寶寶的第一次呼吸

Made in His Image: Baby's First Breath.
By Guliuzza, R. 2009. Acts & Facts. 38 (12): 10-11.

In 1967 Dr. Christiaan Barnard performed the first heart transplant. Until that time, if someone's heart was taken out, they died. People were astounded to learn that not only was a man’s heart removed, but a non-beating donor heart put in, restarted, and he lived. Years of design efforts and testing resulted in a sophisticated invention that circulated blood and functioned as patients' lungs to bring them oxygen--the all-important "heart-lung" machine.



No doubt in the same hospital in 1967 was a brand-new mother. Her baby had just made a similar transition of survival on an exceedingly better "lung machine," but no reporters covered it. Although the first event was a great feat of human engineering, the second has never been explained by any natural process.


Childbirth is so common it is easy to overlook the fact that a baby thrives in a total water world for nine months--a world that is utterly impossible for any person to live in immediately after their very first breath. That feat is accomplished by the baby possessing--only in the womb--blood vessels with a different arrangement and structure than an adult's.






The Adult Circulatory Arrangement

In an adult human heart, the bottom two chambers, the ventricles, do most of the higher pressure pumping, pushing the blood through one-way valves away from the heart through arteries. The upper two, the atria (plural of "atrium"), receive blood under low pressure from veins and rapidly preload the ventricles by pushing blood into them, also through one-way valves.


The heart is also divided into left and right halves, separated by a solid wall of tissue called a septum. There are two circuits for blood flow from the heart: one to the lungs and back, and one to the body and back. The right heart starts blood on its circuit to the lungs, where less-oxygenated blood picks up a new load of oxygen. The left heart pumps freshly oxygenated blood at "normal" blood pressures (much higher than the right side) to the rest of the body.


In adults, oxygen-rich blood travels away from the heart through arteries under high pressures, and oxygen-poor blood flows toward the heart through veins under low pressure. Clearly, the heart and lungs are completely codependent in accomplishing the purpose of getting oxygen to all places in the body.






The Fetal Circulatory Arrangement


For a baby in the womb, almost everything about those vital functions is just the opposite for one important reason: the baby develops fully functional lungs that are yet inactive for oxygen exchange. Consequently, in order for a baby to survive, three major structural differences must exist that enable life in his temporary home.


First, the baby must have a substitute lung--a pretty tall order for even brilliant biomedical engineers. The placenta, a remarkable organ, has a brief existence, but it fulfills a myriad of vital functions--especially as the fetal lung and kidney. Second, the circuit to the lungs must be bypassed, so vessels must change to allow this temporary detour. (A new route that detours around a circuit is called a shunt.) Third, blood vessels must not only connect placenta to baby, but also inside from the point of attachment to normal vessels that lead to and from the heart. The umbilical cord meets the need for a placental-fetal connection, with one large-diameter vein and two smaller arteries. Inside the baby, these continue as the umbilical vein and umbilical arteries.






The umbilical vein carries oxygen-rich blood toward the heart. At a spot next to the liver, it connects to a large vein carrying less-oxygenated blood back to the heart. Interestingly, the two combined streams of blood do not tend to mix. It just happens that when they reach the right atrium, the more oxygenated blood stream is adjacent to a temporary opening in the septum, where it passes through to the left atrium because the blood pressure in the right side of baby's heart is higher than the left side--the opposite of the post-birth situation. The right heart still pumps blood to the lungs, but because the lungs have not yet expanded, the resistance to blood flow is very high and, therefore, the pressure is high. Some blood does make it to the right ventricle (about 10 percent) and flows through the lungs, which is the right amount to meet metabolic needs but not for oxygen-carrying purpose--which does not yet exist.




The temporary opening has a piece of septum tissue over it that is located in the left atrium. Thus, it acts like a "trap door" valve so that high pressure on the right side can push it open with each beat. In adults, it would make no sense for the artery carrying oxygen-poor blood to the lungs to connect by a big blood vessel to the artery carrying oxygen-rich blood (the aorta) to the body. But the baby does have this big connecting vessel in order to bypass the lungs and send oxygen-rich blood from the placenta to the body. Most of this blood travels to the part of the body with the highest oxygen demands--the growing brain.


