Are they still teaching med students physio?

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VanDiemen

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This all started when a student asked how a pneumonia patient hyperventilating on room air could have a low arterial PO2, and low arterial Pco2. "How can you be getting rid of co2 but not able to at least get the PO2 above 75mmHg?" That question was not the problem.
However, throughout the course of the discussion it became clear that most of the students had no physio foundation.
In arterial blood what's higher? The dissolved co2 content or the dissolved o2 content? They all got it wrong. Apparently they went through 4 years of college and two years of med school without actually knowing what the hell partial pressure is. One student dismissed it as a "trick question", since the o2 "number" is higher.
They were not really clear on diffusion vs perfusion limited, thinking it was purely to do with permeability through the alveolar membrane.
Later on, the discussion shifted to acid base. No one even knew what the blood buffer line was; they had been looking at Davenport diagrams for two years but couldn't answer any questions about them.

These are students who were admitted to a pretty decent US medical school. I'm not trying to act like I'm better then them or anything like that. I don't consider myself to be very intelligent; my older brother is an electrical engineer and has made me very aware of how little math and science foundation I myself have. But I feel like my med school classmates were at least a little better prepared.
Anyone else feel that students are showing up to clerkships with no in depth understanding?

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This is what happens when people are admitted to colleges, medical schools etc. based mostly on interviews and resumes, and not mostly on objective knowledge tests (as in Europe and most places abroad). Out of curiosity, what were their Step 1 scores?

"Trick question"? Spoiled generation of know-nothing whiners. This goes hand-in-hand with the current crisis of PC college education.

You guys have no idea how strong the exact sciences foundation is for people coming from some less developed countries (former Soviet Union, Eastern Europe, some Asian countries) compared to the US. We are as good at political correctness as they are at math and physics.

Poor performance at exact sciences, including math, shows lack of reasoning, with pretty good predictive value for poor medical thinking.
 
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Physiology isn't even required for admission to most med schools.

Of course, what is learned between admission and clerkships is more to the point.....
 
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If a CRNA can do it, why can't they?
 
Physiology isn't even required for admission to most med schools.

Of course, what is learned between admission and clerkships is more to the point.....
The problem is what you build physiology on. If somebody lacks knowledge of thermodynamics and gases, how the heck will she understand partial pressure, solubility etc.? Medical school is too late to learn physics.
 
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FFP is right about the hard sciences in other countries.

There's no excuse to not knowing some of the stuff you talked about. But to give them the benefit of the doubt, maybe your questions were being asked in a confusing, "read my mind" kind of way?

  • What's higher in arterial blood? Well... oxygen partial pressure. Were you trying to argue that pCO2 was higher?? (see even I got confused reading your post)
  • Metabolic vs respiratory acidosis/alkalosis was taught well at my school I feel, and probably is at most. It's a core Step 1 concept. But if you started pimping me about wtf a "davenport diagram" or "buffer line" is I would have had a blank stare. They did teach us about Stewart strong ion model though.
Also would want to know these students step scores. Maybe you just got a dumb bunch.
 
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This sounds like the cliche "back in my days, things were so much better"....don't worry we will uphold tradition and bash the next generations of physicians as well.
 
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This sounds like the cliche "back in my days, things were so much better"
Or like the fall of an empire, once the good life spoils the generations that did not build it, just benefit from it.
 
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This sounds like the cliche "back in my days, things were so much better"....don't worry we will uphold tradition and bash the next generations of physicians as well.

Or like the fall of an empire, once the good life spoils the generations that did not build it, just benefit from it.


Kids these days get a new iphone every year and already have facebook, twitter, and youtube accounts.

Back in my day, only one kid on the block had a nintendo.

In summary: GET OFF MY LAWN!!!
 
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FFP is right about the hard sciences in other countries.


  • What's higher in arterial blood? Well... oxygen partial pressure. Were you trying to argue that pCO2 was higher?? (see even I got confused reading your post)
The amount of carbon dioxide dissolved in arterial blood is higher, by like ten fold. I asked very specifically using the exact words in my post, placing emphasis on the word 'content'. It shouldn't be confusing if you understand what 'partial pressure' means. Think back to Henry's Law.
 
This is beyond physics. This is lack of basic physiology knowledge, about how gases are transported in the blood, and why.

I personally couldn't care less about Davenport diagrams, by the way.
 
This is beyond physics. This is lack of basic physiology knowledge, about how gases are transported in the blood, and why.

