News flash: ALL blood pressure monitors are imperfect!Oct 04 '05 (Updated May 24 '09) Write an essay on this topic.
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The Bottom Line Even the "gold standard" mercury monitors have their shortcomings--including the potential for inaccuracy. The average "home" user will be best served by a fully automatic, electronic blood pressure monitor.
PREFACE: We've still got a way to go before the "ideal" blood pressure monitor becomes available. The (virtually) ideal blood pressure monitor doesn't yet exist, albeit its advent may not be that far off. Today's "mechanical aneroid" and "oscillometric electronic" technologies are both inherently imperfect (due to the limitations of their respective measurement principles, not to mention structural strain from continual usage). And even the most finely crafted mercury monitors, while more nearly accurate when new, eventually can become inaccurate (with sheer time and continual use), not to mention their own inherent design shortcomings, some of which inevitably introduce a measure of "human error" into any given blood pressure reading (see more about that below). In this unfolding millennium, when an ever-increasing percentage of humankind will be implementing "at-home" self-monitoring, what we really need for blood pressure measurement is the best of both the "mercury" and the "electronic" worlds: an electronic device largely modeled after the conventional mercurial-column principle but lacking the latter technology's "analog" shortcomings (and health risks). Such "hybrid" devices have already been proposed, and I have little doubt that they could--and should--become widely and affordably available within the next decade, if not far sooner. Such devices will likewise probably incorporate an alternative "kilopascals" system of measurement to complement (and eventually supplant) the conventional "millimeters of mercury" system. When such technology finally becomes widely adopted, we will have taken one giant leap toward "absolute accuracy" for blood pressure measurement--both "clinical" and "at-home". But as we continue to await that happy day, there is no good reason not to avail ourselves of today's "next-best" technologies for self-measurement of blood pressure. A high percentage of the human population already suffers from incipient or full-blown hypertension, and even today's "imperfect" monitors could be veritable lifesavers if used judiciously and regularly. * * * Verify your health--even if you're feeling fine--via periodic, "at-home" monitoring. Mind you, I am not now, nor have I been--in recent years--hypertensive. But, at age 51, I've lately become motivated to take reasonably frequent readings of my blood pressure (i.e., as often as "every day" or at least "every other day"). In all my prior years, "blood pressure" had simply not been a topic that particularly intrigued me, albeit I had long ago been admittedly very relieved to be "rejected" for military service during my mandatory physical in 1972 due to a fleeting bout of high blood pressure (which, a week later, had returned to "normal"!). Having lost considerable weight over the past few months via dietary changes, I wanted to assess my general state of health, starting with such basic matters as body-fat percentage and, yes, blood pressure. I already knew (from periodic readings at my doctor's office in recent years) that my blood pressure was by no means "high". However, I wanted to see for myself if my weight loss (not to mention the daily consumption of (only pharmaceutical-grade!) fish oil capsules) is helping me to achieve even more healthfully low blood pressure levels. So far, the answer seems to be "yes". For, whereas my doctor's office blood-pressure reading in late February of 2005 was "110 (systolic) over 72 (diastolic)", a reading taken three months later at that same office after I'd been "dieting" for two full months) was "98 (systolic) over 68 (diastolic)". Of course, that reading alone proved little, if anything. (Everyone's blood pressure can naturally fluctuate within a fairly considerable range.) But, coupled with many more recent readings that I've been recording in succeeding months, the above comparison does seem to hold approximately true. In other words, I've seen that my average blood pressure has fallen by several points. And, by gradually increasing the amount of exercise I get each week, I hope to reduce it a bit further still. Regarding "home monitoring" of one's general health, not only did I purchase a "bathroom scale" that reports my body-fat percentage (see my review of the Taylor #5563 Body Fat Analyzer Scale with Multi Color Display), but also I retrieved from storage a long-neglected "A&D" (brand) blood pressure monitor that I'd bought back in 1997 for my late mother (at her doctor's suggestion) and which I'd inherited. [See my review of the "A&D UA-702 Manual Blood Pressure Monitor".] This latter device is actually not a purely "manual" monitor but rather an electronic monitor with an attached, rubber bulb that you repeatedly squeeze to inflate the monitor about 30 "units" (i.e., "millimeters of mercury" or "mm Hg") higher than your expected "systolic" blood pressure. [Tyros duly note: the "systolic" number is the "higher" or "upper" number of any blood pressure reading: for example, a reading of "120 over 80" or "120/80" would mean that your "systolic" pressure is 120. The systolic number indicates arterial pressure when your heart is contracted, that is, pumping. On the other hand, the "lower" or "bottom" number of any blood pressure reading is termed the "diastolic" pressure, and it indicates the pressure when your heart is at rest or between beats.] I found my A&D "manually-inflated" (but otherwise "electronic") monitor to be pretty easy to use; moreover, its readings compared reasonably closely to those of my doctor's "medical-grade" aneroid monitor. (I took that monitor into the doctor's office on two separate occasions, thereby getting a pretty good idea of how it compares.) Generally, my blood pressure monitor's readings were within 2 to 6 units of the readings via my doctor's "professional" monitor. This placed it within the oft-cited range of "plus or minus 5%" that I've read is a benchmark for acceptable performance from a "home" blood pressure monitor relative to a "professional" (ostensibly fully accurate) monitor. *** [UPDATE AS OF 11-9-05: On a still more recent visit to my doctor's office, my blood pressure was taken, as usual, by a nurse; then I waited a minute before calmly taking a subsequent (comparative) reading via my familiar Omron/ReliOn (electronic/auto-inflate) monitor. To my surprise, the latter unit gave me a reading that was significantly higher (about 12 mm Hg, systolic). However, after the nurse left the room, I peered more closely at the dial of their "medical-grade" aneroid monitor, and I noticed that its pointer was conspicuously outside (to the right of) the bottommost "zero box", suggesting that any readings via that unit likely would be at least five mm Hg too low! Moreover, there's no telling but what still further discrepancy could have resulted from that continually used (aging?) monitor simply needing "revalidation" at various points throughout its entire range. Finally, who knows how precisely the (young) nurse actually performed/interpreted my blood-pressure reading via her manual deflation, her simultaneous listening to faint "beginning" and "ending" sounds through the stethoscope, and her simultaneous viewing of the analog gauge's pointer against the tiny marks on the dial? (See my below remarks regarding the potential for "human error" inherent with all analog monitors.) I should add that recent (at-home) comparison tests of my Omron/ReliOn electronic monitor with my brand-new Baum (mercury) and Omron (medical-grade aneroid) units confirm that my electronic monitor is itself virtually accurate; hence, I now suspect that the doctor's frequently used WelchAllyn aneroid unit badly needs readjustment (or replacement)! In this general vein, I'd already read about a study that tested hundreds of clinical monitors and found a disturbingly high percentage of them significantly inaccurate; now I doubly believe it! Moral: don't implicitly trust that a blood-pressure reading from the medical establishment is necessarily precisely accurate. It could be "off" by perhaps four or five units (mm Hg)--if not more. ] *** The Quest for Accuracy. ARM POSITION IS IMPORTANT: Regardless of which category of blood-pressure monitor you choose, it is virtually always advisable to position your arm thusly (assuming you are sitting upright): with your arm slightly bent at the elbow, allow your forearm to REST upon a flat surface at the same level (altitude) as your heart. Do NOT hold your forearm in that position via muscular effort; instead, just let your forearm REST (upon a flat surface) such that it’s extended straight forward at heart level. If you ignore the above advice and position your arm at a significantly lower level, you will surely get a reading that is deceptively high, perhaps by about ten units! Unfortunately, in my experience many (probably the majority of) professional health-care practitioners do casually ignore the above advice. And considering that many newly arrived patients in doctor's offices are initially bustled into a tiny waiting room and are almost immediately measured for blood pressure (before