Tuesday, June 12, 2007

Oxygen

Whoever said you can't get too much of a good thing didn't know about neonates and oxygen. We try to keep a premature baby's oxygen saturation - the level of oxygen in their blood - in a certain range, 88% to 94% for example, because not only can too little oxygen be harmful, but also too much can be harmful, especially to the eyes and lungs. We continuously measure the oxygen saturation with a monitor and adjust the amount of oxygen we give the baby based on what the monitor tells us. If the oxygen saturation goes too high or low, an alarm on the monitor goes off to let us know so we can adjust the amount of oxygen we're giving.

Over the past several years we have learned that it's better to keep the baby's oxygen level at a lower range than previously done. We used to keep their oxygen saturations at, say, 92 to 97%, whereas now they might be kept at 88 to 94 % or maybe 85 to 92%, the level varying from NICU to NICU.

There's one problem, though. It can be tough to get the people who adjust the amount of oxygen given, primarily the nurses, to accept that too much oxygen is bad for a baby and that it really is important to keep the oxygen level from going too high. It's pretty easy to get a nurse to increase the amount of oxygen given when a baby's oxygen saturation falls to, say, 80%, but it seems harder to get them to decrease the amount of oxygen given when the saturation is, say, 98%. It's understandable; all our life we're taught how we need enough oxygen. The too much oxygen thing almost goes against our nature.

One way we try to keep the oxygen levels lower is by setting lower the level at which the monitor alarms. If we want to keep the oxygen saturation level below 92%, we would probably set the monitor so it alarms when the saturation goes above 94%. Here, too, we have a problem sometimes with getting the nurses to set the alarm at a lower level that we used to, and this bothers me some. Why do we have trouble getting some of the nursing staff to do this?

It's not because it's not explained to them. A few years ago when we decreased our suggested oxygen saturation range and monitor alarm limits we gave inservices to the nurses explaining why we were doing so, showing them the research that proved it was beneficial. Some nurses caught right on and were very conscientious in adjusting the amount of oxygen given and the alarm limits, but others didn't seem to take it too seriously. My experience is not unique, because an article in the latest Pediatrics shows that in the NICU studied the upper monitor alarm limit was set correctly only 23% of the time, with it usually being set too high.

Why, I wonder, is change so hard for some people? Change can be hard for me, too, but when it's explained to me why a change will be better, I change. Also, if a standing order or policy changes, I follow the new standing order or policy. So why don't some of the nurses follow the new policy of setting the oxygen alarm limits lower? It can drive me a little batty at times.

Please don't take this as a broadside against nurses. Some of them change admirably and want to keep up with the latest information. Also, nurses are hardly the only people who have trouble changing. I know there are some doctors who are set in their ways or are just not conscientious about making certain important changes. But still, it bugs me.

A few years ago I gave one of the inservices explaining why we now wanted to keep the oxygen levels in a baby's blood lower. One of the nurses dozed through most of my presentation, which was short and, hey, not that boring. When my inservice was done, I said,"Okay, now, let's keep those oxygen saturations in the normal range."

The nurse sniffed sarcastically. "Oh, is that what we have to do now?" like it was a totally ridiculously thing to do and a waste of her time. I wanted to kick her behind out the door. We're taking care of babies here, not making widgets, so when a change improves their care, doggone it, we'd better change.

36 Comments:

Anonymous Anonymous said...

I know this is off topic, but what are the survival chances for these babies known as the Morrison 6. Born at the end of 22wks gestation and weighing between under 11oz. to 1.3 pounds?(http://www.kare11.com/news/ts_article.aspx?storyid=257270)
From a purely medical standpoint, is there much hope? Can a baby weighing less than 11 oz. (even one a week or two more mature) ever survive?

I feel for these parents. They have had to make some difficult decisions. Taking fertility meds/turning down selective reduction/using extensive measures to resusitate and support life (just an educated guess on that one), these are all choices that I am thankful I have never had to make.

