This case report describes the surgical repair and management of a peritoneopericardial diaphragmatic hernia (PPDH) in a pregnant dog. A 3-year-old pregnant Golden Retriever presented with vomiting, lethargy, and pale gums. Diagnostic testing revealed a PPDH, with liver and omentum herniated into the pericardial sac. The dog underwent surgery to repair the diaphragmatic tear. Post-operatively, the dog experienced hypotension, tachycardia, and ventricular arrhythmias requiring intensive care. Over nine days of supportive care and monitoring, the dog's condition stabilized. The puppies were later delivered via cesarean section

1. Case Report
Surgical repair of a peritoneopericardial
diaphragmatic hernia in a pregnant dog
Gretchen D. Statz, DVM, Kari E. Moore, DVM, DACVECC and Robert J. Murtaugh, DVM, MS,
DACVIM, DACVECC
Abstract
Objective: To describe the surgical repair and pre- and postoperative management of a peritoneopericardial
diaphragmatic hernia (PPDH) in a pregnant dog.
Case summary: A pregnant dog was presented for vomiting, lethargy, and pale mucous membranes. Pulsus
paradoxus was noted on physical examination. The dog was diagnosed with a PPDH via thoracic
radiographs, abdominal ultrasound, and an echocardiogram. The hernia was surgically repaired and the dog
received supportive medical care until the puppies were old enough to be delivered via cesarean section. The
mother and all puppies survived.
New or unique information provided: This is the first report that describes the surgical repair and
postoperative management of a PPDH in a pregnant dog.
(J Vet Emerg Crit Care 2007; 17(1): 77–85) doi: 10.1111/j.1476-4431.2006.00200.x
Keywords: cesarean section, congenital anomaly, nutritional support, pediatrics, pulsus paradoxus
Introduction
There is no direct communication between the thoracic
and peritoneal cavities in normal dogs and cats.
Communication between the cavities can occur as a re-
sult of congenital or acquired hernias. Peritoneoperi-
cardial diaphragmatic hernia (PPDH) is the most
common congenital anomaly of the pericardium in
dogs and cats.1,2
The defect that results in a PPDH is
thought to be caused by abnormal development of the
septum transversum.1–4
The cause of the anomaly may
include prenatal injury, genetic defect, or teratogen.1,2
The defect has been reported in littermates,5,6
but has
not been proven to be heritable.2,3
In humans, PPDH is
often acquired secondary to trauma; however, in ani-
mals, it is almost always congenital.1,7,4
Acquired
PPDH is less likely in dogs and cats because there is
no communication between the pericardial and perito-
neal cavities after birth.1,7
With congenital PPDH, Com-
munication occurs between the abdomen and the
pericardial sac, potentially allowing herniation of ab-
dominal viscera into the pericardial sac.1,7–9
Dogs with
PPDH can remain asymptomatic for years before de-
veloping respiratory, gastrointestinal, or cardiac abnor-
malities.1–3,8
PPDH has been reported in combination
with other congenital abnormalities. In the dog, PPDH
has been associated with abnormalities involving the
cranial abdominal wall, caudal sternum, diaphragm,
pericardium,1,5,8,10,11
heart,5,6
pulmonary vasculature,12
and intrapericardial cysts.13,14
In cats, PPDH has been
associated with polycystic kidney disease,15
portosys-
temic shunts,9,11
hepatic cysts,16,17
myelolipomas,18
and
chylothorax associated with lung lobe torsion.19
In 1
study of dogs, Weimaraners were over-represented8
and in another study of cats, it was reported that Per-
sians may be predisposed to PPDH.20
There is 1 report
in the literature of a pregnant dog diagnosed with
PPDH21
; however, the dog and the puppies died shortly
after initial diagnosis. To the authors’ knowledge, there
is no reported case of a pregnant dog with a PPDH
that has survived both the surgical repair of the hernia
and subsequent staged cesarean delivery of viable
puppies.
Case History
A 3-year-old, 35 kg, intact female Golden retriever was
presented to the referring veterinarian for vomiting,
Address correspondence and reprint requests to:
Gretchen D. Statz, 15021 Dufief Mill Road, Gaithersburg, MD 20878.
E-mail: gretchen.statz@vcamail.com
Dr. Moore’s current affiliation: VCA Sacramento Veterinary Medical and
Surgical Referral Center, Sacramento, CA.
From the VCA Veterinary Referral Associates, Critical Care and Internal
Medicine Department, Gaithersburg, MD (Statz, Murtaugh) and the
Department of Clinical Sciences, Cummings School of Veterinary Medicine
at Tufts University, North Grafton, MA (Moore).
