This document discusses abdominal compartment syndrome (ACS). It defines ACS as a sustained intra-abdominal pressure (IAP) above 20 mmHg associated with new organ dysfunction. Normal IAP is 5-7 mmHg. Intra-abdominal hypertension is defined as IAP above 12 mmHg and is graded. ACS can result from primary abdominal causes or secondary extra-abdominal causes and leads to organ dysfunction through reduced blood flow. Accurate IAP monitoring via bladder pressure is important for early detection and treatment to prevent organ failure.

1. Abdominal Compartment Syndrome
By
Maged Abulmagd,MD,EDIC

2. ? What it is ?
A disease process that dramatically increases
organ failure and death for medical and surgical
ICU patients

3. What is a normal intra-abdominal
pressure
or
IAP
This is the pressure within the abdominal cavity
5 – 7 mmHg is normal in a critically ill adult

4. Intra – abdominal Hypertension
IAH
• Defined as sustained or repeatedly elevated
abdominal pressure
• >12 and is graded

5. Grades of IAH
• Grade I 12 – 15 mmHg
• Grade II 16 – 20 mmHg
• Grade III 21 – 25 mmHg
• Grade IV >25 (ACS)

6. IAH
• Sustained pressure, >12 that has significant
effects on abdominal organs and cardiac output
with subsequent dysfunction of both abdominal
and extra-abdominal organs

7. Understanding Abdominal Compartment Syndrome
• APP – Abdominal perfusion pressure
• MAP – Mean arterial pressure
• IAP – Intra-abdominal pressure
• APP = MAP – IAP
• A critical IAP that leads to organ failure is
variable by patient & a single threshold cannot
be applied globally to all patients
• APP is superior to IAP, arterial pH, base deficit
& lactate in predicting organ failure & patient
outcomes

8. Definition of ACS
• A sustained IAP > 20 mmHg (with or without an
APP of <60 mmHg) that is associated with new
organ dysfunction/failure
• Adverse physiological effects caused by massive
interstitial and retroperitoneal swelling which
leads to organ or multi-organ failure
• Historically IAPs as high as 40 mmHg had been
acceptable; therefore, most clinicians are
concerned when IAP reaches 20 – 25 mmHg

10. Abdominal Compartment Syndrome
• Primary ACS – associated with injury or disease
in abdomen/pelvis requiring early surgical or
interventional radiological screening
• Secondary ACS is from conditions not
originating in the abdomen/pelvis
• Recurrent ACS is the redevelopment of ACS
following previous surgical or medical treatment
of primary or secondary ACS

11. Common Causes of ACS
• Primary causes
– Abdominal trauma with
bleeding
– Pancreatitis
– Ruptured abdominal aortic
aneurysm
– Retroperitoneal hematoma
– Obstructions/ileus
– Pneumoperitoneum
– Abcesses
– Visceral edema

12. Common Causes
• Secondary Causes
– Acute respiratory distress
syndrome
– Major trauma or burns
– Massive fluid resuscitation
– Hypothermia <33 degrees
Celsius
– Acidosis with pH < 7.2
– Hypotension
– Massive blood transfusion > 10
units
– Coagulopathy
– Sepsis

13. Common Causes
• Chronic Causes
– Obesity
– Liver failure with ascities
– Malignancies

14. Ischemia Inflammatory
response
Capillary leak
Tissue Edema
(Including bowel wall and mesentery)
Intra-abdominal hypertension
Fluid
resuscitation
Physiologic Insult/Critical Illness

16. Pathophysiological Consequences
of ACS
• Cardiovascular
– Reduced Cardiac Output
• Compression of the
inferior vena cava and
portal vein
• Reduced blood return to
the heart
• Afterload increased from
mechanical compression of
vascular beds and
vasoconstriction

17. Pathophysiology
• Cardiovascular
– Reduced Stroke volume
– Tachycardia
– Increased pressure on
great vessels making
hemodynamic monitoring
challenging with falsely
elevated and misguiding
pressures
– Increased risk for
thromboembolic events
secondary to venous stasis

18. Pathophysiology
Pulmonary
– Reduced lung compliance
secondary to diaphragmatic
elevation leads to
– Hypoventilation and
ventilation-perfusion
mismatch
– Increased work of
breathing
– Hypoxia and hypercarbia
– Respiratory failure

