Philosophies of Biomedical Instrumentation, or, A Panopticon, a Pandemic

A final lecture delivered to the students of BIOMEDE 458 / EECS 458, April 15, 2020

Philosophy is best understood through metaphor. At the very least the former’s points and pricks are made more tolerable by the latter. To explain my philosophy of biomedical instrumentation today I deploy two: a panopticon and a pandemic. 
 
The first metaphor I chose for the class: a panopticon. A panopticon is a structure in which everyone confined can more or less see everyone within and therefore will tend to police their own behavior to align with that they most regularly see and interact with. Some, for example those that design some prisons, will then sprinkle in a little paranoia by placing at the center of it, a room of outward facing mirrors. The hoped for effect is one in which behavior is both more stabilized (more people can see you) and less risk is taken (you can see more of yourself). Authority then puts its thumb on the scale when it claims someone in the room can see everyone. I disagree with the consequence of its fear-centered incarnation but the effect – an amplification of the self as community – is useful at instilling practices. In the making of measurements we must agree to units, agree to scale, agree to tolerances, because we need to agree that we are sensing the same world.
 
Instrumentation – good instrumentation – requires community policing. It requires high standards and industry regulation. It requires those who participate in the designing of such instrumentation, the making of such instrumentation, the testing of such instrumentation, the using of such instrumentation, all trust each to their jobs and to do them well. Those designing devices to be used on human beings, should probably (a) have some notion of basic human anatomy and physiological functions, (b) some skills in at least one of the engineering arts, and (c) apply what one knows of the other in a way that helps as many as one can in a way that you yourself would be proud. Put in three words: knowledge applied ethically. 
 
The community about you will rely on instruments. The authority of those instruments will be an alloy of trust and reliance. Trust that (a) what a device is telling you is some semblance of reality, (b) what the device is telling you is accurate/precise/to within such a margin of error, and (c) if something’s not working right. Tell me the truth, the whole truth, and nothing but the truth. So help you any god you find. Reliance because a device has been designed by those in this community of instrumentationists to be dependable so as to be depended on. Show that you know what you’re doing and know that others will show you the same.
 
Hence, the “all seeing” structure of the panopticon helps participants to know they see others, that others see them, and that all are doing the same. To stand and understand the scrutiny of one’s peers, when every single measurement you take should have at least three well trained eyes on it, should be the chief responsibility of any metrologic class. One is never enough in measurement.
 
To be peer reviewed is at a minimum to have one’s words taken seriously. To be a peer is to understand the words of another of skill in the art. During this class, you presented the writings of many others and made their content accessible. For example:
  • N. S. presented on Cardiac Biophysics;
  • J. G. followed up on Biopotential Amplifiers;
  • I. H. taught us Bandpass Selection for Biopotential Amplifiers;
  • B. M. showed us Oscilloscope Voltage Measurement;
  • P. V. drew the parallel to Cardiovascular System Monitoring;
  • S. D. went through the foundations of Pulse Oximeters;
  • J. B. demonstrated Signal Conditioning Data Acquisition, and Spectral Analysis;
  • R. P.M. gave an overview of Physiological Signal Processing;
  • J. C. explained Respiratory Biophysics;
  • L. N. explained Renal Biophysics and Dialysis;
  • R. P. conveyed some of the Implications and Applications of Signal Analysis in the Frequency Domain;
  • K. A. explained Parameter Behavior;
  • T. E. related it to Diagnosis and Therapy;
  • L. R., – or, K. M., FBI – characterized Fraud and Misconduct in Clinical Trials;
  • A. S. taught us How to be Welcome (or at Least Tolerated) in the Operating Room and Laboratory;
  • L. M. relayed Intellectual Property Strategy for Med-Tech Start-Ups;
  • M. B. concluded her presentation of Riegel v. Medtronic, Inc. saying “Go Ginsburg” while fist pumping in the air;
  • R. R. gave us the Keys to Creating Value for Early Stage Medical Device Companies;
  • L. W. told us when to Transfer to Manufacturing;
  • C. Y. shared with us some of the Regulatory Affairs of Medical Devices;
  • M. A. explained how to verify Electromagnetic Compatibility of Medical Devices
  • M. S. told us about Writing a Test Plan, well; and
  • N. P. distilled the findings of a World Health Organization report on the mismatch between medical device development and human health needs across the globe.
 
And for each and every one of them, there were two of you teaching us twice as much as all that. The readings you can put eyes on every now and again represent approximately 2,400 pages of collected musings of dozens of individuals on what they know about the biomedical enterprise and specifically that portion of it focused primarily on medical devices that measure – biomedical instrumentation – the intended subject of this class. If you find yourself burdened with an overabundance of free time, consider taking one of the readings of this class off the shelf and spending a moment considering its contents. You will rarely be worse for having read.
 
