Abdominal Compartment Syndrome

Question 1

What are the World Society of Abdominal Compartment Syndrome (WSACS) thresholds for intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS)

Answer 1

Normal: 5 - 7
IAH Grade 1: 12 - 15
IAH Grade 2: 15 - 20
IAH Grade 3: 20 - 25
IAH Grade 4: > 25
ACS: > 20 with new organ dysfunction

(all figures in mmHg)

Question 2

How might you classify risk factors for ACS?

Answer 2

• Reduced abdominal wall compliance
• Increased intra-luminal contents
• Increased intra-abdominal contents
• Capillary leak/fluid resuscitation

Question 3

Give some examples of risk factors for ACS related to reduced abdominal wall compliance

Answer 3

Acute respiratory failure
Abdominal surgery with a tight closure
Major trauma/burns
Prone position
Head elevation > 30 degrees
Central obesity

Question 4

Give some examples of risk factors for ACS related to intra-liminal contents

Answer 4

Gastoparesis/ileus
Pseudo-obstruction

Question 5

Give some examples of risk factors for ACS related to increased intra-abdominal contents

Answer 5

Haemoperitoneum
Pneumoperitoneum
Ascites

Question 6

Give some examples of risk factors for ACS related to increased capillary leak

Answer 6

In general, any process that leaks to SIRS:
- Sepsis
- Burns
- Pancreatitis
- Major trauma
- MOF etc.

Question 7

Define abdominal perfusion pressure (APP)

Answer 7

APP = MAP - IAP

Question 8

What is the main target abdominal perfusion pressure?

Answer 8

60 mmHg

So MAP needs to be pushed to a minimum of 60 + IAP

Question 9

Define the renal flirtation gradient pressure

Answer 9

Filtration gradient = MAP - IAP - Proximal Tubular Pressure

Question 10

Describe the process for measuring IAP

Answer 10

Intra-vesical approach is preferred
Catheterise patient and allow urine to drain
Connect pressure transducer to the Foley catheter sample port. Set this up with a pressure bag just like you would an arterial line, so you can flush the line
Clamp the urinary catheter distal to the pressure transducer connection
Lie patient flat and zero the transducer at the iliac crest in the mid-axillary line
Instil 25 mL saline into the bladder (1 mL/kg if < 20 Kg). A three way tap and syringe will be needed.
Wait 60 seconds
Take the measure at end expiration and in the absence of abdominal wall contraction