being allowed to sit and rest for perhaps ten minutes), and considering that many patients are naturally a bit nervous anyway in such settings (hence their blood pressure is further elevated), the potential obviously exists for significantly inaccurate blood-pressure readings and even, conceivably, faulty diagnoses. I soon found myself wanting an even more precisely accurate electronic monitor, and so I recently purchased a "fully automatic" ReliOn HEM-780REL (which is manufactured by Omron for Wal-Mart and is functionally identical to Omron's own "HEM-780" unit--or at least the version prior to Omron's very recently introduced "replacement" model bearing that same designation). [See my review of the Omron Automatic Blood Pressure Monitor with ComFit Cuff, Model HEM-780.] This type of monitor automatically inflates the arm cuff for you, which not only saves you energy and hassle but also can potentially increase the accuracy of your blood pressure readings. For, according to Dr. Thomas Pickering's insightful, well-written discussion in the book Blood Pressure Monitoring in Cardiovascular Medicine and Therapeutics (2001, Humana Press), "It is often not appreciated that the physical act of inflating one's own sphygmomanometer cuff produces a transient elevation of blood pressure of around 12 mmHg, which lasts about 10 [seconds]." (Note: "sphygmomanometer" is merely a synonym for "blood pressure monitor".) Dr. Pickering adds that "if the cuff is deflated too quickly, it is possible that the pressure will not have returned to baseline, so that spuriously high systolic readings may be recorded." Now, while my own unscientific experiments have suggested that the act of manual inflation is not necessarily a huge factor, I nonetheless wanted to see if I could get still more accuracy with a fully automatic monitor from a reputable manufacturer. Hence my recent purchase of the Omron-made unit. So far, I am pretty reasonably satisfied with my new ReliOn/Omron "automatic-inflation, electronic" blood pressure monitor. Regarding accuracy, its readings (both systolic and diastolic) actually compare fairly closely to those via my preexisting, A&D monitor, albeit I do detect a general pattern of very slightly closer, overall adherence (by my "Omron" unit) to the average readings derived via my doctor's office's "professional," aneroid devices. Constituting a more clear-cut advantage of my Omron-made unit, its easy-to-wear, relatively more comfortable "easy-wrap" cuff is "preformed" and lacks (doesn't require) the metal "D ring" that is ubiquitous with so many other products (including my "A&D" monitor). Noting also Omron's touted "IntelliSense" ("fuzzy logic") inflation technology that quickly detects/estimates the minimum degree of inflation required for a given user, this high-tech cuff certainly is far more comfortable (or should I say less uncomfortable?) than many competing products' basic, "traditional" cuffs. Alternative (electronic) technologies. By the way, while I can wholeheartedly endorse many electronic monitors whose cuffs fit (conventionally) around the user's upper arm (bicep), I would think twice before choosing one of the "wrist" monitors (whose accuracy, reportedly, has been vastly improving but--in many cases--is not yet fully as reliable as that of the better "arm cuff" monitors). Now, IF a given user's bicep diameter were so inconveniently large as to make it impossible to obtain a fully compatible, satisfactory, "extra-large" cuff from the manufacturer, well, then resorting to a "wrist" monitor might be the best alternative. Even in such special instances, I would strongly urge you to do some consumer research regarding the documented accuracy of particular models. (Perhaps your public library could provide the most recent reviews from the likes of Consumer Reports magazine?) And, again, when taking readings, remember always to maximize accuracy by positioning the cuff at virtually the same level (altitude) as your heart. I would absolutely avoid the "finger" monitors (whose accuracy, reportedly, generally remains downright unreliable). Why not use "public" monitors? As a rule, don't take too seriously any readings taken via those "free" blood pressure machines found in many supermarket and drugstore "pharmacy" departments. Those continually used, public units reportedly can get seriously out of calibration. I personally have gotten ridiculously inflated readings via such machines! You'll likely obtain far more accurate readings by spending the requisite money for your own electronic "home" monitor--even if it merely includes "manual" inflation (but do opt for the convenience and, conceivably, very slightly greater accuracy of "automatic" inflation if you can