Because I believe you will number among these peers of yours who have written those 2,400 pages, throughout the semester you collectively submitted approximately 400 short summaries of medical devices, representing the current tools in the hands of current medical professionals. Your parallel efforts led to a shared document amounting to over 100,000 words on myriad medical instruments. May this be but a single example to you of the power of collective action. You can even read some of them too!
 
To help parse and receive information about at least a few of these summaries you joined in groups to learn from one another.
  • B. A. summarized cochlear implants and H. H. expanded that to include bone conducting hearing aids;
  • H. A. described image guided systems as a “Google Maps” of the body and K. W. described how those images were made via computed tomography;
  • N. S. explained how smart insulin pumps and A. S. explained what smart inhalers do and we all wondered aloud what about them was “smart”;
  • S. R. showed the cutting edge(s) of robotic surgery and A. S. sounded the benefits of the good vibrations coming from a bioresorable bone anchor;
  • N. P. discussed laser-powered eye surgery and M. S. highlighted UV powered electronics;
  • R. K. gazed to outer space for a medical device and T. E. probed our very neurons for one;
  • J. W. advocated for the benefits of CPAP and S. D. of the necessity of ventilators; and
  • H. L. shared the Cellex qSARS-CoV-2 IgG/IgM Rapid Test while M. A. shared the Xpert® Xpress SARS-CoV-2 automated molecular test for that disorder we hear about these days.
I hope this class has shown you yourself within your community. I hope you have seen more of your community than you might otherwise have. Every single person here today has quite literally surveyed the biomedical professional landscapes and shared their experiences with us. On the subject of laws we have
  • R. K. to thank for interviewing someone who “helped establish the UM Export Controls Review Committee (ECRC), which helps UM researchers maintain compliance on export-controlled items”.
  • A. S. spoke with the Associate Director of Licensing for Medical Devices at the University of Michigan Office of Tech Transfer, a patent attorney by training.
  • M. T. told us it “was lovely learning more about patent law in the biotech and medical device industry from” Vice President of the Intellectual Property Counsel for a therapeutics company.
  • M. G. recorded a Clinical Account Specialist as saying “About once a week, a failure or complication is seen. […] It’s not typical for a patient to be impacted by the failure of a device in the field […]: there are fail-safe switches in place so certain errors that could impact a patient do not occur.”
  • C. S. showed how a manager of clinical informatics “implemented several changes in [the company] to force providers (or make it hard to not follow the correct workflow) into making sure they checked MAPS (state registry of all controlled substance prescriptions) when prescribing a controlled substance, […] ensuring that patients who received opioids were educated […].
  • A. R. relayed from the field that, “In public health, many people go in thinking that there is something wrong for a particular community and try to build a solution only to realize that it’s not what the community actually wants or needs. The best way to bring about practical change is to form relationships to understand what they are actually experiencing.”
  • M. B.’s interview subject expanded upon this point: “There is something to be said for consumer discovery early on. Current physicians don’t like to implement changes that bring unnecessary risk to patients (the possibility that they can’t do it right or confidently) During development it is important to ask clinicians what they want. There is not a ton of appetite for new things, they are very busy and have a lot to do, they don’t have time to learn how to use a new device. Some innovators will identify a problem and rush to commercialize it without consumer discovery. They need to talk to hundreds, even thousands of people to see what problems they encounter, their standard practices, etc. to understand the potential market and if the changes are viable to actual practitioners.”
  • I. G.’s interview subject, a physician in the Pediatric Cardiology outpatient clinic, reminded us that “Under the Sunshine Act all gifts $10+ from manufacturers to physicians and hospitals are made public.”
  • S. R. reflected from a pediatrician’s standpoint that “the most common medical devices used are pulse oximeters to read oxygen saturation, glucometers to test glucose levels, and cardiorespiratory monitors.”
  • R. P. explained how a dental assistant in Canada “trains new employees to minimize potential problems [by] demonstrat[ing] how to use certain equipment […] and encourage[ing] them to ask any questions if they are unsure about anything.”
  • H. L. interview an Anesthesia Resident who posited that “AI could be used predominately in administrative work, such as discharge paperwork, hospital bed management, emergency department management, scheduling assignments, ED triage, and even trends in certain hospitals like measures of health.”
  • R. R. communicated that someone working for a company that provides IT for dozens to hundreds of hospitals across the Midwest and east coast thinks “To make this a viable approach, the patient needs to undergo some sort of standard evaluation method, which may be difficult to make universal.”
  • N. A. said “A 510k [pathway] allows medical device companies to bypass the extensive clinical testing that comes with a pre-market approval from the FDA. They can avoid this testing by citing a similar predicate device that was already approved by the FDA.”
