Thursday, June 21, 2007


The 620 gram baby was born at 24 and one-seventh weeks gestation, based on a 17 week ultrasound. Her temperature on admission was a little low, 35.9 degrees. We gave her 2.5 cc's of surfactant and placed her on a ventilator with settings of a rate of 46, peak inspiratory pressure of 20, Peep of 4, FiO2 of .60, and an inspiratory time of 0.3 seconds. Her first blood gas had a pH of 7.26, pCO2 of 50, and pO2 of 56. Bingo.

We also started her on ampicillin 100 mg/kg/day and gentamicin 5 mg/kg every 48 hours. We started her fluids at 120 cc/kg/day but by age 24 hours her sodium was 153, potassium 5.4, chloride 118, and bicarbonate18, and the fluids were increased to 170 cc/kg/day. That made her blood sugar go up, though, to 278 so we started an insulin drip at .06 units/kg/hour or 0.3 cc's per hour. When her sodium rose to 156 we had to increase fluids further to 200 cc/kg/day. On the second day we started feeds at 1 cc every 3 hours or 13 cc/kg/day.

The above numbers are not from a real patient but rather a fictional composite of many patients like this. The number of numbers used in neonatology can be daunting. Some medical students and residents rotating through have trouble handling it.

Personally, though, I love the numbers, and they are one reason I went into neonatology. I love the way we can manipulate the baby's sodium levels by the amount of water we give him and the blood gases by changing the ventilator settings. Remember the story problems you used to have to do in elementary school math? Well, I loved those things, and neonatology is like the ultimate story problem.

The challenge, of course, is remembering that these babies are not just a mass of numbers but real human beings. We can get so caught up in adjusting the fluids in a tiny baby like this that it seems almost as much like a physiology experiment as it is care for a live baby. Sometimes I like to go look at the babies, see their fingers and toes and ears. I like to see the moms visiting them and letting the baby's fingers wrap around her finger. I like the numbers because they are part of a human baby, and managing them helps them become larger and better humans.


Anonymous Karen in KC said...

I think making the connection between the numbers and the tiny human being associated with them is what makes a good doctor.

9:37 AM  
Anonymous Anonymous said...

I had some friends recently whose newborn was readmitted to the PICU at 3-4 days old with dehydration and hypernatremia (I think--based upon their description of things). Naturally the kid was worked up for sepsis as labs q 4 hrs. Baby's sodium kept coming back elevated no matter what they did until somebody finally figured out that the abx, mixed with normal saline, were causing the roller-coaster values.
Glad somebody likes those numbers! They're dicey in such little ones!

Olga, RN

10:19 PM  
Blogger Betsy said...

My comment has nothing to do with today's post. I just happened to check some of my links and found out you're back! I'm glad to see it. I've never commented on your blog before but I have read it for a while (since you first posted on the preemie list, I think) and I really enjoy it. The first line of your first post back (the bearded lady) is one of the best lines I've read in a long time.

10:32 PM  
Blogger JuliAnn said...

ND... I think it is so scary (and cereal) that I actually understood all of those numbers and correlations, as I remembered going through all of that with my twins! As I was reading it, I slipped back into our first NICU for the first few dreadful days... If only you added 10% NO...

10:42 PM  
Blogger daedalus2u said...

If you like numbers, then you should like the concept of looking at heart beat inter-interval variability. In healthy adults, the interval between heart beats varies chaotically. As the adult gets sicker and sicker, the fractal dimension of the chaos gets smaller and smaller. That is the interval gets more and more regular.

I think that would give a very good indication of how well the baby was doing. Not a substitute for any of the other measurements, but something to integrate them all together. I think that would be an objective measure that you could use to regulate things that now are somewhat arbitrary, such as O2 sat.

10:44 PM  
Anonymous Anonymous said...

Cereal is something you eat. I think you were going for "surreal."

--The Grammar Police

8:25 AM  
Anonymous Dianne said...

The above numbers are not from a real patient but rather a fictional composite of many patients like this.

I'm relieved. I don't like the looks of that anion gap...of course, most likely you see worse regularly and are unimpressed.

11:26 AM  
Anonymous ami said...

I love numbers too. Numbers can describe almost anything.

One could say that they can't describe what it is to be humans. But also, being able to understand numbers and use them to symbolize things is one of those peculiar things that makes us human.

And that just gave me a great idea for a story. Thanks!

12:34 PM  
Blogger Dream Mom said...

I love numbers too and especially data analysis. As far as Dear Son, I can usually tell when things aren’t right and when I need to get him some help. I try to correlate his behavior changes to the numbers, when I see them. For example, at home, I know his normal pattern of breathing and also what’s abnormal. When he begins to breathe pretty hard, usually at a breath every second or less, I begin to look for other changes like a fever, his overall appearance or how hard he’s working. When I get to the ER, I also know that this heavy breathing is typically associated with low oxygen saturation levels around 87-89 or so.

It’s also helpful to learn the numbers so I can provide good information. For example, when Dear Son got to the ER with his pneumonia, I was very concerned about the fever lowering his seizure threshold. I gave him his morning seizure meds in the ER and they took seizure levels shortly thereafter. Later in the day, we were transferred to Big Academic Medical Center. They reviewed the levels and saw one was high and wanted to withhold the medication. I explained that it wasn’t a good idea, since it was done after his morning meds and the level would be high. I also explained that he’s a hyper-utilizer (sp?) of his meds and the level was fine. I stated that he gets trough levels of the medication and they were done six weeks ago and were fine. They counter argued that the medication had a half life. My concern was that we had a fever we couldn’t control and fevers lower the seizure threshold. If I skip a med, he might have more seizures and we have a worse problem than just the pneumonia since Dear Son can go south pretty fast. I stated that Peds needed to consult Neuro Doc prior to making any changes of his meds. They asked me to withhold that med, did a trough level, the level was fine and I gave him his med. Mother was right. I know my child.

Bottom line is that numbers are important but like you said, they don’t tell the whole picture.

3:58 PM  
Blogger neonataldoc said...

Thanks, everyone. Dream mom, you're right, we shouldn't pooh pooh the concerns of a mother, especially the mother of a special needs child.

Daedalus2u, I've seen some abstracts at the research meetings looking at variability in heart rates - or the lack of it - in predicting sepsis in babies. It's pretty interesting stuff.

9:22 PM  
Blogger fancypantsnancy said...

well i always knew that there is a place in society for math nerds!

12:32 AM  
Blogger sexy said...







1:37 AM  

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