Journal of Veterinary Emergency and Critical Care 17(1) 2007, pp 77–85
doi:10.1111/j.1476-4431.2006.00200.x
& Veterinary Emergency and Critical Care Society 2006 77

2. lethargy, and pale mucous membranes. The owner re-
ported that the dog ate normally the morning of pres-
entation, but had vomited bile several times after
eating. There was no known history of trauma or tox-
in exposure. The dog was artificially inseminated
54 days before presentation and bred naturally by the
same male the following day. Live feti were visible on
ultrasonographic examination on approximately day 25
of pregnancy.
On presentation to the referring veterinarian, the dog
was normothermic 38.2 1C (100.8 1F), tachycardic
(180 beats per minute [bpm]), and tachypneic. On phys-
ical examination, the dog was depressed, had weak
femoral pulses, increased respiratory effort, and pale
mucous membranes. The abdomen was soft and non-
painful, with palpable fetal movement in the caudal
abdomen. The initial packed cell volume (PCV) and
total solids (TS) were 45% (reference range 37–55%) and
4.5 g/dL (reference range 6–7.5 g/dL), respectively. The
result of an abdominal radiograph was interpreted as
normal for a dog at this stage of pregnancy. The dog
was referred for further diagnostics and treatment. At
the time of presentation, the dog appeared depressed.
Physical examination revealed pulsus paradoxus,
muffled heart sounds, and mild nipple and vulvar en-
largement. The dog was afebrile (38.9 1C [102 1F]), ta-
chycardic (160 bpm), and had pale, tacky mucous
membranes. Blood was drawn for a minimum data-
base (blood glucose [BG], PCV/TS, Azostixa
[Azo]),
complete blood count (CBC), and chemistry profile. The
BG was 84 mg/dL (reference range 82–117 mg/dL), the
Azo was 5–15 mg/dL (reference range 5–26 mg/dL),
the PCV was 48% (reference range 37–55%), and the TS
was 5.6 g/dL (reference range 6–7.5 g/dL). The CBC
showed a leukocytosis with a mature neutrophilia, a
monocytosis, and a mild thrombocytosis. The remain-
der of the CBC was within normal reference ranges.
The chemistry profile revealed a mildly elevated
creatinine, mild hypernatremia, hypocarbia, hype-
rbilirubinemia, and an elevated alanine transferase
(ALT), aspartate transferase (AST), and lipase. The
sample was moderately hemolyzed. The remainder of
the chemistry profile was within normal limits. Initially,
the dog was treated with a 90 mL/kg bolus of lactated
Ringer’s solution (LRS)b
intravenously (IV) to treat its
tachycardia and presumed hypovolemia. The LRS was
continued at a rate of 4.2 mL/kg/hr. After the initial
bolus, the indirect blood pressure (BP) was measured
via an oscillometric technique.c
The systolic BP was
99 mmHg, the diastolic BP was 67 mmHg, and the mean
arterial pressure (MAP) was 86 mmHg. An 18-gauge
jugular catheterd
was placed into the right jugular vein
for measurement of central venous pressure (CVP). The
CVP after the initial fluid bolus was elevated at
23.2 cmH2O (reference range 0–3 cmH2O). Thoracic rad-
iographs showed an enlarged cardiac silhouette with an
unusual irregular fluid-filled opacity along the ventral
portion of the thorax extending to the diaphragm (Fig-
ure 1). Differential diagnoses for the opacity included
pleural effusion, fat, or a PPDH. An abdominal ultra-
sound was performed and showed live feti within the
uterus, with an estimated pregnancy time of approxi-
mately 50 days. A round 6 3.6 cm structure surround-
ed by anechoic fluid was seen caudal to the heart
(Figure 2). The structure seemed to communicate with
the liver in the abdomen, but had a slightly different
echogenicity when compared with the liver. The he-
patic veins were considered enlarged, suggestive of
vascular compromise or possibly secondary to IV fluid
therapy. The presence of liver tissue in contact with the
heart in the left cranioventral thorax was suggestive of
a diaphragmatic hernia. Based on the appearance of the
liver tissue, necrosis secondary to vascular compromise
Figure 1: Right lateral thoracic radiograph showing an enlarged
cardiac silhouette.
Figure 2: Abdominal ultrasound image showing liver tissue in
contact with the heart.
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G.D. Statz et al.