7:02 PM  
Anonymous Anonymous said...

Amen about the oxygen! My child has severe lung disease and has limits of 85 to 98 on the monitor, but if the monitor frequently dips below the limits, anyone (including RT or nursing) comes in and cranks the O2 and leaves it, sometimes in the 70% range. I watched one nurse leave the FIO2 at 94% and then sit down and read a book. I had to go to the doc to lower it. It's not just a mindset. If this was their child, these things would NEVER happen!

7:19 PM  
Blogger Judy said...

It's not ALL the nurses. Maybe at your hospital it is, but truly it isn't all the nurses at all the hospitals.

I occasionally find a monitor alarm setting out of range, but it's not particularly common where I work. That may be because the nurse practitioners are quite militant about it and have been known to write incident reports when it happens. Same with some of the staff nurses.

While it's reasonable to expect that the oxygen will be adjusted if the PO2 stays out of range for more than a couple of minutes, it's not reasonable to tweak it the second it goes out of range. You get into a yo-yo pattern with some kids where the swings get wider and wider. Same goes for readings at the lower end of the scale in those kids, though. Sometimes you have to give things a minute to settle.

Turn it up and read a book? I'm appalled.

7:36 PM  
Blogger JuliAnn said...

Today marks the anniversary of my son's discharge from the NICU... 164 days after birth!

Your post rings so near and dear to my heart, as both of my children ended up needing laser for ROP. The nurses at our NICUs (because we occupied three of them during their stays) were actually pretty good about preaching this policy, but not very good about paying attention to the alarms... beep, beep, beep, beeeeeep until we finally broke... One day I timed Livi's high sat alarm... twenty seven minutes later, I decided to intervene.

The excuse we kept getting, and I wonder what your comments are on this, you can't "chase" babies. We had older nurses who would patiently watch the babies, but would not decrease or increase 02 unless alarms continued for hours... silent buttons... Then we had some younger nurses who would turn it up and down minute by minute as the alarms sounded. I tend to think somewhere in the middle was better for our children, but I never really found a consensus about this...

Also, I am wondering what the parameters are after discharge? When we brought T home on .75L 02, we were told to wean above 93% by our Neonatologist... our home nurse however, freaked out by this. I found out about two months later that the pulmonologist didn't want him lower than 92%. Any thoughts?

8:03 PM  
Blogger Julia said...

Drives me nuts as well! Especially when for example a kid has been doing poorly and is on 100% FiO2 but their nurse won't turn them down....Lets just screw them up some more shall we?

9:02 PM  
Blogger Emily said...

Grrrrr.... This is something that really peeved me about the bigger NICU where Noah stayed for the last 4 months of his NICU time. For the first 2 months the nurses were very careful to limit the amount of O2, but when we moved to the bigger (supposedly better) NICU there was rarely any alarm set for satting too high. Noah typically required between 25-35% O2, but would desat bigtime if he was messed with. The nurses would turn him up to 100% if they were messing with him and the forget to turn it down. When I questioned one nurse about it I was actually told that I shouldn't concern myself with looking at the medical equipment. Yeah, right.

9:33 PM  
Anonymous Anonymous said...

Kicking people out the door who won't do what is in the best interest of the patients based on the latest medical information and after being officially instructed...shouldn't this kicking be done as a matter of course? This is why I sat at my baby's bedside 16 hours a day and called every hour I wasn't there and combed the Internet for the latest publications in neonatology. Unfortunately I probably took up too much time questioning things, but apparently my gut feeling that I could not completely trust the medical staff to do the right things was accurate.

10:26 PM  
Blogger Jacqui said...

I swear the nurses and docs in special care never communicated during our stay. The docs would be telling us that there is no way our child would be going home on oxygen while the head nurse would be telling me to put in the paperwork for the home oxygen. In the long run, with the doctors backing I weaned Moo off oxygen. But the nurses were almost mean to me for insisting that he not stay on oxygen for longer than what was absolutely necessary. And as soon as I left special care each day, the nurses would come along and turn the oxygen back on and up. It was an incredibly frustrating time for us.

