First, let's decipher the jargon. An echocardiograph is a device which derives information about the heart by analyzing a reflected ultrasonic wave. I designed this echocardiograph to measure the relative intracardiac volume. By graphing the intracardiac volume over time, one can obtain clues to certain diseases that are manifested by alterations in the slope of the ventricular ejection rate (such as idiopathic hypertrophic subaortic stenosis, or IHSS).

A phonocardiograph is a device that graphs heart sounds, and an electronic stethoscope—as you may have guessed—simply (well, not so simply . . . see below) amplifies cardiopulmonary sounds. I wanted a phonocardiograph that I could carry in my pocket, but the wonders of technological miniaturization had yet to filter down to phonocardiographs (which are wheeled around on carts, but are generally tucked in some inaccessible cranny of the hospital). I devoted two years of my youth to making this device, forsaking snowmobiles, dating, and sleep. And who says that doctors aren't dedicated? :-) The most daunting challenge was to make a printer that was small and lightweight and used very little power and was easily fabricated and didn't cost much to manufacture and didn't require complex interface circuitry and had a long life and yet was capable of producing excellent graphs. Fulfilling all of those Boolean "ands" wasn't easy, but I eventually contrived a printer which not only met each of those criteria, but excelled at every one of them.

Whew! The printer is done. What's next? The electronics for the echocardiograph. Comparatively, this was a breeze. I made a circuit whose output was proportional to the variation in the phase angle of the reflected ultrasound, using this to derive relative intracardiac volume.

The next task was to make an audio amplifier that amplified cardiopulmonary sounds (and Korotkoff's a.k.a. "blood pressure" sounds, since stethoscopes are also used in determining blood pressure) but didn't make the ambient noise objectionable. The sounds of interest are low frequency sounds, and the ear and most microphones are more sensitive to higher frequency sounds, such as typical room noise (speech, babies crying, phones ringing, monitors beeping, drunks yelling . . . the usual emergency room din). A standard microphone and amplifier would be a disaster, preferentially amplifying what you didn't want to hear. I started from scratch and examined the existing commercially-available electronic stethoscopes, which I thought were garbage. The ones I tried easily clipped (distorted) even moderately loud sounds, sounded tinny, and lacked a phonocardiograph or echocardiograph. I tried out dozens of microphones and built hundreds of amplifiers, spending several hundred hours per year listening to cardiac sounds (if there was a world's record for this, I probably would have won it). My best design was good at rejecting outside noise, but gave the listener the startling acoustic impression of not just hearing the sounds very well, but of actually being inside the patient's chest! In contrast, a standard stethoscope sounded as if one were listening through a wall of cardboard, rubber, and concrete.

I made a whole family of related devices. Some were just electronic stethoscopes, some were like the unit pictured above but without the echocardiograph, some transmitted the sounds in FM so that medical students could listen simultaneously to a patient, and another enabled a standard cardiac monitor to function as a phonocardiograph. Another series of models (e.g., the Trauma Scope) was designed for use by paramedics in noisy environments (the back of an ambulance, for example) in which conventional stethoscopes are often useless (because of the phenomenon of masking, in which perception of a sound is blunted [or masked] by another simultaneous sound). These models incorporate a circuit which I termed a Transhertz Audio Processor, which electronically converted the low frequency sounds to a higher frequency. Hearing "lub-dub" can be difficult, but hearing "beep-BEEP" is easy. All of the information in the original sound was still present (I used the envelope of the lower frequency sound to amplitude modulate a higher frequency stream of sound). And you're wondering why I'm not yet married???

The IMD pictured in the foreground is a pocket version of the IMD shown behind it. Both have identical circuitry, except that I designed a much smaller printed circuit board for the pocket version. The sensor is located at the tip of the probe (the length of the horizontal green line overlying the upper probe tip should give you a reasonable idea of the size of the sensor). In use, a sterile probe cover was placed over the probe, which was then introduced into the puncture wound to locate and remove the metal. Once the probe cover was inserted and the metallic foreign body located, the sensor probe could be withdrawn from the probe cover, which provided a handy "tunnel" through which a small instrument could be placed to extract the metallic FB. I also designed versions in which the removal instrument was integrated into the probe, and a version in which a powerful magnet could remove some ferromagnetic foreign bodies.

