|
|
 Case
Study
Neonatal
Teaching Case:
Diaphragmatic Hernia
by
Michael E. Speer, MD
Case
presentation
This
3.3-kg white male with a known left-sided diaphragmatic hernia
was born at an outlying hospital to a 26-year-old G5P1Ab3, class
A diabetic mother at 39 weeks’ gestation. Labor was induced at
the mother’s request. Delivery was vaginal; Apgar scores were
8 and 8 at 1 minute and 5 minutes of life. Fetal membranes had
ruptured 3 hours prior to delivery. Intrauterine diagnosis of
a left-sided diaphragmatic hernia had been made by a routine fetal
ultrasound at 18 weeks’ gestation. Maternal laboratory values:
Blood type, O+; GBS, (+); RPR, NR; HIV, (-); HBsAg, (-). The mother
had received 2 doses of penicillin before delivery. After delivery
the infant was intubated, vascular lines were placed, and he was
transferred to the NICU at Texas Children’s Hospital in Houston.
Physical
exam showed an active male infant breathing against the ventilator.
HR 140-150; RR 45-55; BP 70/40. No abnormal findings were noted
except breath sounds were absent over the left hemithorax and
heart sounds were heard best over the right hemithorax.
Over
the first 24 hours of life the patient’s respiratory status deteriorated.
The infant was subsequently paralyzed and ultimately responded
to inhaled nitric oxide (iNO) at 20 ppm. INO was stopped on the
6th day of life. The following day, the patient developed hypercarbia,
worsening chest radiographs, and decreased urine output. A volume
challenge and another trial of iNO were attempted without success.
An echocardiogram did not demonstrate any anatomical abnormalities;
specifically, the right ventricular function was normal. The physical
examination was unchanged except for the development of abdominal
distention.
Surgical
repair of the diaphragmatic hernia was performed the same day.
The large diaphragmatic defect was repaired with a patch. Chylous
ascites was noted; the bowel appeared to be intact. A central
line was not placed at this time. After repair and removal of
the ascitic fluid (400 mL), the respiratory status of the infant
markedly improved. But, over the next 24 hours, the abdominal
distension recurred. A second exploratory surgery was undertaken
and found a reaccumulation of the chylous fluid (~300 mL). A drain
was placed, the umbilical venous catheter was removed, and a central
line was inserted. After surgery the ascites did not recur.
Denouement
Abnormal
fluid collections may occur when catheters, in this case the umbilical
venous catheter, are in an aberrant position. The increased intraluminal
pressure caused by an IV pump increases fluid flux across the
vessel wall resulting in increased fluid in the interstitial tissue,
which, in this case, resulted in ascites and pleural fluid accumulation.
Sometimes, Doppler studies can be used to better ascertain the
location of a catheter. The chylous appearance of the fluid in
this case was due to TPN and Intralipid® infused through the venous
catheter.
(Intralipid
is a registered trademark of Riker Laboratories, Inc., Northridge
CA.)
|
