This document discusses abdominal compartment syndrome (ACS), which refers to organ dysfunction caused by increased intra-abdominal pressure known as intra-abdominal hypertension (IAH). The key points are: 1. ACS can impair nearly every organ system but is often underdiagnosed. Diagnosis requires measuring intra-abdominal pressure via bladder catheter. 2. Management consists of supportive care initially but may require surgical decompression of the abdomen in severe cases. 3. Following decompression, temporary abdominal closure techniques are used until definitive closure can be achieved or a planned hernia results.

1. By
Mahmoud Zaghloul Raslan, MD
Surgical Consultant, MGH, Madina

2. Abdominal compartment syndrome
refers to organ dysfunction caused by
intraabdominal hypertension (IAH).
It may be under-recognized because:
- it primarily affects patients who
are already quite ill
- organ dysfunction may be
incorrectly ascribed to progression of
the primary illness.

3. Since treatment can improve organ
dysfunction, it is important that
the diagnosis be considered in the
appropriate clinical situation
without any delay

4. Intraabdominal hypertension
(IAH) and abdominal
compartment syndrome
(ACS) are distinct clinical
entities and should not be
used interchangeably.

5. Intraabdominal pressure (IAP) :
It is the steady state pressure concealed
within the abdominal cavity. For most
critically ill patients, an IAP of 5 to 7
mmHg is considered normal.
Patients with increased abdominal girth
that developed slowly e.g. the mobidly
obese and pregnant individuals may
have chronically higher baseline IAP (as
high as 10 to 15 mmHg) without adverse
sequelae

6. Abdominal perfusion pressure
(APP):
It is calculated as the mean
arterial pressure (MAP) minus
the IAP
APP = MAP - IAP.
Elevated IAP reduces blood
flow to the abdominal viscera

7. Abdominal perfusion pressure
(APP) was found to be better
than other resuscitation
endpoints e.g. hourly urinary
output for predicting the
outcomes.
A target APP of at least 60 mmHg
is correlated with improved
survival from IAH and ACS.

8. Intraabdominal hypertension
(IAH)
It is defined as a sustained IAP
of ≥12 mmHg.

10. Intraabdominal hypertension
(IAH) can be further graded as
follows:
- Grade I = IAP 12 to 15
mmHg
- Grade II = IAP 16 to 20
mmHg
- Grade III = IAP 21 to 25
mmHg
- Grade IV = IAP >25 mmHg.

11. Hyperacute IAH :
- Elevation of the IAP lasting only
seconds.
- It is due to laughing, coughing,
straining, sneezing, defecation, or
physical activity. IAH with ACS due to
gastric over-distention following
endoscopy has been described.
Acute IAH:
- Elevation of the IAP that develops over
hours.
- It is usually the result of trauma or
intraabdominal hemorrhage and can lead
to the rapid development of ACS.

12. Subacute IAH :
- Elevation of the IAP that develops
over days.
- It is most common in medical
patients and can also lead to ACS.
Chronic IAH:
- Elevation of IAP that develops over
months (pregnancy) or years
(morbid obesity).
- It does not cause ACS, but does
place the individual at higher risk for
ACS if they develop superimposed
acute or subacute IAH.

13. Abdominal compartment syndrome
(ACS):
- It is defined as a sustained IAP
>20 mmHg (with or without APP
<60 mmHg) that is associated with
new organ dysfunction.
For clinical purposes, ACS is better
defined as IAH-induced new organ
dysfunction without a strict IAP
threshold, because no IAP can
predictably diagnose ACS in all
patients.

14. Patients with an IAP < 10
mmHg generally do not have
ACS, while patients with an IAP
> 25 mmHg usually have ACS.
Patients with an IAP 10-25
mmHg may or may not have
ACS, depending upon individual
variables such as blood pressure
and abdominal wall compliance.

15. Higher systemic blood
pressure may maintain
abdominal organ perfusion
when IAP is increased, since
the abdominal perfusion
pressure (APP) is the
difference between the mean
arterial pressure and the IAP.