afford it). Settle for nothing less than an "average" reading! With ANY blood pressure monitor, it may be a good idea to take at least two readings during the same session. (Albeit you generally should pause for at least two minutes--some experts even advise a full ten minutes--between readings, so as to give your arm's brachial artery sufficient time to recover from having been compressed by the tight cuff.) As the user relaxes, it is often the case that a subseqent reading (or two) will be lower than the initial reading taken during a given session. Let your computer assist you! I also find that it's helpful to record all my readings onto my computer spreadsheet software such that I can quickly behold an average of any number of past (or recent) readings that I may wish to focus on. Moreover, such handily stored "computerized" readings could be easily shared (presumably with one's physician) via hard-copy printouts, removable disks, faxes, or e-mail. But... what about "old-fashioned" monitors? So far I've chiefly discussed electronic blood pressure monitors. Let me now proceed to share my modest knowledge about (and/or personal experience using) traditional "analog" (i.e., "non-electronic") monitors. The various analog monitors generally fall under two headings: (1) "mercury" monitors (also called "mercurial column" monitors); and (2) "aneroid" monitors (also called "mechanical aneroid" monitors). Generally, the finest ("medical-grade") mercury and aneroid models--if properly calibrated and maintained--are more precisely and reliably accurate than virtually any of the electronic models for home use. However, unlike the much easier-to-use electronic monitors, both mercury and aneroid monitors require the use of a stethoscope, which, if not "built-into" the arm cuff, must be purchased separately. Until you gain experience, using a separate stethoscope can be rather tricky--even to the point of frustration--if you're taking your own blood pressure; nonetheless, any reasonably dexterous person can manage it by positioning the stethoscope's "microphone" partly beneath one edge of the cuff (near the brachial artery) prior to inflation. Mercury monitors. Mercury blood pressure monitors generally look like rather large, old-fashioned, glass thermometers and nowadays are being gradually phased out of many public institutions due to concerns about the potential for environmental contamination from mercury spillage. Nonetheless, many "experts" still swear by mercury monitors and maintain that they are the "gold standard" among all blood pressure monitors. Indeed, it is commonly suggested that aneroid (and electronic) monitors be annually tested for accuracy by comparing them to mercury monitors, the latter serving as the benchmark for accuracy. You can still find these venerable, mercurial-column monitors in some health-care facilities; moreover, you can even buy one for your personal use from various on-line vendors or medical-supply retailers. Some mercury models are portable "desktop" units, while others are wall-mounted. Acceptable units can be purchased for around $75 to $100 or more. They generally include (manually inflatable) arm cuffs, but they seldom, if ever, include the stethoscope that is simultaneously required to take a blood pressure reading. Thus, expect to spend perhaps $10 to $50 extra for a serviceable stethoscope. When taking your own blood pressure with this approach, the "chest piece" (also called the "bell" or "microphone") of the separate stethoscope must be temporarily positioned beneath one edge of the arm cuff. Again, doing this--not to mention correctly applying the cuff itself--can be tricky if you've no other person to assist. But if you're reasonably dexterous and patient, it is, nonetheless, possible. (I speak from personal experience here.) I myself was on the very verge of ordering a mercury monitor, for who wouldn't appreciate their renowned accuracy? But then I did a bit of research online and by telephone. While I still believe that the best mercurial-column models do constitute the highest standard for accuracy, I nonetheless gradually learned the "dark side" of mercury monitors in general. For one thing, they are NOT necessarily "permanently" calibrated. In fact, much like their aneroid brethren, they may need to be "recalibrated" at least every few years, partly due to mercury gradually escaping/vaporizing via the valve(s) of the apparatus. Such gradual loss of mercury from the column eventually becomes extreme enough to make blood pressure readings inaccurate. At that point, such a monitor would need to be "recalibrated" (presumably at some substantial cost) by a qualified service center. Also, if a mercurial-column monitor isn't in a