I personally couldn't care less about Davenport diagrams, by the way.
This isn't basic physiology. Basic physiology is knowing how co2 is carried in the blood. This is asking if you know the solubility of co2 in blood. Being able to remember which is .003 and which is .03 after 1 month of respiratory physiology during first year and when your being asked on the spot is tough. You're an anesthesia attending and think about this frequently. 3rd/4th year med students are worried about causes of abnormal uterine bleeding, how to tie a one handed knot, which dsm edition they'll be tested on and which specialty they're going to choose...
 
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FFP is right about the hard sciences in other countries.

There's no excuse to not knowing some of the stuff you talked about. But to give them the benefit of the doubt, maybe your questions were being asked in a confusing, "read my mind" kind of way?

  • What's higher in arterial blood? Well... oxygen partial pressure. Were you trying to argue that pCO2 was higher?? (see even I got confused reading your post)
Also would want to know these students step scores. Maybe you just got a dumb bunch.
What was your step score? Seems like your basic physiology is lacking.
 
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This all started when a student asked how a pneumonia patient hyperventilating on room air could have a low arterial PO2, and low arterial Pco2. "How can you be getting rid of co2 but not able to at least get the PO2 above 75mmHg?" That question was not the problem.
However, throughout the course of the discussion it became clear that most of the students had no physio foundation.
In arterial blood what's higher? The dissolved co2 content or the dissolved o2 content? They all got it wrong. Apparently they went through 4 years of college and two years of med school without actually knowing what the hell partial pressure is. One student dismissed it as a "trick question", since the o2 "number" is higher.
They were not really clear on diffusion vs perfusion limited, thinking it was purely to do with permeability through the alveolar membrane.
Later on, the discussion shifted to acid base. No one even knew what the blood buffer line was; they had been looking at Davenport diagrams for two years but couldn't answer any questions about them.

These are students who were admitted to a pretty decent US medical school. I'm not trying to act like I'm better then them or anything like that. I don't consider myself to be very intelligent; my older brother is an electrical engineer and has made me very aware of how little math and science foundation I myself have. But I feel like my med school classmates were at least a little better prepared.
Anyone else feel that students are showing up to clerkships with no in depth understanding?

Exactly as Relaxis said, we are on respiratory right now (have not done renal yet) and while I understand the physical chemistry principles and reviewed physio from last year and would have probably guessed CO2, I did not exactly remember that CO2 was ~24 times more soluble in the blood than oxygen. First Aid (not that this should contain all the relevant knowledge from years 1+2) simply mentions how CO2 and O2 are dissolved and carried in arterial blood. We went through ABG's in our small groups and related them to a patient case, but the solubility never came up.

I could see how it could seem like a trick question because the pp of O2 is higher, but any med student should at least know the relative pp of CO2 and O2 in air and thus be able to deduce that answer to the student's original question.
 
The amount of carbon dioxide dissolved in arterial blood is higher, by like ten fold. I asked very specifically using the exact words in my post, placing emphasis on the word 'content'. It shouldn't be confusing if you understand what 'partial pressure' means. Think back to Henry's Law.
That law tells you nothing about the behavior of different molecules relative to each other. As you know, it says pressure is directly proportional to the amount of that molecule dissolved. How does thinking about that help? Perhaps you should step off your horse and remind them about polarity and such.
 
This isn't basic physiology. Basic physiology is knowing how co2 is carried in the blood. This is asking if you know the solubility of co2 in blood. Being able to remember which is .003 and which is .03 after 1 month of respiratory physiology during first year and when your being asked on the spot is tough. You're an anesthesia attending and think about this frequently. 3rd/4th year med students are worried about causes of abnormal uterine bleeding, how to tie a one handed knot, which dsm edition they'll be tested on and which specialty they're going to choose...
Knowing whether there is more O2 or CO2 dissolved in the blood is respiratory physiology 101. Same goes to how O2 can be low, despite the patient hyperventilating.
 
Maybe they can take Physio 101 and FFP can take How Not to be a Dbag 101.
 
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This is what happens when people are admitted to colleges, medical schools etc. based mostly on interviews and resumes, and not mostly on objective knowledge tests (as in Europe and most places abroad). Out of curiosity, what were their Step 1 scores?
GPA? SAT? MCAT?
 
Maybe they can take Physio 101 and FFP can take How Not to be a Dbag 101.
I am an attending, honey, so I do care when a medical illiterate is allowed to take care of patients. I am not a douchebag, just a responsible mature adult. When you'll get there you'll understand. One of my attendings in residency would kick you out of the room if you were unable to answer basic questions; why waste time and energy, trying to teach advanced stuff?

American medical students are more spoiled than the average 2 year-old, at least by certain med schools. And weak medical students make weak doctors; if they don't know the basic stuff by now, it will be just harder later, the same way one cannot learn calculus if one has no idea of algebra.