19. Pathophysiology
• Respiratory
– Increased peak airway
secondary to decreased
lung compliance
– Increased risk of
barotrauma

20. Pathophysiology
• Renal
– Increased IAP leads to
decreased renal blood flow
and decreased glomerular
filtration
– Oliguria may be observed
with IAP of 15 - 20
– An IAP of >30 leads to
anuria
– Increase of antidiuretic
hormone and activation of
renin-angiotensin-
aldosterone system
– Increased water retention

21. Pathophysiology
• Abdominal Visceral
– Reduced blood flow which
leads to intestinal ischemia
– Decreased blood flow to all
abdominal organs

22. Pathophysiology
• Central Nervous System
– Increased thoracic and
central venous pressure
leads to
– Decreased cerebral outflow
of blood
– Increased intracranial
pressure which leads to
decreased cerebral
perfusion pressure

23. Measuring Intra-Abdominal Pressure

24. Importance of accurate measurement
• Physical examination yields low levels of
detection of IAH/ACS
• Early detection and intervention reduces
morbidity and mortality.
• Diagnosis is dependent on frequent and accurate
measurement of IAP (watching trends)
• Cost effective, safe and accurate

25. Assessment Guidelines
• New ICU admission
• Evidence of clinical deterioration
• Pt has two risk factors for IAH/ACS
– Decreased abdominal wall compliance
– Increased intra-luminal contents
• ileus, gastroparesis, obstruction
– Increased abdominal contents
• Pneumoperitoneum, hemoperitoneum, ascities, liver
dysfunction
– Capillary Leak/fluid resuscitation

26. IAH/ACS Assessment algorithm from
World Society of Abdominal Compartment
Syndrome (WSACS)
www.wsacs.org
Excellent references

27. Types of Measurements
• Direct Pressure via intraperitoneal catheters
• Indirect Pressure
– Gastric Measure
– IVC
– Rectal
– Urinary bladder pressure – Gold Standard

28. Urinary Bladder Pressure
Most technically reliable
Correlate closely with pressures measured directly
in the abdominal cavity
Reliably reproducible
Transduced through a Foley catheter

30. Intermittent Monitoring
• Open Systems
• Closed Systems

31. Equipment needed for open measurement
• Disposable transducer
• 12” pressure monitoring
tubing
• 4-way stopcock
• Red dead-ender
• 60 cc, lure-lock syringe,
sterile
• Sterile normal saline
• Clamp, non-sterile
• Level

32. Procedure for open, intermittent monitoring
• Collect and gather all
supplies
• Attach stopcock to end of
sterile transducer
• Important to maintain
sterile technique to avoid
contamination and
potential infectious
process

33. Procedure for open, intermittent monitoring
• Attach pressure tubing to
the remaining end of the
transducer

34. Procedure for open, intermittent monitoring
• Fill 60 cc syringe with 40
cc of sterile normal saline
• Attach syringe to side
port of the stopcock
• Flush stopcock, pressure
tubing and transducer
with the normal saline
ensuring all air is removed

35. Procedure for open, intermittent monitoring
• Clamp the urinary drain tubing distal to the sampling port
• Cleanse the sampling port with alcohol
• Using sterile technique attach the pressure tubing to
the LuerLok connecting sampling port of the urinary
catheter

36. Procedure for open, intermittent monitoring
• Instill 25 cc of sterile normal saline into urinary
catheter via the sampling port (Larger vol. of NS can result in
falsely elevated IAP measurements)
• Briefly release the clamp to allow fluid from the bladder
to fill tubing and reclaim
• Read the IAP as a mean pressure at end expiration 30 –
60 seconds after instillation.
• Perform with patient supine
• Notify MD for sustained IAP greater than 12 mmHg
unless otherwise ordered.