16. Abdominal wall compliance initially
minimizes the extent to which an
increasing abdominal girth can elevate
IAP .
- When a critical abdominal girth is
reached, abdominal wall compliance
decreases abruptly. Further increases
in abdominal girth beyond this critical
level result in a rapid rise of IAP and
ACS if untreated.
- Increased abdominal wall
compliance due to chronic increased
abdominal girth (e.g. pregnancy,
cirrhosis with ascites, morbid obesity)
may protect against ACS .

17. The incidence of IAH is less
well characterized.
- The incidence of ACS in
trauma patients varies
considerably.
- It ranges from 1 to 14
percent in different studies.

18. ACS was considered present if there was:
- persistent IAH
- progressive organ dysfunction
despite resuscitation and
- improvement following
decompression

20. ACS can be classified as:
- Primary ACS is due to injury or disease in
the abdominopelvic region (e.g. abdominal
trauma, hemoperitoneum, pancreatitis);
intervention (surgical or radiologic) of the
primary condition is often needed.
- Secondary ACS refers to conditions that
do not originate in the abdomen or pelvis
(e.g. fluid resuscitation, sepsis, burns).
- Recurrent ACS defines a condition in
which ACS develops again following
previous surgical or medical treatment of
primary or secondary ACS

24. ACS generally occurs in patients who are critically ill due to any of a wide
variety of medical and surgical conditions. Some of these include:
-Trauma : Injured patients in shock who require aggressive fluid
resuscitation are at risk for ACS.
- Burns: Patients with severe burns (>30 percent total body surface
area) with or without concomitant trauma are also at risk for ACS.
Importantly, ACS must be distinguished from other intraabdominal
problems that occur in these critically ill patients (eg, necrotizing
enterocolitis, ischemic bowel).
- Liver transplantation: IAH (IAP >25 mmHg) was found following liver
transplantation in 32% patients.
- Abdominal conditions : Massive ascites, bowel
distension, abdominal surgery, or intraperitoneal bleeding can
increase intraabdominal pressure.
- Retroperitoneal conditions: Retroperitoneal pathologies, such as
ruptured abdominal aortic aneurysm, pelvic fracture with
bleeding, and pancreatitis, can lead to ACS.
- Medical illness: Conditions that require extensive fluid
resuscitation (e.g. sepsis) and are associated with third spacing of
fluids and tissue edema can increase IAP.
- Post-surgical patients: Patients undergoing operations in which
they are given large volume resuscitation, particularly with crystalloid
in the face of hemorrhagic or septic shock, are at risk for ACS.

25. IAH can impaire the function of
nearly every organ system,
thereby causing ACS .

27. It is desirable to recognize IAH early, so it
can be treated before progressing to
ACS.
Symptoms:
- Most patients who develop ACS are
critically ill and unable to communicate.
- The rare patient who is able to convey
symptoms may complain of malaise,
weakness, lightheadedness, dyspnea,
abdominal bloating, or abdominal pain.

28. Physical signs:
- Nearly all patients with ACS have
a tensely distended abdomen.
Despite this, physical examination
of the abdomen is a poor
predictor of ACS.
- Progressive oliguria and
increased ventilatory
requirements are also common in
patients with ACS.

29. - Other findings may include
hypotension, tachycardia, an
elevated jugular venous pressure,
jugular venous distension,
peripheral edema, abdominal
tenderness, or acute pulmonary
decompensation.
- There may also be evidence of
hypoperfusion, including cool skin,
obtundation, restlessness, or lactic
acidosis

30. Imaging findings:
- Imaging is not helpful in the diagnosis of
ACS.
- CXR may show decreased lung volumes,
atelectasis, or elevated hemidiaphragms.
- Computed tomography (CT) may
demonstrate tense infiltration of the
retroperitoneum that is out of proportion
to peritoneal disease, extrinsic
compression of the inferior vena cava,
massive abdominal distention, direct
renal compression or displacement,
bowel wall thickening, or bilateral
inguinal herniation

31. Definitive diagnosis of ACS
requires measurement of the
IAP.
This is particularly true for
patients who have trauma, liver
transplantation, bowel
obstruction, pancreatitis, or
peritonitis because these
conditions are known to be
associated with ACS.

