Causes of Intra-abdominal Pressure(IAP) Elevation Abdominal Wall: burn eschar, repair of gastroschisis or omphalocele, reduction of large hernias, pneumatic anti-shock garments, lap closure under tension, abdominal binders Chronic: central obesity, ascites, large abdominal tumors, PD, pregnancy
Are we seeing more ACS? Increased Incidence? Syndromes created by medical “progress” ICU’s full of sicker patients Fluid resuscitation due to early goal directed therapy for sepsis? Increased Recognition?
Physiologic SequelaeCardiac: 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
Physiologic SequelaePulmonary: 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)
Physiologic SequelaeGastrointestinal: 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
Physiologic SequelaeRenal: 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
Physiologic SequelaeNeuro: 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
Physiologic Sequelae Direct impact of IAP on common pressure measurements: IAP elevation causes immediate increases in ICP, IJP and CVP (also in PAOP)15 liter bag placed on abdomen(Citerio 2001)
Physiologic SequelaeMiscellaneous Elevated intra-abdominal pressure causes: Reduces perfusion of surgical and traumatic wounds Reduced blood flow to liver, bone marrow, etc. Blood pooling in pelvis and legs “Second hit” in the two event model of MOF? The Result: Poor wound healing and dehiscence Coagulopathy Immunosuppression DVT and PE risks
How common is this syndrome?Malbrain, Intensive Care Medicine (2004):Abdominal Total MICU SICUpressure: Prevalence prevalence prevalence IAP > 12 58.8% 54.4% 65%IAP > 15 28.9% 29.8% 27.5%IAP > 20 8.2% 10.5% 5.0% plus organ failure
Does IAH / ACS affect patient outcome?Ivatury, J Trauma, 1998: Intra-abdominal hypertension after life-threatening penetrating abdominal trauma: prophylaxis, incidence, and clinical relevance to gastric mucosal pH and abdominal compartment syndrome. 70 patients with monitored for IAP > 25 mm Hg 25 had facial closure at time of surgery: 52% developed IAP > 25 39% Died 45 cases had abdomen left “open”: 22% developed IAP > 25 10.6% Died
Does IAH / ACS affect patient outcome?Points: Clinical signs of IAH are unreliable and only show up late in clinical course (once ACS occurs). IAH and ACS increase morbidity, mortality and ICU length of stay. Preventive therapy plus early detection and intervention can reduce these complications in many patients. Monitoring early (not waiting for clinical signs) in all high risk patients allows early detection and early intervention.
IAH/ACS Management Fluids – two edged sword Fluids will absolutely improve cardiac indices if the patient has inadequate RV filling- so early in the course they are necessary However, over resuscitation will lead to worsened edema Abdominal perfusion pressure - optimize fluids first then add vasopressors. Shoot for a perfusion pressure > 60 mm Hg Sedation, Paralytics Cathartics / enema to clear bowel? Colloids Hemofiltration Paracentesis Need significant free fluid on US Decompressive laparotomy
IAH/ACS Management : Abdominal Perfusion Pressure APP = MAP - IAP Abdominal perfusion pressure reflects actual gut perfusion better than IAP alone. Optimizing APP to > 60 mm Hg should probably be primary endpoint Cheatham 2000 Optimizing APP reduced incidence of ACS - 64% versus 48% Death - 44% versus 28%
IAH/ACS Management: Decompressive LaparotomyRigid Abdomen in ACS Post decompressive laparotomy
Decompressive Laparotomy Delay in abdominal decompression may lead to intestinal ischemia Decompress Early!
Decompressive LaparotomyPost-operative dressing Several days post-op
Intra-Abdominal PressureMonitoringBladder pressure monitoring through the Foley catheter is: The current standard for monitoring abdominal pressures (Consensus, World Congress ACS Dec 2004) Comparable to direct intraperitoneal pressure measurements, but is non- invasive (Bailey, Crit Care 2000) More reliable and reproducible than clinical judgment (Kirkpatrick, CJS 2000; Sugrue World J Surg 2002)
“Home Made” Pressure Transducer TechniqueHome-made assembly: Transducer 2 stopcocks 1 60 ml syringe, 1 tubing with saline bag spike / luer connector 1 tubing with luer both ends 1 needle / angiocath Clamp for Foley Assembled sterilely in proper fashion
University of Utah: IAP monitoring algorithm Entry criteria defined in table Nurse is empowered to enter any patient fulfilling these criteria
Final ThoughtDo NOT wait for signs of ACS to be present before you decide to check IAP By then the patient has one foot in the grave! You have lost your opportunity for medical therapyMonitor ALL high risk patients early and often: TREND IAP like a vital sign Intervene early, before critical pressure develops
QUESTIONS? IAH and ACS Educational Web sites: www.Abdominalcompartmentsyndrome. org