37. Disadvantages with open, intermittent monitoring
• Collecting a number of items
• Correct assembly
• Risk of infection every time system is accessed

38. Closed Monitoring
• AbViser, Wolfe Tory Medical, SLC, UT
• Pre-assembled kit
• Adapts to Foley catheter and any transducer
• Reduces risk of infection
• Readily available, easily assessable data

40. Measuring Bladder Pressure
• Position patient flat & supine
• Read Mean pressure
• End Expiration

41. Management Considerations
Early detection via frequent monitoring of at risk
patients
Screen for IAH/ACS in new ICU admissions with
new or progressive organ failure
Look for trends of increasing abdominal pressures
Preserve organ perfusion and treat clinical
conditions with grades I & II

42. Management Considerations
Early surgical consultations for at risk patients
Early intervention for ACS or Grade III
Anticipate emergent surgical interventions to
prevent tissue damage/death

43. Management Considerations
• Anticipate patient to return with an alternative
surgical closure or “open” abdomen.
• The abdominal contents will not be sutured into
the abdominal cavity
• Alternative closures vary from surgeon to
surgeon
Examples:
The “Bogata Bag” – A 3 L IV bag, open and
sterilized and applied to the abdominal opening

45. Management Considerations
• KCI Vac Pac
• Sponge overlies abd.
Dressing/contents
• Attached to
continuous suction
canister
• Covered over with
occlusive dressing

46. Management Considerations
• Ioban Dressing
• An occlusive dressing
with iodine
impregnation
• Surgical towels will
overlie abdominal
contents with JP
drains – Ioban
overlies abdomen

47. Another Excellent Reference,
IAH/ACS Management Algorithm from
WSACS
www.wsacs.org

48. Conclusion
• Know the difference between IAH and ACS
– IAH = Abdominal pressure >12 and graded via severity
– ACS = Abdominal pressures > 20 – 25
Identify At risk patient populations
abdominal trauma/major burns
Pancreatitis
Ruptured AAA
abdominal obstructions/ischemia
ect….

49. Conclusion
• Understand the pathophysiology
– Ischemia/inflammation – inflammatory response –
capillary leak + fluid resuscitation = tissue edema in an
uncompromising cavity = ACS = tissue/cell death = bad
Perform an accurate assessment of abdominal pressure
using Abdominal bladder pressure monitoring via Foley
catheter or AbViser – Wolfe Torey Medical
Anticipate patient interventions/outcomes
Support/educate family

50. Case Study - 63 Y.O. male pt with pancreatitis is admitted
to the ICU. Pt has history of gallbladder disease, COPD
and ETOH abuse. He has been without ETOH reportedly
for approximately 24 hrs. VS upon admission are T 38.0,
HR 130, BP 90/62, MAP 61, RR 30 – 34 & O2 sat of 91%
on 100% NRB, wt approximately 125 kg. His breathing is
labored and he has c/o SOB. He is also mildly agitated &
resistive to O2 therapy with Bi-Pap. His lung sounds are
diminished bilaterally. Denies recent increase in cough.
His abdomen is firm and distended. States unknown last
BM but + for N/V.

51. • He has a Foley catheter in place with
approximately 100 cc of dark, amber urine in the
collection chamber. Lab values show H&H of
10.2/31.0, wbc 20, K 5.0, Na 142, Foley was
placed approximately 4 hours ago in the ED. His
peripheral arterial pulses are weak and thready
and his BLE show signs of PVD. He is currently
receiving bolus # 3 of NS.

52. Does this patient need IAP monitoring?
Is he at risk?
What could you use as a reference if you were
unsure?

53. After consulting with your attending MD, it is
decided that a baseline ABP reading would be
appropriate for this patient. Your initial ABP is
15mmHg.

54. Does this value represent intra-abdominal
hypertension or abdominal compartment
syndrome?
What is his APP based on his MAP and IAP?

55. What grade would you give this value?
Why is this patient at risk?
How would you proceed?

56. After reporting the findings to the resident,
serial ABP readings are ordered Q6 HR. His SBP
continues to remain low with a map consistently <
65 & his respiratory status continues to
deteriorate. The resident also orders another
fluid bolus.
• With what you have learned about IAH /ACS
management, what clinical suggestions could you
collaborate on to advocate for your patient?
•

57. After collaboration with the medical team the decision is
made to intubate as his O2 sats continue to drop and RR
rate cont. to increase. After intubation and appropriate
sedation, the patient continues to have an increasingly
firm abdomen, increased HR and decreased SBP and map
<60 despite added norepinephrine. He is also now vented
with a respiratory rate of 24 – 30 and has become
increasingly agitated. His urine output for the last 2
hours is 30 ml. You repeat the ABP prior to the 4 hr
interval and you notice that his ABP value has risen to 20
after two separate measurements. What could you
expect at this point?

58. • www.abdominalcompartmentsyndrome.org
• The World Society of Abdominal Compartment
Syndrome, www.wsacs.org