Renal implications of increased intra-abdominal pressure: are the kidneys the canary for abdominal hypertension?

Introduction: Increased intra-abdominal pressure (IAP) or intra-abdominal hypertension (IAH) is a cause of organ dysfunction in critically ill patients and is independently associated with mortality. The kidneys seem to be especially vulnerable to IAH induced dysfunction and renal failure is one of the most consistently described organ dysfunctions associated with IAH. The aim of this paper is to review the historical background, awareness, definitions, pathophysiologic implications and treatment options for IAP induced renal failure.

Methods: This review will focus on the available literature on IAH-induced renal dysfunction. A Medline and PubMed search was performed in order to find an answer to the question "What is the impact of increased IAP on renal function in the critically ill?". The resulting references were included in the current review on the basis of relevance and scientific merit.

Results: Renal dysfunction in IAH is a multifactorial process. The mechanisms involved have not been clarified completely. However, decreased cardiac output, altered renal blood flow and hormonal changes have been implicated. Decompression seems to have a beneficial effect on renal dysfunction, although there are some conflicting data. This may be due to the fact that there is no consensus on indications for decompression, both in terms of IAP values and of timing. An overview of current literature is provided and some interesting leads for future research are suggested.

Conclusion: IAH can cause renal dysfunction. Therefore, IAP measurements should be considered in our daily practice and preventive measures should be taken to avoid (deterioration of) renal failure in patients with IAH. Decompression may have a beneficial effect in patients with established IAH and renal failure.