Abdominal Compartment Syndrome in Trauma

1. Abdominal Compartment Syndrome in Trauma David Chow Supervisors: Dr KC Chan, Dr KW Chan

2. Important message • Abdominal compartment syndrome (ACS) is a clinical condition in which elevated intraabdominal pressure (IAP) leads to impaired end-organ perfusion of the viscera and kidneys causing gut ischaemia and renal insufficiency. (Not limited to traumatic injury) • Ultimate result is multiple system organ dysfunction and death if not appropriately diagnosed and treated.

4. What is IAP? • Intra-abdominal pressure (IAP) - the steady-state pressure concealed within the abdominal cavity - include: abdominal organs volume; space occupying lesions (blood, fluid, tumor); abdominal wall compliance

5. What is APP? • Abdominal perfusion pressure (APP) - analogous to cerebral perfusion pressure - APP = MAP – IAP - a target APP of at least 60mmHg for improved survival from ACS

6. Filtration gradient (FG) • = glomerular filtration pressure (GFP) – proximal tubular pressure (PTP) • FG=GFP-PTP=MAP-2xIAP (at IAH) • Inadequate renal perfusion pressure and renal FG as key cause of IAP induced renal failure • Oliguria is one of the first visible signs of elevated IAP

7. IAP measurement • Various methods have been proposed for IAP measurement • the most widely accepted one was by intra-vesicular pressure.

8. Bladder pressure measurement

9. IAP Measurement standard • In mmHg • Supine • End-expiration • Transducer zeroed at mid-axillary line • Instillation volume of no greater than 25ml NS • 30-60 seconds after instillation of priming fluid (to allow bladder detrussor muscle relaxation) • Absence of abdominal muscle contraction

10. Normal IAP • > 15mmHg can cause significant end-organ dysfunction, failure and patient death

11. Intra-abdominal hypertension (IAH) • Sustained or repeated pathological elevation in IAP >=12mmHg • Most clinicians concerned only when IAP exceeds 20-25mmHg

12. Abdominal Compartment Syndrome (ACS) • Sustained IAP > 20mmHg (with or without an APP <60mmHg) that is associated with new organ dysfunction/failure • i.e. ACS = IAH + organ dysfunction

14. Signs of ACS • Abdominal distension • Oliguria refractory to volume administration • Elevated ICP • Hypercarbia • Hypoxemia refractory to increasing FiO2 and PEEP • Refractory metabolic acidosis

15. Pathophysiology

16. Primary ACS • Primary ACS is a condition associated with injury or disease in the abdominopelvic region that frequently requires early surgical or interventional radiological intervention. • E.g. traumatic injury, ascites/fluid, abdominal tumor

17. Secondary ACS • Secondary ACS refers to condition that do not originate from the abdominopelvic region. • E.g. sepsis/capillary leak, burns, massive resuscitation

18. Recurrent ACS • Recurrent ACS refers to the condition in which ACS redevelops following previous surgical or medical treatment of primary or secondary ACS

19. How often does ACS/IAH occur? • IAH is quite common but under-diagnosed in ICU. Incidence and prognosis of intraabdominal hypertension in amixed population of critically ill patients: A multiple-centerepidemiological study* Critical Care Medicine 2005

20. Risk factors for IAH/ACS • Diminished abdominal wall compliance e.g. trauma/burn, high BMI, central obesity, tight closure after abdominal surgery • Increased intra-abdominal contents e.g. gastroparesis, ileus, IO • Increased abdominal contents e.g. hemo/pnuemoperitoneum, ascites • Capillary leak / Fluid resuscitation e.g. acidosis, coagulopathy, pancreatitis, sepsis, etc.

21. If two or more risk factors for IAH/ACS are present, a baseline IAP measurement should be obtained. • If IAH is present (i.e. sustained IAP > 12mmHg), serial IAP measurement should be performed throughout the patient’s critical illness.

22. IAH/ACS management • Four principles: - serial monitoring of IAP - optimization of systemic perfusion and organ function - institution of specific medical interventions to reduce IAP - prompt surgical decompression for refractory IAH

23. IAH/ACS Management • While surgical decompression is commonly considered the only treatment, non-operative medical management strategies play a vital role in the prevention and treatment of IAH-induced organ dysfunction and failure.

24. Medical treatment options • Improve abdominal wall compliance - Neuromuscular blockade - sedation and analgesia - avoid head of bed > 30 degrees • Evacuate intra-abdominal contents • Evacuate abdominal fluid collections • Correct positive fluid balance - avoid excess fluid resuscitation • Organ support

26. Surgical abdominal decompression • Immediate decompressive laparotomy reduces IAP and restores systemic perfusion • Appropriate for patients with ACS refractory to less invasive treatments • Should not be delayed until organ failure is irreversible

27. Surgical decompression should be performed in patients with ACS that is refractory to other treatment options • Presumptive decompression should be considered at the time of laparotomy in patients who demonstrate multiple risk factors for IAH/ACS

30. ACS in trauma • Although there can be different reasons leading to the development of ACS, the most common scenario of ACS is after major abdominal trauma.

31. Incidence • Study conducted in Zurich in 2000: • 17 patients out of 311 patients with severe abdominal and/or pelvic trauma developed ACS Incidence and clinical pattern of the abdominal compartment syndrome after “damage-control” laparotomy in 311 patients with severe abdominal and/or pelvic trauma Wolfgang Ertel, MD; Andreas Oberholzer, MD; Andreas Platz, MD; Reto Stocker, MD; Otmar Trentz, MD Critical Care Medicine 2000

32. Damage control surgery in trauma • Deadly Triad of trauma patient: Coagulopathy, hypothermia and metabloic acidosis • Basic principles • Control haemorrhage • Prevent contamination • Avoid further injury

33. Peritoneal packing

34. After damage control surgery in trauma patient • Massive intestinal edema • Intra-abdominal packing • Retroperitoneal haematoma • Leading to increasing IAP • If tight closure of abdominal wound made, may lead to ACS!!

35. To tackle the problem • Let the abdominal wound open!! (The need for temporary closure and staged re-operation) • Absorbable mesh closure • Plastic IV bag closure • Vacuum pack dressing • Wittmann patch • KCI VAC dressing

36. Absorbable mesh closure

37. Plastic IV (BOGOTA) Bag closure

38. Vacuum Pack closure

39. KCI VAC dressing

40. The need for re-operation • For removal of clots and abdominal packs • Complete inspection of any missed injuries • Restoration of intestinal integrity • Proper abdominal wound closure

42. What is the role of intensive care? • Prevent the occurrence of the deadly triad: metabolic acidosis, hypothermia and coagulopathy • Prevention of abdominal compartment syndrome • Serial monitoring of IAP • Early detection of risk factors and signs of ACS/IAH • Consult surgeon for consideration of abdominal decompression if persistent IAP with impending organ failure

43. Independent predictors for mortality in IAH • IAH during ICU admission • Age • APACHE II score • Type of intensive care admission • Presence of liver dysfunction

44. References • Results from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome. I. Definitions.Malbrain ML et al. Intensive Care Med. (2006) • Results from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome. II. Recommendations.Cheatham ML et al. Intensive Care Med. (2007) • Incidence and prognosis of intraabdominal hypertension in a mixed population of critically ill patients: a multiple-center epidemiological study.Malbrain ML et al. Crit Care Med. (2005) • Incidence and clinical pattern of the abdominal compartment syndrome after "damage-control" laparotomy in 311 patients with severe abdominal and/or pelvic trauma.Ertel W et al. Crit Care Med. (2000) • www.wsacs.org • www.trauma.org