3. could not be ruled out. An echocardiogram showed a
small left ventricle with adequate contractility. The
right heart also appeared small, but the right atrium
could not be fully assessed. There was echodense ma-
terial in the pericardial sac thought to represent ab-
dominal contents such as the liver or omentum from a
PPDH. Owing to the presence of hepatic vascular com-
promise, poor perfusion, pulsus paradoxus, elevated
CVP, and a concern for increasing cardiovascular com-
promise with progression of the pregnancy, surgery
was deemed necessary. Preoperative analgesic medica-
tion included butorphanole
(0.2 mg/kg IV), and antibi-
otic therapy was initiated with cefazolinf
(21 mg/kg
IV). General anesthesia was induced with ketamineg
(2.9 mg/kg IV) and diazepamh
(0.14 mg/kg IV). Inha-
lation anesthesia was maintained with isofluranei
in
oxygen. The dog was kept on a surgical ventilator with
a tidal volume of 550 mL, a respiratory rate of
16 breaths/min, and a peak pressure of 20 cm H2O. A
ventral midline celiotomy was performed. The uterus
was exteriorized and the PPDH was located. The rent in
the diaphragm was expanded to allow the entrapped
liver and omentum, as well as fluid, to be released from
the pericardium. The rent in the diaphragm was closed
with 2-0 Polydioxanonej
in a cruciate pattern. A draink
was placed through the existing rent in the diaphragm
and exited out a separate stab incision in the abdomen.
The drain was connected to a closed collection system
for intermittent manual suction. Following complete
exploration of the abdomen, the abdomen was lavaged
with warm sterile saline and closed routinely. Intra-
operatively, the dog experienced significant hypotension
(MAP 35 mmHg) and was administered hydroxyethyl
starch (HES)l
(3.8 mL/kg/hr IV) and dobutaminem
(5 mg/
kg/min IV). After starting the dobutamine, the MAP in-
creased to 70 mmHg and remained normotensive for the
remainder of the procedure. Ventricular premature com-
plexes (VPCs) were observed on continuous electrocar-
diogram and the dog remained tachycardic with a heart
rate greater than 140bpm for the majority of the proce-
dure. The dog vomited a small amount after extubation.
Ventricular tachycardia persisted postoperatively with a
heart rate between 140 and 160 bpm and faint pulses.
Postoperatively, the systolic BP was 134 mmHg, the di-
astolic BP was 82mmHg, and the MAP was 92 mmHg.
Postoperative analgesia was provided with butorphanol
(0.2 mg/kg IV) every 4–8 hours as needed for pain. A CRI
of lidocainen
(50 mg/kg/min IV) was administered to
treat the sustained ventricular tachycardia and resultant
poor perfusion. A postoperative arterial PaO2 revealed
hypoxemia (63 mmHg, reference range 85–95 mmHg)
that was treated with supplemental oxygen administered
via nasal catheter. Postoperatively, the dog received an
initial bolus of lactated Ringer’s (1 L), followed by LRS
supplemented with 20mEq/L of potassium chlorideo
at
4.3mL/kg/hr and HES at 0.7 mL/kg/hr. The fluid ther-
apy took into account maintenance requirements
(2.5 mL/kg/hr) along with ongoing losses including flu-
id removed from the pericardial drain (1.8 mL/kg/hr
initially). Cefazolin (21mg/kg IV q 8 h) was continued
until the time of discharge. The dog remained in the in-
tensive care unit (ICU) for 9 days after the initial surgery.
The electrocardiogram (ECG) was monitored continu-
ously, and the temperature, heart rate, respiratory rate,
BP, and oxygen saturation were monitored every 4–6
hours until the time of discharge. The minimum database
was monitored every 8 hours until the time of discharge.
CVPs were monitored for 48 hours postoperatively until
the initiation of parenteral nutrition that was adminis-
tered through the central line.
Occasional VPCs were observed on ECG for approx-
imately 96 hours postoperatively, with a heart rate
ranging from 120 to 160 bpm. The lidocaine was dis-
continued on the third postoperative day. The MAP
consistently remained above 70 mmHg postoperatively,
and the CVP remained elevated with a range of
14–28 cmH2O.
After oxygen supplementation was initiated, the ox-
ygen saturation remained between 94% and 97% on
oxygen supplementation. Arterial blood gas analyses
on the first postoperative day revealed mild hypox-
emia (PaO2 84 mmHg). Arterial PaO2 on Day 4 was
112 mmHg after a brief period of exposure to room
air. By Day 6, oxygen supplementation was success-
fully discontinued. The CBCs, chemistry profiles,
coagulation profiles, and electrolytes were monitored
periodically throughout the dog’s hospitalization. A
coagulation profile was evaluated on Day 3 postoper-
atively, a CBC on postoperative Day 1, and a chemistry
profile on postoperative Days 1, 3, and 7. Electrolytes
were also monitored separately on Days 3 and 4, and
minimum databases were evaluated every 8–12 hours.
