ABDOMINAL COMPARTMENT SYNDROME

1. ABDOMINAL COMPARTMENT SYNDROME

2. Abdominal Compartment Syndrome Definition “…….. multiple organ dysfunction caused by elevated intra-abdominal pressure.” Tim Wolfe, MD

3. ABDOMINAL COMPARTMENT SYNDROME • GI complications affect up to 3% of cardiac surgery cases. • Depending on the complication rate the mortality rates can be as high as 64% • Known to occur with massive resuscitation, liver transplantation, elective surgical procedures, “septic abdomens” and with severe burns

4. Understanding Abdominal Compartment Syndrome • APP – Abdominal perfusion pressure • MAP – Mean arterial pressure • IAP – Intra-abdominal pressure • APP = MAP – IAP • APP is superior to IAP, arterial pH, base deficit & lactate in predicting organ failure & patient outcomes

5. Measurement of intraabdominal pressure • Measurement of bladder (ie, intravesical) pressure is the standard method to screen for IAH and ACS. It is simple, minimally invasive, and accurate (additional pressure is not imparted from its own musculature).

6. 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

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

8. 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

9. Common Causes of ACS • Primary causes • is due to injury or disease in the abdominopelvic region • Abdominal trauma with bleeding • Pancreatitis • Ruptured abdominal aortic aneurysm • Retroperitoneal hematoma • Obstructions/ileus • Pneumoperitoneum • Abcesses • Visceral edema

10. Common Causes • Secondary Causes • refers to conditions that do not originate in the abdomen or pelvis • 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

11. Common Causes • Chronic Causes • Obesity • Liver failure with ascities • Malignancies

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

13. Physiologic Sequelae Cardiac: • Increased intra-abdominal pressures causes: • Compression of the vena cava with reduction in venous return to the heart • Elevated ITP with multiple negative cardiac effects • The result: • Decreased cardiac output increased SVR • Increased cardiac workload • Decreased tissue perfusion, SVO2 • Misleading elevations of PAWP and CVP • Cardiac insufficiency Cardiac arrest

14. Physiologic Sequelae Pulmonary: • Increased intra-abdominal pressures causes: • Elevation of the diaphragms with reduction in lung volumes • Cytokines release, immune hyper-responsiveness The result: • Elevated intrathoracic pressure (which further reduces venous return to heart, exacerbating cardiac problems) • Increased peak pressures, Reduced tidal volumes • Barotrauma, atelectasis, hypoxia, hypercarbia • ARDS (indirect - extrapulmonary)

15. Physiologic Sequelae Gastrointestinal: • Increased intra-abdominal pressures causes: • Compression / Congestion of mesenteric veins and capillaries • Reduced cardiac output to the gut The result: • Decreased gut perfusion, increased gut edema and leak • Ischemia, necrosis, cytokine release, neutrophil priming • Bacterial translocation • Development and perpetuation of SIRS • Further increases in intra-abdominal pressure

16. Physiologic Sequelae Renal: • Elevated intra-abdominal pressure causes: • Compression of renal veins and arteries • Reduced cardiac output to kidneys The Result: • Decreased renal artery and vein flow • Renal congestion and edema • Decreased glomerular filtration rate (GFR) • Acute tubular necrosis (ATN) • Renal failure, oliguria/anuria

17. Physiologic Sequelae Neuro: • Elevated intra-abdominal pressure causes: • Increases in intrathoracic pressure • Increases in superior vena cava (SVC) pressure with reduction in drainage of SVC into the thorax The Result: • Increased CVP and IJ pressure • Increased intracranial pressure • Decreased cerebral perfusion pressure • Cerebral edema, brain anoxia, brain injury

18. CLINICAL PRESENTATION • Symptoms — Most patients who develop ACS are critically ill and unable to communicate. • The rare patient who is able to convey symptoms may complain of malaise, weakness, lightheadedness, dyspnea, abdominal bloating, or abdominal pain. • Physical signs — Nearly all patients with ACS have a tensely distended abdomen. Despite this, physical examination of the abdomen is a poor predictor of ACS. Progressive oliguria and increased ventilatory requirements are also common in patients with ACS. • Imaging findings — Imaging is not helpful in the diagnosis of ACS

19. Abdominal Compartment Syndrome • INDEX OF SUSPICION: Setting • Ascites • Bowel distention: mech obstruction/ileus • Bowel edema: resuscitation or ischaemia • Retroperitoneal hematoma • Hemoperitoneum • Coagulopathy • Trauma • Abdominal packing after damage control surgery

20. Abdominal Compartment Syndrome • DIAGNOSIS: Index of suspicion • When any signs of intra-abdominal hypertension are present: • Abdominal distention • Refractory oliguria • Hypercarbia • Refractory hypoxemia • Increasing PIPs • Refractory hypotension

21. Abdominal Compartment Syndrome • DIAGNOSIS; • Most papers suggest several measurements during a 24 hr period: every 4 hrs • Repeat measurements are indicated by the clinical appearance of the abdomen and on the clinical situation (index of suspicion)

22. Abdominal Compartment Syndrome • Management: • Medical: • Maintain APP (>60mmHg) • Sedation / Analgesia • NMB • Supine positioning • NG / Colonic decompression • Fluid resuscitation • diuretics

23. Abdominal Compartment Syndrome • Surgical: • Percutaneous tube drainage • Abdominal decompression (DCL)

24. Abdominal Compartment Syndrome • TREATMENT: SURGICAL DECOMPRESSION / DAMAGE CONTROL LAPAROTOMY • Surgical decompression involves opening the abdominal wound and packing the wound open or closing it with a plastic dressing (Bogata Bag) • Delayed closure can be done once the edema / bleeding has resolved • Ascites can be drained percutaneously

26. Abdominal Compartment Syndrome • SUMMARY: • IAP – measureable / preventable / treatable • ACS – end organ dysfunction from untreated or undertreated elevated IAP • Measurement: simple technique with an 18 g needle through the Foley port and a CVP transducer • Damage control – the standard for avoiding or treating elevated IAP or ACS