Abdominal compartment syndrome

Physiology

A abdominal compartment syndrome symbolizes the pathophysiologic results of an elevated intra-abdominal pressure. Various clinical conditions are associated with this syndrome and can include massive intra-abdominal or retroperitoneal hemorrhage, severe gut edema or intestinal obstruction, and ascites under pressure. Abdominal compartment syndrome follows a destructive pathway similar to compartment syndrome from the extremities. Whenever elevated compression occurs in this type of hollow space organs will begin to collapse under the pressure. As the pressure increases and reaches a point where the abdomen can no longer be distended it begins to effect the cardiovascular and pulmonary systems. Whenever abdominal compartment syndrome reaches this time without surgery and help of the silo the patient will in all probability die. There's a higher mortality rate associated with abdominal compartment syndrome.

Numerous systems are involved in this syndrome. First, the increased intra-abdominal pressure is transmitted to the pleural space so that lung compliance decreases. Hypoventilation and alteration of ventilation/perfusion distribution lead to hypoxemia and hypercapnia. When mechanical ventilation is applied, high inspiratory pressures in many cases are required to deliver tidal volume. Second, the combined increase in abdominal pressure and also pleural pressure leads to a decrease in venous return, immediate compression from the heart, and increased afterload (especially in the right ventricle). Third, perfusion towards the intra-abdominal organs can be critically reduced by the combined results of the decreased cardiac output, increased interstitial pressure, and increased outflow pressure.

This can lead to oliguria and renal failure. Splanchnic ischemia also occurs as resembled by a decreased mucosal pH, reduced liver metabolism, and bacterial translocation. Additionally, perfusion of the abdominal wall might be decreased, to ensure that wound healing might be impaired. Finally, intracranial pressure may also be increased because of the decrease in cerebral venous return in addition to increased venous pressure.The magnitude of the syndrome and also the involvement of the various organs depend on the amount of the intra-abdominal pressure.

The standard intra-abdominal pressure ranges between 0 and 5 mmHg. When it's slightly increased to between 10 and 15 mmHg, cardiac index is usually maintained as well as increased because abdominal viscera are mildly squeezed and venous return increases. Respiratory and renal symptoms are unlikely to happen. Hepatosplanchnic blood flow may decrease. At this point, intravascular volume optimization will most likely correct these alterations. When intra-abdominal pressure is moderately increased to involving 15 and 25 mmHg the full syndrome might be observed, nevertheless typically responds to aggressive fluid resuscitation, and surgical decompression should be thought about. With high pressures (a lot more than 25 mmHg) surgical decompression related to fluid resuscitation and transient use of vasoconstrictive agents is mandatory.

When surgical decompression is not feasible, using an adverse abdominal pressure should be thought about.The diagnosis of this syndrome is difficult because it usually occurs in critically ill patients along with other reasons for circulatory or respiratory failure. One should always think about the abdominal compartment syndrome when confronted by acute circulatory failure with extensive systolic-diastolic pressure alternative and elevated filling up pressures. Following exclusion of cardiac tamponade and increased pleural pressure (tension pneumothorax, position asthmaticus, etc), the intra-abdominal pressure ought to be measured.Current methodology for intra-abdominal pressure assessment depends on the measurement of bladder pressure. Alternative methods include indirect estimations of inferior vena cava pressure, rectal and gastric pressure measurements, and direct measurement from the intra-abdominal pressure through direct puncture. Throughout experimental conditions, bladder pressure is closely related to abdominal pressure.

During laparoscopic surgery, the particular simultaneously measurment of intra-abdominal pressure by direct puncture and bladder pressure was done. The two pressures were clearly not identical, due to the fact bladder pressure methodically overestimated the true abdominal pressure; this may result in an over-diagnosis of intra-abdominal compartment syndrome. Despite the fact that these data were obtained using a rigorous methodology (and the authors rightly point out that the quantity of fluid accustomed to prime the Foley catheter ought to be restricted to 50 ml to prevent bladder distension), you ought to be aware of some constraints. Very first, although ethical considerations precluded the use of intra-abdominal pressures higher than 15 mmHg, it's, however, dangerous to extrapolate these results to higher pressure levels, where clinical manifestations of the intra-abdominal compartment syndrome are much more severe. Second, bladder pressure might be greater than the abdominal pressure in some conditions.

Any time patients are lying inside a flat position, the bladder pressure will represent the sum of the the exogenously applied pressure (gas pressure) and the pressure exerted through the viscera (which may be roughly estimated since the height of these viscera), whereas the directly measured intra-abdominal pressure only takes into account pressure of the insufflated gas. Third, bladder pressure increments reflected increments in intra-abdominal pressure on an individual basis, which could advocate the use of very early bladder pressure monitoring in patients prone to building an intra-abdominal compartment syndrome. Finally, most clinical studies have used bladder pressure measurements, so that clinical manifestations happen to be classified based on bladder pressure levels rather than to directly measured intra-abdominal pressure levels. The research has shown that bladder pressure measurements require cautious interpretation, but many of us still believe that they will remain a simple, safe, along with valuable tool for diagnosing the abdominal compartment syndrome in critically ill patients.