A 35 year old was admitted following a simultaneous kidney pancreas transplant. The procedure had been complicated and she had received a large volume transfusion and crystalloid infusion.Her initial intraabdominal pressures were elevated at 22cmH2O on admission to the intensive care. It continued to escalate over the next 48 hours peaking at 29. She was managed with sedation, NG tube and abdominal perfusion pressures kept above 60mmHg. The tranplanted pancreas remained functional, but the renal transplant showed delayed graft function. On day 4 there was a reduction in her abdominal pressure and her urine output correspondingly increased.

What is the current evidence for the management of intra abdominal hypertension (IAH)?

David Garry

 

Normal IAP in critically ill patients is around 6-7mmHg. IAH is defined as an IAP greater than 12 mmHg, abdominal compartment syndrome (ACS) is defined as an IAP greater than 20 with new organ failure(s) (1).

In 2007 the World Society of Abdominal Compartment Syndrome (WSACS) published evidence based recommendations for the assessment and management of IAH and ACS (1).

Assessment
• If 2 or more risk factors for IAH/ACS, a baseline IAP measurement should be obtained – GRADE 1B
• IAP measurement – if IAH is present, serial measurements should be performed – GRADE 1C

Medical treatment
• APP should be maintained above 50-60mmHg in patients with ACS/IAH – GRADE 1C
• Sedation & analgesia – insufficient evidence
• Neuromuscular blockade – GRADE 2C
• Gastric decompression – insufficient evidence
• Fluid resuscitation should be rationalised – GRADE 1B

Surgical decompression
• Should be performed in patients with ACS refractory to other treatment options – GRADE 1B
• In patients with multiple risk factors, should be performed at time of laparotomy – GRADE 1C

A study published by Chetham in 2010(2) showed that application of a continuously revised IAH/ACS management algorithm resulted in a significant increase in patient survival to hospital discharge from 50% to 72%. They looked at 478 patients over a period of 6 years requiring an open abdomen for the management of IAH and ACS. Their algorithm changed over the 6 year period with lower thresholds for IAP and thus earlier surgical intervention. The results showed that earlier use of an open abdomen (based on IAP thresholds) decreased the time of definitive abdominal closure, a reduction in numbers of patients requiring skin grafting of their exposed viscera, reduced entero-atmospheric fistulas, decreased ICU, decreased ventilator days and a significant decrease in mortality.

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Lessons learnt
It is important to identify patients at risk of IAH, both for consideration of decompression at the time of laparotomy, or for measurement of their IAP on admission to the ICU. Applying an evidence based management algorithm in patients at risk of IAH/ACS may lead to better outcomes.

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References
1 Malbrain ML et al. Results from the International Conference of Experts on Intra-abdominal Hypertension and Abdominal Compartment Syndrome. Intensive Care Med 2006:32:1722-1732

2 Cheathem ML. Is the evolving management of intra-abdominal hypertension and abdominal compartment syndrome improving survival? Crir Care Med 2010;38:402-407

3 Keulenaer BD. Is it important to measure intra-abdominal pressures and is it time to pay attention? Intensive Care Monitor 2010;17:21

4 Sugrue M et al. Clinical examination is an inaccurate predictor of intraabdominal pressure. World J Surg 2002;26:1428-1431

5 Malbain et al. Prevalence of intra-abdominal hypertension in critically ill patients: a multicentre epidemiological study. Intensive Care Med 2004;30:822-829