Monday, June 30, 2008

How premature does a baby have to be to have trouble breathing?

Any baby can have trouble breathing after birth, regardless of prematurity or size, but breathing problems are much more common in babies who are very early, very small and underdeveloped, or very large. Some common reasons for respiratory distress syndrome (breathing trouble requiring oxygen or other support) in newborns include:




  • Prematurity - lungs are underdeveloped. Typical pregnancies last 38-42 weeks gestation (how long the baby is cooking from the mother's last menstrual period). Respiratory distress syndrome is generally mild to moderate from 34-37 weeks in healthy babies and becomes increasingly severe if the baby comes earlier. Babies less than 28 weeks very often require special medication delivered right into their lungs call Surfactant, to help keep their lungs from collapsing between breaths.
  • Infection - infection in the mother can be passed to the baby. Babies who have respiratory distress that lasts more than a few hours or is severe at or shortly after birth are generally screened for infection (also known as sepsis) and given 48 hour courses of Gentamicin and Ampicillin (antibiotics) even if no infection is identified. Because of immature immune systems, even if the baby has no outward signs of infection other than respiratory distress and the cultures come back negative, the baby could still have a hidden infection.
  • Heart and circulatory defects - there are many kinds of heart defects and circulatory problems that can result in poor perfusion to the lungs or to the body, resulting eventually in breathing problems. Some heart problems don't cause noticeable problems until the baby's body starts to accommodate to life outside the womb by closing down special circulatory pathways that the fetus needs, but a breathing baby doesn't. This can take several hours or even days.
  • Diabetic mothers - these babies are usually very large - >9lb at birth and can be very large even if born early. Because of mother's chronic high blood sugar, baby doesn't develop in quite the pattern expected and can suffer respiratory distress, low blood sugars soon after birth, heart problems, and multiple birth defects, particularly if the diabetes was poorly controlled during the pregnancy. Gestational diabetes - a form that goes away after the baby's birth, can cause the same problems.
  • Anatomical defects - certain birth defects which are rare but can cause severe respiratory distress include anything that prevents the lungs from fully forming or expanding, anything that impairs circulation, brain or brain stem malformations, and anything that causes severe pain or nervous system irritability.





A photo of acrocyanotic feet. Acrocyanotic means a bluish tinge on the periphery of the body - the hands and feet. Notice the purplish heels especially

And since this is for writing and I'm assuming you'll be describing the scene and the problems, here's a quick rundown on how a normal respiratory effort looks and some of the trouble signs:

  • Respiratory rate 30-60 breaths per minute - too fast or too slow can be bad. As a nurse, I'd rather see too fast than to slow, though. Breathing too slow (or not at all) is an ominous sign of trouble.
  • No grunting noises - babies in distress often make a little grunting sound at the end of each breath. The reason for this is they are trying to keep a little pressure in their lungs at the end of the breath, to keep their lungs from collapsing. It's imperative that lungs stay slightly open after a breath, because lungs that are completely closed require many times as much effort to open back up.
  • No nasal flaring - The sides of their noses will flare out if they are trying hard to get more oxygen. Think of someone you've seen about to launch into a tirade and how their noses widen a bit as they get their breath to blow like Mount Vesuvius.
  • No head bobbing - Babies in distress will bob their heads with each breath in an effort to open the airways wider to breath in and narrow them down a bit when breathing out.
  • Breath sounds clear and equal - breath sounds may sound a little "wet" or crackly in some babies, particularly if born by C-section as there isn't a lot of squeezing to get that excess water out of the lungs like a vaginal birth. If the breath sounds are decreased or absent on one side, this could indicate that the baby has a collapsed lung, or is having a problem called pnuemothorax, which means baby has developed a hole in the lung which allows air to collect in the cavity between the lung and the chest wall, compressing the lung more and more with each breath and not allowing it to re-expand. This can lead to a life-threatening condition known as "tension pneumo" in which so much air has built up in the chest cavity that it is pushing everything over - the lungs and eventually the heart - and pressing so hard it's decreasing circulation. Pneumothorax and tension pneumos are treated by inserting a "chest tube" into the chest cavity that allows the air to be slowly pulled back out and gives room for the lung to re-expand and heal
  • No central cyanosis (blue tinge around face, lips, or the center of the body). It's ok for baby's hands and feet to be blue or purplish for the first 24-48 hours, but an overall pink color (pink as in a healthy coloring, not as in salmon or caucasian) is preferred. Babies with very dark skin can be assessed by looking at lips and tongue - if those are pink, no worries

Treatment for respiratory distress in the newborn is pretty organized. If breathing, baby would first be given oxygen either by nasal cannula (see photo at right), by "blow-by" which means blowing oxygen across the baby's face, or by face mask. If that doesn't work, hand-bagging would start, which means using a mask and bag with a special valve to force air into the baby's lungs. A baby being hand-bagged will quickly be intubated (have a small plastic tube inserted past the vocal cords and into the lungs) and would either continue to be bagged through the tube or be hooked up to a ventillator. Deep suctioning through the breathing tube is likely to occur and Surfactant may be given to help the baby keep the lungs open between breaths. Unless the lungs are seriously malformed, this is usually sufficient. In some very rare cases, if the baby was born at a fetal care center or a center that was prepared for an unusual defect, a baby unable to be helped by hand-bagging or ventillator might be put on ECMO which is a long-term (up to 3 weeks, sometimes) heart-lung bi-pass machine. This has MANY risks and about a 50% chance of survival, depending on the reason it is used.



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