The function of this device is essentially identical to those large metal detectors that people use to detect buried treasures (or priceless objects such as rusty old nails). However, those devices use sensing coils that are as large as a plate. The trick to making my IMD was to miniaturize the sensor, then develop a circuit to interface with it. I hate to disappoint the Nobel Prize Committee, but this was an easy task that took all of about 20 minutes or so. Although my sensor was very small, it was sensitive enough to detect even flakes of metal. I bought the best metal detector I could find at Radio Shack for my Mom as a Christmas present (she thought that treasure hunting would be fun), but that device couldn't begin to compare with my IMD for sensitivity, even though I was seemingly at a disadvantage by having such a small sensor to work with.

The IMD detects metals that are either ferrous (e.g., iron or steel) or nonferrous (e.g., aluminum, copper, or the favorite metal in large cities: lead). This latter capability came in handy one night in the ER. I had a patient who had been shot in his chest, but the bullet wasn't in his chest—and it didn't pop a hole right through him, either. To make a long story short, I ordered an x-ray of his abdomen, thinking that the bullet deflected off a rib and tunneled into his belly. I looked at that x-ray, but no bullet was found. I was almost ready to get out my Ouija board or call the Psychic Friends Network for some guidance, but I decided to give the ol' IMD a try. I scanned the IMD over the abdomen, and located the bullet (a wimpy .25 Auto, which explains why it bounced off the rib) near his right flank.

The IMD was a hit in the ER. I contend that doctors love gizmos, especially when they materially improve patient care. One of the plastic surgeons that I worked with in the early 1990s used my IMD on a patient in the ER, and some general surgeons borrowed it for a few days . . . and, frankly, didn't want to give it back! Over the years, I've had other surgeons want to buy my IMD, so there seems to be a market for this device. I also discovered an ancillary use for the IMD: entertaining pediatric patients. They were mystified by the cute audio tone it emitted when the sensor approached metal. Anything to entertain the kids!

I designed the IMD to have two basic modes of operation: invasive (probing inside the body), or noninvasive (surface scan mode). The latter could be used to quickly determine the approximate location of a foreign body, and it could also be used to scan people for guns, knives, and needles. Unless you've worked in an ER, you probably don't know how common it is to find such things on ER patients—often why they become patients!

ANOTHER TANGENT: The large IMD is the first device I made using homemade membrane switches (for the on and off functions). I really had no compelling reason to make the membrane switches (I could have used standard mechanical switches), but I didn't have a date that weekend so I decided to indulge my burning desire to make a membrane switch. To add to the gee-whiz factor, I added audio feedback to the switches and put a backlit "ON" indicator light behind the membrane switch panel.

I made four different detectors, each having a different operational principle. If the case for the white prototype in the picture looks familiar, you're correct. To save time, I gutted an electronic thermometer and substituted my own sensor and electronics. I used this device for a couple of years in the ER, and it worked fantastically. Except for the case, the total cost was less than $1. With high-volume production, the entire device could be made for about 25 cents.

The mold on the bottom is the positive master mold I made for the high-tech version of the intubation detector. In use, the endotracheal tube would be placed into the U-shaped recess. That would activate the contact switch and turn the device on, sending an infrared beam across the recess, through the endotracheal tube, to a detector on the opposite side.

Cardiac output is the amount of blood pumped by the heart each minute. Mathematically, it's simply the product of the heart rate multiplied by the stroke volume (CO = HR x SV). Determining the cardiac output is very helpful in diagnosing and monitoring a variety of different diseases (many of which do not directly involve the heart), but measuring cardiac output is a fairly complex and risky procedure that generally involves threading a large catheter into a patient. Hence, while cardiac output should be routinely measured along with other vital signs such as pulse and blood pressure, it is only measured in critically ill patients in an ICU or similar setting. To eliminate the risk and to make measurement of cardiac output so quick and easy that it could be performed on every patient, I made a device which performs that task and—get this—can be made for less than what some families spend for a meal at McDonald's. However, I wasn't satisfied with measuring just cardiac output, so I added some functionality to expand its usefulness. I'll discuss this addition in the topic presented immediately below.

