Acute elevation of intra-abdominal pressure contributes to extravascular shift of fluid and proteins in an experimental porcine model

Abstract

BackgroundIntra-abdominal hypertension and abdominal compartment syndrome contribute significantly to increased morbidity and mortality in critically ill patients. This study describes pathophysiologic effects of the acutely elevated intra-abdominal pressure on microvascular fluid exchange and microcirculation. The resulting changes could contribute to development of organ dysfunction or failure.Methods16 pigs were randomly allocated to a control-group (C-group) or an interventional group (P-group). After 60 min of stabilization, intra-abdominal pressure of the P-group animals was elevated to 15 mmHg by Helium insufflation and after 120 min to a level of 30 mmHg for two more hours. The C-group animals were observed without insufflation of gas. Laboratory and hemodynamic parameters, plasma volume, plasma colloid osmotic pressure, total tissue water content, tissue perfusion, markers of inflammation and cerebral energy metabolism were measured and net fluid balance and fluid extravasation rates calculated. Analysis of variance for repeated measurements with post-tests were used to evaluate the results with respect to differences within or between the groups.ResultsIn the C-group hematocrit, net fluid balance, plasma volume and the fluid extravasation rate remained essentially unchanged throughout the study as opposed to the increase in hematocrit (P < 0.001), fluid extravasation rate (P < 0.05) and decrease in plasma volume (P < 0.001) of the P-group. Hemodynamic parameters remained stable or were slightly elevated in the C-group while the P-group demonstrated an increase in femoral venous pressure (P < 0.001), right atrial pressure (P < 0.001), pulmonary capillary wedge pressure (P < 0.01) and mean pulmonary arterial pressure (P < 0.001). The protein mass decreased in both study groups but was significantly lower in the P-group as compared with the C-group, after 240 min of intervention. The increased intra-abdominal pressure was associated with elevated intracranial pressure and reduced tissue perfusion of the pancreas and the gastric- and intestinal mucosa.ConclusionElevation of intra-abdominal pressure has an immediate impact on microvascular fluid extravasation leading to plasma volume contraction, reduced cardiac output and deranged perfusion of abdominal organs.

The effect of crystalloid infusion on body water content and intra-abdominal pressure in patients undergoing orthopedic surgery under spinal anesthesia

“…There is increasing evidence that fluid infusion affects postoperative outcomes, and plays a crucial role in critically ill patients. 8,9,13,14 Excessive perioperative fluid loading leads to extravascular fluid accumulation and weight gain, which corresponds with increased mortality and morbidity during the early postoperative period. 6,8,15 Several meta-analyses have reported that goaloriented fluid therapy significantly reduces renal and pulmonary postoperative complications, and accelerates the first bowel movement, the resumption of normal diet, and shortens the length of stay in hospital.…”

“…Indeed, a growing data set presents an increase in IAP following inflammatory-related intestine edema. 9,24,25 Surgery-related injury induces the release of proinflam- matory cytokines, such as tumor necrosis factor α (TNFα), vascular endothelial growth factor (VEGF), many interleukins, histamine, and E-selectine, which may disturb vascular permeability, and increase fluid shift into the extravascular space. 26,27 Moreover, surgery-related perioperative stress induces the release of antidiuretic hormone, cortisol and corticotrophins, and stimulates the renin-angiotensin-aldosterone system to increase salt and fluid retention.…”

“…7 Unfortunately, positive perioperative fluid balance leading to tissue edema following a surgery-related increase in vascular permeability is associated with severe postoperative complications. [7][8][9] The adverse effects of fluid overload are most evident in the lungs and gastrointestinal tract. Fluid overload leads to pulmonary edema, which may decrease gas exchange, and makes the patients more susceptible to infections.…”

“…Moreover, VE connected with surgeryrelated inflammatory response results in interstitial edema, increasing intra-abdominal pressure (IAP). [7][8][9][10] Regrettably, the adjustment and control of fluid overload is difficult and BIA seems to be a more user-friendly method for managing perioperative fluid therapy.…”

Pressure Distribution during Negative Pressure Wound Therapy of Experimental Abdominal Compartment Syndrome in a Porcine Model

“…no linear relationship negligible correlation with irrelevant relationship low correlation, definite but small relationship moderate correlation with significant relationship high correlation with strong relationship very high correlation with strong dependable relationship [8,10,11,[14][15][16]. ACS definition in an animal model can be stated if an artificially increased IAP leads to circulatory, renal, respiratory insufficiency [9].…”