I have very few expectations from students on clinical rotation, but I do expect them to know basic medical science well. Otherwise, it's all just a house of cards. Sadly, I have these experiences not with students, but interns.

There is a misunderstanding that practical aspects matter more than their theoretical underpinnings, which is very wrong. Medicine is not monkey see, monkey do. Medicine is monkey see, monkey read, monkey discuss, monkey read some more, monkey see some more, monkey do, and the cycle continues. There is a lot of reading and knowledge involved. Consider it the moat of our profession from barbarian invasions by nurses.
 
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I am not arguing your intelligence. And I respect you professionally, as I do all my own attendings. You all (in real life and interwebs) have moved on to a level that I have not.

It is simply that I find myself disagreeing with the tone of pretty much every post of yours I have ever read.

You sound like a bitter, miserable, and petty person. I hope you are happier in real life than your portray here.
 
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Knowing whether there is more O2 or CO2 dissolved in the blood is respiratory physiology 101.
Ok fine. I bet you still had to double check and look it up first though. I mean those 3 cc/dL of co2 dissolved probably cross your mind daily.
 
American medical students are more spoiled than the average 2 year-old
Good thing you came to the states and were able to identify this. Did you repeat medical school here, or is that just an observation made from overhearing conversations in the break room?
 
Ok fine. I bet you still had to double check and look it up first though. I mean those 3 cc/dL of co2 dissolved probably cross your mind daily.
I don't expect anybody to know that number, or other complex formulas by heart. But I would expect them to know that O2 is predominantly transported by hemoglobin, while CO2 is predominantly dissolved in the blood. It's the concept. Same goes for understanding that CO2 is much more diffusible than O2. Again, it's not the exact number that matters. Same goes for pCO2 x ventilation = constant, hypoxia is caused by hypoventilation or V/Q mismatch and other basic concepts . I don't think it's too much to ask, and that's why I agreed with the OP.
 
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I don't expect anybody to know that number, or other complex formulas by heart. But I would expect them to know that O2 is predominantly transported by hemoglobin, while CO2 is predominantly dissolved in the blood. It's the concept. Same goes for understanding that CO2 is much more diffusible than O2. Again, it's not the exact number that matters. Same goes for CO2 x ventilation = constant, hypoxia is caused by hypoventilation or V/Q mismatch and other basic concepts . I don't think it's too much to ask.
It's not too much to ask, but if we're doing this, you need to realize that co2 is not predominantly dissolved in blood. It is transported through the blood predominantly as bicarbonate, then carbaminos and only 5%ish is dissolved.

And you're right, it's not too much to ask and I'm sure there are plenty of deficiencies in the system, but I don't think spoiled is quite the right term.

And btw you are pretty epic with the post-post editing. Could make following the thread a little confusing.
 
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It's not too much to ask, but if we're doing this, you need to realize that co2 is not predominantly dissolved in blood. It is transported through the blood predominantly as bicarbonate, then carbaminos and only 5%ish is dissolved.
You are right. :)

That doesn't change the fact that knowing that CO2 is much more soluble than O2 is basic stuff. Again, one does not have to know the numbers.

Same goes for my bicarbonate, just not in the middle of the night.
 
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And you're right, it's not too much to ask and I'm sure there are plenty of deficiencies in the system, but I don't think spoiled is quite the right term.
Let's use "overprotected", or "sheltered", if you want to be more PC.

Spoiled is the right term when compared to the more militaristic approach I was educated in, where one would never permit oneself to debate one's seniors, or to report attendings for innocent jokes with their own long-term staff, just because the student was feeling "uncomfortable", or to question one's grades or evaluations etc. I mean it's kindergarten level. And just read the media about college professors sharing the same kind of personal experience with millenials.
 
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Let's use "overprotected", or "sheltered", if you want to be more PC.
I think it's less a trend toward kindly sheltering med students, as it is a trend toward protecting the hospital and attendings, aka the plague of defensive medicine writ large.

20 years ago med students were given real responsibilities, placed invasive lines, etc under supervision of interns and residents. I was a pre-med in 1995 and I distinctly remember shadowing and hanging out with med students and interns who did things. Residents were gods who ran the place.

10 years ago med students mostly watched while interns and residents were supervised by attendings. I was a CA-1 in 2006 and on my ICU rotation that year, interns were fighting with us lofty PGY2s to get their first a-line, central line, intubation. We wrote orders on rounds with the attending standing there, and did very little of consequence on our own.

These days it's rare for a med student to do anything but watch, interns are given the autonomy of a 2000s med student, and the residents are micromanaged by attendings.

All for concern of medicolegal liability and patient safety ... some of which is grounded in reality but much of which is just fear.