32. Measurement of intraabdominal
pressure:
- IAP can be measured indirectly
using intragastric, intracolonic,
intravesical (bladder), or inferior
vena cava catheters.
Measurement of bladder (ie,
intravesical) pressure is the
standard method to screen for IAH
and ACS. It is simple, minimally
invasive, and accurate.

33. Postoperative (abdom. Surgery) pts
Pts with abdominal trauma
Ventilated pts with other Organ
Failure
Pts with signs of ACS:
 Oliguria, hypoxia, hypotension,
acidosis, mesenteric ischemia, ileus,
elevated ICP.
Pts with high cumulative fluid balance
Pts with abdominal packing

36. Management of IAH and ACS
consists of supportive care
and, when needed, abdominal
decompression.
Some exceptions include
escharotomy release to relieve
mechanical limitations due to
burn eschars and percutaneous
catheter decompression to relieve
tense ascites.

37. Supportive care:
- Goals:
- Reduction of intraabdominal
volume.
- Measures to improve abdominal
wall compliance .

38. Nasogastric and rectal drainage
are a simple means for
reducing IAP in patients with
bowel distension.
Hemoperitoneum, ascites, intra
abdominal abscess and
retroperitoneal hematoma
occupy space and can elevate
IAP. In some cases, these
collections can be evacuated
using percutaneous techniques.

39. Patient should be placed in a supine
position.
Abdominal wall compliance can be
improved with adequate pain
control and sedation.

40. Ventilatory support:
- High peak and mean airway
pressures can be problematic. Tidal
volume reduction, a pressure-limited
mode, and/or permissive
hypercapnia may be necessary.
Positive end-expiratory pressure
(PEEP) may reduce ventilation-
perfusion mismatch and improve
hypoxemia.

41. Hemodynamic support:
- For patients with IAH, limiting
the amount of fluid
administration may decrease the
risk of developing ACS.
- Some clinicians prefer to use
colloids under this circumstance
instead of crystalloids.

42. There is no role for diuretic therapy
in the resuscitation of patients with
acute ACS.
The only appropriate management is
to open the abdomen.

43. SURGICAL DECOMPRESSION:
- There is general agreement that
surgical decompression is indicated
for ACS.
- Decompressing the abdomen
prior to the development of ACS is
becoming increasingly common
and may improve survival.

44. Various approaches include:
- Surgical decompression for
all patients whose IAP is
greater than 25 mmHg.
- Many clinicians suggest
surgical decompression at a
lower IAP (e.g. 15 to 25
mmHg.

45. Surgical decompression is considered
when the IAP is 20 mmHg or greater,
regardless of signs of ACS..
Most surgeons perform
decompression and then maintain
an open abdomen using temporary
abdominal wall closure.
Surgical decompression can be
performed in the operating room if
the patient is medically stable for
transfer or at the bedside in the
intensive care unit.

46. MORBIDITY AND MORTALITY:
- Failure to recognize IAH prior to the
development of ACS causes tissue
hypoperfusion, which may lead to
multisystem organ failure, and
potentially death.
- Although the development of IAH
alone is not a predictor of multiorgan
failure, mortality for patients who have
progressed to ACS range from 40 to
100%.

47. INTRODUCTION:
- Refers to a defect in the
abdominal wall that exposes the
abdominal viscera.
Damage control surgery associated
with trauma and ACS is the most
frequent reason for open
abdomen.

48. Etiology:
- The most common circumstances
that result in open abdomen include
the following:
1. Damage control surgery:
- It is an operative strategy that is used
to manage immediately life-
threatening conditions by delaying
definitive management of less severe

49. 2. Abdominal compartment syndrome
(ACS):
-Increased volume in the abdomen
is typically the result of an increase
in interstitial fluid as is seen with
large volume resuscitation, but
space occupying fluid (blood or
ascites) in the peritoneum or
retroperitoneum can also
contribute.