The immediate postoperative PCV/TS declined to 32%
and 3.8 g/dL, respectively. The TS declined to 3.0 g/dL
within 36 hours postoperatively, at which point the dog
was given a transfusion of fresh-frozen plasma
(13.7 mL/kg IV). The PCV reached a low point of
24% 48 hours postoperatively. The Azo remained
normal. The BG was 72 mg/dL. Dextrose (2.5%) was
administered as a CRI. Coagulation profiles remained
normal. The postoperative CBC showed leukocytosis
because of mature neutrophilia, low hematocrit, low
hemoglobin, low red blood cell level, and a high mean
cell hemoglobin concentration. The chemistry profile
Day 1 postoperatively showed hypocalcemia, which
corrected to normal after consideration of the hypo-
albuminemia, hypophosphatemia, hypoproteinemia,
hypoalbuminemia, hyperchloremia, low anion gap,
Veterinary Emergency and Critical Care Society 2006, doi: 10.1111/j.1476-4431.2006.00200.x 79
PPDH in a pregnant dog

4. high alkaline phosphatase, ALT and AST, and a low
g-glutamyltransferase (GGT). The chemistry profile
3 days postoperatively showed similar abnormalities,
with a normal anion gap and carbon dioxide level
and an improving ALT and AST. There was recurrent
hyperbilirubinemia and a new finding of hypocholes-
terolemia. The chemistry profile 7 days postoperatively
again showed similar abnormalities with normal phos-
phorus, chloride, AST, ALT, and GGT. New abnormal-
ities at that time included an elevated amylase.
Electrolytes were normal throughout, other than a mild
hypokalemia of 3.0 mEq/L (reference range 3.4–
5.4 mEq/L) on Day 4 postoperatively. The pericardial
drain was left in place for approximately 36 hours. An
average of 63 mL/hr of serosanguineous fluid was as-
pirated from the tube for the first 10 hours after surgery.
Fluid production then decreased to an average of
14 mL/hr until the tube was removed. The dog expe-
rienced anorexia, vomiting, and frequent regurgitation
for 5 days after surgery. Sucralfatep
(1 g slurry PO q 8 h),
cimetidineq
(5 mg/kg IV q 8 h), and metoclopramider
(1.5 mg/kg/day IV CRI) were initiated for gastric reflux
and possible esophagitis. A nasogastric (NG) tubes
was
placed the day after surgery and was used to suction
gastric contents and for provision of nutritional support
beginning 2 days after surgery. Parenteral nutrition was
started on Day 2 postoperatively in an attempt to meet
the nutritional needs of the bitch and the puppies. The
maintenance energy requirement for the postoperative
bitch in the late stage of gestation was calculated to be
approximately 2000 kcal/day. The parenteral nutrition
was started on Day 2 postoperatively at 1/3 the calcu-
lated energy requirement, increased to 2/3 on Day 3
postoperatively, and was at 100% of the estimated en-
ergy requirement by the fourth postoperative day. The
parenteral nutrition was initially supplemented with
enteral feeding of Peptament
(10 mL) every 4 hours via
the NG tube. The Peptamen was slowly increased over
the next several days, and Esbilacu
was added to help
provide proper protein, fat, and minerals for the dam/
bitch. The Peptamen and Esbilac were continued until
the fifth postoperative day, when the feeding tube
clogged and the dog began to tolerate syringe feeding
of A/D.v
The parenteral nutrition was continued for
6 days until the dog began to eat an adequate amount
on its own. The dog remained recumbent for several
days after surgery and developed rear limb edema on
the fourth postoperative day. The dog was treated with
furosemidew
(0.8 mg/kg/hr IV CRI) for 72 hours, a CRI
of HES (0.7 mL/kg/hr IV), and physical therapy of the
rear limbs including massage and passive range of mo-
tion. A progesterone level on Day 58 of gestation was
1.9 ng/mL (reference range o2 ng/mL 36–48 hours be-
fore whelping) and a recheck abdominal ultrasound on
Day 61 of gestation showed live puppies. On Day 61 of
gestation (7 days after the initial surgery), a cesarean
section was performed. The decision to perform sur-
gery was based on the low progesterone level and a
decline in body temperature consistent with impending
whelping.22
General anesthesia was induced with prop-
ofolx
(4 mg/kg IV), and the dog was maintained with
isoflurane in oxygen. A ventral midline celiotomy was
performed, followed by an en bloc ovariohysterectomy
and cesarean section. Seven live puppies were removed
from the uterus.