Are med students really weaker than they used to be? Probably ... we've significantly expanded med school matriculation numbers in the last 20 years, and we're taking more applicants, particularly at new DO schools which pride themselves on a more holistic approach.

But mostly I just think the onset of responsibility has been shifted a few years to the right. Actual duty and responsibility to patients are powerful motivators to get your **** together and learn things. We shouldn't be surprised that med students aren't growing when we won't let them do anything.
 
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Good thread. Couldnt follow this at all without refresher.
FFP this is what my point is. Those students are not anesthesiologists, nor are they thinking about respiratory physiology all day like you are (and as I plan to). I guarantee you they all understood it 2 years prior to that pimp session in clinicals.

If a fricking boss like lobelsteve needed a refresher you can bet your ass those students did as well.

Do students a favor and help reinforce those concepts instead of being flabbergasted they gave the wrong answer. The militaristic approach to medicine has ended, get over it. Now seniors are actually expected to know what, why and which studies support. Information access has changed this, and most would think this is for the better. I imagine those that have a problem with it are the ones that know the least.

Still, there is no room for disrespect, poor attitudes or mal-behavior. Those incidents hopefully make it to the evaluations, and if they don't, it's your fault. Schools may not like it negative comments, but tough ****.

As for the 'innocent' jokes, do you think medicine is some protected part of society that is immune to the repercussions of current social rules? Do you go meet new people on the street and tell them jokes that you would tell your best friends? Would you go to a business meeting and tell those jokes to your team in front of people you just met? I like 'innocent' jokes too, but have some common sense and decency for those around you. Adapt or go work in private practice.
 
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I think it's less a trend toward kindly sheltering med students, as it is a trend toward protecting the hospital and attendings, aka the plague of defensive medicine writ large.

20 years ago med students were given real responsibilities, placed invasive lines, etc under supervision of interns and residents. I was a pre-med in 1995 and I distinctly remember shadowing and hanging out with med students and interns who did things. Residents were gods who ran the place.

10 years ago med students mostly watched while interns and residents were supervised by attendings. I was a CA-1 in 2006 and on my ICU rotation that year, interns were fighting with us lofty PGY2s to get their first a-line, central line, intubation. We wrote orders on rounds with the attending standing there, and did very little of consequence on our own.

These days it's rare for a med student to do anything but watch, interns are given the autonomy of a 2000s med student, and the residents are micromanaged by attendings.

All for concern of medicolegal liability and patient safety ... some of which is grounded in reality but much of which is just fear.

Are med students really weaker than they used to be? Probably ... we've significantly expanded med school matriculation numbers in the last 20 years, and we're taking more applicants, particularly at new DO schools which pride themselves on a more holistic approach.

But mostly I just think the onset of responsibility has been shifted a few years to the right. Actual duty and responsibility to patients are powerful motivators to get your **** together and learn things. We shouldn't be surprised that med students aren't growing when we won't let them do anything.
So on point.
 
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You have several years on these students with clinical experience, have heard many more lectures, and have done much more reading. You have a higher level of knowledge than we do. How can you take the stance that your students are dumb because they don't know something? If your students are deficient in an area, you could teach them. I studied chemistry at a decent college including graduate level courses with high step scores at a decent med school and I would have been just as dumb as your students. You don't learn everything in the first two years and the clinical years are there to supplement your knowledge. I didn't remember what a davenport diagram was until I googled it and refreshed my memory but I probably could not answer basic questions about it either.
 
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As a current student, I'll just chime in and say that there is NO WAY we are learning as much MEDICINE as you guys used to.

Why? The ceaseless, unending, time sucks of "professionalism" lectures, mandatory useless requirements, etc. etc. etc.

The med school bucket is overflowing, and not with medical content; that's been displaced by so much feelgood crap from administrators who left clinical practice decades ago.
 
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I want to make it clear that I was totally patient and nice with the med students. Just did my job and helped them to learn.
But I had to come here and vent I guess, because I only graduated med school a few years ago and I remember our physio/ basic chemistry knowledge being much stronger. Maybe I'm just selectively remembering... who knows, but I honestly am trying to compare their knowledge with where I was when I was an MS3.
I thought the questions were all fair. In order to explain why o2 cannot rise while co2 is still able to fall, you have to talk about blood content, and this was honestly something that these students didn't ever think about.
Let me give you another example: How much oxygen is picked up in the lungs versus how much co2 is dumped? These students thought that way more oxygen was picked up since the O2 went from 40 mmHg to 100 mm Hg, while co2 only decreases by ~5mmHg. They were surprised when I told them it only differed by about 20 percent less co2 usually.
I never thought that any of these concepts were esoteric. They seemed to be things you learned on day one, and if they weren't taught to you, then you would ask about them since things wouldn't add up.
I remember once a nurse talking to a family member of a copd patient about PFT results. The family member asked why it was hard to breathe out forcefully, but breathing in was easier? Shouldn't they be the same if the 'pipes' are narrow? The nurse stuttered out 'expiration is just different'. I dread the day when someone asks a doctor the same question and gets the same answer.
 
