1. 1 ABDOMINAL COMPARTMENT SYNDROME CVICU Rounds Dr. Alan Sobey

2. 2 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

3. 3 Abdominal Compartment Syndrome OUTLINE –Definition –History –Measurements –Significance –Summary

4. 4 Abdominal Compartment Syndrome Definition: Elevated intra-abdominal pressure (IAP) –Sustained increase in the intra-abdominal pressure over normal: > 12mmHg –Multiple etiologies –NB: not the same as ACS –ACS is a late consequence of increased IAP

5. 5 Abdominal Compartment Syndrome Definition: Compartment Syndrome –Compartment Syndrome: An increase in pressure within an enclosed space or cavity that causes physiologic dysfunction of its contents. Ex: extremities following fracture or revascularization of a limb

6. 6 Abdominal Compartment Syndrome Definition: ACS –The adverse physiologic effects due to increased intra-abdominal pressure. –Prolonged and unrelieved pressure may lead to respiratory compromise, renal impairment, cardiac failure, shock and death. –Generally it is measured from the intracystic pressure (bladder pressure).

7. 7 Abdominal Compartment Syndrome HISTORY: –Fietsam et al (1989) first presented the notion of the abdominal compartment syndrome (ACS) to describe the collective effects of increased intra-abdominal pressure (IAP) on the body. –Their description was in the setting of ruptured abdominal aortic aneurysms.

8. 8 Abdominal Compartment Syndrome HISTORY: –Trauma literature now a major source of information. –In general, the trauma literature has recognized that end organ dysfunction occurs in the presence of a grossly distended and tense abdomen. –Open abdomen concept

9. 9 Abdominal Compartment Syndrome PATHOPHYSIOLOGY: –Usual intra-abdominal pressure is assumed to be near atmospheric –Sugerman et al: increased with increasing abdominal girth –Kron et al: 3 – 15 mmHg (5-7)

10. 10 Abdominal Compartment Syndrome PATHOPHYSIOLOGY: –As the volume in the abdomen rises so does the pressure: the increase in pressure is in proportion to the abdominal wall compliance Increase in pressure is in proportion to the increase in the intra-abdominal pressure.

11. 11 Abdominal Compartment Syndrome PATHOPHYSIOLOGY: –Corresponding decrease in hepatic / splanchnic / renal perfusion – presumably due to compression of these vascular beds. –20% of the rise in the IAP is transmitted to the thoracic cavity: Increase in juxtacardiac pressure. Impaired ventricular filling.

12. 12 Abdominal Compartment Syndrome PATHOPHYSIOLOGY: Increased left ventricular afterload (with decreased CO and increased PCWP) Increased work of breathing due to decreased diaphragmatic excursion and impairment of chest wall movement. Increased intracranial pressure (significant in the head injured trauma patient)

13. 13 Abdominal Compartment Syndrome CONSEQUENCES: SUMMARY Decreased cardiac output Elevated RAP and PCWP Reduced hepatic perfusion Lactic acidosis Splanchnic hypoperfusion Raised ICP Peripheral edema with tendency to thrombosis Increased work of breathing Elevated airway pressures during mechanical ventilation Abnormal V/Q matching with hypoxemia

14. 14 Abdominal Compartment Syndrome ETIOLOGY Intra-peritoneal or retroperitoneal hemorrhage Ascites Bowel obstruction Post-op edema Pneumoperitoneum Laparoscopy

15. 15 AcidosisHyperthermiatransfusion CoagulopathySepsis: intra or extra abd Bacteremia pancreatitisLiver dysfunction Mechanical ventilation PneumoniaAbdominal surgery (DCL) Massive resuscitation Gastric or colon dist’n Hemo- peritoneum Burns and trauma BMIAbdominal tumors Prone ventilation

16. 16 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

17. 17 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

18. 18 Abdominal Compartment Syndrome DIAGNOSIS: Measuring the pressure –Insert a Foley catheter and clamp the tube distal to the sample port –Instill 5-1000mL of saline into the bladder so as to leave a continuous column of fluid from the bladder to the sample port on the Foley –Insert a 18g catheter into the sample port and connect to a CVP transducer –Level the transducer at the symphysis pubis Fusco et al J Trauma 2001

19. 19 Abdominal Compartment Syndrome Measurement: WSACS –Cmpletely supine –Relaxed abdominal wall –mid-axillary line –25 mL saline into the bladder

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22. 22 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)