50. 3. Septic abdomen:
- Bowel perforation with severe
contamination of the peritoneal
cavity can result in recurrent intra-
abdominal sepsis.
- Under this circumstance, it may be
desirable to leave the abdominal
wall open and use negative-pressure
wound therapy to remove residual
or reaccumulated fluid or pus.

51. 4. Refractory intracranial
hypertension :
- A more controversial indication
for open abdomen is refractory
intracranial hypertension
associated with traumatic brain
injury.

53. Complications of open
abdomen:
Related to fluid efflux from the abdomen,
exposure of the bowel, and abdominal
muscle retraction.
- Fluid loss:
- A significant amount of fluid can be lost
through an open abdomen.
- Protein loss:
– The fluid that is secreted by the
peritoneum is rich in protein with about 2
grams of protein lost from the abdomen for
each liter of fluid removed.

54. - Fistula formation:
– With open abdomen, the bowel is
frequently manipulated and is at risk
for injury.
- Loss of domain:
- With open abdomen from a midline
abdominal incision, the musculature of
the abdominal wall retracts the fascia
laterally.
- The use of a negative pressure wound
system helps to counteract the lateral
forces on the abdominal wall and may
allow primary closure of the fascia and
skin .

56. Temporary closure techniques:
- In some patients, delayed primary
closure of the abdominal fascia is
possible once edema subsides.
However, if closure is premature, ACS
can recur.

66. ABDOMINAL CLOSURE — Each
time the patient is returned to
the operating room, the
abdomen is assessed for
potential closure.

67. Fascial closure:
1. Primary fascial closure:
- Associated with the lowest rate
of complications following
management of the open
abdomen.
- Because of the high hernia rate,
biologic mesh reinforcement
during primary fascial closure is
frequently used.

68. 2. Functional closure:
- Functional closure refers to the
bridging of a residual fascial
defect with a biologic mesh (in-
lay technique).
- Once the biologic mesh is
placed, the skin is closed over
surgical drains placed into the
subcutaneous space.

69. 3. Planned ventral hernia:
- If primary fascial closure or
functional closure cannot be
achieved.
- Skin-only closure:
A skin-only closure
approximates the skin over the
fascial defect leaving a ventral
hernia.

70. - Split-thickness skin
graft:
- If the skin cannot be
approximated, the viscera within
the wound are allowed to adhere
to each other and to the
abdominal wall. Once the
abdominal contents have
“solidified” and there is a healthy
bed of granulation tissue overlying
the bowel, a split-thickness skin
graft can be placed.

84. Increased IAP is called intraabdominal
hypertension (IAH). Abdominal
compartment syndrome (ACS) refers to
organ dysfunction caused by
intraabdominal hypertension.
ACS can impair the function of nearly
every organ system.
Diagnosis of ACS requires that IAP be
measured. Symptoms, physical signs,
and imaging findings are insufficient to
diagnose ACS.

85. Management initially consists of careful
observation and supportive care. In
some cases abdominal compartment
decompression is required.
We suggest that surgical
decompression is not delayed until the
development of ACS (Grade 2C).
Following surgical decompression, an
open abdomen is maintained using a
variety of temporary abdominal
closure techniques.

86. Following temporary abdominal
closure, the patient is monitored in
ICU.
- Abdominal dressings associated
with the closure (adhesive
dressings, gauze, negative pressure
systems) are changed, as needed,
and the abdominal contents
inspected every two to three days.

87. We suggest the use of a negative pressure
system (towel or sponge based) to control
and quantify fluid loss (Grade 2C).
Once the indication for the open abdomen
has resolved, the abdomen is
closed, preferably with a primary fascial
closure. If primary fascial closure cannot
be achieved, functional closure can be
performed.
If the gap between the fascia is deemed to
be too large for a functional
closure, primary skin closure can be
performed, or skin grafts placed once a
layer of granulation tissue has developed.

88. The message is:
- Be ACS-minded.
- Decompress early.
- Apply TAC techniques.
- Definitive abdominal closure
as early as possible.