1. Abdominal Compartment Syndrome Vijith Vijayasekaran Advanced Trainee Plastic and Reconstructive Surgery Royal Perth Hospital

2. Abdominal Compartment Syndrome (ACS) 70 yo 33% TBSA flame Burns 70 yo 33% TBSA flame Burns Face, upper and lower limbs Face, upper and lower limbs Co morbidity – epilepsy Co morbidity – epilepsy Day four deterioration in general condition Day four deterioration in general condition ↑ HR ↑ HR Abdominal distention and pain Abdominal distention and pain ↓ Sats ↓ Sats ↓ Urine output ↓ Urine output ↑ urea(11 → 18) and creatinine ( 88 → 140) ↑ urea(11 → 18) and creatinine ( 88 → 140) Pulmonary edema Pulmonary edema ICU admission ICU admission

3. Abdominal Compartment Syndrome Continued abdominal distension Continued abdominal distension Acute renal failure Acute renal failure Respiratory failure with increased airway pressures Respiratory failure with increased airway pressures Exploratory laparotomy Exploratory laparotomy Dilated, dusky small bowel and colon Dilated, dusky small bowel and colon Global ischemia Global ischemia Small bowel mesentery – pulsatile bleeding Small bowel mesentery – pulsatile bleeding Abdomen not closed due to poor ventilation Abdomen not closed due to poor ventilation IV bag used to close defect IV bag used to close defect

4. Abdominal Compartment Syndrome Day Six closure of laparotomy following general Improvement Day Six closure of laparotomy following general Improvement Day 14 burns debridement Day 14 burns debridement Prolonged hospital stay Prolonged hospital stay

5. Abdominal Compartment Syndrome “Intra-abdominal hypertension (IAH) associated with organ dysfunction’’ - Khron et al “Intra-abdominal hypertension (IAH) associated with organ dysfunction’’ - Khron et al Adversely impacts pulmonary, cardiovascular, renal, splanchnic, Musculo/skeletal and integumentary systems Adversely impacts pulmonary, cardiovascular, renal, splanchnic, Musculo/skeletal and integumentary systems Significant morbidity and Mortality Significant morbidity and Mortality Baseline IAP 2-6 mm Hg Baseline IAP 2-6 mm Hg

6. Abdominal Compartment Syndrome - Pathophysiology Respiratory (IAP>15 mm HG) Respiratory (IAP>15 mm HG) Reduced Compliance Reduced Compliance ↓Total Lung Capacity ↓Total Lung Capacity ↓functional residual capacity and residual Volume ↓functional residual capacity and residual Volume ↑ Pulmonary Vascular resistance due to increased intra thoracic pressure ↑ Pulmonary Vascular resistance due to increased intra thoracic pressure Pulmonary organ dysfunction manifests by Hypoxia, Hypercapnia and increased ventilatory pressures Abdominal decompression → early reversal of pulmonary respiratory failure

7. Abdominal Compartment Syndrome - Pathophysiology Cardiovascular Dysfunction (IAP>20mmHg) Cardiovascular Dysfunction (IAP>20mmHg) Reduced cardiac output progressively falls with increased IAP Reduced cardiac output progressively falls with increased IAP Decreased venous return from direct compression of SVC, IVC and Portal Vein Decreased venous return from direct compression of SVC, IVC and Portal Vein Cardiac Compression and reduced end diastolic Volume Cardiac Compression and reduced end diastolic Volume Reduced stroke volume Reduced stroke volume

8. Abdominal Compartment Syndrome - Pathophysiology Renal Dysfunction Renal Dysfunction Pre Renal dysfunction Pre Renal dysfunction -decreased renal perfusion secondary to altered cardiac output -decreased renal perfusion secondary to altered cardiac output Renal Dysfunction Renal Dysfunction Increased renal vascular resistance as a result of direct renal compression of the renal arterioles and veins Increased renal vascular resistance as a result of direct renal compression of the renal arterioles and veins Oliguria at IAP > 15-20mmHG Oliguria at IAP > 15-20mmHG Anuria at IAP > 30 mmHG Anuria at IAP > 30 mmHG

9. Abdominal Compartment Syndrome - Pathophysiology Reduced splanchnic circulation with impaired portal and mesenteric perfusion Reduced splanchnic circulation with impaired portal and mesenteric perfusion Impaired bowel perfusion linked to abnormalities in gut mucosal Barrier late septic complications → ↑late septic complications Impaired bowel perfusion linked to abnormalities in gut mucosal Barrier late septic complications → ↑late septic complications Impaired blood flow to the abdominal wall musculature Impaired blood flow to the abdominal wall musculature Elevated ICP - elevated CVP Elevated ICP - elevated CVP