The dog recovered uneventfully from the second
surgery and remained in the ICU. Postoperatively, the
dog was continued on LRS, HES, parenteral nutrition,
cefazolin, butorphanol, sucralfate, and cimetidine. The
PCV/TS declined from 24% and 4.0 g/dL preopera-
tively to 16% and 3.2 g/dL postoperatively. The dog
was transfused with a unit (7 mL/kg IV) of type-
specific DEA 1.1 positive packed red blood cells and
2 units (13.7 mL/kg IV) of fresh-frozen plasma. The
post-transfusion PCV/TS increased to 23% and 3.6 g/
dL, respectively. Over the 48 hours after the cesarean
section, the dog was weaned off of the IV fluids, HES,
and parenteral nutrition. The puppies were allowed to
nurse every 4 hours. They were given supplemental
bottle-feeding with Esbilac to help ensure adequate ca-
loric intake and to avoid undue stress on the dam dur-
ing the post-surgical period. They were stimulated
manually to urinate and defecate until the mother was
able to stimulate them on her own. The dog remained
stable and began to eat on its own the day following the
cesarean section. The dog was discharged from the
hospital 48 hours after the caesarean section. At recheck
examination, 12 days after discharge from the hospital,
all puppies were radiographed and no evidence of
PPDH was found in any of the puppies.
Discussion
The purpose of this report is to discuss the diagnostic,
anesthetic, and surgical management, along with the
postoperative care of PPDH in a pregnant dog where
the bitch and puppies survived staged surgical inter-
ventions. PPDH is a common congenital anomaly in
dogs and cats.1,2
Although numerous case reports have
been published5,6,8–10,13–17,23–28
in both species, only one
report describes the condition in a pregnant dog.21
The
previous report involved a 3-year-old female Pointer
that was examined for anorexia, lethargy, green vaginal
discharge, and multiple lactigenous mammary glands.
Cranial abdominal and thoracic radiographs revealed a
PPDH with herniation of mineralized fetuses into the
pericardial sac. The dog died shortly after the radio-
graphs were taken, and the diagnosis was confirmed on
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G.D. Statz et al.

5. postmortem examination. To the authors’ knowledge,
this is the first report of PPDH in a pregnant dog where
the bitch and puppies survived. In the case described
here, clinical signs did not occur until late in the preg-
nancy. The onset of clinical signs may have been related
to excess abdominal pressure from the pregnancy,
causing the liver to move through the hernia into the
pericardial sac. As is often the case with PPDH, the dog
presented with gastrointestinal signs (vomiting) in ad-
dition to lethargy, pale mucous membranes, and pulsus
paradoxus.
Successful management of PPDH involves surgical
correction of the hernia.1,2,11,24,29
Anesthesia induction,
maintenance, and monitoring were complicated in this
case by the pregnancy. Mid-to-late stage pregnancy in
both dogs and humans results in a decrease in BP, mild
tachycardia, and an increase in cardiac output to pro-
vide adequate fetal blood flow.30,31
Because fetal blood
flow is not autoregulated and uterine perfusion is pres-
sure dependent, the stability of the mother’s cardio-
vascular system is important in maintaining the health
of the feti.32
Most anesthetic drugs cross the placenta
and the blood–brain barrier of the feti33
so drug effects
on the feti must also be considered. Anesthetic drugs
used in this case were chosen in consultation with the
staff anesthesiologist and theriogenologist. The goal
was to provide rapid induction with quick intubation
and oxygenation, cardiovascular support, and minimal
effect on the feti.