Thank you for the post.

10:31 PM  
Blogger Special Survivors said...

I wish this research had been available when my son was in the NICU. He has CLD/BPD and had two eye surgeries for ROP, both conditions due to his long term intubation.

Thanks for the info.

12:11 AM  
Anonymous Anonymous said...

I often find the ones resistant to change seem to be the old militant types! They seem to say what a load of bother over nothing and up the limits. It can be especially worse at night, so often when you come on an early shift you will find upper limits on an older CLD baby at 98/99/100% - this leads me to wonder if it is laziness?!

RL

4:15 AM  
Blogger Nurse M said...

This comment has been removed by the author.

5:38 AM  
Blogger Nurse M said...

I was not offended by your post and I thought it brought up a valid point but I am surprised by a lot of the comments, I have to admit.

As a nicu nurse.. honestly I have to admit that I think part of the reason we don't set the alarm limits to what they should be is.. well... the alarm. We have alarms limits in our unit that are approximately what you stated in your post and the majority of the time the alarm limits are set correctly.
I don't think you can make everyone happy to be honest. There are just SO many alarms that after awhile it gets easy to just tune them out, which is NOT a good thing (of course). It isn't on purpose but we can get desensitized. For some babies a lot of the time we leave the alarm limits as they should be in order to be able to wean fiO2 appropriately, however sometimes there are babies just need the amount of oxygen they have. They will sat 98-98-98, so you wean even as much as 2% and they bottom out. Which is worse?
In those cases the high alarm may get turned off because at this point you just can't wean the kid. It isn't laziness but it is knowing your patient. In these cases you often may wait 15 minutes to see if the baby is truly ready to be weaned. I can't speak for every nurse but I know that in my unit at least we are very vigilent of the fio2 regardless of the monitor and often we wean the oxygen by the frequent blood gases that tell us the paO2 (oxygen concentration) in the blood... not just what the monitor says. That is one scenario which may not be understood to parents who may not necessarily see or understand the blood gas results.
The other situation is what I mentioned in the first sentence... there are just too many alarms. I have gotten to the point that I only really want to hear alarms that I need to hear (which are the bad ones). Example: you are with another baby and look up across the room and see that often babies will do that 99-ding ding. Ding Ding...then all of a sudden, "can someone get that baby- he is sating in the 50's." "What, he was just at 99?" The dings are the same for a sat of 99 and a sat of 50, so eventually when you tune out the alarm because the baby is high satting.... you miss the important one that the baby seriously desating.
I can't speak for other hospitals, but at our hospital the alarm limits are part of the safety check with each shift change. It isn't a perfect system but we do our best. We try to identify the priorities. We try to keep parents happy who complain of all the alarms. We try to stay vigilent and be aware of when things are really wrong and the less alarms the better.
That being said.. turning a baby up to 100% and leaving him, as well as the alarm limit off it inappropriate and dangerous. We aren't perfect but we are trying to do the best we can.

5:42 AM  
Anonymous Anonymous said...

My daughter and I both had to stay in the hospital a few extra days after she was born. Thankfully, she was never in NICU but still wasn't well enough to go home.

My daughter was at my bedside 24/7 and her doctors gave me very specific instructions relating to her care. My husband and I became increasingly frustrated at the nurses who would browbeat us for following her doctors' orders. We would respond, "Well, Dr. X told us to do this, ...its in her chart." It never mattered, the nurses thought they were Rambo and that a doctor's orders was a mere suggestion at best.

I was appalled at the level of disrespect these nurses had for our doctors, residents, and those poor, abused, medical students. I discussed my concerns with our Attending, especially about the nurses trying to undo his orders. He was very angry and addressed the problem with his nurses. After that episode, the nurses became compliant with his orders but were ready to club me like a baby seal.