So baby is content in the womb with temporary umbilical arteries and vein, a temporary opening in the septum, the temporary pulmonary artery-aorta shunt vessel, high pressure in the lungs and right side of the heart, and low pressure on the left side. With the onset of labor, culminating in delivery, that world is set to radically change. However, crucial mechanisms are built into the temporary structures that enable a safe transition out of the womb.






Vital Circulatory Changes Occurring at Birth


The umbilical cord vessels have features that respond to changes in quantities of oxygen dissolved in blood, stretching, substances commonly called adrenalin, and trauma. Obviously, during delivery and the severing of the cord all of these are present. The cord, which has an unusually strong muscle layer surrounding the vessels, reacts with a rapid and powerful constriction of the arteries and vein that is complete in less than a minute. This stops blood flow to and from the placenta, which has two effects. It greatly reduces the risk of either baby or mom losing a lot of blood and also causes an immediate drop in the amount of oxygen baby is getting.


Very sensitive sensors--inside certain blood vessels measuring carbon dioxide content, and also on the skin detecting temperature drops--stimulate the nervous system's breathing center. Under normal circumstances, increased carbon dioxide blood levels coupled with decreased body temperature after exiting the birth canal trigger an irresistible urge for baby to take a strong breath and inflate his lungs for the first time. The lungs have been prepared for this event by special cells producing a compound called surfactant, which significantly reduces the tension holding non-inflated lung tissues together--otherwise, forces required to open the lungs would be too high for almost all newborns to accomplish. Once inflated, pressures necessary to pump blood through the lungs drop 90 percent from their intra-womb high values.






Thus, pressure in the right side of the heart immediately drops well below the pressure in the left side. The "trap door" valve (actually two flaps of skin that neatly fold and interlock when pushed together) covering the septum's temporary opening in the left atrium is pressured shut. Cells begin to grow over the edges of the valve, fusing it to the septum. Less than a minute after birth, signals from baby's nervous system cause strong sphincter muscles to close off the umbilical vein where it attaches near the liver and also close off the temporary pulmonary artery-aorta shunt. (That large vessel permanently closes over the next one to two days.)




The baby's body has started all changes that continue through adulthood. During the next year, those internal umbilical vein and arteries transform from blood vessels into stabilizing ligaments. So in the one critical minute after delivery, the baby's body has initiated actual structural changes enabling it to survive in its radically different environment with all temporary vessels, shunts, and openings functionally closed in the first 30 minutes.


Conclusion


The reality of fetal to newborn circulatory changes is this: structures indispensible for life in the womb are incompatible with life out of it, and at birth all structures are rapidly reversed, resulting in the opposite effect on survival. In either case, if the offspring dies, evolution ends. Darwin wrote, "If it could be demonstrated that any complex organ existed which could not possibly have been formed by numerous, successive, slight modifications, my theory would absolutely break down."1


Consider it broken...if not a catastrophic failure. Why? Given that a transplanted heart living inside someone is truly an incredible achievement--at what level of accomplishment is getting a whole person to live inside another person? Absolutely incredible--which is what the Lord Jesus Christ is! As clearly seen, He creates, He directs, He provides, He cares--indeed, everything He does is beautiful beyond description.

Reference

1.Darwin, C. 1859. On the Origin of Species. London: John Murray, Chapter VI, 189.

Will & Selene's Baby Shower

今天晚上我們在Orchard Park Community Center為Will和Selene即將出生的小寶寶辦了一個 Baby

Shower, 來美國這麼多年了,這卻是我第一次參加 baby shower呢! 大部分的台灣朋友們還是習慣

等寶寶出生滿月後再辦滿月酒, 不過我覺得baby shower這種老美的玩意其實很有意義, 跟bridal

shower一樣, 在朋友即將步入人生另一個重要的階段前, 大家齊聚一堂,獻上最真誠的祝福, 我想

肚子裡的小寶寶一定也能感受到大家的期盼與愛吧! 而美國人的習慣通常是在baby shower之前,

準爸媽會在網路上的店家進行 gift registry, 選定一些他們想要的禮物, 朋友們就可以根據這個清

單決定要送什麼禮物給準爸媽. 就跟結婚前一樣啦, 這樣不但可以省去挑選禮物的煩惱, 也可以

避免買到重複的禮物, 根據準爸媽的需求送給他們最需要的東西!　


