Thursday, January 1, 2009

Electronic Stethoscope Oddities

Happy New Year!

If acoustic stethoscopes — the kind physicians have used for over two hundred years — are the equivalent of typewriters, then electronic stethoscopes are like word processors. Okay, this analogy is non-intuitive, but hear me out. Electronic stethoscopes, like word processors, are newer, more expensive than the previous generation, and are — well — electronic, with all the advantages and disadvantages this implies.

The advantages to electronic stethoscopes are many. As I've written previously in my review of the Littman Electronic Stethoscope Model 3000, it's simply easier to hear heart and lung sounds with an electronic stethoscope than it is with an acoustic stethoscope. (For real-world examples of this, see the previous review.) Plus, some models, like the Littmann 4100 Electronic Stethoscope, allow you to record and playback — think copy and paste — heart and lung sounds for reference or teaching.

But anything electronic is prone to failure, and when electronic stethoscopes fail, they fail spectacularly. Don't misunderstand: I'm a fan of my Littman Model 3000, but it's worth pointing out the oddities you should expect if you decide to purchase one of these things. (Some of these observations are taken from my postings on Twitter.)

First — and this might sound obvious — the electronic stethoscope requires batteries. Eventually, these batteries will die. Unexpectedly. At exactly the wrong moment. Almost certainly, when you're examining a patient. At this time, your electronic stethoscope will make a sad little noise, then — silence. An eerie silence. And unless you're walking around with an extra AA battery in your pocket — which you will suddenly realize is probably a good idea — you will then say, apologetically, "I'm sorry. The battery in my electronic stethoscope just died."

Second, if you carry around an iPhone or a BlackBerry, you will experience intermittently the faint faraway static of your mobile device as you're listening to the heart of a patient. And while this doesn't interfere with your physical exam, it's unnerving.

Finally, if you were planning to place another type of diaphgram on your electronic stethoscope — such as the excellent SafeSeal stethoscope covers by DRGdon't. It will cause unbelievable amounts of feedback. As I learned recently, placing incompatible diaphragms on electronic stethoscopes makes your patients' hearts sound like they're being played by Jimi Hendrix.

(Also posted on Tech Medicine.)

Wednesday, October 15, 2008

Netter for the iPhone

Would have loved this during anatomy. Looking at the video, I can almost smell the gristle and formaldehyde again. This is one of the few medical apps I haven't used, though — any medical students find it helpful?

Saturday, October 4, 2008

Precious Bodily Fluids, a New Nephrology Blog

de: Struktur von Milchsäure; en: Structure of ...Image via Wikipedia

Dr. Joel Topf is one of only two or three blogging nephrologists (including Dr. Arnold Kim, who publishes MacRumors.com, so that may not count). Joel writes the excellent Precious Bodily Fluids blog. PBF not only contains a wealth of clinical information, but scores huge points for the Dr. Strangelove banner. He's also the author of The Fluid, Electrolyte, and Acid-Base Companion, perhaps the easiest-to-understand primer on these brain-twisting disorders. Via Precious Bodily Fluids:
Yesterday I gave a great lecture on interpreting ABG results. I added a problems set for gap-gap analysis and added a section on the osmolar gap. I also improved the anion gap section with my new favorite mnemonic. Forget PLUMSEEDS, forget MUDSLEEPS, forget MUDPILES. The new hotness is GOLD MARK:

* G Glycols
* O 5-Oxoproline (pyroglutamic acid)
* L L-Lactic acid
* D D-Lactic acid

* M Methanol
* A Aspirin
* R Renal failure
* K Ketoacidosis

Thursday, October 2, 2008

Urinary Tract Wallpaper

Via the talented Shannon Wright:



Thursday, September 25, 2008

Sparklines and Hantavirus Nephropathy

Monday, September 15, 2008

How to Blog, by Merlin Mann

How To Blog
View SlideShare presentation or Upload your own. (tags: advice blogging)
And the talk itself, here.

Saturday, August 30, 2008

Transitioning Blog Comments to Disqus

I'm transitioning Kidney Notes' blog commenting system to Disqus. The old comments will — hopefully — still be there, but things may look strange for a bit.

Reblog this post [with Zemanta]

Thursday, July 31, 2008

Hello Health


Hello Health, originally uploaded by KidneyNotes.

Monday, July 7, 2008

The Controvery Over Cardiac CTAs

heart with coronary arteriesImage via Wikipedia

A few minutes later, Dr. Hecht studied the results. As he had expected, the angiogram revealed that Mr. Franks’s arteries were healthy. In some places, plaque had blocked 25 percent of their blood flow, but in general, cardiologists do not consider blockages clinically relevant until they reduce blood flow at least 70 percent.