I don't mean any disrespect towards nurses, but there is still a big difference between a RN and MD. These particular nurses didn't seem to understand that and my daughter and I received very poor care as a result.

Julie

8:24 AM  
Anonymous Christina said...

I wondered about nurse staffing in your hospital after reading your post. Are there lots of travelers/registry/floats/per diem nurses who weren't there for your presentations and who don't know the whole rationale for keeping the O2 levels low? Although experienced staff members should be advising them each shift, I can see how this piece of info could get lost in the 2 minute orientation that most floats get to a unit. Obviously there are the old timers who don't change easily, but un-informed nurses might be more of an issue than it appears. I know sometimes there will be an inservice on some new piece of equipment in my PICU offered multiple times over two days. Well if you don't work either of those days, (quite possible for many people who only work one or two days a week- none of us work more than three) you don't see the inservice. Then if there is no central communication system (eg, a good nurse manager who EFFECTIVELY communicates these changes in practice via email or some other way) then many nurses may just not be that aware.
Just a thought...
I'm sorry to read all the parents' comments here where they felt so antagonistic with their childrens' NICU nurses...

10:20 AM  
Blogger JuliAnn said...

Maybe I should point out that we love most of our NICU nurses... in fact we still make lunch dates with our primary nurse, and stop by to see the others as often as we can. But as a parent in the NICU, our opinion some how got disregarded more often than not. Everyone considered themselves more qualified and more experienced than us. The concept of parental instincts was relatively meaningless. I found this with the doctors, nurses, and RTs alike. Unfortunately though, the nurses are often the "go-betweens" as they have the most contact with parents. I think they take a lot of the flack for all of the frustrations involved in neonatal care.

12:06 PM  
Blogger daedalus2u said...

I couldn't agree more ND. One of the adverse effects of too much O2 is that it destroys NO. I think that is some of the things that leads to the instability of O2 saturation. At high O2, NO is destroyed, which causes vasoconstriction, which leads to reduced perfusion and hypoxia which leads to more superoxide and less NO. Superoxide can also cause nitric oxide synthase to become uncoupled, so it produces superoxide instead of NO.

The coupling of NO and superoxide is not well appreciated, and the interpretation of some experiments using nitric oxide synthase inhibitors are not always clear. There have been experiments that show an increase in the time for hyperbaric O2 to cause seizures when NOS inhibitors are given. The assumption is that this relates to less NO, but it could actually be due to less superoxide because NOS can produce both.

High O2 may be "ok" in the short term, but really bad in the long term.

One of the things that I am working on is how vascular spacing is regulated. I think that a lot of it has to do with NO levels between capillaries. The vasculature is well regulated, that is when there is not enough more is made, when there is too much, the excess is ablated. "Not enough" might be determined by low O2 level, but "too much" can't be determined by O2 level (because the upper O2 limit is set by air). I think the spacing is set by low NO. O2Hb is the source of O2, but also the sink of NO. NO and O2 have similar diffusion properties, if a cell is "diffusively close" to O2Hb, that will show up as a certain NO level.

In diabetic retinapathy, a common characteristic is "nicking", that is where vessels cross the diameter is decreased. Either vessels are sources of something that causes nicking, or are sinks of something that prevents it (or both). I suspect that "nicking" is also observed in preemies.

2:10 PM  
Anonymous Anonymous said...

To me it sounds like some nurses really don't believe that satting too high for awhile is something that would be a priority (eg, reducing alarms to keep parents happy would be a higher priority). But what ND has said is that the latest information shows that it IS a serious problem, albeit counterintuitive. A baby is not actually "fine" when he is hanging out at 97, 98, 99% and "in trouble" when he is at 50...is is in trouble in both situations. So I think the comments here have pretty much confirmed what ND is saying.

5:14 PM  
Blogger Ex Utero said...