Despite the fact that American physicians have a low threshold for ordering CAT scans and chest x-rays, many people with latent illnesses do not have diagnostic testing performed until their condition progresses to the point that they develop a recognizable symptom or sign of the disease. By then, however, it may be too late. The primary reasons why CAT scans and chest x-rays aren't ordered more often is because those tests expose the patient to radiation and because of their financial cost. Besides that, the time that it takes to perform those procedures is often an impediment, especially in emergency rooms. To overcome these obstacles I invented a device that quickly (within a few seconds) and inexpensively (cost per use is less than a dime) scans a patient without any radiation to detect cancer, pneumonia, pneumothorax (collapsed lung), pulmonary effusions, mediastinal shift or enlargement, and other abnormalities.

So what is wrong with the traditional aluminum/foam bar splints used in most emergency rooms? Gee, where do I begin? Those splints have sharp edges, they're easily bent out of their correct shape, their foam acts like a magnet for dirt and germs, they're bulky, and they don't do a good job of maintaining precise alignment of the finger during the healing process. Oh, and they're ugly, too. Other than that, they're fine.

My splint is made from a plastic material that can be quickly (within seconds) molded to fit any finger. Once formed, it is very rigid, providing excellent stability (including lateral stability, which is a weak point for aluminum bar splints), but the splint is very comfortable to wear. I don't know why, but my finger feels better with the splint on than with it off—it's that comfortable. It has no sharp edges, it is much less bulky than a bar splint, and the plastic inherently repels dirt (if needed, it can be quickly rinsed). The only drawback is that it can trap skin moisture, but that problem is easily solved by punching a few holes in it to allow the skin to "breathe." (* See below) These holes do not substantially detract from the strength of the splint (engineers often purposely design holes in many different structural elements to lighten them).

* I now have a laser cutter/engraver, which is a computer-controlled high-intensity laser that can machine parts from plastic, wood, rubber, foam, leather, fabric, paper, and cardboard. It can also etch or mark on metal, stone, ceramic, and glass. With that laser, I could make thousands of tiny holes in the splint in a flash—literally.

YET ANOTHER TANGENT: I had an incredibly difficult time capturing the luminous quality of the phosphorescent material on film. I tried a standard camera, a digital camera, a scanner, a videotape recorder, and nothing did a good job of showing the glow-in-the-dark effect that I think is so appealing.

Back in the good old days, ER doctors such as myself who wished to test for the presence of blood in stool would dab a bit of fecal material onto a Hemoccult card and squeeze a couple drops of developer from a bottle onto the test and control areas of the card. Obviously, it doesn't take a rocket scientist to correctly perform this test. However, the government evidently thinks that people smart enough to pass medical school can't be trusted to drop fluid onto excrement even though we can read EKGs and x-rays, do surgery, and perform countless tasks that are considerably more challenging. (I suppose that making ludicrously preposterous decisions is the hallmark of a good bureaucrat.) So, to make a long story short, several years ago the government took developer away from the docs and made this the province of lab techs. We could smear feces onto the card, but we could not be trusted to unscrew a bottle and drop fluid onto the poop — unless we took special competency testing, kept a log, and jumped through other hoops mandated by bureaucrats with IQs of 85. Frankly, this is insulting. It's also a waste of money and time.

Years before the government stepped in, I was tired of locating a bottle of developer at the start of every shift, so I developed a new Hemoccult card that would develop itself. Of course, if the government hears about this card, they'll take away the new Hemoccult cards because it won't suffice to simply take away the developer. This raises the specter of ER docs running to the lab after doing rectal exams so they can smear feces onto cards that are jealously guarded by lab techs — and probably some armed federal agents, too. Can you tell that I'm just a tad miffed by how the government is micromanaging our lives? I wouldn't be so offended by this if people with more brainpower (i.e., the doctors) were not being dictated to by people with less brainpower (i.e., the bureaucrats).
 

Update: I was delighted to hear from Dr. Mueller three years later, who is still going strong at age 83, and recently published a book entitled The Outer Edge of the Wave (ISBN 1-4120-7030-9).