Ketamine was chosen to provide rapid induction and
for its positive cardiovascular effects.30
It has been
shown to maintain or increase blood pressure and to
increase uterine blood flow in near-term ewes34
and
does not appear to adversely affect puppy survival at
2 hours post-cesarean delivery.35
Despite the potential
benefits, ketamine may not have been the best choice in
this case for several reasons.36
Although ketamine
causes increased cardiac output in healthy animals, it
has negative inotropic effects if the sympathetic system
is blocked or maximally outputted. Ketamine rapidly
crosses the placental barrier37
and, in 1 study, the use of
ketamine and midazolam before enflurane anesthesia
caused the most severe neurological depression of the
puppies compared with 3 other anesthetic protocols.33
In that same study, ketamine was associated with a 10%
mortality rate within the first 24 hours after surgery
compared with an overall neonatal mortality rate of
4%.33
In another study, ketamine was the only injectable
anesthetic that decreased the likelihood that all of the
puppies in the litter would spontaneously breathe at
birth.38
Diazepam was used in this case for its sedative
and muscle relaxant effects. Diazepam rarely alters car-
diovascular function, but can lead to decreased muscle
tone in puppies.30
Propofol was chosen for the cesarean
section for its rapid onset and short duration of action,
with minimal residual effects on the feti.39–41
It has been
associated with a positive effect on canine neonatal
survival at 7 days.35
Propofol does cross the placenta
and is eliminated more slowly by the neonate than by
the mother.33
In 1 study, puppies delivered from bitches
induced with propofol showed less neurologic depres-
sion than the puppies delivered from bitches induced
with ketamine and midazolam.33
These puppies
showed less neurologic dysfunction, but more respira-
tory depression than puppies delivered from bitches
induced with thiopentone.33
In another study, propofol
showed no negative effect on puppy vigor (breathing,
movement, or vocalization) after cesarean delivery
when compared with other anesthetic drugs.38
Prop-
ofol can cause bradyarrhythmias and can decrease
myocardial contractility and preload, which decreases
cardiac output, BP, and uterine blood flow.30
Propofol
can also lead to periods of apnea, which, if not correct-
ed with quick intubation and manual ventilation
of the veterinary patient, can lead to fetal hypoxia
and acidemia.30
Isoflurane was used to maintain anesthesia in this
case. It has been associated with improved canine neo-
natal survival at 7 days compared with other anesthetic
drugs including methoxyflurane, xylazine, and keta-
mine.35
Isoflurane can have undesirable side-effects,
including vasodilation resulting in significant hypoten-
sion and respiratory depression requiring mechanical
ventilation.42
Both of these effects are dose dependent43
so a light plane of anesthesia is ideal. Inhaled anesthe-
tics have been associated with decreased movement
and breathing in puppies after cesarean delivery.38
This
finding is important because ventilation is the primary
route of drug elimination and respiratory depression
cannot be reversed until the puppy begins to breathe.38
Sevoflurane would have been a better choice, but was
not available. The cardiovascular and respiratory ef-
fects are similar to isoflurane; however, it has very rap-
id induction and recovery times.42
It is a good choice
for cesarean deliveries because of rapid elimination by
the neonates.42
Local epidural anesthesia may have been helpful in
this case to decrease the amount of anesthetic drugs
necessary and to decrease fetal absorption and the con-
comitant respiratory depression that can be associated
with the use of general anesthetic agents.29
In one
study, epidural anesthesia produced the least respira-
tory and neurologic depression in puppies after cesar-
ean section compared with injectable and inhaled
anesthetics33
and was thought to be the best anesthe-
tic technique for cesarean section in the bitch.33
Local
anesthetics can also increase the quality of analgesia for
the dam postoperatively.44
In humans, the maternal
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6. mortality rate is 17 times lower when local anesthetic
techniques are used compared with general an-
esthesia.45
However, local anesthetics are not without
side effects and in humans can result in hypotension by
inducing sympathetic blockade,30
respiratory depres-
sion because of intercostal muscle paralysis, and spinal
headaches.44
Butorphanol was used perioperatively to provide
analgesia and sedation. In retrospect, this was not an
ideal choice for this patient. Butorphanol is indicated
for mild-to-moderate pain and provides only a short
duration of analgesia.42
In dogs, the analgesic effects
last as little as 30–60 minutes after IV administration.42
Pure m-opioid agonists would have been more effective
at reducing doses of induction and maintenance drugs
and would have provided better maternal analgesia.30
As a general class, opioids have not been associated
with increased mortality in puppies delivered via ces-
arean section.35
Fentanyl would have been a good
choice as an induction agent and perioperative analge-
sic in this dog. It is a powerful m-agonist42
with a rapid
onset and short duration of action.30
Fentanyl can be
used as an induction agent and can be titrated to effect
using a CRI (1–5 mg/kg/hr) during and after surgery. In
humans, fentanyl caused no change in Apgar scores,
blood gases, or uterine blood flow.30
The dog in this
case was treated with a CRI of lidocaine for the ven-