Love is like oxygen... OXYGEN! You get too much it makes you high... Not enough and you're gonna die... gonna die. Love makes you high!

I think some NICU nurses must have that song stuck in their head, when they're twiddling with the flow meters.

10:21 PM  
Anonymous Anonymous said...

my problem with o2 orders is some of these very brittle bpd'ers get orders for o2 sats to be within 92-85% range they literally need 0.1 liter of o's via nasal cannula then they start alarming an spo2 of 94% and the second you try to wean them they dip down to 70% how much lower than 0.1 liters can you go? but then the neo's come in asking why the pt isn't on room air and weaned since there sats reflect 94%-92% all night. with 4 pt's you can't be expected to sit and give wiffs of o2 to 1 pt all night long to play the sat game. i wish some of the doc's would give a broader range for spo2 say 85-95%. I've heard more than once how we were making a former 25 weeker blind with o2. why the negitivity? it's very hard to keep some of these preemies in a tight sat range and to be forced to choose between sight and hypoxia is some times a hard call. namely since ABC is been drilled into our brains since the start of our medical education.

2:10 AM  
Blogger daedalus2u said...

I started thinking more about ROP and my suspicion it is more due to low NO than to high O2. I found some photos of ROP retina, and (to me), some of the morphology of vessels is characteristic of low NO. In particular the "tortuosity" that develops.

Tortuosity can only develop if the flow modifies the morphology and then the morphology modifies the flow. It is a feedback mechanism like the meandering of a stream. The stream erodes a bank in one direction and deposits sediments on the other bank leading to the migration of the stream. In a stream it is the erosion of the opposing bank by suspended sediments and the flow of water that causes the meander. What aspect of blood flow might do the same in blood vessels?

Blood is not homogeneous, it is composed of red blood cells (RBCs) and plasma. Red blood cells are denser than plasma, and so in an acceleration (a curved flow), the RBCs will tend to migrate to the outside of the flow, much like the sediment in a river is denser than the water. Do red blood cells "erode" blood vessels? Certainly not via a mechanical mechanism. Via contact? Probably not. Blood flow in blood vessels is at a fairly low Reynolds number, there is shear at the wall, and in large vessels the wall shear tends to keep the RBCs away from the vessel wall. In capillaries, the RBCs actually do contact the vessel and deform (one of the reasons sickle cell RBCs clog up capillaries because they are more rigid. If simple contact caused vessel wall regression, then small vessels would not be stable. Could the RBCs be a source of a diffusible signal? O2 does diffuse away from RBCs, but the O2 gradient (the change in O2 concentration vs. distance) is very small (virtually non-existent) at the vessel wall. Could the RBCs be a source of something else? What the vessel wall is going to "see" is the sum of this signal from all RBCs. If the fluid is "deep", that is has a depth greater than the diameter of a single RBC, it will act as a volume source, rather than as a point source. The gradient away from a volume source scales as the dimensions of the volume, not the dimensions of the individual point sources. For the flow to modify the geometry of the vessels, the flow has to change some signal on a length scale smaller than the vessel.

How about the RBCs being a sink of something? RBCs are the sink for NO, with hemoglobin destroying NO at near diffusion limited kinetics. The extravascular space is hemoglobin free, so there would be very sharp gradients in NO lifetime between the inside and outside of a vessel. These gradients would be on the same length scale as the RBCs. So in a hairpin turn, NO levels would be lower on the outer edge because the RBC concentration is a little higher due to sedimentation. Shear does activate nitric oxide synthase in the vessel wall and does cause vasodilatation. A slight imbalance (due to low basal NO) might throw that balance off and cause deranged regulation.

Could disrupted NO be sufficient? NO is both anti-apoptotic and pro-apoptotic. NO does regulate vascular neogenesis through HIFa, VEGF, and other signaling cascades. High O2 does lower NO levels through production of superoxide.