  • S. D. had a first-year Medical Student “explain[] that there are four factors to consider for consent, those being: (1) the patient or the guardian should not be coerced, (2) the patient should be completely competent and able to make a clear decision, (3) the patient must be educated clearly on what they are being asked to give consent to, and (4) the patient’s best interest should be factored as a priority”.
  • To S. H., a clinical fellow being from the Netherlands, expressed that his country had “universal health care for citizens in the form of community insurance, which is the same for everyone but care is provided based on the individual. […] Because of this, people in the Netherlands do not wait until a problem becomes a medical emergency to go to the doctor, unlike in the United States. All citizens are also guaranteed paid sick leave in the Netherlands, which he thinks will help stop the spread of the corona virus, because people do not go to work sick.”
  • And A. L. recounted the differences in opinion between a medical professional practicing Internal Medicine at Christ Hospital and Jersey City Medical Center who “believes patients should not be able to control their own medical device. That should be done only by a medical professional and the professional should make their own medical judgement given the clinal scenario” and a nurse practitioner at C.S. Mott Children’s Hospital who “feels that patients should have a lot more control. The best way to go about doing something like this would be to have guidelines and recommendations from professionals. […] [S]he explained that giving patients some freedom to control their own devices would save them a lot of time from coming in and out of the hospital. She believes healthcare should be a partnership with the patients, and patients who are mentally stable and aware should be allowed more control in their care because it is their health.”
On the subject of businesses
  • A Senior Engineering Director interviewed by L. M. interviewed noted that “Because there are limited resources for funding, business leaders decide where funding should be directed. The decision is a combination of both research and business people, and also the legal teams.”
  • A Division Chief of Physical Medicine who spoke with A. B. spoke with said, “decisions are made with considerations of recommendations given from providers, relationship with the company, as well as the service, reliability, and reputation of the device.”
  • A chief medical officer at a hospital in Ghana told J. B. he “makes decisions regarding quantity of devices, budget for the department, and models of the devices.”
  • Someone working at Michigan Medicine relayed to K. W. that “we often are able purchase equipment at a major discount through package deals (e.g., purchase x-ray, ultrasound, MRI equipment from the same company), so price isn’t as big a factor as it could be for others.”
  • In pediatric emergency care, A. S. told us “providing individualized care is highly important […] in an emergency environment where each patient requires one-on-one attention.”
  • An Operations Manager in a health system mentioned to S. J. “that hospitals are more adaptive than one would think to accept the change. Hospitals want to provide “the latest and greatest” device in the market so long [as] it is feasible and fits all the qualifications. For any n[e]w equipment, hardware or software, a business plan is created to weigh the pros and cons of implementation”
  • A professor starting a company for applications of his research stated to P. Y. “His devices will be priced by the market but will depend on two factors: costs of the fixed parts of the device and costs of the disposable parts of the device. In fact, for most medical devices the cost for the disposable portions are significantly higher than the instrument themselves, leading to a free-rental strategy similar to printers and the high cost of cartridges.”
  • A person who runs an acupuncture clinic mentioned to J. C. “that a long time ago, supplies were itemized to be reimbursed by insurance. Medicare has changed the method of billing items such that everything is lumped into a single item of “supply”. A lot of insurance companies do not even cover supplies.”
  • Someone with 25 years of industry and consulting experience in the medical device sectors told S. K. “Ultimately, it is the payer customer that is paying for the medical technology and rendering reimbursement to your clinical customers for purchasing and using your medical technology. It is extremely important that companies include the payer customer in their R&D and commercial planning efforts.”
  • A Senior Scientist in Translational Histopathology opined to M. A. “It is very crucial to know what you will be having to face before you start something. This is true in all aspects of life. You don’t want to dive into water before knowing how deep or shallow it is. It’s the same deal with research and biotech businesses.”
  • An Associate Professor of Internal Medicine told S. N. that “US hospitals dispose of outdated equipment on a regular basis as newer models and technology become accessible. Some will require that vendors of new equipment take old equipment back to enable safe disposal, however few hospitals realize that it is actually possible to contractually organize for vendors to re-purpose or responsibly recondition take-backs.”
  • A partner at a local venture capital firm explained to N. P. “healthcare venture capital is far more stable compared to other sectors due to the constant demand for healthcare, and that he sees a lot of growth in the non-invasive cost cutting sector of healthcare.”
  • A. R. spent 10 “extremely insightful” minutes with a General Partner at a venture capital firm.
