When doctors have a simulated operating room

The doctor who was in charge of the operation said:

When Zhang Yi said this, a doctor in his thirties behind Wang Xiaomian asked:

"Yes, what's so special about this? Many heart diseases, especially heart failure caused by aortic stenosis, have reduced compliance and pressure difference."

Zhang Yi looked at him and asked:

"Yes, but the color Doppler ultrasound showed that there was no stenosis in the main blood vessels. What does this mean?"

Damn!

Zhang Yi actually asked questions!

It's okay to ask!

The main reason is that they can't answer this question! !

After Wang Xiaomian looked around, everyone was more confused than him.

Then he could only blink awkwardly and said:

"This...this means...that we should do another color Doppler ultrasound?"

Well, he, the director, still couldn't answer.

Zhang Yi shook his head.

He pointed to the color Doppler ultrasound report and said:

"It means that the reduced compliance has nothing to do with the stenosis of the aortic valve, or it has little to do with it. So it's useless even if this patient is sent to the operating table for surgery.

Because even on the operating table, there is no narrow place that needs to be repaired.

Let's think about another question, why didn't the drugs you used to increase myocardial contractility and dilate blood vessels work, but the patient's condition worsened?"

Wang Xiaomian still shook his head.

If I knew, I wouldn't have come to you, brother!

Outside the office, Xu Minjun's family members didn't believe Zhang Yi.

But when the doctors were in a meeting, they still secretly listened at the door.

Zhang Yi glanced at the door and waved to the family members:

"You can come in and listen if you want."

The family member named A Ling immediately walked in with her hands on her hips.

She was not afraid!

She wanted to listen carefully to how this young man treated her mother!

Seeing the family members sitting down, Zhang Yi continued:

"This means that this drug is not only useless, but will accelerate the deterioration of the disease.

Then we need to think carefully about under what circumstances, increasing myocardial contraction will make the patient's heart worse!

Here I want to tell you about an equation called the Bernoulli equation.

That is, the mechanical energy of the fluid is conserved, kinetic energy + gravitational potential energy + pressure potential energy = constant.

The most famous inference is that when the flow is constant, the flow rate is large and the pressure is small.

So for the patient Xu Minjun, my diagnosis is: obstructive hypertrophic cardiomyopathy, but her obstruction is not an ordinary fixed aortic stenosis obstruction!

It is a dynamic obstruction!"

Wang Xiaomian: "??? Dynamic...dynamic obstructive heart disease?!"

"That's right!"

Zhang Yi nodded.

The other doctors around him opened their mouths in surprise!

Dynamic obstructive heart disease? !

Some doctors said they had never heard of it!

Lu Gao and Liu Zifei looked at each other in bewilderment!

Wow!

There is such a disease? !

Suddenly, Wang Xiaomian stood up and said excitedly:

"Yes! Dynamic obstruction! Yes, yes! That's it!

I remember that I accidentally read an academic paper on heart disease on the Internet ten years ago!

It talked about this!

However, this disease is very rare, and some patients do have this disease.

However, since it was not found in the early stage, the doctor directly used anti-heart failure drugs such as dopamine and digitalis.

As a result, the patient didn't hold on in the end, and died before everyone could react!

Oh my! I just understand now! This patient is very likely to have obstructive hypertrophic cardiomyopathy!"

Wang Xiaomian said excitedly while pulling Zhang Yi's arm.

Zhang Yi looked up and looked at the confused and bewildered expressions of the people around him.

Zhang Yi pulled out a piece of white paper from the printer paper next to him.

Then he took out a pen from his bag and drew two cross-sections of the heart for everyone on the spot.

One is a normal heart blood flow diagram.

One is a dynamic obstruction blood flow diagram.

Zhang Yi raised the drawing in his hand and said:

"Because the patient's ventricular wall is thickened, although the examination results show that the main blood vessels are not narrowed.

But you must not ignore the thickening point.

This patient's thickening is 38mm, and normal myocardium is considered hypertrophic if it exceeds 35mm.

Look at the distance between the ventricular wall and the aortic outflow, it is very close.

Will the thickening of the ventricular wall affect the outflow of the aorta?

The answer is yes, it will definitely.

Except for the family members, everyone present is a medical student and can understand my picture.

Pay attention, the aorta and the aorta

There is no stenosis in the valves, but because of the thickening of the ventricular wall, it will cause a certain amount of compression on the outflow.

Then the outflow channel will become smaller than the inflow of the mitral valve.

At this time, the inference of the Bernoulli equation comes out.

The height of the heart remains unchanged, and the gravitational potential energy will not change, but the outflow is relatively narrow.

When blood flows out of a relatively narrow channel, the flow rate will increase and the kinetic energy will increase.

But the fluid has its mechanical energy conservation.

The gravitational potential energy remains unchanged, and the kinetic energy increases. How can we keep the constant constant?

The only way is to reduce the pressure of the outflow channel.

(Kinetic energy + gravitational potential energy + pressure potential energy = constant)

If the outflow pressure is small, will the pressure of the mitral valve inflow channel be relatively large?

So the blood flow will produce a pressure difference.

This pressure difference causes the mitral valve to be sucked to the outflow of the aorta due to the pressure difference when it opens.

Once the mitral valve blocks the outflow, the situation will be more serious.

Everyone should know what pressure difference is.

For example, you can often see yellow waiting lines marked on the ground at train stations and movable property stations.

This is the pressure difference line.

Once you cross the pressure difference line, in front of a fast-moving train, the strong pressure difference will directly sweep away people or objects standing still.

Very dangerous!

So the mitral valve is not deliberately trying to block the aortic outflow.

It is because the pressure difference makes it unable to control itself.

Therefore, dynamic obstruction is different from those fixed obstructions of aortic stenosis.

The heart must not be allowed to beat too fast, the faster the pressure difference will be.

The greater the pressure difference, the mitral valve will directly block the outflow.

If the outflow is blocked, the aorta will have no blood supply to the whole body.

At that time, the patient will have edema all over the body, the blood flow dynamics will collapse, and people will easily die suddenly.

Therefore, the treatment plan for dynamic obstruction is to never use drugs that increase ventricular contractility.

Digitalis dopamine and other drugs must not be used!

We should do the opposite and treat it with drugs that reduce ventricular contractility.

That is, drugs such as beta blockers and non-dihydropyridine calcium channel blockers.

These drugs can reduce ventricular contractility.

With less contractility, the outflow velocity will slow down, and the pressure difference will also decrease.

Once the pressure difference is small, will the mitral valve not be sucked over to block the outflow?

Then will the patient's symptoms be alleviated? "

Zhang Yi's "class" is over.

But the whole office became silent!

Everyone looked at Zhang Yi with shock, admiration or disbelief...