這次因為時間比較匆促, 所以Will他們並沒有做baby registry, 不過大家還是帶來很豐富的禮物喔!

參加的朋友也好多阿! 幸好借了community center,不然在家裡辦的話一定會擠不下! 團康高手永

遠的主持人永信也準備了刺激又有趣的活動, 從尿布裡的驚喜到以baby為主題的小隊對抗賽, 大

家玩得超high的! 謝謝永信和凱尹精心策劃的活動, 也謝謝Will & Selene為大家準備了豐盛的晚

餐和小禮物~


藉這個機會和許久不見的大家見面聊天也超開心的! 不然每天的生活圈只有家裡與實驗室, 都快

發霉了~~ 還是好懷念以前每個星期五/六晚上的紅酒趴阿...跟好朋友一起聊天喝酒打麻將真是

紓壓的好方法!


Will和Selene的寶寶出生後,他們一定也會忙得昏天暗地, 暫時不能常常和大家一起hang out囉! 今天聽

Will 說他們去上產前衛教的課時, 那位女醫生告訴他們說生產的痛苦會比你想像的再痛苦十倍! (據說

聽到這準媽媽們的表情都凝結了...)



但是, 小孩所帶給你的快樂, 卻會是你想像中的一百倍!!!

(這時新手爸爸奇芊在一旁洋溢著幸福的表情,以過來人的姿態猛點頭說"真的!真的!")

(然後Will就吐槽他說 "阿你又沒痛到....又不是你生的....")


用十倍的痛苦換來一百倍的快樂, 怎麼算都是非常值得的投資阿!!

看身邊的朋友紛紛結婚生子, 一個個"家庭"正在誕生, 只是身在他們周圍, 都可以感受到那強烈的緊密

的力量, 家庭,真的是可以支撐一個人奮鬥努力的最大支柱與動力呀! 尤其是小生命的誕生, 總讓人充滿

無限的希望.


祝福Will & Selene, 祝福奇芊&小黃, 祝福姊姊&姊夫, 祝福所有已經或即將擁有新生命的朋友們, 願光與

愛永遠圍繞在你們身旁, 願每一個小天使的降臨, 都讓這世界更美好!

2009 is not my year...what about 2010?!

我很少下這種武斷性的結論,或是用"衰"來形容自己的遭遇. 生活總是有起有落,而一向樂觀的我也總相信命運掌控在自己手上, 一切總會有轉機. 但是最近的我, 真的已經到了一個臨界點. 心力交瘁, 甚至開始有玉石俱焚的念頭.

從2009年中開始, 身邊好友開始紛紛離開, 然後九月, 眼睜睜看著死神從我面前奪走心愛的貓貓. 接下來又是一連串紛爭的開始. 和實驗室的好友因為莫名其妙的小事鬧的有些不愉快, 然後樓上和隔壁新搬來的鄰居開始不停的製造噪音,溝通無效, office和警察都找過了還是一樣, 非得要我忍無可忍衝進去跟他們吵架,只差沒真的打起來.

除了實驗的不順, 工作上的壓力,連晚上回到家都不能好好休息. 這世界是怎麼了?

每當我開始想要振作,開始告訴自己不要陷在負面的情緒裡頭, 開始試著相信生命是美好的, 就會有另一塊大石頭掉下來把我壓得死死的, 又把我推回絕境.

我真的不知道我還要忍受多久, 還可以忍受多久

還有什麼

一起來吧

通通來吧

就不要逼我變成惡魔

新的一年，晴天會來臨嗎?

我告訴自己
未來的這半年
再怎麼辛苦 再怎麼痛苦 犧牲什麼
都無所謂了
這是我能為自己當初的夢想所做的最後一搏
結束後
我就要頭要不回的離開實驗室

因為
我不屬於這裡