  • A regulatory affairs specialist said to M. R. “how, often times, engineers like to focus on the design of products, but in a business setting the regulatory affairs is just as important.” He noted this is “Kind of a biased response given that [they] work[ in] this position.”
  • An R&D manager told A. W. that “Engineers are responsible for the product risk analysis documentation, wherein they weigh how likely a risk is to occur vs. the severity of occurrence.”
  • An R&D Engineer told J. L. of the “need to collaborate with the manufacturing teams to ensure there is the ability to bring a new product to full scale production.”
  • R. P. M. warns us “In the event of a complete power outage including back up, the only tools that would be available to continue to provide sufficient care to critical patients are generators and hand-held ventilators.”
  • A currently practicing physician said to S. D. in response to the current state of affairs, “Clinicians will be forced to look at what truly needs to be done for patients and change how they are approached. […] The backlog of cases that need to get done after the pandemic passes (guesses in a few months) will be huge and cause a large back up (physicians already were pressed for OR time).”
  • And a currently practicing resident nurse explained to L. W. that “Hand washing frequently and thoroughly several times throughout the day is the best defense against any illness, including flu. If you are sick, you help protect your community by staying home when you have a fever and covering your mouth with your arm if you cough or sneeze.”
On regulating these businesses by applying those laws
  • A Regulatory and Clinical Affairs at a company that “operates in multiple countries” said to H. H. “the USA, EU and Canada typically have the gold standard when it comes to regulatory laws and standards meaning that many other countries typically follow the precedent those countries follow. However, even keeping up with the changing standards and laws in a few countries was a lot of work and could get very complicated. He said that compiling these standards and controls as well as ensuring that your development team is complying with these changes can be challenging.”
  • A. B. interviewed a hardware engineer at Baxter Renal Care, who conveyed a few standards you have to meet for medical devices including the “International electrotechnical commission (IEC), International Organization for Standardization (ISO), and Association for the Advancement of Medical Instrumentation (AAMI).”
  • A scientist at Eli Lilly and Co told C. Y. they think “most of the regulations enforced in drug development are there to ensure that safe, high quality medicines are released to help better the lives of the patients depending on them.”
  • A Clinical Programs Coordinator told A. S. “the FDA regulatory process is the biggest hold up to new and improved medical devices being placed in hospitals. [… and] sometimes this process takes too long and doesn’t allow advancement in fields that need it.”
  • A professor in the EECS department at UM told B. M. “his team’s goal was not to “create a new device”; rather, their goal was to cause the smallest possible change to a device which had already passed FDA regulations (in fact, they legally reverse-engineered these devices for their own research).”
  • K. N. interviewed a research professor who “sees all this bureaucracy as a necessary part of the research process [and] would rather have to deal with paperwork than to accidentally come into contact with unknown pathogens and cancerous materials that could cost [them] their lives.”
  • A nurse at a hospital in Detroit told J. D., “the system needs to be flexible in terms of emergency it still needs to do its job in trying to keep people as safe as possible”
  • A family nurse practitioner for 24 years told M. L. “CLIA waived testing is also very helpful and easy to do because every test has a policy that serves as a step-by-step “recipe”. With the pandemic occurring, COVID needs to be a CLIA waived test so you can test for it on site in an office, reaching a wider population.”
  • A nursing assistant told J. W. “that most of the devices that are used for patient care are pretty good and reliable, but that the computers they use to manage patient information desperately need to be upgraded.”
  • A Clinical Programs Coordinator told N. H. “I believe one of the most difficult devices to work with are the electronic medical records. Although they have come a long way, they still provide too many places to document the same information which can become confusing – especially a patients recorded medication list. It seems like they could have integrated this feedback by now, […]and yet the issues remain.”
  • A project manager told K. A. “HIPAA requires that hospitals develop and follow procedures that ensures the confidentiality and security of all their patients.”
  • A person at a pharmaceutical company said to E. K. “how health care decisions are highly personal in […] and hopes that […] individuals would be fully informed in advance by health-care providers of the nature of the device in question and aware of the corresponding limitations.”
  • N. H., research lab manager, “The discussion then led to how women typically are more harmed by medical devices than men, due to exclusion of women from clinical trials.”
  • A senior clinical engineer told H. A. that the “department prepares an annual capital planning list for every department based on age, recalls, clinical needs, and OEM end-of-support notifications, and leave it up to each department to decide purchase priority based on their budgets.”
  • An Assistant Professor of orthopedic surgery conveyed to J. G. that “the hospital’s policy is to replace the device after its service life is over. However, if a new device would provide improved functionality or higher quality of care, then hospital would be willing to upgrade the device before the service life date. He also mentioned that this typically happens when company representatives approach surgeons with the new products.”