tricular arrhythmia during the first postoperative peri-
od. Lidocaine infusions may augment opioid-induced
analgesia in dogs46
and may have provided some ad-
ditional pain control in this case. If used cautiously,
lidocaine is considered safe in pregnant dogs.36
During
the anesthetic and surgical procedures, every attempt
was made to maintain uterine perfusion by monitoring
and maintaining the MAP of the dam/bitch above
70 mmHg. Hypotension during the initial surgery was
likely due to a combination of factors including hypo-
volemia, hypotensive effects of the anesthetic drugs,
secondary to late gestation,30
and decreased cardiac
output secondary to the increase in intrapericardial
pressure causing a decrease in cardiac filling and car-
diac preload. Hetastarch was administered to maintain
colloid osmotic pressure and systemic arterial BP, and
dobutamine was added as a positive inotrope when the
dog’s mean arterial BP declined to an unacceptable
level. Dopamine and dobutamine have actually been
shown to decrease uterine blood flow in pregnant ewes
at doses of 4–40 mg/kg/min and should generally be
reserved for persistent nonresponsive hypotension.47
Ephedrine has been shown to preserve uterine blood
flow in sheep better than other a-1 agonists,30
but has
not been evaluated in pregnant dogs. The dog in this
case developed peripheral edema 4 days after the initial
surgery. Differential diagnoses for the edema in this
case included hypoalbuminemia, vasculitis, dependent
edema secondary to recumbency, decreased venous re-
turn because of increased intra-abdominal pressure,
and fluid overload. Hypoalbuminemia (1.3 g/dL, refer-
ence range 2.5–3.0 g/dL) was present in this case and
may have been a contributing factor. Colloid osmotic
pressure measurement would have been useful, but
was not performed. Hetastarch was added to increase
colloid osmotic pressure and restore fluid balance. The
CVP was elevated in this case, making decreased ve-
nous return or fluid overload likely. CVP is a measure-
ment of pressure within the intrathoracic portion of the
cranial vena cava and is only slightly higher than the
right atrial pressure.48
Right atrial pressure has been
shown to decrease in pregnant dogs49
and, therefore,
the CVP would be expected to be low in this case. CVP
is affected by cardiac output, venous volume, and ve-
nous return to the heart.48
The initial elevated CVP was
likely because of increased right ventricular end di-
astolic pressure secondary to pressure from the herni-
ated tissue within the pericardial sac. The persistently
elevated CVP measurements after the initial surgery
were unexpected and may have been an indication of
increased blood volume secondary to fluid overload,
fluid retention associated with pregnancy, or reduced
cardiac compliance. A carefully controlled furosemide
CRI and physical therapy were initiated to help reduce
the edema. Furosemide is a loop diuretic that binds to
and impairs the Na1
K1
2Cl cotransport mechanism in
the thick ascending limb of the loop of Henle.50
It in-
creases urinary sodium and chloride excretion and re-
duces vascular volume.50
Furosemide also increases
venous capacitance, possibly due to prostaglandin re-
lease.50
These effects result in a fluid shift from a third
space into the vascular space, thus reducing edema.
Furosemide is considered safe in pregnant dogs if used
cautiously.36
The dog in this case became significantly
anemic and hypoalbuminemic after surgical repair of
the PPDH. Factors contributing to the anemia may in-
clude blood loss associated with surgery and hemodi-
lution along with the relative anemia found during
pregnancy. Anemia in pregnant animals occurs due to
increased plasma volume, which increases to provide
adequate fetal blood flow.30
The hypoalbuminemia
postoperatively was likely due to a combination of
hemorrhage during surgery, hemodilution, and de-
creased nutrient intake. Hypoalbuminemia in this case
could contribute to poor wound healing and low onco-
tic pressure. The dog was treated with HES to increase
oncotic pressure and fresh-frozen plasma along with
supplemental nutrition to provide sources of protein.
The liver enzymes and alkaline phosphatase were also
elevated after the initial surgery. The ALT and AST
elevations were likely related to enzyme release into
Veterinary Emergency and Critical Care Society 2006, doi: 10.1111/j.1476-4431.2006.00200.x
82
G.D. Statz et al.

7. circulation from the prior hepatocellular hypoxia and
ischemia associated with the liver tissue that was en-
trapped in the pericardium. Likewise, the alkaline
phosphatase elevation may have been related to
cholestasis during liver entrapment. Nutritional sup-
port after surgical repair of the PPDH was another
concern in this case. Fetal size increases rapidly during
the last 3–4 weeks of gestation, which causes a 15–25%
increase in energy requirements.51
A 20–50% increase
over maintenance caloric intake is required from the
fourth to seventh weeks to provide adequate energy for
fetal growth and to prepare for lactation.52
Increasing
the fat content in the diet provides increased caloric
density and should be balanced with a proportionate
increase in protein, vitamins, and minerals.52,53
The dog
in this case experienced postoperative vomiting and
regurgitation, which made total enteral nutrition diffi-
cult. An NG tube was placed to provide for partial en-
teral nutritional support and to maintain the health of
the enterocytes. Esbilac has been recommended by the
manufacturer as a nutritional supplement for pregnant
and lactating bitches to provide additional fat, protein,
and minerals and was administered via the NG tube.