was picked up since the O2 went from 40 mmHg to 100 mm Hg, while co2 only decreases by ~5mmHg. They were surprised when I told them it only differed by about 20 percent less co2 usually.
You mean you 'tricked' them twice with the same question, just worded differently!? Yikes man, that's insanity now. Two solubility questions and they missed both of them!? Ridiculousness.

100-40 = 60 * .003 ml/mmHg/dl -> .18 ml/dl dissolved O2 picked up
45-40 = 5 * .03 ml/mmHg/dl -> .15 ml/dl dissolved CO2 dropped off

or is it,

Total CO2 content -> 52-48 = 4 ml/dl CO2 difference between venous and arterial blood
divided by
Total O2 content -> ~20-15 = 5 ml/dl O2 difference between arterial and venous blood

which would be a 20% difference, and a better solution perhaps depending on what you were asking.

Next time tell the students to sit down and think about it rather than blowing your load on your one pimp question that you ask in multiple permutations. That's what surgeons do.

Put yourself in other peoples shoes man. We learned the concepts, we just need to keep thinking about and integrating them. How would you feel if lobelsteve asked you to draw a proper vertebral body and about rexed lamina. Probably want to brush back up on that anatomy, eh? I just did.
 
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In order to explain why o2 cannot rise while co2 is still able to fall, you have to talk about blood content, and this was honestly something that these students didn't ever think about.
Go ahead and explain it and let's see what kind of answer you were expecting. Then we can identify the nature of the confusion and help you ask a better question next time. Are you talking about PaO2 and PaCO2 in a pathological situation? If so, perhaps a discussion about diffusion/perfusion is appropriate, rather than confusing them with more solubilities and blood content.
 
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I've been learning a lot reading this thread. Good review. As a 4th year these .03 and .003 numbers felt distantly familiar, and with some review it's starting to come back.

The reason the students got your questions wrong is because those aren't anything like step 1 questions. I scored very well on step 1 and 2 and would have been stumped by half of your questions (although not understanding why a pna pt can have both low co2 and o2 is kinda baffling).

For step you need to understand basic respiratory acid base stuff, Haldane/Bohr effects, be familiar with the terms diffusion limited vs perfusion limited, and the zones of the lung.
 
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I want to make it clear that I was totally patient and nice with the med students. Just did my job and helped them to learn.
But I had to come here and vent I guess, because I only graduated med school a few years ago and I remember our physio/ basic chemistry knowledge being much stronger. Maybe I'm just selectively remembering... who knows, but I honestly am trying to compare their knowledge with where I was when I was an MS3.
I thought the questions were all fair. In order to explain why o2 cannot rise while co2 is still able to fall, you have to talk about blood content, and this was honestly something that these students didn't ever think about.
Let me give you another example: How much oxygen is picked up in the lungs versus how much co2 is dumped? These students thought that way more oxygen was picked up since the O2 went from 40 mmHg to 100 mm Hg, while co2 only decreases by ~5mmHg. They were surprised when I told them it only differed by about 20 percent less co2 usually.
I never thought that any of these concepts were esoteric. They seemed to be things you learned on day one, and if they weren't taught to you, then you would ask about them since things wouldn't add up.
I remember once a nurse talking to a family member of a copd patient about PFT results. The family member asked why it was hard to breathe out forcefully, but breathing in was easier? Shouldn't they be the same if the 'pipes' are narrow? The nurse stuttered out 'expiration is just different'. I dread the day when someone asks a doctor the same question and gets the same answer.

Your questions are very difficult to understand even when I'm sitting here comfortably without feeling the pressure of trying not to look stupid. The way your students are thinking about things makes sense intuitively. It's your job to help them think more like a doctor so they can be ready for treating patients. If your students aren't understanding something then it's your failure as a teacher that they still don't understand after a discussion
 
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Go ahead and explain it and let's see what kind of answer you were expecting. Then we can identify the nature of the confusion and help you ask a better question next time. Are you talking about PaO2 and PaCO2 in a pathological situation? If so, perhaps a discussion about diffusion/perfusion is appropriate, rather than confusing them with more solubilities and blood content.