After Mr. Franks finished dressing, he joined Dr. Hecht, who went over the results, explaining that his heart appeared healthy and that he would not need a stent. Still, Dr. Hecht recommended that Mr. Franks have another CT angiogram next year to check that the plaque was not thickening. Mr. Franks agreed, pronounced himself satisfied and left.

For Mr. Franks, the test was quick and painless. But it subjected him to a significant dose of radiation.

Based on a reporter’s notes about the duration of the scan and the power output reported by the scanner, Dr. Brenner of the Center for Radiological Research estimated that Mr. Franks had received 21 millisieverts of radiation — even more than a typical test, equal to about 1,050 conventional chest X-rays.

Given the radiation risks, Dr. Ralph Brindis, another cardiologist, said Dr. Hecht had erred. Because Mr. Franks had already taken a nuclear stress test with normal results, he did not need a CT angiogram, said Dr. Brindis, vice president of the American College of Cardiology. And particularly because the scan’s results were benign, he said, Dr. Hecht should not have recommended a follow-up test.

“The biggest problem we have with radiation is that the doses are cumulative and additive,” Dr. Brindis said. “So the concept of doing serial CT testing on asymptomatic patients, I think, is abhorrent. I cannot justify that.”

Dr. Hecht said he sharply disagreed with Dr. Brindis. The scan was appropriate for Mr. Franks, despite his normal results from the nuclear stress test, because of Mr. Franks’s other risk factors for heart disease, including his higher-than-average calcium score, Dr. Hecht said. And he said he recommended a follow-up scan next year so he could see how quickly the plaque in Mr. Franks’s arteries was thickening.
The article attempts to reconcile two sharply opposing points of view. In my opinion — and I hasten to add that I'm not a cardiologist or radiologist — cardiac CTAs are at the same level of clinical usefulness and acceptance now that CTAs of the pulmonary arteries were several years ago. It took years for a CTA of the pulmonary arteries to a widely accepted test for diagnosing or excluding pulmonary emboli. Within the next several years, I would expect that CTAs of the coronary arteries will become a well-accepted test for diagnosing or excluding coronary disease.

Zemanta Pixie

Thursday, June 26, 2008

Resistant Hypertension: Diagnosis, Evaluation, and Treatment, from the AHA

Conventional (mechanical) sphygmomanometer with aneroid manometer and stethoscopeImage via Wikipedia

Resistant Hypertension: Diagnosis, Evaluation, and Treatment: A Scientific Statement From the American Heart Association Professional Education Committee of the Council for High Blood Pressure Research -- Calhoun et al. 51 (6): 1403 -- Hypertension
Resistant hypertension is a common clinical problem faced by both primary care clinicians and specialists. While the exact prevalence of resistant hypertension is unknown, clinical trials suggest that it is not rare, involving perhaps 20% to 30% of study participants. As older age and obesity are 2 of the strongest risk factors for uncontrolled hypertension, the incidence of resistant hypertension will likely increase as the population becomes more elderly and heavier. The prognosis of resistant hypertension is unknown, but cardiovascular risk is undoubtedly increased as patients often have a history of long-standing, severe hypertension complicated by multiple other cardiovascular risk factors such as obesity, sleep apnea, diabetes, and chronic kidney disease. The diagnosis of resistant hypertension requires use of good blood pressure technique to confirm persistently elevated blood pressure levels. Pseudoresistance, including lack of blood pressure control secondary to poor medication adherence or white coat hypertension, must be excluded. Resistant hypertension is almost always multifactorial in etiology. Successful treatment requires identification and reversal of lifestyle factors contributing to treatment resistance; diagnosis and appropriate treatment of secondary causes of hypertension; and use of effective multidrug regimens. As a subgroup, patients with resistant hypertension have not been widely studied. Observational assessments have allowed for identification of demographic and lifestyle characteristics associated with resistant hypertension, and the role of secondary causes of hypertension in promoting treatment resistance is well documented; however, identification of broader mechanisms of treatment resistance is lacking. In particular, attempts to elucidate potential genetic causes of resistant hypertension have been limited. Recommendations for the pharmacological treatment of resistant hypertension remain largely empiric due to the lack of systematic assessments of 3 or 4 drug combinations. Studies of resistant hypertension are limited by the high cardiovascular risk of patients within this subgroup, which generally precludes safe withdrawal of medications; the presence of multiple disease processes (eg, sleep apnea, diabetes, chronic kidney disease, atherosclerotic disease) and their associated medical therapies, which confound interpretation of study results; and the difficulty in enrolling large numbers of study participants. Expanding our understanding of the causes of resistant hypertension and thereby potentially allowing for more effective prevention and/or treatment will be essential to improve the long-term clinical management of this disorder.
Zemanta Pixie

