Why Engineers don't Practice Medicine

2/19/07 Day 40

We have the day off from MDA and much of our time is going to be consumed by getting ready for Ann to go back into the hospital tomorrow or generally cleaning up. Not very exciting. So I have decided to make today's blog entry a bit more on the technical side. The Doctor's and Nurses at MDA all tease me for being an Engineer, but at least people don't hire Engineer's for "opinions" on wheather a building will stand up or a machine will work. Like Jackie Mason "I kid! I kid! You sumtz!"

This is a graph of Ann's cumulative WBC counts from the start of this event to her last blood test. So what we are really looking at is the rate of growth of the WBCs. Up until the 1st round of chemo all of the WBCs are cancerous so that portion of the curve represents the uncontrolled rate of growth of the leukemic cells. Everything after the 1st round of chemo is for the most part healthy WBCs.

What is interesting is the time period between the end of each round of chemo and the start of the recovery of Ann's WBC count. The time period between the 1st round the the start of recovery of healthy cells was 9 days. After the second round that number dropped to 5 days. This combined with our Doctor wanting to get Ann in early by a couple of day for round 3 indicates to me that Ann is presumptively doing well. At least as far as her recover from each round of chemo.

As I mentioned in another post we have meet people in the leukemia clinic who have had to have their treatments delayed because they got infections. Precisely because they couldn't get their WBC count to recover quickly enough. The added time between chemotherapy rounds allows more chance for secondary infection and gives the cancer breathing room.

The next graph is of Ann's cumulative RBC count from the point at which she entered MDA. As you can see from the graph the day she entered MDA she had no detectable RBCs (zero). The rate of growth of her RBCs from the start of round 1 is linear and it mainly due to the constant infusions she was receiving at the time. This generates a steep trend that is marked on the graph.

After round 1 was over the constant infusions of RBC units ended and the linear trend of RBC production dropped to the second linear trend line on the graph. Ann has had one or two RBC units transfused over this period but nothing as drastic as the first few nights in the hospital. Further the trend suggests that Ann is producing RBCs at a more or less steady pace, even factoring the effect of the chemo from round 2. Her overall RBC counts are still under what a adult female of her age should be by as much as approximately 15% but the growth curve trend is steady and positive.

The last graph is Ann cumulative Platelet count. When Ann entered MDA she had a Platelet count of 38 K/uL and they immediately began transfusions (along with RBC units). In fact the amount of Platelets in Ann's blood has been a on going concern by the the staff here because it dictates when she can have LPs. If Ann's Platelet count drops below 14 k/uL then she automatically goes to the transfusion unit.

Overall this graph is less clear, it indicates that Ann is making Platelets in the absence of chemo and transfusions. But they are also being consumed just as quickly. I would hypothesize that the effect of the chemo and damage to the body (bruising, ect) consumes large numbers of Platelets at a rate faster than Ann's body is able to produce them at this moment. And Platelets may just be particularly suspetable to chemo drugs.

So there you have it, probably a prime reason people don't go to Mechanical Engineer's for medical analysis. Still I am pleased that Ann's condition has rebounded quickly after each of the rounds of chemo she has had so far (apart from the Cytarabine side effect) and I dearly hope it continues to be that way. If that is any measure of success then Ann looks like she is doing better that some people we met who started treatment at the same time she did.