If low NO in the retina is the problem, how can NO levels be increased? Not via breathing air. NO is rapidly destroyed by hemoglobin, so NO (as NO) can't be carried by the blood. The nasal passages do produce NO (a few hundred ppb (by volume)), so NO in breathing air at a certain level is a physiological treatment. Much higher levels in breathing air are non-physiologic and still would not deliver NO systemically.

How much would NO need to be increased? The main sensor for NO is soluble guanylyl cyclase, sGC. It is half maximally activated at about 20 nM/L. This is 0.6 ppb (by weight). The increase that would be needed is less than this, maybe even only a few nM/L. Certainly 20 nM/L would be way too much. How can such a small amount be precisely delivered to such a diverse area of tissues on such a small length scale (less than the diameter of blood vessels)? Not via any artificial mechanism. The only hope would be if there was some natural system that could deliver the proper amount of NO given the right substrates to start with.

I suspect that there are natural mechanisms to deliver NO like this. S-nitrosoalbumin is the most abundant S-nitrosothiol in blood, and can transnitrosate with other thiols to make low molecular weight S-nitrosothiols such as glutathione S-nitrosothiol (GSNO). My research is in how a biofilm of autotrophic ammonia oxidizing bacteria can generate NO and NOx on the skin, some of which is absorbed and generates long lived NOx species which do have systemic effects. I suspect that S-nitrosoalbumin is one of them.

9:00 AM  
Blogger 23wktwins'mommy said...

Here's my question. You are close to discharge and you know you'll be taking your BPDer home on O2 via a nasal cannula. Plus, they already had their ROP laser surgery. They are trying to get the cooridination down to feed, and trying to continuously gain weight. What is the point of weaning? While home your little one will be on 100% O2 anyway, and the weaning will be much slower through pulmonologist orders. So why set a high sat alarm a few weeks prior to discharge?
This question was asked by our primary nurse, and the order was written to turn off the high sat. We were going home on 100% O2 anyway, no need to keep weaning causing more calories to be spent, thereby taking away from weight gain.
What do you think about those kids who are going home on O2 anyway? Is it beneficial to wean before discharge?

10:37 AM  
Anonymous Anonymous said...

So basically in a lot of cases there just isn't enough staff allocated to giving proper medical care, so the choice is to decide between hypoxia and blindness!? What about devoting brainpower to figuring out the staffing issues? As a parent, If you are too busy to sit and adjust my baby's o2 level whiff-by-whiff, I'd gladly do it 24/7 for months on end for you to avoid both hypoxia and blindless; I'd glady mortgate my soul to PAY someone to do it if I couldn't be trusted or trained...figure out how to give me some OPTIONS instead of giving me YOUR woes about being overworked and understaffed. What if your baby was in the NICU, would your approach be acceptable to you?

12:15 PM  
Blogger Beverly said...

I have been a neonatal nurse for 39 years. We have also lowered our sat parameters to 84-95%. We have had inservices as to why this is so important. Since doing this our ROP has decreased considerably. Having said that, it is easy to be critical of those in charge of keeping those limits, but, have you ever tried to do it??? IT IS MIGHTY HARD TO DO...We nurses really love our babies and want to do the best for them. So, ease up and answer a few of those alarms too.

Love to read your blog. I can tell you are young. Keep writing and I will keep reading.

8:19 PM  
Blogger neonataldoc said...

First of all, let's not be too hard on the neonatal nurses, because for the most part, they do a great job. And there are lots of alarms going off, and it is hard to keep some kids in the prescribed oxygen saturation range.

Beverly: "I can tell you are young." Thanks so much! But I'm not really that young.

Re weaning the oxygen before discharge on oxygen: It needs to be individualized. Most kids will not have a continuous pulse oximeter at home, so at some point you choose an oxygen level and stay there.

Thanks to everyone else for your comments. Sorry I don't have time to respond to all of them!

10:51 PM  
Anonymous Anonymous said...

