Intra-abdominal hypertension: definitions, monitoring, interpretation and management.

This review will describe the definitions on intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS). In order to understand these definitions the reader must be aware of the interactions between intra-abdominal pressure (IAP) and intra-abdominal volume (IAV), explaining why dramatic IAP increases can be observed in some patients related to anthropomorphic measurements, body positioning, use of positive pressure ventilation, or relatively small accumulations of fluid or blood. The adverse effects related to increased IAP have been named IAH for moderate cases and ACS for advanced cases. In order to improve clinical communication as well as evaluation of the scientific literature, the World Society for the Abdominal Compartment Syndrome (WSACS) has published its first guidelines and definitions in 2006. The definitions and guidelines have recently been revised according to evidence based medicine and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) methodology. This review will be based on the revised guidelines. The standard method to measure IAP is via the bladder and as experience with IAP measurement has evolved considerably, a number of tips and potential pitfalls are listed.