precisely vertical position (on your desktop or wherever), its accuracy will be affected. Additionally, I've read that the appearance of the mercury can, with age, become "dirty looking" and harder to read (due to oxidized mercury within the column). In this vein, it should likewise be noted that a mercurial-column monitor needs to be positioned (viewed) at eye-level, lest "human error" be introduced into the reading. And even when the monitor is properly positioned, experience and excellent technique are required to read precisely the meniscus (the curved upper surface) of a mercury column. Simultaneously, it seems to me that yet another bit of human error might be introduced into the reading due to slight uncertainty regarding the "exact" beginning (systolic) and ending (diastolic) points of the "Korotkoff" (heartbeat/circulatory) sounds perceived through the stethoscope. [It is only fair to note that the last two problems involving human error are (essentially) equally inherent with readings taken via aneroid monitors.] Not only are all mercury monitors that I've seen of the manual-inflation variety, but also their "release/deflation valves" have conventional, "rotary knob" configurations. Those little metal knobs, in my experience, can make (manual) deflation relatively tricky to control for the neophyte, especially if you're trying to manage it with just one hand while taking your own blood pressure. And if the home user (unlike a seasoned nurse) is even slightly frustrated from thusly fumbling with such a touchy little knob (while simultaneously listening expectantly through a stethoscope and striving to view his precise systolic and diastolic numbers via the analog, mercury column!), very possibly his blood pressure will be elevated slightly from the additional effort. (Also see my below, comparable remarks regarding cheap, store-bought, aneroid monitors.) You'll need reasonably good hearing and more than a modicum of manual dexterity--not to mention an unflappable, patient nature!--to use such a complicated device to measure your own blood pressure accurately. Some "home" users--with but a little practice--will be fully up to the challenge; but others had best stick with the relative ease and simplicity of an electronic monitor even if its overall accuracy remains somewhat less reliable than what's obtainable via a top-quality mercury monitor. Considering the above factors (along with awareness of the very slight potential for environmental contamination from a toxic mercury spill), I've been biding my time before deciding whether to buy a mercury monitor. Given my penchant for such gadgetry, and given my keen desire to maximize accuracy, one of these days I'll likely finally spring for one of the most reputable mercury models (which can cost well over $100, not including a stethoscope), but this is a decision I'm in no mood to rush. [UPDATE AS OF 11/9/05: Well, I did indeed finally take the plunge: I bought a Baum ("Baumanometer") "Desk Model" (catalog # 0320) mercury monitor for $128 via Balkowitsch Enterprises in Bismarck, North Dakota. This attractive instrument is clearly top-quality in all respects. Its readings do appear to be fully, reliably accurate, and they actually correspond pretty closely with the readings via my above-discussed Omron/ReliOn electronic monitor. I am very satisfied with my purchase of this impressive mercurial monitor, which any physician would surely be proud to display and use. Since this unit's glass tube is coated with protective mylar, even were the glass to break, there would still be no leakage of liquid mercury; hence, any concerns about spillage are essentially negated. Moreover, from anecdotal reports, these Baum units will last many years longer than others before ever needing recalibration or maintenance. In sum, this unit could be a fine choice for the demanding "home" user wanting "the ultimate" in "clinical" accuracy. Even so, I must reiterate I only recommend this splendid mercurial device for those prepared to cope with its inherent difficulties discussed above. Many "home" users would be better off (and save money) settling for a much easier-to-use electronic monitor like my above Omron/ReliOn unit.] Aneroid monitors. Now, regarding the aforementioned aneroid monitors (such as you will most commonly encounter at your doctor's office nowadays), these devices--along with mercury monitors--have been around for many years. Such a monitor features the familiar "clock-like", round, analog gauge (aka "meter", "dial", or "manometer") with a pointer (or "arrow") indicating (during the early phase of a reading) your systolic and (during the final phase of a reading) your diastolic blood pressure numbers. Aneroid monitors--like