  • L. L. relays a post-doc focusing on marketing the application of nanoparticles to detect and diagnose the breast cancer saying “All the consumers will be vulnerable population, they deserve to be treated by the safe drugs and medical devices. He told me his belief is that only if you do regulation, you can assure the quality and safety of products. He doesn’t believe the commercial company can be trusted to regulate their products by themselves.”
On the consequences of our arts
  • An associate professor of neurology told J. S. “When it comes to surgery, there is a tradeoff between the extent of [benefit] and the harm incurred to patients. If you remove the entire brain, there will definitely not be any seizure because there isn’t a brain, but this isn’t a good idea.”
  • A consumer safety officer for the Food and Drug Administration and J. C. agreed, “the overall consequence reduction of commercialized products relies heavily on physicians and patients’ judgment. A physician should always be well informed about the regulatory and scientific process to ensure product safety. Consumers should also report any health-related issues as it is their report that initiates further FDA investigation to mitigate health related consequences.”
  • A Product Engineer mentioned to J. S. that much of their day-to-day work includes Product Investigation, Root Cause Analysis, and Clinical Evaluations, wherein “they undergo a detailed failure analysis and attempt to list every failure/error they predict could happen with their device. They list probable risks and their percent chance of happening, even if this is incredibly small. Each failure is rated on a 1 (Patient Discomfort) to 4 (Death) scale”.
  • An ICU nurse told D. J. “if she loses a patient, she helps transfer their body down to the morgue.”
  • A nurse with experience various hospital systems told B. P. “When a patient is very ill, they are connected to a number of different monitors, all outputting continuous data that needs attention [and] it’s very easy to get preoccupied with the numbers, and lose track of the patient sitting in the bed.”
  • A pediatrician in the making told D. K. “Sometimes the treatment that the patients undergo may only extend their life by a few years or even a few months, so at a certain point, it may not be worth the extra pain and money”.
  • A pediatric endocrinologist explained to L. F. that “Insurance companies require a middleman to deliver devices from the company that manufactures it to the patient.”
  • A nurse in the Henry Ford health system talked with P. V. “about the problems that arise when patients aren’t fully informed about the medical devices they use.”
  • A Physiatrist stated to T. E. “that devices recommended are very significant for patients to use especially for rehabilitation. The main targets for treatment plans are to improve function, increase quality of life, and reduce pain. He stressed that it is essential that patients are thoroughly taught how to use device so that they actually use it, as patient compliance can sometimes prove an issue.”
  • A Professor of Cardiovascular Physiology at the University of Michigan told N. S., “we need government sponsored basic science because pharmaceutical companies don’t really do basic science anymore, so our universities provide a pipeline to industry for future medical innovation [and] a large aspect of basic science funding, even indirectly, is education.”
  • M. S. was told by a nurse with the Saint Joseph Mercy Health System in Michigan that “Humans are the weakest component of any security system”.
  • An Anesthesiology specialist relayed to L. N. that “when it comes to medical devices, “I always trust them 100%”.”
  • Various resident doctors and staff at the University of Michigan Emergency Department Critical Care Center said to I. H. “There are devices that are very good at either saving a patient’s life or prolonging the inevitable […] and sometimes it’s nearly impossible to tell which it will be at the onset of the treatment.”
  • An ear, nose and throat surgeon explained to B. A. how “tools and devices are periodically checked and maintained. They are also checked right before being used in a procedure. If the device is found to be broken during this check, a backup can be used. However, on busy days with multiple operations, a backup might not be available. In this case a technician would try to fix it.”
  • A Research Biomedical Engineer told B. N. “When there are deadlines involved and proof-of-concept/function is the current focus”, getting work done now can trounce usability and safety “at times.”
  • A retired psychiatrist showed L. R. “the moral of the story is that it’s fun to think about ethics and positive choices, but that gets thrown out the window the moment money gets involved. Short-term economic benefit can have a lasting impact on peoples’ lives.”
  • A postdoc said to H. T. that “Contextualizing things within the scientific processes, […] one can explicitly say that this is the point of the scientific process, to be challenged and peer reviewed”.
I hope you all rise to the challenges of your communities and survey them regularly. It is what we try to instill in you here in Michigan. The state of Michigan’s motto is Si Quaeris Peninsulam Amoenam Circumspice – “If you seek a pleasant peninsula, look about you”. You will always find yourself in your community, if you but look. It will be bettered as you are bettered. As you trust and rely on your community and your community comes to trust and rely on you,you will all be the bettered if you share what you know, know what you share. 
 