Another update: A person who read the above posting sent the following message to me: "Your site is erroneous. Dr. Eric Mueller did not invent Hemoccult. He may have been responsible for creating guaiac paper, but my father, Dr. Joseph F. Pagano, head of R & D for Smith Kline Labs in Philadelphia, invented and perfected this test many years ago."

Prescriptions written on prescription pads are easily forged and often illegible, leading to dispensing errors and sometimes deaths. Furthermore, the time that it takes to write prescriptions is time that'd often be better spent doing something else. To overcome these problems I developed an electronic device not much larger than a standard prescription pad that would allow the doc to hit a button or two on a keypad, after which a printed prescription would pop out of the printer. I thought that pharmaceutical companies would love this idea because they could give these prescription printers to doctors. Of course, the pharmaceutical company would program in memory all of their drugs, and there'd be blank spots in memory for the doc to program in his frequently prescribed drugs, too. Doctors would love it because it'd save them time, because it'd eliminate the chance of being sued for writing a sloppy prescription that contributed to a medication dispensing error, and because doctors tend to love nifty gizmos. Drug companies would love it because they're forever looking for ways (and spending billions of dollars in the process) to get docs to write prescriptions for their drugs instead of competitive drugs. What more direct way is there to facilitate this? I can't conceive of anything better.

Since the prescription printers were intended to be freebies, I had to keep the price low (my target was less than $10 per printer). To make this feasible I thought of a way to program cheap ROM (read-only memory) so that it functioned as RAM (random-access) memory, ROM, a microprocessor, and all the required accessory chips for a conventional computer. So, my device was just a ROM chip, a few transistors to drive the printhead, and a few other very inexpensive components. I also developed a new printhead that could be made for less than a penny but yet gave a very good print-out and required very little power (much less than traditional thermal printheads). My printhead was also very small and lightweight.

A couple of investors from Detroit heard about my idea, so we formed a corporation to market it. Inexplicably, they also brought in two electronic engineers who worked for Ford Motor Company. Those engineers weren't familiar with using a ROM chip as a standalone computer, so they redesigned it from scratch using conventional RAM, ROM, and other interface chips. Their game plan was to produce "their way" as a prototype and "my way" as the lower cost, smaller, lighter production version. I couldn't comprehend why it made sense to produce a larger, heavier, more costly prototype, but since they agreed to eventually come back to my way, I didn't object.

Other than the enigma of trying to understand why we should produce a clunky prototype, all went well until Bill & Hillary Clinton were elected President & Co-President. One of their proposals they threatened was to limit the freebies given to doctors by drug companies. This scared the investors (now heading the company — inventors like me are too dumb to head companies), so they decided to postpone this project to see how things would shake out. Eventually, Bill & Hillary lost their battle to implement their healthcare reform ideas, but by the time this was evident everyone had moved on: one of the investors married a vice-president of Hudson's, one engineer moved to England, and I moved to northern Michigan.

This idea preceded the above idea but still has some utility since many prescriptions for the foreseeable future will be manually written in ink. My idea was to produce a pen that deposited ink in a way that was immediately recognizable for verification of authenticity by pharmacists, yet could not be produced by someone unless he owned a very special ink pen manufacturing company. Basically, the raison d'être for this invention was to thwart people who forge prescriptions. Certainly, it'd be possible for junkies to steal an irreproducible pattern ink pen (the distribution of which would be limited to doctors only), but to use it they'd have to steal a prescription pad or obtain a valid prescription for altering. Therefore, this wouldn't stop all prescription forgery, but it'd certainly limit it since junkies would now need to get their hands on one more thing.

I have dozens of other medical inventions, including one that is probably worth billions of dollars. My current project is not a medical invention per se, but it could nevertheless do more to foster health than most medical inventions. Virtually everyone will want to buy that device, which will indelibly affect (for the better!) our lives, and the lives of succeeding generations. Yes, I know, you're probably skeptical of anyone professing to have "it will change the world" ideas because you probably yawned after seeing other inventions that never lived up to their pre-release hype, such as Dean Kamen's Segway. However, I think that people won't just want my invention, they will crave it, and couldn't imagine living without it and going back to the "old way" of doing what it does. As a lark, I might give one of these devices to the sixth-grade teacher who called me "slow" (see above). Wouldn't that be a nifty tangible manifestation of the power of abductive thinking? :-)