The document outlines the monitoring and management of intra-abdominal pressure (IAP) in critically ill patients, detailing the definitions, measurement procedures, and diagnostic criteria for intra-abdominal hypertension and abdominal compartment syndrome. It includes acceptable IAP ranges, risk factors, clinical presentations, and recommended equipment for monitoring. Lastly, the document provides procedural instructions and references for further reading on IAP management and its implications in critical care settings.

1. INTRA-ABDOMINAL
PRESSURE
Libin JOSE
Registered Nurse – Intensive Care Unit, Cairns Hospital

2. LEARNING
OBJECTIVES
Outline
The IAP monitoring procedure including steps, equipment and Key
principles.
Identify The ranges of IAP and interpret IAP to differentiate IAH and ACS.
State The diagnostic criteria for Abdominal Compartment Syndrome.
Define Intraabdominal hypertension.
Define Intra – Abdominal Pressure

3. WHAT IS INTRA-ABDOMINAL PRESSURE?
Intra-abdominal
Pressure is defined as
“a steady – state
pressure concealed
within the abdominal
cavity”.

4. WHAT IS AN ACCEPTABLE
IAP?
•Any Guess?
•Normal = 5mmhg.
•A critically ill patient = 5 - 7 mmhg.
•Obese patients = 15 mmhg.

5. WHAT IS INTRA-ABDOMINAL
HYPERTENSION (IAH)?
•Intra-abdominal Hypertension (IAH) is diagnosed
when a patient has three documented IAP
measurements of 12 – 20 mmhg, 4-6 hours apart.
•IAH, if not treated will progressively develop into
Abdominal Compartment Syndrome (ACS).

6. • Grade I, IAP 12-15 mmHg
• Grade II, IAP 16-20 mmHg
• Grade III, IAP 21-25 mmHg
• Grade IV, IAP > 25 mmHg
HOW TO GRADE INTRA-
ABDOMINAL HYPERTENSION?

7. DEFINE ABDOMINAL
COMPARTMENT SYNDROME?
•Abdominal compartment
syndrome is defined as
end-organ dysfunction
caused by intraabdominal
hypertension (IAH).

8. THE DIAGNOSTIC CRITERIA OF ACS
1. A patient has an IAP of more than
20 mmhg
2. With or without an abdominal
perfusion pressure (APP) <
60mmHg
3. Associated with single or multiple
organ dysfunction or failure.

9. HOW TO CALCULATE APP?
• Abdominal Perfusion pressure is calculated
by subtracting the IAP from simultaneous
mean arterial pressure (MAP) measurement.
APP = MAP - IAP

10. WHAT ARE THE CATEGORIES
OF ACS?
Abdominal compartment syndrome can be divided into the following 3 categories:
1. Primary or acute abdominal compartment syndrome occurs when intra-abdominal
pathology is directly and proximally responsible for the compartment syndrome.
2. Secondary abdominal compartment syndrome occurs when no visible intra-
abdominal injury is present but injuries outside the abdomen cause fluid
accumulation.
3. Chronic abdominal compartment syndrome occurs in the presence of cirrhosis and
ascites or related disease states, often in the later stages of the disease.

11. CLINICAL PRESENTATION
• Marked hypotension.
• Increased ventilatory pressures, specially
increased Peak Inspiratory pressure.
• Oliguria.
• Raised intra – abdominal pressure.
• Hypoxia, hypercapnia and respiratory acidosis.
• Lactate will be high on ABG.

12. RISK FACTORS FOR DEVELOPING
IAH• Abdominal surgery
• Anaemia
• Acidemia
• Acute pancreatitis
• Age
• Gastroparesis / Gastric distention / Ileus
• Hemoperitoneum or pneumoperitoneum or intraperitoneal fluid
collection.
• Hypothermia
• Increased head of the bed angle
• Intraabdominal infection

13. RISK FACTORS FOR
DEVELOPING IAH
• Liver dysfunction / cirrhosis with ascites
• Major trauma
• Massive fluid resuscitation or fluid overload
• Mechanical ventilation
• Obesity and increased BMI
• PEEP>10
• Poly-transfusion
• Prone positioning
• Sepsis
• Shock or hypotension

14. EFFECTS OF
INCREASED
INTRA-
ABDOMINAL
PRESSURE IN
EACH BODY
SYSTEM

15. HOW TO MEASURE THE IAP
• The World Society of the Abdominal Compartment Syndrome (2013) suggests
that
“IAP should be expressed in mmHg
and measured at end-expiration
in the complete supine position
after ensuring that abdominal muscle
contractions are absent
and with the transducer zeroed at the level of
the midaxillary line”.

16. THE GOLD STANDARD FOR
IAP MEASUREMENT
• IAP monitoring using a Foley’s catheter is known as
the gold standard where urinary bladder is acting
as the medium for the monitoring.
• Intermittent or continuous IAP monitoring using
bladder is the most commonly used and the
recommended method.

17. WHAT IS OUR WORK
INSTRUCTION
• We use intermittent monitoring using UnoMeter - Abdominal Pressure™ Kit.
• When two or more risk factors are present, and at the request of the Intensive Care
Consultant a baseline IAP should be recorded.
• If IAH is present, serial measurements should be performed through out the patient’s
critical illness.
• Measurements should be taken at least four hourly.
• Change the system every 7 days.

18. EQUIPMENTS
• Indwelling urinary catheter (IDC) - already
insitu, in most cases, if not a new urinary
catheter insertion kit is needed.
• 1 x new Metered Urinary Drainage Bag
• UnoMeter Abdo-Pressure™ Kit
• Sterile drape
• Alco wipes or Chlorhexidine solution and gauze
• Sterile gloves
• Skin Marker Pen (to mark the reference point)

19. HOW TO CONNECT TO AN EXISTING
IDC?
• The disconnection of the closed urine drainage system must be performed under sterile
conditions.
• Use sterile field, gloves, and antiseptic solution.
• Perform hand wash
• Unpack the UnoMeter tubing and close the red clamp.
• Attach UnoMeter Pressure™ between the patients IDC and the urine drainage bag.
• Place tubing around patients leg without loops

20. IAP MEASUREMENT
• Clean the IDC latex port with an AlcoWipe
• Prime UnoMeter™ with 20ml sterile 0.9% saline
• Place zero point on tubing next to patients reference point
• Open the red clamp. Measure intra-abdominal pressure
• Close the red clamp. Place tubing around patients leg without loops.
• Document pressure under “Abdominal Pressure” on the Metavision Neurovascular
Observations page

21. THE PRINCIPLES OF IAP
MESUREMENT
1. Expressed in mmHg (scaling on UnoMeter Abdo-Pressure™
Kit is in mmHg).
2. Measured in end-expiration.
3. Performed in supine position (standard head position: flat.
Can be in 30 degree head elevation as per special agreement
e.g. head trauma) Must be measured in the same position
every time.
4. Performed with an instillation volume of 20ml of NaCl 0.9%.
5. Measured 30-60 seconds after instillation to allow for bladder
detrusor muscle relaxation.
6. Measured in the absence of active abdominal muscle
contractions (no coughing or active movements.

22. A VIDEO
DEMONSTRATION?
• Video URL
https://www.youtube.com/watch?v=U8
9HGnJeo2s

23. WATCH A VIDEO

24. Any Questions?

25. FEEDBACKS

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31. THANK YOU