Tuesday, June 24, 2008

Gastric Bypass May Improve Renal Function in Obesity Related Glomeruopathy

Roux-en-Y gastric bypass.Image via Wikipedia

Gastric Bypass Can Improve Renal Function in Patients With Morbid Obesity, Via Medscape:
Patients with morbid obesity who also have chronic renal disease (CRD) may improve or stabilize renal function after gastric bypass, according to a study presented here at the American Society for Metabolic & Bariatric Surgery 25th Annual Meeting.
[Interesting. Obesity related glomerulopathy is mediated by hyperfiltration, which might theoretically be reversible with gastric bypass.]
Zemanta Pixie

Monday, June 2, 2008

Life Hacks for Doctors: An Introduction


The Efficient MD Blog
The Efficient MD Wiki

Life Hacks for Doctors is the Slideshow of the Day on Slideshare

Just received this email:

Your slideshow Life Hacks For Doctors has been selected as the 'Slideshow of the Day' on the SlideShare homepage.

Our editorial team would like to thank you for this awesome creation.

- The SlideShare team
Nice start to the week. On the home page, Slideshare also highlights other slideshows on Doctors, Medicine, and Web 2.0.

Sunday, June 1, 2008

Manhattan Solstice

Thursday, May 29, 2008

Fierce on fungus. Kinder to kidneys.

Saturday, May 24, 2008

Nephrogenic Systemic Fibrosis


Nephrogenic systemic fibrosis, a scleroderma-like condition, is related to the use of gadolinium in patients with severe renal failure. This dialysis patient developed nephrogenic systemic fibrosis just 3 months after being exposed to gadolinium for an MRA.

Monday, May 12, 2008

Introducing The Efficient MD Wiki

Visit the Efficient MD Wiki at http://wiki.efficientmd.com.

Wikis — collaborative websites — are powerful tools for education. The Efficient MD Wiki is designed to help healthcare professionals and medical students discover clinical pearls, useful resources, life hacks, and strategies to improve the practice of medicine.

Although this Wiki is currently in its infancy, it is growing rapidly and needs your help. Please post your ideas, mnemonics, best practices, tricks, timesavers, presentations, helpful links, or other advice you'd care to share. (Don't worry if your writing is disorganized. Someone will always edit it later.)

While posting anonymously is allowed, if you'd like to have a link to your personal website added to the home page — as our way of saying thanks — please join the wiki and send us a message.

Please see the posting guidelines and disclaimer. The Efficient MD Wiki is an ongoing experiment, and comments are welcome.

Sincerely,

Joshua Schwimmer, MD, FACP, FASN; The Efficient MD Blog (in association with the American College of Physicians); Clinical Instructor in Medicine, Columbia University College of Physicians & Surgeons and Clinical Assistant Professor of Medicine, New York University School of Medicine

Ves Dimov, MD; Clinical Cases and Images; Clinical Assistant Professor of Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University

(Also posted on The Efficient MD Blog.)

Saturday, May 10, 2008

Currently Reading: Little Brother

Wednesday, May 7, 2008

"Lipitor titration is a failed step."

AtorvastatinLipitor Image via WikipediaThree Vytotin/Zetia reps just came to me and said, "When do you feel comfortable using Zetia? After all, Lipitor titration is a failed step. It only reduces LDL by 6%."

I gently referred them to the PROVE IT trial, asked them to come back when they had positive mortality data, and walked away.

Has anyone else encountered this strategy by the Zetia reps?


Tuesday, May 6, 2008

You'd Never Confuse Diabetes Mellitus With Diabetes Insipidus. The New York Yimes Has It Wrong.

Mechanism of insulin release in normal pancreatic beta cells.  Insulin production is more or less constant within the beta cells, irrespective of blood glucose levels. It is stored within vacuoles pending release, via exocytosis, which is triggered by increased blood glucose levels.Image via WikipediaI'm still puzzling over this article in the New York Times, "Some Diabetics Don't Have What They Thought They Had." The article seems to imply -- and some other news outlets have picked up -- that some children diagnosed with type 1 diabetes mellitus (DM) actually have diabetes insipidus (DI). What the article means to imply, I think, is that some children with type 1 DM actually have maturity onset diabetes of the young (MODY). (I've looked, but I could not find a situation in which you'd ever confuse type 1 DM and DI. In DI, for example, you wouldn't have glucose in the urine.)

Why is this important? Because if the myth propagates through the media that you can easily confuse DI and DM, countless younger adult patients with DM will approach their doctors demanding that they be tested for DI, which will require a lengthy explanation of how the two could not be confused...

On the other hand, I've seen patients with MODY misdiagnosed as having type 1 DM -- and they eventually are able to stop insulin and switch to oral therapy. This is the real message of the NYT article, I think, and it's great when it happens.