Okay that's a good idea, I welcome any help. So, one student mumbled something about co2 being 'more soluble', I told him yes that was true and that co2 is 20 times more soluble in blood and more able to diffuse the alveolar barrier, but that was not the reason a patient with shunt would have low Pao2 AND low Paco2. I told them to imagine an extreme case: half the cardiac output is flowing past unventilated alveoli and not participating in any gas exchange. This shunted blood is going to mix with the unshunted blood in the left atrium and their gas contents are going to average together to produce the final partial pressures in the arterial blood. The blood that is still participating in gas exchange now has to 'make up' for the shunt. So, the patient hyperventilates and the Alveolar pco2 drops and the po2 rises. However, the key lies in the fact that the unshunted blood can drop its co2 content a lot more than it can increase its o2 content. I told them this is why even giving high inspired PO2 (like ~600mmHg) through a mask will do very little for the arterial PaO2 in a patient with large shunt. I gave a much lengthier explanation than I have typed here, and pulled up diagrams of o2 and co2 content vs partial pressure showing the sigmoidal relationship of oxygen and more linear relationship for co2. I did my best and maybe I just don't know how to explain things, but I felt like I kept hitting roadblocks everywhere. Like I just kept uncovering things that students had misunderstood. It was like this with EVERY topic we covered.
I'm not giving up teaching and want to improve, since at least somebody from this school will eventually go into anesthesia or ccm.
I think that maybe the problem goes back to premed education. People are entering med school with a VERY superficial understanding of physics/chem. Like not even high school level. Little things that need to be clarified just get glossed over. I'm not blaming the students.
 
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Okay that's a good idea, I welcome any help. So, one student mumbled something about co2 being 'more soluble', I told him yes that was true and that co2 is 20 times more soluble in blood and more able to diffuse the alveolar barrier, but that was not the reason a patient with shunt would have low Pao2 AND low Paco2. I told them to imagine an extreme case: half the cardiac output is flowing past unventilated alveoli and not participating in any gas exchange. This shunted blood is going to mix with the unshunted blood in the left atrium and their gas contents are going to average together to produce the final partial pressures in the arterial blood. The blood that is still participating in gas exchange now has to 'make up' for the shunt. So, the patient hyperventilates and the Alveolar pco2 drops and the po2 rises. However, the key lies in the fact that the unshunted blood can drop its co2 content a lot more than it can increase its o2 content. I told them this is why even giving high inspired PO2 (like ~600mmHg) through a mask will do very little for the arterial PaO2 in a patient with large shunt. I gave a much lengthier explanation than I have typed here, and pulled up diagrams of o2 and co2 content vs partial pressure showing the sigmoidal relationship of oxygen and more linear relationship for co2. I did my best and maybe I just don't know how to explain things, but I felt like I kept hitting roadblocks everywhere. Like I just kept uncovering things that students had misunderstood. It was like this with EVERY topic we covered.
I'm not giving up teaching and want to improve, since at least somebody from this school will eventually go into anesthesia or ccm.
I think that maybe the problem goes back to premed education. People are entering med school with a VERY superficial understanding of physics/chem. Like not even high school level. Little things that need to be clarified just get glossed over. I'm not blaming the students.

This is where I got confused.

Here's my unstanding: Consolidation in lung --> area not being ventilated but still perfused --> initial rise in pCO2 detected by chemoreceptors triggers hyperventilation (also some hypoxic pulmonary vasoconstriction shunting blood flow away from poorly ventilated lung area) --> alveolar hyperventilation in ventilated lung lowers pCO2 (because CO2 is very soluble and perfusion-limited?) --> pO2 remains low because the amount of poorly ventilated lung is just too much to be fully compensated for by hyperventilation + vasoconstriction (?)

Go ahead and criticize my basic science knowledge, but while you're at it I'd love for someone to explain the gaps in my understanding. It's been a few years since I took physiology and this is the "simplified" intuitive model ingrained in my brain I've held onto.
 
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I told them to imagine an extreme case: half the cardiac output is flowing past unventilated alveoli and not participating in any gas exchange. This shunted blood is going to mix with the unshunted blood in the left atrium and their gas contents are going to average together to produce the final partial pressures in the arterial blood. The blood that is still participating in gas exchange now has to 'make up' for the shunt. So, the patient hyperventilates and the Alveolar pco2 drops and the po2 rises. However, the key lies in the fact that the unshunted blood can drop its co2 content a lot more than it can increase its o2 content. I told them this is why even giving high inspired PO2 (like ~600mmHg) through a mask will do very little for the arterial PaO2 in a patient with large shunt. I gave a much lengthier explanation than I have typed here, and pulled up diagrams of o2 and co2 content vs partial pressure showing the sigmoidal relationship of oxygen and more linear relationship for co2. I did my best and maybe I just don't know how to explain things, but I felt like I kept hitting roadblocks everywhere. Like I just kept uncovering things that students had misunderstood. It was like this with EVERY topic we covered.
I'm not giving up teaching and want to improve, since at least somebody from this school will eventually go into anesthesia or ccm.
I think that maybe the problem goes back to premed education. People are entering med school with a VERY superficial understanding of physics/chem. Like not even high school level. Little things that need to be clarified just get glossed over. I'm not blaming the students.