mercury monitors--must be used in conjunction with an arm cuff that is manually inflated via a rubber bulb; and the gauge's pointer must be carefully watched as the cuff is deflated via a rotary knob or trigger; moreover, you must simultaneously use a stethoscope (whose "chest piece" is either separate from--or, more commonly, "built into"--the cuff). The stethoscope's chest piece (a.k.a. "bell" or "microphone") must be positioned approximately over your arm's brachial artery (generally near the elbow crease of your inner arm). It should be reemphasized that aneroid monitors' analog gauges (meters or dials)--like the mercurial columns of their "gold standard" cousins--can be marginally misread by the human observer. This could be doubly true if the meter's pointer is not viewed precisely "straight on". (This partly involves the basic optical phenomenon termed parallax.) Hence, unlike electronic monitors with digital, LCD displays, all analog monitors involve the continual potential for "visual" human error. Aneroid monitors generally are not considered to be quite as accurate as their mercurial-column counterparts, but--if periodically checked/calibrated for accuracy--the better models can come very, very close to "perfection". Indeed, some "experts" report that there is no significant difference between the accuracy of a professional quality aneroid unit and a mercury unit. But what about the "home" variety of aneroid monitors, such as you can buy for about $20 at Walgreens and Wal-Mart? Well, a couple months ago I personally bought and tested two such devices from those very two retailers. First of all, I suspected that their calibration might be somewhat too high (they seemed consistently to give numbers that were about ten units higher than the systolic and diastolic readings from my doctor's professional aneroid monitor, not to mention my own, aforementioned, electronic monitors). But--"accuracy" aside--I just found those "cheapie" aneroid units to be frustratingly unwieldy for taking my own blood pressure. I concluded that it was all just too much of a hassle to have to listen through an uncomfortably tight-fitting stethoscope to try to "pinpoint" (often with feelings of great uncertainty) the fleeting "initial thumping" and "final swishing" sounds that represented the respective systolic and diastolic readings--not to mention simultaneously scrutinizing a hard-to-read, little "analog" dial to obtain an inescapably rough guess as to which analog number to remember (before jotting it down subsequently via pen and paper). Still worse, the cheaply crafted, wee, "deflation" rotary knob (adjacent to the rubber inflation bulb) was hard enough to initially loosen (and thereafter regulate) with two hands, much less one; and you simply can't get an accurate BP reading unless you can precisely regulate the rate of deflation via that tricky, imprecise little knob (while simultaneously, anxiously listening for the faint, tell-tale-heart sounds through the too tightly fitting stethoscope!). Moreover, the general, physical awkwardness of such (cheap!) aneroid devices makes for a real hassle (contrasted with modern, user-friendly, digital monitors' configurations). In other words, it was a bit of a "royal pain" to get the three latex-rubber tubes all running the right direction without inadvertently knocking the (breakable) little analog gauge off your lap or your desktop, as the case may be. All of this hassle, by the way, means that the user will likely, inevitably raise his blood pressure by several points, contrasted with an automatically inflated, "one-touch", electronic monitor. In sum, I can't really endorse such "old-fashioned" units (at least not the cheapest ones) for the average "home" consumer. I promptly returned those two units to their respective retailers! However, recalling that my doctor's own "medical-grade" aneroid unit had seemed consistently to give me readings pretty close to those I was getting via my two electronic monitors, I still wasn't ready entirely to give up on the "aneroid" concept. Thus, recalling that my doctor's unit bore the renowned "WelchAllyn" logo, I began searching the web for a reasonably affordable facsimile that I could buy for home use. Eventually, I did indeed finally buy a (purportedly) "virtually medical-grade" aneroid monitor; namely, the WelchAllyn/Tycos "Adult Home Blood Pressure Kit" ($47.00) via the "Steeles.com" web site. [To see it, go to their site and find "item 5098-75".] This cool-looking, aneroid unit gives me readings that are rather consistent but generally about 2 to 5 mm Hg higher than what my Omron electronic monitor gives. (In other words, the discrepancy is pretty trivial, and the WelchAllyn/Tycos unit