10. Abdominal Compartment Syndrome – Measurement Many techniques available Many techniques available Transduction of pressure from indwelling catheters Transduction of pressure from indwelling catheters Urinary bladder and gastric catheters are the most commonly used Urinary bladder and gastric catheters are the most commonly used ACS – IAP > 20 -25 mmHg and accompanied by manifestation of organ dysfunction ACS – IAP > 20 -25 mmHg and accompanied by manifestation of organ dysfunction

11. Abdominal Compartment Syndrome – diagnosis IAH(>20mmhg) associated with Physiological changes IAH(>20mmhg) associated with Physiological changes Respiratory failure with elevated ventilatory pressures – elevated hemi diaphragms with loss of lung volume (early) Respiratory failure with elevated ventilatory pressures – elevated hemi diaphragms with loss of lung volume (early) Hemodynamic abnormalities of - ↑HR, ↑SVR and PVR, ↓CO Hemodynamic abnormalities of - ↑HR, ↑SVR and PVR, ↓CO Renal Dysfunction progressing from oliguria to anuria Renal Dysfunction progressing from oliguria to anuria

12. Abdominal Compartment Syndrome – Management Supportive RX Supportive RX Early abdominal decompression of at risk patients Early abdominal decompression of at risk patients Laparotomy Laparotomy Percutaneous decompression with peritoneal lavage catheter Percutaneous decompression with peritoneal lavage catheter Abdominal decompression with temporary cover eg plastic or silicone coverage, skin only closure, mesh grafts etc Abdominal decompression with temporary cover eg plastic or silicone coverage, skin only closure, mesh grafts etc

13. Abdominal Compartment Syndrome – Outcomes High mortality and morbidity ( 10 – 70 %) High mortality and morbidity ( 10 – 70 %) Mortality when associated with burns – up to 100 % in untreated cases Mortality when associated with burns – up to 100 % in untreated cases

14. Abdominal Compartment Syndrome – and Thermal injury Few studies Few studies Incidence Incidence Unknown Unknown Hobson et al (1014 pts Burns ICU admissions), Latensar et al, Ivy et al Hobson et al (1014 pts Burns ICU admissions), Latensar et al, Ivy et al Diagnosis was suspected high peak inspiratory pressure or oliguria despite aggressive fluid resuscitation Diagnosis was suspected high peak inspiratory pressure or oliguria despite aggressive fluid resuscitation 1% overall incidence 1% overall incidence 30 % of pts TBSA> 40% 30 % of pts TBSA> 40% Mean TBSA 70% Mean TBSA 70% 60% cases in Pediatric population 60% cases in Pediatric population 60% developed ACS within 24 hours of admission (3.1ml/kg /%TBSA) 60% developed ACS within 24 hours of admission (3.1ml/kg /%TBSA) 40 % late presentation 11 D to several months after acute burn 40 % late presentation 11 D to several months after acute burn

15. Abdominal Compartment Syndrome – and Thermal injury Pathophysiology Pathophysiology Massive fluid resuscitation and accumulation of tissue edema Massive fluid resuscitation and accumulation of tissue edema Late onset due to sepsis Late onset due to sepsis

16. Abdominal Compartment Syndrome – and Thermal injury Risk Factors Risk Factors Inhalation injury Inhalation injury Large TBSA burns Large TBSA burns Extensive full thickness torso burns Extensive full thickness torso burns

17. Abdominal Compartment Syndrome – and Thermal injury Parameters that improved after decompression Parameters that improved after decompression Bladder pressure – 40 mm Hg → 26 mm Hg Bladder pressure – 40 mm Hg → 26 mm Hg Peak inspiratory pressure – 37 cm H 2 O → 32 cm H 2 O Peak inspiratory pressure – 37 cm H 2 O → 32 cm H 2 O Fluid requirements 78 ml / 1 ml Urine output to 26 ml Fluid requirements 78 ml / 1 ml Urine output to 26 ml

18. Abdominal Compartment Syndrome – and Thermal injury Methods of decompression Methods of decompression Laparotomy Laparotomy Bed side percutaneous catheter placement at early stage 15 -20 mm Hg ( Latensar et al) Bed side percutaneous catheter placement at early stage 15 -20 mm Hg ( Latensar et al)

19. Abdominal Compartment Syndrome – and Thermal injury Outcome Outcome 40 % survived to discharge 40 % survived to discharge Method of decompression – no impact on survival Method of decompression – no impact on survival 50 % survival rate in pediatric population and 33 % in adult population 50 % survival rate in pediatric population and 33 % in adult population