Again, I am no one here but a lowly CCRN, but I find this explanation very good and in keeping with what has been shared with me over the years. IDK, your explanation seems quite fine to me. Kind of being tough on yourself I think. It's not your fault that people need to go home and do some serious reading/studying. Perhaps in this end, this is indeed what you inspired them to do--no pun intended.

Hard to believe the issue of shunting wasn't a big factor for them. Also, it helps to see how compensation factors try to work, but given a particular pathology, they may fall short.
 
Okay that's a good idea, I welcome any help. So, one student mumbled something about co2 being 'more soluble', I told him yes that was true and that co2 is 20 times more soluble in blood and more able to diffuse the alveolar barrier, but that was not the reason a patient with shunt would have low Pao2 AND low Paco2. I told them to imagine an extreme case: half the cardiac output is flowing past unventilated alveoli and not participating in any gas exchange. This shunted blood is going to mix with the unshunted blood in the left atrium and their gas contents are going to average together to produce the final partial pressures in the arterial blood. The blood that is still participating in gas exchange now has to 'make up' for the shunt. So, the patient hyperventilates and the Alveolar pco2 drops and the po2 rises. However, the key lies in the fact that the unshunted blood can drop its co2 content a lot more than it can increase its o2 content. I told them this is why even giving high inspired PO2 (like ~600mmHg) through a mask will do very little for the arterial PaO2 in a patient with large shunt. I gave a much lengthier explanation than I have typed here, and pulled up diagrams of o2 and co2 content vs partial pressure showing the sigmoidal relationship of oxygen and more linear relationship for co2. I did my best and maybe I just don't know how to explain things, but I felt like I kept hitting roadblocks everywhere. Like I just kept uncovering things that students had misunderstood. It was like this with EVERY topic we covered.
I'm not giving up teaching and want to improve, since at least somebody from this school will eventually go into anesthesia or ccm.
I think that maybe the problem goes back to premed education. People are entering med school with a VERY superficial understanding of physics/chem. Like not even high school level. Little things that need to be clarified just get glossed over. I'm not blaming the students.

This has little to do with premed physics or chem knowledge. I, like most med students, took advance placement physics and chemistry in high school and 2-3 years more of physics and Chem when we got to college and if you were to ask us those solubility questions right after the MCAT we would murder the questions easily. However, its like learning a new language, if you don't use it, you lose it. Because when we all got to med school the emphasis wasnt on the things you're talking about, we had way too much shyt to have to memorize....i was too busy drawing the brachial plexus on my arm to remember that CO2 is 20 times more soluble than 02. We worked our azz off in med school, most of us studied on average 10-12hrs a day...there has been time where ive studied 18hrs straight for an entire week right before big final exams. So i take exceptions to it when you guys call us lazy, we worked our butt off and made immense sacrifices so we deserve to be here every bit as you do. But like i said don't worry we are going to uphold tradition and bash the next generations of physicians. And you think our applied physics and chem knowledge is bad, wait till you work with the new wave of med students who are coming in 4 years, because i heard the new mcat is cutting down on hard sciences and replacing with crap like sociology and behavioral science.
 
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This has little to do with premed physics or chem knowledge. I, like most med students, took advance placement physics and chemistry in high school and 2-3 years more of physics and Chem when we got to college and if you were to ask us those solubility questions right after the MCAT we would murder the questions easily. However, its like learning a new language, if you don't use it, you lose it. Because when we all got to med school the emphasis wasnt on the things you're talking about, we had way too much shyt to have to memorize....i was too busy drawing the brachial plexus on my arm to remember that CO2 is 20 times more soluble than 02. We worked our azz off in med school, most of us studied on average 10-12hrs a day...there has been time where ive studied 18hrs straight for an entire week right before big final exams. So i take exceptions to it when you guys call us lazy, we worked our butt off and made immense sacrifices so we deserve to be here every bit as you do. But like i said don't worry we are going to uphold tradition and bash the next generations of physicians. And you think our applied physics and chem knowledge is bad, wait till you work with the new wave of med students who are coming in 4 years, because i heard the new mcat is cutting down on hard sciences and replacing with crap like sociology and behavioral science.


