Thursday, July 12, 2007

My time in the MICU

This past week I spent most of my time in the Medical Intensive Care Unit (MICU). While I was there, I got to do rounds for the first time (everywhere I have been thus far don't generally do rounds), which was interesting. I got to hear residents, medical students and attendings discuss patients and treatment plans, and was amazed at how much they can have memorized at any given time.
While there I also got to here about how a diabetic who comes into ER for volume depletion and hyperglycemia (to much sugar in the blood) can be brought from the brink of death (seriously) to outpatient status in less than a day. This seemed to make the attending very happy/excited. He explained that even though one would think that giving insulin would be the first thing to do (to push the sugar into the cells), since the patient was volume depleted, and the volume depletion is part of the source of the hyperglycimia (remember reduced volume=increased concentration), it would be one of the worst things you do (since the sugar will take water with it as the sugar moves into the cells, making the volume depletion worse/fatal). He said first you stabilize the airways and then give saline (to up the circulatory volume), and THEN you give insulin. BAM! And the guy can go home the next day.

Also while I was there I got to witness an interesting procedure that serves as the solution to a problem I had only ever seen in radiology CT images prior to that day. The problem: plueral effusions (liquid in the chest cavity). The solution: Poke a hole and drain it (simple, no?). See, normally the lungs fill the chest cavity with the surface of the lung literally attached to the surface of the thoracic cavity (left image, However sometimes fluid builds up in the cavity and pushes on the lung which can make it difficult to breathe. Especially when the amount approaches a full litre. The schematic (bottom left image, and how one looks in a CT scan can be seen (bottom right image, can be seen below. But basically, the solution is literally poke a hole and suction out the fluid by hand (kind of like a bilge pump).

Finally, I heard an interesting talk on two case studies from patients in the MICU. One of the patients has cystic fibrosis, and the discussion went on to discuss the epidemiology of the disease. Since I want to possibly go into public policy after getting my degree, epidemiology is an interesting topic for me. Briefly, cystic fibrosis is a genetic (autosomal recessive) disease that leads to progressive disability and eventually death. The genetic mutation effects the creation of chloride channels, effectively creating channels with a lower conductance. This
The interesting part of the discussion is when the attending leading the talk began discussing how genotypes persist for reasons. An example of this logic is how sickle cell anemia primarly affects populations at risk for malaria and the former grants a certain level of resistance to the later. So the attending asked

"What disease's effects would be reduced by the reduction of chloride channel conductance?"
Here are the hints:
  1. Third World Disease
  2. Remember: Chloride channel conductance reduction => decreased fluid loss
  3. GI Tract
Answer: Cholera! If you can't lose the ions, you can't lose the water, and therefore you can't dehydrate.

Now that was a cool excercise in logic.

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