Abdominal Compartment Syndrome John Hartley Academic Surgical Unit The University of Hull

Abdominal Compartment Syndrome (ACS) Definition “The adverse physiological consequences of an acute elevation in intra-abdominal pressure” Oliguria Increased airway pressures Reduced cardiac output

Abdominal Compartment Syndrome Historical background The perils of elevated intra-abdominal pressure… 1890’s elevation of IAP caused death in animal models 1911 cardiovascular effects of raised IAP identified 1913 effects of raised IAP on renal function 1980’s abdominal decompression for  IAP

Abdominal Compartment Syndrome Kron Il, Harman PK, Nolan SP. Ann Surg 1984:199:28-30

Abdominal Compartment Syndrome Pathophysiology ICP

Abdominal Compartment Syndrome Causes of raised intra-abdominal pressure (IAP) Retroperitoneal Intraperitoneal Oedema in necrotising pancreatitis Haemorrhage Pelvic haematoma Visceral oedema Retroperitoneal haematoma Abdominal packing Bleeding after aortic surgery Bowel dilatation Oedema related to resuscitation Mesenteric venous obstruction Pneumoperitoneum Acute ascites

Abdominal Compartment Syndrome At risk patients Major trauma Damage control surgery Laparotomy for bleeding, ischaemia etc Re-laparotomy for postoperative complications Massive volume resuscitation

Abdominal Compartment Syndrome Clinical features Abdominal distension ELEVATED IAP Consequent organ dysfunction Importance Decompression can reverse abnormal physiology Probable fatal progression if left untreated

Abdominal Compartment Syndrome Measurement of IAP Indirect assessment of IAP by bladder pressure 50-100ml saline into bladder Manometer readings from symphysis pubis

Abdominal Compartment Syndrome Problems What value of IAP should cause concern? Level beyond which ACS is irreversible? ABSOLUTE IAP UNHELPFUL >20mmHg significant in all pts >15mmHg significant in many >12mmHg significant in some Malbrain ML. Intensive Care Med 1999;25:1453-58

Abdominal Compartment Syndrome Survey of British practice 137 of 207 hospitals (66.2% response) 1.5% (n=2) no knowledge of ACS Some measurement IAP 76% (n=104) Upon suspicion of ACS 93% (n=97) No consensus on frequency of measurement or indication for decompression Ravishankar N, Hunter J. Br J Anaesth 2005;94:763-6

Abdominal Compartment Syndrome Incidence Prospective measurement of IAP in 9 months admissions to trauma ICU 15 of 706 pts IAH (2%) 6 of 15 pts with IAH developed ACS (1%) 50% mortality in ACS and 2 of 9 with IAH Hong JJ, Cohn SM, Perez JM et al Br J Surg 2002;89:591-6

Abdominal Compartment Syndrome Abdominal decompression Reversal of abnormal parameters in approx 80% Mean survival approx. 50% Intervention too late? Inevitable SIRS and MOF? PREVENTION BETTER THAN CURE Sugrue MD’Amour S. J Trauma 2001;51:419

Abdominal Compartment Syndrome Proposed grading for ACS based on IAP Grade IAP (mmHg) (cmH2O) Signs Treatment I 10-15 13-20 No signs ACS Maintain normovolaemia II 16-25 21-34  PAWP + oliguria ? Volume resuscitation III 26-35 35-48 Anuria,  CO  PAWP Consider decompression IV >35 >48 Mandatory decompression Burch JM, Moore EE, Moore FA et al. Surg Clin North Am 1996;76:833-842

Abdominal Compartment Syndrome

Abdominal Compartment Syndrome Conclusions Concept of ACS important True incidence and significance unclear Increasing awareness and measurement of IAP may lead to: - Better understanding of pathophysiology - Evidence based management

Abdominal Compartment Syndrome World Society on Abdominal Compartment Syndrome www.wsacs.org Antwerp 24th-27th March 2007

Abdominal Compartment Syndrome Renal effects IAP 15-20mmHg  RBF and GFR with anuria when >30mmHg No effect of stenting Parenchymal compression and  renal vascular resistance Reversible by decompression Harman PK, Kron IL, McLachlan HD et al Ann Surg 1982;196:594-7

Abdominal Compartment Syndrome Gut and hepatic effects  splanchnic and hepatic blood flow  flow in animal models with IAP>10mmHg Ischaemia at >40mmHg Gastric mucosal acidosis with  IAP improves with decompression Ivatury RR, Porter JM, Simon RJ et al J Trauma 1998,44:1016-21

Abdominal Compartment Syndrome Other means of detection CT changes - Narrowing of IVC - Direct renal compression - Bowel wall thickening - “Rounded abdomen” Splanchnic hypoperfusion and acidosis Abdominal perfusion pressure

Abdominal Compartment Syndrome Management of ACS – the issues Indication for decompression Timing of decompression “point of no return” Subsequent laparostomy management

Abdominal compartment syndrome Definition The adverse physiological consequences that occur as a result of an acute increase in IAP

Abdominal compartment syndrome Management of ACS Indication for decompression Timing of decompression “point of no return” Subsequent laparostomy management

Abdominal Compartment Syndrome Effects of intra-abdominal hypertension (IAH) Gut and hepatic effects Renal effects Cardiovascular effects Respiratory effects CNS Abdo wall

Abdominal Compartment Syndrome Cardiovascular effects  venous return by compression of IVC and portal vein  intra-thoracic pressure,  LV compliance, cardiac contractility and CO  peripheral oxygen delivery

Abdominal Compartment Syndrome Respiratory effects Elevation of diaphragm,  thoracic volume and compliance,  intra-pleural pressure  airway pressures to maintain ventilation Compressive atelectasis and V/Q mismatch, hypoxia, hypercarbia, acidosis

Abdominal Compartment Syndrome Acute elevation of IAP above 30mmHg caused oliguria in 11 postoperative pts Re-exploration and decompression in 7 pts resulted in immediate diuresis. 4 pts not re-explored developed renal failure and died. If IAP > 25mmHg in the early post period is assoc. with oliguria and normal blood pressure and cardiac index, the patient should undergo re-exploration and decompression of the abdomen Kron Il, Harman PK, Nolan SP. Ann Surg 1984:199:28-30

Abdominal Compartment Syndrome CNS effects Impaired venous return and cerebral pooling  intra-cranial pressure Ertel W, Oberholzer A, Platz A et al Crit Care Med 2000; 28:1747-53

Abdominal Compartment Syndrome Early detection Survey trauma surgeons USA 6% measured IAP routinely 59% selectively Mayberry JC, Goldman RK, Mullins RJ. J Trauma 1999;47:509-513