But shared knowledge alone is not enough. We must learn to apply what has been shared. This is why instrumentation must always be paired with the laboratory. Investigation and speculation are ever bettered by ever better tools. When asked what you learned during your laboratory experimentations with some biomedical instrumentation, I have a subset of you1 on record as saying the following:
  • I learned how to make a LabView program;
  • learned a lot about what LabVIEW can do;
  • I learned a lot about how labview handles large datasets i.e. how to use arrays in any level of detail;
  • I learned how to input arrays and manipulate them to find the heart rate from an ECG signal in LabVIEW
  • I also improved my knowledge of LabVIEW further by gaining experience with arrays and the different structures within LabVIEW (flat sequence, case, while loop, etc.);
  • I also learned how to create sequences and while loops in LabView;
  • I learned how collectors work, how to work with arrays in LabVIEW, and how to implement Equations. I also learned about different Algorithms to acquire the beats per minute such as a[n] amplitude based approach, a max value based approach, minimum distances between peaks, etc.;
  • I learnt some useful VIs in labview that I can definitely revisit and reuse in the future when I am developing something else;
  • I really learned a lot about how to process signals using LabVIEW;
  • I learned how to use Labview software, like how to use DAQ assistant to acquire signals, how to use notch filter for reducing noisy signals;
  • I learned how to build a notch filter;
  • I learned that the hardware notch filter is superior to the software notch filter;
  • How to build a notch-filter and remove DC noise from a signal to get the low amplitude signal;
  • I learned how to create a notch filter in hardware as well as creating a T junction filter to increase gain;
  • I also learned how to construct a Twin-T notch filter;
  • I also learned how to use a T-Network in the feedback line of an op-amp to generate enormous gains
  • I also learned how to construct and fine-tune a split t junction amplifier;
  • I learned how powerful filters can be for amplifying a particular part of a signal;  
  • I learned the different types of noise;
  • I learned a significant amount about filtering signals;  
  • how to build digital filters to alter a signal;
  • I learned how to make hardware filters and amplifiers on the breadboard.
  • I finally learned how to use a breadboard properly.  
  • How to PHYSICALLY build filters/amplifiers, troubleshoot with pesky wires/breadboards/etc;
  • I relearned how to properly construct filters with the proper pinouts and best trouble shooting practices, especially the benefit of using the oscilloscope;
  • I improved my oscilloscope technique significantly as well;
  • I also became more comfortable using the oscilloscope and in my abilities to use pin-out/other schematics to build a physical circuit;
  • I learned […] more than just surface level application and how to debug for many problems that came up;
  • I learned many different ways of troubleshooting circuit designs
  • I learned a lot about debugging circuits;
  • I learned a ton about different types of circuits that I did not know previously;
  • I learned that what works on paper does not usually work in practice;
  • I learned that 100 microfarad capacitors are bad to use;
  • I also learned how trial and error until finding the method that works can be inefficient and long, but also helpful;
  • I learned how a potentiometer works;
  • How to use potentiometers;
  • I learned an important application of voltage followers when you want to reduce the impact of a load on a voltage measurement;
  • I also learned that good wire management reduces a lot of noise;
  • I learned that the presence of low frequency noise, such as the signal from the lungs, can mess up a peak detector that looks for global maximums;
  • I also learned how difficult it is to stabilize such a signal under movement;
  • I also learned how to construct a peak detector that looked for local maximums;
  • I learned a lot about making electrical systems, especially regarding problems with things getting unplugged or ripped, dealing with unexpected outputs, and general troubleshooting practices;
  • how to solder;
  • I learned how to solder more;
  • I also learned how to solder […];
  • I also improved my soldering technique;
  • I also gained a bit of drilling experience;
  • I learned the importance of managing complex hardware so that the device can be used practically;
  • how to combine both hardware and software into one large working system to be able to get a reading off of a human;
  • I also learned how to apply my knowledge of circuits to real world examples of medical devices;
  • I mainly learned a lot about how software can communicate with hardware;
  • This […] taught me how to combine both hardware and software into one large working system to be able to get a reading off of a human ;
  • I gained a deeper understanding for the power of an analog to digital conversion;
  • I learned a lot of little things;
  • I learned to use common sense;
  • to always be as patient as possible, despite obstacles;
  • I learned how a heart works, how to quantify how a heart works;
  • I learned what a heart beat looks like in terms of the arterial waveform;
  • I learned what oxygen saturation is, why it is useful;
  • that Hemoglobin’s absorption spectra can allow us to calculate how much of it is oxygenated;
  • How light absorption can be used to calculate oxygen concentration using the Beer-Lambert Law;
  • I also learned a lot about the Beer-Lambert Law;
  • I also learned the relationship between exercise and heart rate and respiration and heart rate;
  • that light goes much farther through human tissue than I once thought;
  • I also learned a little bit about light absorption and extinction coefficients;
  • I learned that some signals from the body are very finicky to acquire and patience is a necessity when dealing with them;
  • I learned that the best way to get started is to research and plan ahead some, but ultimately one must just start;
  • I learned a little bit about the range for biological signal acquisition, how to design a two stage amplifier, and the approximate strength biological signals can be read from the skin;
  • I learned how to write notes in a cautious way;
  • I learned how to be patient with myself in creating a circuit, as it takes time and it is okay to make mistakes;
  • I learned that understanding the information in the datasheet is very important.
  • I gained more confidence using datasheets and manuals;
  • Also learned that instrumentation amp (AD620) has weird input impedance effects and it also leaks current out of the inputs;
  • I became much more comfortable with making filter circuits and reading/characterizing bode plots;
  • One thing I learned […] is that if you stare at and wrestle with something for a really, really long time, you will eventually figure it out;
  • I learned that getting the right results doesn’t mean your method is correct;
  • I also learned how signal processing is complicated and how troubleshooting requires a lot of critical thinking to determine the problems;
  • I learnt a lot actually. [It] helped me understand the importance of the sequence of events […] in circuit design with materials I’d never worked before;
  • I learned I need to do a better job standing up for myself, and letting others know when they are making major mistakes;
  • I learned a lot about […] the importance of setting expectations early on [and] I think that if I had been upfront about what I expected from my group members that I would have gotten results from people;
  • I also learned how to work in a team better and make sure we communicate about what is happening;
  • I learned that good teamwork makes [a] project a lot of fun!;
  • I learned how to be patient with myself and my group members during this process;
  • I also learned that sometimes what we plan will not always work […]; and
  • I learned […] how important [] an instrument [] can be.  
Perhaps we did not learn this all or in equal measure. But I think it demonstrates we as a community learned a lot. From this your peers2 developed this wisdom:
  • Pay attention to every single detail;
  • Noise is the enemy;
  • Test by applying a known signal;
  • Double check every single component before rushing to get results;
  • Communicate better with software[/hardware] engineers about what exactly our inputs/outputs are; and
  • If we were more patient, we would […] go[] down a different […] route that would […] save[] us.
Take the time to do things right and well and good and give others time to do the same. I chose the panopticon as a metaphor for this class because I appreciated the mental imagery of seeing one’s self reflected while seeing everyone else. That’s more or less what the Greek roots of the word tell us “pan” – “all”, “every”, “wholly inclusive” – “optos” – “seen”, “visible”, “sight”, “light” – “con” – “bound together”. As a symbol for the class it should be taken to mean that your community is out there before you and I hope your can see yourself in it.
 
