The Oxygen Experiment

Although Mozy was 9 days late, he was born with a condition called respiratory insufficiency, which is more common in premature babies than those who are full term (and late). He even spent a night in the NICU to stabilize the condition. Its causes range from high altitude (thin air) to insufficient surfactant, or inefficient surfactant conversion at birth (when the lungs switch from breathing amniotic fluid to breathing air. That first cry plays a huge role in the conversion, helping lungs expand and fill with air). Whatever the case, he needed oxygen for 3 weeks, a slow 1/16mLH administered by nasal tube.

At 2 weeks old, we did the first overnight test to see if the lungs had matured more. Basically the pediatrician puts in an order with a home oxygen supply company, who loan you a pulse oximeter. You are supposed to monitor over at least a 6-hour period with the subject off oxygen, then send in results. The pediatrician usually calls within a couple of days with her observations. Even though I thought the numbers looked good, we were crushed when the pediatrician told us Mozy's numbers were to borderline to get him off the oxygen. For the next test a week later, I really wanted to see the numbers myself, and ensure that the oxygen machine we had at home was working.

At 3 weeks old, we did the second test. This time, I sat for the first three hours (between feedings) and recorded the numbers every minute (180 readings). Either I'm a bad parent for conducting experiments on my kid, or I miss the lab environment at university, or I'm just a nerd. Either way, the first 60 readings were while he was on oxygen so I could see how efficiently his lungs were performing: 98% saturation on average. So the darn oxygen machine was doing its job; I couldn't blame that if this test failed.

Without oxygen, I took 120 readings and plotted them thus:

As can be seen, he had mostly 95% saturation (median and average are both 95%) over that period. The normal range is 94% and above, according to NIH. In fact, he was above the threshold 88% of the time! I would have been so surprised, or even reject the results, had the pediatrician called and said the second test was a failure too. I'd show her my numbers and demand to see hers. My first 3 hours would have had to match her set for me to accept her conclusion (which would mean that Mozy slowly deteriorates in lung function the longer he is off oxygen). But thank God the pediatrician confirmed our expectation: Mozy did not need to be on oxygen anymore, everything looked great.

You can't imagine the freedom: no more noisy oxygen maker or a slacking a line from it wherever the baby is taken. No more oxygen canisters when we travel, and irritation on his upper lip from the oxygen tube. He had grown strong enough to rip the tube off his face, and it worried us how hazardous that could be. Better sleep!