Surg - Viva - Abdominal Compartment Syndrome

Question 1

Normal intra abdominal pressure

Answer 1

5-7mmHg

Question 2

What is intra abdominal hypertension and compartment syndrome defined

Answer 2

1) Abdominal Perfusion Pressure = MAP - Intra-abdominal pressure

Intra abd hypertension is IAP >12 mmHg

Grade 1 - 12-15
2 - 16-20
3 21-25
4 >26 mmHg

Comparrment syndrome - Sustained of > 20mmHg that is associated with new organ dysfunction

(Occurs with or without an APP of < 600mmHg

Question 3

Risk factors of IAH and ACS

Answer 3

Low abdominal wall compliance
Surgery with tight closure
Trauma, burns, obesity
Proning

Increased abdominal content
Intralumin - ileusm gastroparesis, psuedo obstruction
Extraluminal - ascites, haemoperitoneum, pneumoperitonieum

Capilary leak
 Sepsis
 Pancreatitis
 Burns
Hypothermia, acidosis, transufion
Positive fluid balance, fluid resus

Mechanical vent
PEEP?>10
Increased head of bed angle
Shock/hypotension

Question 4

How do you measure intra abdominal pressure

Answer 4

Direct - needle into abdomen - laparoscopy

Indirect - Transduce in a viscous, such as bladder, stomach, colon, uterus

Intra-vesical pressure commonly used via bladder catheter

25ml sterile saline put into bladder and drainage bag reconneted and cross clamped

16G needle connected to pressure transducer introduced via the culture port site of catheter.

Question 5

Resp effects of IAH

Answer 5

Atectasis and collapse, diaphragm splinting
Reduced chest wall and lung compliance
VQ mismatch, hypoxaemia and hypercapnia
PEEP worsens venous return and CO

Question 6

Cardiac effects of IAH

Answer 6

Raised IAP directly pressures the vasculature
Reduced cardiac output as reduced venous return
increased afterload by arterial compression

Reducing cardiac output reduced the perfusion pressure

Question 7

Neuro effects of IAH

Answer 7

Raised ICP secondary to impaired venous return do to raised intra thoracic pressure

Hypoxaemia and hyperapnoea causes cerebral vasodilation, worsening ICP

Question 8

Renal effects of IAH

Answer 8

Pressure on renal vasculature
Reduced CO –> reduced renal blood flow
Pressure on renal outflow tract, increased pressure in tubules,and reduces filtration gradient

Activation of RAA system, worsens the insults

Question 9

Gastric/hepatic IAH

Answer 9

Hypoperfusion worsened by venous hypertension, –L bowel wall oedema

Bowel ischaemia and translocation, risk of sepsis
Reduced hepatic flow

Biliary stasis

Question 10

Principles of management

Answer 10

ABCDE approach and treat abnormalities

Optimise phsyiology and metabolic derangement

First - spot it - monitor at risk patients

Medical management - adequate sedation, analgesia and muscle relaxation, avoid coughing straining

Avoid prone position

Fluid - avoid excess admin, consider RRT for fluid removal

Evaculate the GI tract - gastric decompression, prokintetics, laxatives

Drain collections, paracentesis

Organ support - APP>60 with vasopressors
Optimise the vent, adequate ventilation with recruitment

Surgical - laparotomy and decompression is definateive

Negative pressure wound therapy for an open abdo (laporostomy)

Question 11

Complications

Answer 11

Death - untreated, mortality near to 100%

MOF

Question 12

Why do an open abdomen

Answer 12

Used to be a last resort

Now preferred strategy in compartment syndrome in both trauma/non trauma patients

Open abdomen approach enables initial control of haemorrhage and/or contamination, allow peritoneal packing, faciliative resus to normal physiology and subsequent re-exploration

Question 13

Specific indications for open abdo

Answer 13

Severe necrotising pancreatitis
Abdominal sepsis
Damage control post trauma
Emergnecy vasculr surgery

Question 14

Issues with open abdo’s

Answer 14

Nursing - skin care around wound moist and could be damaged

Turning and positioning

Pain

Sig. fluid loss, post op losses high, litres per day
Unreliable fluid balance

Protein and nitrogen loss - malnutrtion

Infection - wound care makes sterility difficult

Visceral injury - adhesions
Ileus

Abdo wall hernias,
Maybe never closes

Enterocutaneous fistula

Question 15

ITU management of open abdomen

Answer 15

Pain relief
Nutrition
Nursing

Resus to restore physiology

Correct hypothermia/coag/acidosis
Lung protective vent stratgey
Sedation/analgesia/blockade

Aim RASS -4 in acute phase

Enteral feeding is safe in intact GI tract
Supplemental protein, 2g Nitrogen per litre of fluid content

Abx if needed
Monitor for ACS
Source control - ?bedside washout

Question 16

Devices for temporary closure

Answer 16

Bogota bag - 3 litre bag fixed to the fascia/skin as a ready to use bowel bag

Negative pressure therapy, vacuum pack

Synthetic mesh devices/patches

Velcro sheathes