23. 23 Abdominal Compartment Syndrome INTERPRETATION: NORMAL IAP –3-15 mmHg –Obesity: higher (8 vs. 5 mmHg) –Age: no definite trend –Surgery: no definite trend –Comorbidities: trend to higher IAP with more concurrent illnesses Sanchez et al Am Surg Mar 2001

24. 24 Abdominal Compartment Syndrome INTERPRETATION: –As the pressure rises over 20cm water there will be some evidence of hypoperfusion –Most will accept surgical decompression if the intra- abdominal pressure is over 35 cm. –More recent authors are advocating surgical decompression for IAP of 20-25 mmHg (Cheatham et al) –WSACS: 20mmHg for treatment

25. 25 Abdominal Compartment Syndrome INTERPRETATION: evidence –Decreased ACS with earlier decompression –Decreased mortality with earlier decompression: ? –More pronounced benefit with increasing age

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27. 27 Abdominal Compartment Syndrome Management: –Medical: Maintain APP (>60mmHg) Sedation / Analgesia NMB Supine positioning NG / Colonic decompression Fluid resuscitation diuretics

28. 28 Abdominal Compartment Syndrome Surgical: –Percutaneous tube drainage –Abdominal decompression (DCL)

29. 29 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

30. 30 Abdominal Compartment Syndrome DAMAGE CONTOL LAPAROTOMY: –Stone et al (1982) –Penetrating injuries to the abdomen –Avoid hypothermia / acidosis / coagulopathy –Involves: Rapid control of bleeding and contamination Abdominal packing instead of involved procedures Skin closure only or plastic tent closure (3 L peritoneal / CVVHDF bag)

31. 31 Abdominal Compartment Syndrome DAMAGE CONTROL LAPAROTOMY –Offner et al (Arch Surg) Denver Colo Penetrating and blunt traumas ACS: –Long hospital stay –Increased multisystem organ failure –Increased ARDS

32. 32 Abdominal Compartment Syndrome Offner et al –Technique of closure and ARDS/MSOF and ACS ACSMSOF/ARDS Primary closure 80%90% Skin24%36% Bogota bag18%47%

33. 33 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

34. 34 Abdominal Compartment Syndrome Deompressive laparotomy: Effects Most studies show a significant decrease in the IAP IAH persists in the majority of patients (De Waele et al) MR remained high at 35% Overall benefit for oxygenation (PaO2/FiO2) and increased urine output

35. 35 Abdominal Compartment Syndrome Decompressive Laparotomy: Effects The wound: –Messy –Open - risks for colonization or secondary infection –Delayed closure: how?

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38. 38 Abdominal Compartment Syndrome Decreased renal output: –Harman et al –Dogs –Increased the intra-abdominal pressure to 40mmHg leading to decreased urine output and cardiac output –Resuscitated the dogs to normal CO yet the renal function remained impaired until the abdomen was decompressed

39. 39 Abdominal Compartment Syndrome INTRACRANIAL PRESSURE: –Increased 1.Due to increased intrathoracic pressure from the elevated diaphragms 2.Due to decreased cardiac output –Thus, increases cerebral hypoperfusion and worsens brain injury Citero et al CCM

40. 40 Abdominal Compartment Syndrome Definitions: –IAH: intra-abdominal hypertension Sustained increase in IAP of 12 mmHg or more over 3 recordings separated by 4hrs each –ACS: abdominal compartment syndrome Sustained increase in IAP of 20mmHg or more Single or multiple organ system failure that was not previously present

41. 41 Abdominal Compartment Syndrome Classification: –Primary: Due to injury or disease in the abdomen or pelvis Frequently requires surgery or radiological treatment Ex: trauma or the septic abdomen

42. 42 Abdominal Compartment Syndrome –Secondary: ACS due to conditions arising outside of the abdomen Associated with severe capillary leak requiring resuscitation Ex: sepsis, burns, retroperitoneal hematoma

43. 43 Abdominal Compartment Syndrome Recurrent ACS: –Occurs following either prophylactic decompression or therapeutic surgical decompression of either primary or secondary ACS –Ex: temporary closure device is too tight, inadequate fascial opening, recurrs after the fascia was closed.

44. 44 Abdominal Compartment Syndrome APP: abdominal perfusion pressure APP = MAP - IAP “magic number”: 50-60 Corresponds to the perfusion gradient across the intra-abdominal visera Evidence????

45. 45 Abdominal Compartment Syndrome Diagnosis: Clinical Suspicion Presentation / Suspect with: –Abdominal distention –Oliguria –Increased ventilatory support