The dog was also supplemented with parenteral
nutrition at approximately 2 times her resting energy
requirement taking into account illness energy require-
ments and those of late gestation. The resting energy
requirement was calculated using the standard formula
(30 BW[kg]170) and was multiplied by an illness
factor of 1.4, followed by a factor of 1.25 for late preg-
nancy requirements. Gastric reflux is common in preg-
nant humans because of the increased intra-abdominal
pressure during pregnancy and because of a hormone-
induced relaxation of the gastro-esophageal sphincter.44
Gastric contents become more acidic, and gastric emp-
tying is delayed during pregnancy.32
These changes
lead to important considerations for supportive care in
sick, hospitalized pregnant animals. The dog in this
case was treated with gastroprotectants, H2 receptor
blockers, and promotility drugs to help decrease the
acidity of the gastric contents, protect the lining of the
esophagus and stomach, increase lower gastroesopha-
geal sphincter tone, and stimulate motility of the upper
gastrointestinal tract. The NG tube was also used to
prevent esophageal reflux and potential aspiration
pneumonia by suctioning the gastric contents.
It is important to monitor and treat for hypoxemia in
critically ill and pregnant animals. The dog in this case
had poor oxygenation following surgical intervention
to correct the PPDH. Oxygen desaturation occurs easily
during pregnancy.54
Pregnant animals have a decreased
functional residual capacity and total lung volume.30
Atelectasis has been shown to occur more readily.55
Other possible causes for the decreased oxygen
saturation during the management of this case may
have included pulmonary parenchymal disease such as
pneumonia or pulmonary edema associated with fluid
overload, hypoalbuminemia, or re-expansion injury,
barotrauma because of mechanical ventilation during
anesthesia, hypoventilation, or vasculitis. A decision to
take the dog back to surgery for the cesarean section
was based on several factors including the decline in
body temperature and serum progesterone concentra-
tion. Body temperature declines 12–36 hours before
whelping22
and progesterone levels less than 2 ng/mL
have been consistently documented 36–48 hours before
whelping.22
The dog in this case was too weak to
deliver the puppies on its own, and the increased intra-
abdominal pressure from labor could have been detri-
mental, given the recent abdominal surgery with hernia
repair and the associated healing incisions.
Conclusion
This report describes a case of PPDH complicated by
pregnancy. It demonstrates the fact that PPDH may be
subclinical until a complicating factor like pregnancy
occurs. The standard surgical and post-surgical treat-
ment for PPDH had to be approached carefully in this
case. The bitch was provided with cardiovascular and
respiratory support before, during, and after PPDH
surgery to sustain adequate uterine perfusion. Nutri-
tional support between the staged surgeries in this case
was essential to allow continued growth of the puppies
and to prepare for lactation. This intensive monitoring
and aggressive supportive care for several days after
repair of the PPDH enabled a successful cesarean
delivery and survival of 7 healthy puppies and their
mother.
Footnotes
a
Bayer Corporation, West Haven, CT.
b
Baxter, Deerfield, IL.
c
Dinamap, Johnson Johnson, Tampa, FL.
d
Intracath, Becton Dickinson Vascular Access, Sandy, UT.
e
Fort Dodge Animal Health, Fort Dodge, IA.
f
Smith Kline Beecham Pharmaceuticals, Philadelphia, PA.
g
Fort Dodge Animal Health.
h
Elkins-Sinn Corporation, Cherry Hill, NJ.
i
Abbott Laboratories, North Chicago, IL.
j
Ethicon Inc., Somerville, NJ.
k
Feeding Tube and Urethral Catheter, Tyco Healthcare Group LP,
Mansfield, MA.
l
Hetastarch 6%, Abbott Laboratories.
m
Ben Venue Labs Inc., Bedford, OH.
n
Lidocaine 2%, Abbott Laboratories.
o
Potassium chloride, Abbott Laboratories.
p
Warrick Pharmaceuticals, Corp., Reno, NV.
q
Abbott Laboratories.
r
Faulding Pharmaceutical Co., Paramus, NJ.
s
Pedi-Tube Nasogastric Feeding Tube, Kendall Health Care,
Mansfield, MA.
t
Nestle, Glendale, CA.
Veterinary Emergency and Critical Care Society 2006, doi: 10.1111/j.1476-4431.2006.00200.x 83
PPDH in a pregnant dog

8. u
PetAg Inc., Hampshire, IL.
v
Prescription Diet Canine Feline a/d, Hill’st, Topeka, KS.
w
Phoenix Scientific, St. Joseph, MO.
x
Abbott Laboratories.
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