The Influence of Furosemide on Fluid Balance and Intra-abdominal Pressure in Critically Ill Patients

Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) have been shown to cause organ dysfunction and mortality in different populations of critically ill patients. According to consensus definitions published by the World Society for the Abdominal Compartment Syndrome (WSACS), secondary IAH is due to a disease process outside the abdominal cavity. It is mainly caused by massive fluid resuscitation leading to bowel and abdominal wall edema or increased intra-abdominal volume and decreased abdominal wall compliance. Large observational studies have shown that positive fluid balance is an independent risk factor for mortality. The development of secondary IAH may be one of the mechanisms involved in this phenomenon. This has lead to the hypothesis that prognosis may be improved by managing fluid overload and aiming for a negative fluid balance as soon as possible after the resuscitation phase of the disease.

Several authors have shown in case reports and small series that renal replacement therapy with ultrafiltration can be used successfully to remove excess fluid and lower intra-abdominal pressure (IAP), but renal replacement therapy is invasive and clinicians may be reluctant in considering this therapy in patients with preserved diuresis and kidney function. In an effort to achieve the same goal using a less invasive technique, the new medical management algorithm for IAH published by the WSACS recommends the use of judicious diuresis in order to achieve a negative fluid balance and a decrease in IAP.

However, the kidney is especially sensitive to the deleterious effects of IAH and may be unresponsive to diuretics in the presence of IAH. Also, ongoing inflammation and capillary leak may lead to relative hypovolemia and impaired response to diuretics.

We plan a multicenter study to evaluate the influence of furosemide on fluid balance and IAP in critically ill patients with secondary intra-abdominal hypertension and to document the effect on the function of other organ systems. The aim of this study is to evaluate the feasibility and the safety of the furosemide administration protocol and to provide preliminary data to allow for an adequate power calculation.