I don't believe the sciences are cut. It is just that social sciences have been added. . .along with more biochem.

I wouldn't get bent out of shape and be offended or worried that someone was thinking I was lazy. I can't imagine any MS getting through the process by being lazy . If I had been one of those students there that day, I would just take the experience with VanDieman as an opportunity to learn more, from a pathophys standpoint is all. It's like when you are on rounds in the unit. Some people just get through them, and other people see points of discussion as valuable for further learning and inquiry.
 
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I think it's less a trend toward kindly sheltering med students, as it is a trend toward protecting the hospital and attendings, aka the plague of defensive medicine writ large.

20 years ago med students were given real responsibilities, placed invasive lines, etc under supervision of interns and residents. I was a pre-med in 1995 and I distinctly remember shadowing and hanging out with med students and interns who did things. Residents were gods who ran the place.

10 years ago med students mostly watched while interns and residents were supervised by attendings. I was a CA-1 in 2006 and on my ICU rotation that year, interns were fighting with us lofty PGY2s to get their first a-line, central line, intubation. We wrote orders on rounds with the attending standing there, and did very little of consequence on our own.

These days it's rare for a med student to do anything but watch, interns are given the autonomy of a 2000s med student, and the residents are micromanaged by attendings.

All for concern of medicolegal liability and patient safety ... some of which is grounded in reality but much of which is just fear.

Are med students really weaker than they used to be? Probably ... we've significantly expanded med school matriculation numbers in the last 20 years, and we're taking more applicants, particularly at new DO schools which pride themselves on a more holistic approach.

But mostly I just think the onset of responsibility has been shifted a few years to the right. Actual duty and responsibility to patients are powerful motivators to get your **** together and learn things. We shouldn't be surprised that med students aren't growing when we won't let them do anything.

Agree. I was super lucky to do a surg prelim year in the right community hospital. Intern night float gave me insane experiences that I would never get elsewhere. No in-house attending or upper-level, so forced you to make quick decisions while dialing a phone, lines and chest tubes galore (just did them, no need for senior or attending to come in once I was proficient), lots of resuscitation and blood management, bedside procedures, sutures in ED, etc. Small program, so we were in the or a lot. And it was this way for all the residents. I was such a deer in the headlights my first couple of weeks but I give tons of credit to that program for improving my acute medical decision making and for fostering my love of critical care.

Now at my academic anesthesiology program (I matched to an advanced spot), I see the surg residents basically doing nothing but scut for the first few years. They aren't even getting into the OR until late year 2!!! One of my first call nights as a CA1 I got a page from a surgical resident in the unit a year ahead of me to help her place a femoral art line. Seriously.

The anesthesiology residency is set up better, and they did it that way on purpose. We do livers, CCM, neuro, and some heavy duty vascular cases CA1 year, and the CA1 class starts with cardiac rotations in April so that the CA2 class have done true senior rotations by mid-year.
 
Agree. I was super lucky to do a surg prelim year in the right community hospital. Intern night float gave me insane experiences that I would never get elsewhere. No in-house attending or upper-level, so forced you to make quick decisions while dialing a phone, lines and chest tubes galore (just did them, no need for senior or attending to come in once I was proficient), lots of resuscitation and blood management, bedside procedures, sutures in ED, etc. Small program, so we were in the or a lot. And it was this way for all the residents. I was such a deer in the headlights my first couple of weeks but I give tons of credit to that program for improving my acute medical decision making and for fostering my love of critical care.

Now at my academic anesthesiology program (I matched to an advanced spot), I see the surg residents basically doing nothing but scut for the first few years. They aren't even getting into the OR until late year 2!!! One of my first call nights as a CA1 I got a page from a surgical resident in the unit a year ahead of me to help her place a femoral art line. Seriously.

The anesthesiology residency is set up better, and they did it that way on purpose. We do livers, CCM, neuro, and some heavy duty vascular cases CA1 year, and the CA1 class starts with cardiac rotations in April so that the CA2 class have done true senior rotations by mid-year.

Every program should be like that
 
I think everyone is bringing up good points, but I do think it's important point to keep in mind that it is the students job to be reading up on any clerkship they are starting. Just because it is an elective, doesn't mean you should slack off and not prepare for cases. You should be wanting to learn as much as possible from that elective. I think browsing a basic anesthesia for beginners book could have taught the student these answers had they tried to do some pre-reading before starting the elective (like anesthesia secrets for medical students which you can find online).

I honestly think you just got one of the lower performing students bc most students should be able to understand after you explain it to them (which seems like it didn't happen this time). I don't think this situation should be generalized to all of medical students though (in my opinion). Hopefully you get some more knowledgeable ones next time!
 
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