Abdominal Compartment Syndrome

1. Abdominal Compartment Syndrome

2. Increased Intra-abdominal Pressure IAP & Abd. Compartment Synd ACS • Case • Definition & prevalence • Measurement techniques • Etiology • Consequences • Treatment

3. Definition • Compartment syndrome exists when increased pressure in a closed anatomic space threaten the viability of enclosed & surrounding tissues • ACS organ dysfunction as a result of increased IAP

4. Definition • 77 patients prospectively studied • IAP by measuring bladder pressure • Mean IAP 6.5 mm Hg ( 0.2-16.2 mm Hg). • BMI & previous abd Sx were the only factors associated with high IAP Am Surg 2001 Mar

5. Definition • A lot of literature but no consistent criteria for has been used for diagnosis • What measurement should be used maximum Vs mean Vs median? • What is the gold standard method of diagnosis?

6. Etiology • Surgical { primary } Large volume resuscitation in abdominal trauma or emergency operations Tight surgical suture or burn scars • Non surgical { secondary } peritonitis , pancreatitis , massive ascites bowel obstruction , EGD & NPPV

7. Etiology • One day prevalence in 13 ICU over 6 countries • 97 patients with admission > 24h • IAP measured with bladder pressure q 6 h for 24 hours • Intraabdominal hypertension IAH when IAP = or > 12 mm Hg • ACS when IAP = or > 20 mm Hg Intensive Care Med. 2004 May

9. Etiology • IAH incidence 50.8 % ACS 8.5% • Only BMI >27 was strongly associated with ACS in multivariate analysis • Amount of fluid given renal & coagulation dysfunction have a trend of important only on univariate analysis Intensive Care Med. 2004 May

10. Measurement of IVP • Bladder pressure is the most commonly used method {gastric, rectal & uterine has been described} • Patient supine, measurement during expiration & bladder is empty &Foley catheter is clamped • 18 gauge needle attached to transducer is inserted into the aspiration port & 50 ml NS is injected

13. Bladder Pressure • 37 patient undergoing laparoscopy • Bladder pressure at different volume 0-200 ml • Moderate correlation R 0.62 • Bias 3.2 mm Hg • Lowest bias in patient with N IAP 50 ml in patients with high IAP 0 ml J Trauma 2001 Feb

14. Bladder Pressure • Possible source of errors in measurement Body position , zeroing over or under damping Baseline IAP ? Empty bladder Fluctuation in IAP

18. Measurement Of IAP • Continuous fully automated system • NGT like tube with air pouch at the tip • The pressure transducer is integrated in the monitor • Excellent correlation with insufflatory pressure R .99 with bias .5-2.5 mm Hg Intensive Care Med. 2004 Mar

20. Consequences • Critical IAP IAP at which ACS will develop • Variable from patient to patient • Likely critical IAP is lower in :morbid obesity , pregnancy & CLD with ascites ,previous abdominal surgeries

21. Consequences • CNS: Increase in IAP will increase ICP 15 patients with moderate to severe head injury after resolution of initial elevated ICP. IAP was increased by 15 liter water bag over the abdomen IAP 4.715.5 & ICP 12 15 mm Hg This effect was mediated through increase in the intrathoracic pressure Crit Care Med 2001

23. Consequences • CVS : studies in animals mainly Rt ward & flattening of Frank-Starling curve Decrease in compliance & contractility Decrease in VR Elevated CVP & PCWP not reflector of true intravascular volume use of volumetric parameters in resuscitation

26. Consequences • Respiratory: Animal studies Decrease in chest wall compliance Increase in VQ mismatch & dead space Hypoxia & hypercapnia Best PEEP = IAP Pplt = Pplt – IAP

28. Consequences • GI: In animal studies decrease in blood flow increase risk of bacterial translocation & decrease hepatic lactate clearance In human study Increase IAP induced in 14 cirrhosis with varices elevation in varices pressure size & wall tension Hepatology 2002

29. Consequences • Renal: Decrease in venous drainage because of increased venous pressure Decrease renal perfusion 2ry to arterial vasoconstriction Renin mediated by the fall in cardiac output Decrease in GFR & UOP with pre renal picture

30. Consequences • Renal: Increase IAP was one risk factor in developing hernias & leak in 142 peritoneal dialysis patients Other factors BMI & age Peritoneal Dialysis International 2004

31. Diagnosis • 21/42 trauma patient who had developed IAH diagnosed by bladder pressure were examined clinically Clinical exam sensitivity 56% PPV 35% specificity 87% NPV 64% accuracy 84% Can J Surg 2000 Jun

32. Management • Surgical : Decompression with maintenance of open abdomen (vacuum pack dressing) ? When to operate Abdominal perfusion pressure APP was shown in retrospective study of 144 pt with IAH to be the best predictor of survival J Trauma 2000 Oct

34. Management • Volume resuscitation Higher filling pressure • Mechanical ventilation Lung protective ventilationaim Pplt – IAP Best PEEP = IAP

35. Summary • IAH & ACS is infrequent but serious complication of multiple surgical & medical diseases • Clinical examination had low sensitivity • Till now bladder pressure is the most commonly used method to screen for ACS

36. Summary • The effect of IAH is on all other systems • With the development of continuous intraabdominal pressure monitors IAP may become part of the vitals • Surgical decompression is the main stay of Rx

37. Thanks