The times chose a different metaphor for the class. The times chose pandemic. Isolation, desperation, frustration, tedium and death, boredom and paranoia. This. The metaphors share the same root “pan”, the all encompassing connection. The root underlying “-demic” – “deme” – refers to “people” and is the same as that which appears in our “demographics” and our “democracy”. 
 
That, taken together these two roots describing “all people” now describes mass disease, sickness, and death, is an irony we may all mull on as we hear the throngs of viral barbarians beating down the gates. 
 
Irony only getting us so far, the pandemic itself has been revealing of what this class was meant to entail: community, communication, the communicability of certain attributes – originally that of “knowledge”, now the times press “disease”. But they both provoke perseverance. You all have gone through extraordinary times and have done extraordinarily within them. No one chooses the history they live through. The best we can do is hold ourselves to account and see that in our communities. Help when you can, share what you’ve got, and learn a little along the way. It’s what we should hope for “all people”.
 
With such wisdom in hand, what would do and if you3 could do it all again? 
  • I would have set my expectations higher right of the bat for my team and let them know that;
  • I would have thought […] more openly and not constrained myself to a specific way and function to build it in;
  • I would have taken a greater caution in the design process and carefully determine the best components to use;  
  • I would have conceded earlier in the project […], instead [of] being stubborn.  
  • I would be more assertive;
  • I would try to be more assertive and make sure we don’t move on before one part […] worked;
  • I wouldn’t let [someone] steamroll the hardware aspect. I can make good design choices and I need to let them be heard;
  • I think I would just make sure to have a better plan from the get-go and communicate it to everyone in the team, since I think we were at different pages when we started. I think this would have helped keep everyone on the same page since sometimes we weren’t all sure on what exactly was going on in different parts of the project;
  • I’m always trying to work better with groups/teams, and I think I should have put in some more effort to be cooperative;
  • I actually would ask for help more from classmates;
  • I’d come in better prepared with more knowledge about the circuitry being used so that I could make more meaningful contributions and be more involved in the circuit design process;
  • I would spend more time on the research and planning phase;
  • I think we were too attached to our initial plans, making me reluctant to start over again;
  • I would likely stay less hesitant on trying new things in the beginning […]. I think I had somewhat an unjustified fear in how to proceed and try new things, but many of our initial ideas [are] steps in the right direction;  
  • Speak up more about the initial design that I created that we ended up going with at the end only after we wasted time;
  • I will try to minimize the noise as much as I can also I will use good quality of wires, components, and breadboard;
  • I would add a Voltage follower to the circuit to reduce the current going through the entire circuit;
  • I would also take more time to test that each individual system component was operating as expected before jumping ahead to the next thing;
  • I would try to be more organised and systematic about my work;
  • I would try to integrate the software earlier so that we could identify the problems earlier;
  • I would help more with the hardware, which would help the team completing the hardware and would help me learn about an area I am not proficient;
  • I would try not to pay as much attention to the bells and whistles of the program but instead work on making it as robust as possible in terms of what it’s foundationally supposed to do;  
  • I would have tried to perform more testing of the LabVIEW sooner […] this would have allowed me to better understand the flaws;
  • I would probably have tested our software with a signal from the function generator instead of waiting on our hardware team to make the hardware;
  • I would have advised my team to input a signal from the function generator into the LabVIEW code to test the code at an earlier time;
  • I would keep in mind that the capacitor takes a while to charge and not jump to the conclusion that the circuit set up is wrong;
  • Use smaller capacitors. That would save like 5 hours of debugging and make our device easier to use;
  • I will get smaller capacitor to reduce the saturation time;
  • I would try to double check and finalize all calculations prior to constructing the circuits and moving forward;
  • I would constantly double check components, breadboards, and measurement tools; and
  • I would take Barry’s advice of sometimes just starting over on a new breadboard when it’s been 30 mins and you are fairly certain the circuit is built correctly. 
Luckily, many of you will have a chance to do this all again, should you decide to go into the medical device sectors. However, I believe it was the poet Tomas Kalnoky that put it, “And someday soon my friends, this ride will come to an end / But we can’t just get in line again”. We have reached the end of our ride over this course together my friends, but I hope your biomedical instrumentation journeys are not yet at an end. I hope our time here together has been informative and I instructive within. If I have not taught you all everything there is to know about biomedical instrumentation, I hope to have shown how one community has seen it. 
 
