right and 111 mm Hg on the left. Bothankle pressures increased after exercise.There were no signs or symptoms ofischemia. He was studied again eight monthslater. His pulses were intact . The armpressure was 114 min Hg, and the anklepressures were 126 mm Hg on the right and96 mm Hg on the left. He walked 1000 yardson the flat treadmill at 3 mph with nosymptoms. There was a 24% decrease in theleft ankle pressure after exercise.Comment. This patient, though asymptomatic,is exhibiting disease progression, which willrequire closer fo l low-t ip . This d iseaseprogression could not have been detected ona clinical basis, but was readily detectable



using simple vascular testing technics.ConclusionsPalpation of pulses and inspection of the limb are subjective methods of evaluatingcomplaints that may be related to arterial insufficiency. Since the physician whosepractice includes patients with many varying problems may feel insecure about hisability to evaluate pulses, objective testing methods have a real place in the diagnosticarmamentarium. The Doppler ultrasonic velocity detector may be thought of in thesame manner as one thinks of a stethoscope, as an instrument which extends clinicalperception. It is a rapid and safe tool which can provide relevant, and at timesindispensable, information.Measurement of ankle systolic pressure by the Doppler ultrasonic technic has provento be an objective and repeatable test which correlates well with the anatomicsituation. Exercise testing provides both a functional assessment of the patient’scomplaints and a diagnostic challenge by which small, resting pressure gradientscan be accentuated. Resting pressure measurement, exercise testing, and Dopplerultrasonic survey are extremely simple methods of evaluation by which even minordegrees of occlusive arterial disease may be detected. The equipment necessary toevaluate vascular problems can be purchased for less than $1,000.

References1. Satomura S: Ultrasonic blood rheograph. J Acoust Soc Japan 15:151-1542. Winsor T, Hyman C, Payne JH: Exercise and limb circulation in health and

disease. Arch Surg 78:184-1923. Strandness DE Jr, Bell JW: An evaluation of the hemo-dynamic response

of the claudicating extremity to exercise. Surg Gynecol Obstet 119:1237-12424. Yao ST, Hobbs IT, Irvine WT: Ankle systolic pressure measurements for

arterial disease affecting the lower extremities. Br J Surg 56:676-6795. Strandness DE Jr, Schultz RD, Sumner DS, et al: UItrasonic flow detection:

a useful technique in the evaluation of peripheral vascular disease. Am J Surg113:311-320.

6. Wild JJ, Reid JM: Effect of ultrasound on biological tissues. J Acoust SocAm 25:270-280

7. Strandness DE Jr: Management of Arterial Occlusive Disease. Chicago, YearBook Publishers, Inc.

8. Carter SA: Response of ankle systolic pressure to leg exercise in mild orquestionable arterial disease. N Engl J Med 287:578-582

Mailing AddressPO Box 5669, Aloha, OR 97006

Shipping Address19460 SW Shaw, Aloha, OR 97007

Phone - 503-649-7007Fax - 503-591-9753Toll- Free - 1-800-547-6427

e-mail - [email protected] Site - www.parksmed.com

Manufactured in the U.S.A. by:

Medical Electronics, Inc.

Warranty

We warranty this instrument against defects in materials and workmanship for one year.The warranty period on accessories and probes is six months. All warranty service isperformed at the factory and all items must be returned to the factory prepaid. Specificallyexcluded from this warranty are any items which show evidence of physical abuse.

842, USM Original File-1.1 - Parks Medwhich is in collapsible tubes. Refilling from bulk is much...

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Transcript of 842, USM Original File-1.1 - Parks Medwhich is in collapsible tubes. Refilling from bulk is much...