In a message dated 12/1/2004 8:17:39 PM Pacific Standard Time,
[log in to unmask] writes:
Date:    Wed, 1 Dec 2004 18:50:58 -0800
From:    Jann Sheperd <[log in to unmask]>
Subject: Newborns with 'wet' lungs

I have heard nurses talk about c/s babies having 'wet' lungs, and being
spittier after birth than vag. babies.  I have also noticed that babies that
were quick or precipitous deliveries tend to have the same issue.  Does
anyone else notice this?

Janette M/B RN
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Janette:
You are incredibly perceptive  - and right on target.  The research confirms
that infants born by ELECTIVE cesarean section WITHOUT LABOR, and those born
by precipitous vaginal delivery, have delayed clearance of lung fluid, because
of a complex biochemical change in Cl and Na which happens just before the
onset of spontaneous labor.

As I could not find the article I wanted in my files immediately, I emailed a
good friend (Dr. EE Lawson) who has done research in this area.  His response
is below.

"Without doing a borader literature search I can send you to one of my
articles which  is the original report of the actual mechanism for TTN -
lack of reversing the Cl secretion and is associated with c-section
without labor (or vaginal delivery with precip labor).  Presumably the
onset of the change from Cl secretion to Na absorption occurs in a
period before onset of clinical labor (Strang's work on fetal lung fluid
flux shows that best - late 70's and early 80's), though I did some of
that also both at UNC and when I was a fellow.

The key reference is:

Gowen, C.W., E.E. Lawson, J.L. Gingras, R.C. Boucher, J.T. Gatzy, and
M.R. Knowles: Electrical potential difference and ion transport across
nasal epithelium of term neonates: Correlation with mode of delivery,
transient tachypnea of the newborn, and respiratory rate. J. Pediatrics
113:121-127, 1988.

I think this has now been confirmed by others. Other work by Boucher
and that group explains the Na/Cl channel secretion and water flux.
Primarily their work is oreinted to CF, but Pierre Barker (see below)
has done other work as real careeer stuff in humans and animals.  You
might look up his work in PubMed.

If that one turns you on then try this one for an additonal dose of
lung fluid flux - may be a patrtial explanation of our fluid problems
with RDS/premies.

Barker, P.M., C.W. Gowen, E.E. Lawson, M.R. Knowles. Decreased Na+
absorption across nasal epithelium of very preterm infants with
respiratory distress syndrome. J. Pediatrics  130: 373-77, 1997"

A good review article I found by Barker:
J Appl Physiol. 2002 Oct;93(4):1542-8.Related Articles, Links

Invited review: Clearance of lung liquid during the perinatal period.

Barker PM, Olver RE.

Department of Pediatrics, University of North Carolina, Chapel Hill, North
Carolina 27599-7220, USA. [log in to unmask]

At birth, the distal lung epithelium undergoes a profound phenotypic switch
from secretion to absorption in the course of adaptation to air breathing. In
this review, we describe the developmental regulation of key membrane transport
proteins and the way in which epinephrine, oxygen, glucocorticoids, and
thyroid hormones interact to bring about this crucial change in function. Evidence
from molecular, transgenic, cell culture, and whole lung studies is presented,
and the clinical consequences of the failure of the physiological mechanisms
that underlie perinatal lung liquid absorption are discussed.

Nancy
Nancy E. Wight MD, IBCLC, FABM, FAAP
Neonatologist, Sharp Mary Birch Hospital for Women and Children's Hospital
Medical Director, Sharp HealthCare Lactation Services
San Diego, CA
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