I wish to thank that community for all their hard work each individually. Though their contribution to this class may be “immeasurable”, allow us a moment to recognize their names. Please join me in thunderous applause. 
  • N. A.
  • M. A.
  • H. A.
  • K. A.
  • B. A.
  • A. B.
  • J. B.
  • M. B.
  • A. B.
  • J. C.
  • J. C.
  • J. D.
  • S. D.
  • S. D.
  • T. E.
  • L. F.
  • J. G.
  • I. G.
  • M. G.
  • N. H.
  • N. H.
  • H. H.
  • I. H.
  • S. H.
  • D. J.
  • S. J.
  • R. K.
  • S. K.
  • D. K.
  • E. K.
  • H. L.
  • L. L.
  • A. L.
  • J. L.
  • M. L.
  • L. M.
  • B. M.
  • K. N.
  • B. N.
  • L. N.
  • S. N,.
  • B. P.
  • N. P.
  • R. P. M.
  • R. P.
  • A. R.
  • S. R.
  • A. R.
  • R. R.
  • M. R.
  • L. R.
  • N. S.
  • J. S.
  • J. S.
  • C. S.
  • A. S.
  • M. S.
  • A. S.
  • T. S.
  • A. S.
  • M. T.
  • H. T.
  • P. V.
  • K. W.
  • J. W.
  • A. W.
  • L. W.
  • P. Y.
  • C. Y.
I wish to hear especially loud applause for the efforts of A. S., C. N., and A. S. who put in more work than all of us.
 
Philosophies of biomedical instrumentation are multispectral4:
  • There are those of humanity;
  • There are those of ingenuity;
  • There are those of creativity (“This was my first “open ended” lab experience, so the whole planning, implementing and testing process was a learning experience for me”);
  • There are those of reckless abandon (“I had no idea what concepts were at work so it was cool to see how the device actually works”);
  • There are those of mechanism (“This […] was honestly the first time that I was able to see how long it took for large capacitors to charge up”);
  • There are those quietly seeking (“This module helped me learn more than I originally thought it would”);
  • There are those loudly fulfilling (“I filled a lot of holes in my knowledge of hardware but found it incredibly fun”);
  • There are personal achievements (“In addition to these personal gains, I acquired knowledge of the heart”)
  • There are interpersonal achievements (“I also improved my patience”); and 
  • There are those of persistence (“I practiced debugging the circuit for hours. It is an interesting task and I hope I can master it one day”)
May we all be masters of our crafts one day. To that end, my philosophy of biomedical instrumentation is that there are many philosophies. Hear a few.
 
I turn, finally, to one student’s early words. “Everything in this [class] was new to me[,] from using operational amplifiers to using Labview.” Though said from one, I suspect it resonates in the quiet of many hearts here today. And yet, let the record be that you all have learned much, and I know you will learn more.
 
With that, I thank you for the opportunity to dismiss this class one final time. I hope you all do well on your fast-approaching exams and on your ever-to-the-horizon journeys. I have done what I can for you here and I trust you can do more. 
 
Good luck.
 

  1. N. A., M. A., H. A., K. A., B. A., A. B., J. B., A. B., J. C., J. C., J. D., S. D., L. F., J. G., I. G., N. H., H. H., I. H., B. M., S. H., S. J., R. K., S. K., L. L., A. L., J. L., M. L., L. M., K. N., B. N., R. P., A. R., A. R., L. R., N. S., J. S., C. S., M. S., A. S., T. S., A. S., M. T., H. T., P. V., J. W., A. W., and P. Y.

  2. H. A., J. C., D. J., L. M., S. R., and A. S.

  3. N. A., H. A., M. A., A. B., S. D., H. H., I. H., S. H., D. J., S. J., D. K. M. L., B. M., B. N., L. N., B. P., R. P. M. A. R., A. R., S. R., N. S., J. S., J. S., A. S., M. T., H. T., P. V., L. W., P. Y, and C. Y.

  4. H. A., B. A., N. H., R. K., L. N., M. R., and J. S.