"so the choice is to decide between hypoxia and blindness!?" Welcome to the NICU, anon 12:15p.m., where most every dish is served with a side of rock or hard place.

My 27 weeker was one of those kids who refused to stay in his parameters. He wanted to be 96% period full stop no argument. Try to wean him *ever so slightly* and the chase was on. He could dip dramatically and stay there until his O2 got cranked back up. Then, slowly turn him down bit by bit but as soon as the poor nurses tried to take him below his magic 96, he'd punish them by forcing them to stand at his bedside with a bag at the ready. Finally, they shut his high alarm off, and I spent the rest of his stay watching that high number, gnawing my fingernails til he got the "all better" from the opthamologist.

There was a brief period before JACHO came around where the staff dutifully reset his high alarm to 94. He came this close to becoming a one on one assignment, before they decided to throw away the book again.

I despise an endlessly unattended alarm. I would silence my son's after a few seconds, any time I knew that's all the nurses would do themselves if they ever made it around to look at him. If they didn't want me touching the equipment they better be there to stop me. ;-) How on earth can all that noise be reconciled with a committment to "developmental care"? I'd like to see monitors with no noise at the bedside connected to a wearable beeper (an especially annoying vibrating one), that displays the reason for the alarm. After all, whose attention are we trying to get, the baby's or the nurse's?

My guy ran his poor nurses ragged, most of the time. I have even more empathy for what they went through now that he's two years old and still a handful.

Kassie

11:11 PM  
Blogger daedalus2u said...

Normally there are at least 3 blood chemistry signals that trigger breathing, low O2, high CO2 and high NOx. The last one is not well appreciated, and is the least well understood. Precisely what NOx species it is isn't clear, nor is how it is generated. It appears to be a S-nitrosothiol. There are not any known ways to pharmacologically adjust S-nitrosothiol levels and precisely what they should be under what circumstances is unknown. Normally the 3 signals are summed and breathing initiated. When one of the signals is missing, the other 2 need to get farther out of range before they will trigger taking a breath. I think this is what happens in obstructive sleep apnea. With insufficient NOx, the O2 and CO2 signals need to get farther out of range, (the hypoxia needs to get deeper), and then the control system overshoots, perhaps due to the time delay for blood to flow from the lungs to the neural centers that control breathing.

Normally the pattern of breathing is chaotic, that is the interval between each breath is slightly different and the differences don't follow a pattern. Highly regular or highly patterned breathing is quite pathological, as in Cheyne-Stokes breathing. The 3 known parameters that regulate breathing are non-linear and a system of coupled non-linear parameters does behave chaotically. As the system becomes simplified by removing some of the parameters, it behaves less chaotic (and is closer to failure).

Precisely what causes SIDS is unknown. There is some thought that it does have to do with a disruption of breathing regulation. Putting children on their back is largely protective, but by what mechanism is not clear. An interesting symptom observed in some cases is profuse sweating. When I hear of profuse sweating associated with any disorder, I (compulsively) start thinking of NO and nitrite from a biofilm of "my" bacteria. I would expect that such NO and nitrite would increase basal NOx levels, and would improve the regulation of breathing via the NOx mechanism.

Another parameter that is known to be chaotic is heart rate. The interval between heart beats also varies chaotically. Interestingly, that chaos is disrupted in heart disease and also in sleep disordered breathing such as sleep apnea. I suspect that disruption is due to low NOx status.

I would suspect that the degree of chaos in a preemies heart rate would be a measure of how well they are doing. I would speculate that the "best" O2 level to try to reach would be that level which maximizes the chaotic behavior in their heart rate. That more and less O2 would reduce that chaos and would be less beneficial. Measuring the chaotic nature of heart rate would be completely non-invasive and a display of that chaotic nature for the past several hour would be a good indication (I would speculate) of how they are doing.

8:07 AM  
Anonymous Anonymous said...