does seem--at very least--acceptably accurate for home use.) Now, as to which of these two monitors is actually the more accurate, I suspect the Omron (electronic) unit might be the victor. I posit that (very tentative) remark partly based on the aforementioned premise that the mere act of the user inflating the rubber bulb and subsequently, attentively squeezing the "deflation" trigger likely raises his blood pressure (if only marginally), and partly based on the fact that Steeles.com is, alas, NOT including the original, matching, "Tycos-made" cuff in their "kit". Upon phoning their rep about this, I belatedly was informed (after actually having received my order) that Tycos had stopped making that original cuff about a year ago; hence, Steeles is currently substituting a different (but ostensibly fully compatible) "generic" cuff. Personally, I find it a bit disappointing that such vendors don't see fit to sell exactly what's pictured at their web site. (In this vein, even the color of the included (and conveniently "built-in") stethoscope's tubing is not black, as it appears in Steeles' web site's photo. Instead, I received a stethoscope with "light turquoise" tubing that, while sufficiently pleasing to my sensibilities, arguably doesn't match the other components' hues.) I might add that the aneroid meter itself is actually made in Germany (which is not a problem for me personally), even though the general impression via the site was that ALL "WelchAllyn Tycos" monitors are American-made. Anyway, having used this very pretty, ergonomically well-conceived, aneroid monitor for a couple of weeks, I can report that I do like it and have decided to keep it and just arithmetically "compensate" for its (maybe) marginally too high readings. I especially like its well-designed deflation trigger, which is (relatively) easy to control with one finger, unlike the wee, problematic, rotary knob of so many other aneroid monitors. It's a generally pleasing and effective product, given its price. It's definitely far preferable to the very cheap, tiny, unwieldy aneroid devices available at your average neighborhood drugstore or department store. If you're absolutely determined to own an aneroid monitor, the above WelchAllyn/Tycos model exemplifies the cheapest such unit you should settle for. Perhaps better still, you could shell out at least twice as much money for a "high-end" product like WelchAllyn's "classic hand aneroid" model (i.e., a "fully" medical-grade model). The latter model can be found in many doctors' offices nowadays. [UPDATE AS OF 11/9/05: Note: I finally did buy a high-quality aneroid monitor whose readings do seem to be very accurate (indeed, its readings essentially match those via my above-mentioned Baum mercury monitor). Specifically, at eBay I very recently bought a like-new Omron 11-675DNL. This "wall-mounted" unit has a large, blue gauge (dial) that's a full six inches square, making it remarkably easy to view. It's clearly a hospital-quality, heavy-duty unit (that originally retailed for over $100), and I nabbed it for only $27. Thus, I'm finally "all set" as far as blood-pressure monitors go. (I certainly won't be adding any more to my collection!) Mind you, it bears repeating that neither an aneroid nor a mercury monitor is anywhere near as easy to use as an electronic monitor.] Concluding remarks. When all is said (in this imperfect world where "absolute" accuracy may be essentially unobtainable), the better electronic models are, arguably, "more than sufficiently accurate". I generally endorse such electronic (as opposed to "analog") monitors for the average, "home" consumer. And I most especially endorse those electronic models having the convenient "automatic cuff inflation" feature. (One final time I will reiterate that the mere effort of repeatedly self-pumping a rubber bulb--regardless of what type of monitor it interfaces with--could momentarily elevate the user's blood pressure, thereby potentially diminishing accuracy, albeit probably only marginally.) Regardless of which technology (i.e., "analog" or "electronic", and "manual" or "automatic") that you choose when buying a blood pressure monitor, I congratulate you for taking an interest in monitoring a key facet of your overall health. And don't forget to try recording your readings onto your computer, either via specialized software (including "public domain" freebies) that you could download via the Internet, or, better still, via your own spreadsheet software (which you can endlessly customize and tweak, even including colorful charts graphically, automatically rendering the overall trend of your--hopefully healthfully low--readings).  |
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