"Anonymous said...
So basically in a lot of cases there just isn't enough staff allocated to giving proper medical care, so the choice is to decide between hypoxia and blindness!? What about devoting brainpower to figuring out the staffing issues? As a parent, If you are too busy to sit and adjust my baby's o2 level whiff-by-whiff, I'd gladly do it 24/7 for months on end for you to avoid both hypoxia and blindless; I'd glady mortgate my soul to PAY someone to do it if I couldn't be trusted or trained...figure out how to give me some OPTIONS instead of giving me YOUR woes about being overworked and understaffed. What if your baby was in the NICU, would your approach be acceptable to you?

12:15 PM "

YOUR option is to go to school and become a nurse...that's the only way to solve the nursing shortage and staffing issues...to have enough nurses to go around. If my baby was in NICU, I'd be there as often as possible. If my mom was in ICU, same thing. And for the record, being blind is better than being brain damaged...sorry, if this was mean, but I get so angry when people constantly attack nurses...try working a couple shifts for (or with us) and then see if you can still attack us. Because we are only human, and sadly there are limits to what humans can do.

10:04 AM  
Anonymous Anonymous said...

I feel so relieved now. My daughter's sats were usually in the early 90s, sometimes dipping to mid 80s. I looked at other babies' monitors to see 98-100% and freaked out.
Once out of NICU and into the SPecial care nursery, her Paed turned off her pulse oximeter and told me to just look at the baby and she was fine.
Home with no O2.
SHe did have ROP stage 2, but it self-resolved.
(27 weeker)
Turns out, the lower O2 may be better. :)

6:41 AM  
Blogger michele said...

Appropriate saturation levels are sure a hot topic, as evidenced by this discussion! I am sad to see all the criticism of the staff, particuarly the nurses. Surely, no one is perfect, but much credit is due to them. We are all striving to reduce chronic lung disease in our babies. The bounds we have made over the years could not have happened without the nursing staff actually giving the care. Thank goodness we have dedicated, professional nurses taking care of our most fragile babes.

6:44 AM  
Anonymous Anonymous said...

Hello,
I happened to stumble upon this blog site and the entry "Oxygen" by accident. I am a neonatal fellow doing a QI project re: hyperoxygenating infants and different ways to monitor nursing compliance. I feel for you all out there. We use the Masimo pulse oximeters which have a very unique feature that we think will really benefit units and oxygen monitoring. One of my abstracts "Monitoring Compliance and Preventing Hyperoxia in Premature Infants" will be featured at this years AAP meeting in Oct. If you want more info, you can email me at dsaesim@gmail.com Thanks

10:34 PM  
Anonymous mof3darlings said...

Nothing great about brain damage or blindness not being able to see the world around you. Hoping all babies are blessed and can avoid both disabilties!

2:22 AM  
Anonymous Anonymous said...

Very nice discussion of an important topic. Obviously maintaining oxygen saturations within a prescribed target range is very difficult in sick preemies. The best rates of target range achievement I have seen documented are about 60% (with a dedicated 1:1 clinical research RN managing the inspired oxygen), and by far the majority of time outside the target range is on the high side. For whatever reason, it is very hard to prevent hyperoxia in these babies. As far as I can tell, it is not clear whether the duration of hyperoxia or the hypoxia/hyperoxia swings are the greater risk factor for severe ROP. Finding practical clinical management strategies which will reduce both seems to be the goal. This may mean slightly different strategies in different NICUs. However, improved staff awareness and education, and improved RN:pt ratios likely have a role. It would be interesting to hear other ideas about how target range achievement could be improved, realistically, in a complex NICU environment.

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8:28 AM  
Anonymous Anonymous said...

In the NICU I work in, every year the ROP protocol has to be reviewed by all staff: MD,NNP,RN and RT. And a contract is signed stating you will abide by the protocol. Sat parameter cards are placed on every oximeter if a baby is on any device which o2 an be delivered. ROP, CLD have sharply decreased in the unit. At the end of the day..education is the key

4:05 PM  

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