Visceral Perfusion Research Articles

Effect of increasing cardiac preload, sympathetic antagonism, or vasodilation on visceral blood flow during pneumoperitoneum

An impaired visceral perfusion caused by pneumoperitoneum may contribute to morbidity after laparoscopic surgery. The following three therapeutic concepts: increasing cardiac preload, controlled vasodilation, or selective sympathetic antagonism, were evaluated regarding a possible increase of visceral blood flow during pneumoperitoneum with carbon dioxide. Forty three pigs were assigned to treatment with an increase of preload and vasodilation (group A) or selective sympathetic antagonism with esmolol (group B). In both groups, pigs were assigned to head-up, head-down, or supine position. Perfusion of the vena porta and renal artery was measured by transonic volume flow meters and documented before capnoperitoneum, after induction of a 14-mmHg capnoperitoneum in each body position, after controlled vasodilation with sodium nitroprusside, and after controlled increase of intravascular volume by colloidal infusion. Increasing intravascular volume improved portal blood flow in all body positions (p<0.05), but not renal blood flow. Medication of esmolol did not alter the measured parameters in any body position compared to control. Vasodilation with sodium nitroprusside reduced renal blood flow in supine and in head-up position. An optimal intravascular volume was most effective in improving portal blood flow during capnoperitoneum in this trial. Esmolol had no negative effects on portal and renal blood flow. Patients with renal dysfunction might be treated carefully with sodium nitroprusside during capnoperitoneum.

Effects of Escharotomy as Abdominal Decompression on Cardiopulmonary Function and Visceral Perfusion in Abdominal Compartment Syndrome With Burn Patients

Abdominal compartment syndrome (ACS) can become fatal; however, it has rarely been described as a complication of burn injury. This study clarified the physiologic results of abdominal decompression (AD) for ACS in patients with burn injury in detail. Extensively burned patients admitted to our burn unit between January 2003 and February 2004 were prospectively monitored by pulmonary artery catheter. Physiologic parameters from the catheter, blood gas analysis, intrabladder pressure as a parameter of intra-abdominal pressure (IAP), peak inspiratory pressure, and urine output (UO) were compared before and after escharotomy as AD in patients with ACS. Eight of 36 patients who had sustained more than 30% total body surface area burn developed ACS requiring AD in 18.3 +/- 4.9 hours. AD significantly decreased IAP (52 +/- 9 cm H2O vs. 26 +/- 7 cm H2O), peak inspiratory pressure (53 +/- 13 cm H2O vs. 35 +/- 6 cm H2O), heart rate, and Paco2, and increased cardiac index (1.6 +/- 0.7 L/min/m2 vs. 2.5 +/- 0.9 L/min/m2), abdominal perfusion pressure (50 +/- 11 mm Hg vs. 72 +/- 17 mm Hg), UO (0.45 +/- 0.46 mL/h/kg vs. 2.0 +/- 2.1 mL/h/kg), and oxygen delivery index (290 +/- 195 mL/m2/min vs. 455 +/- 218 mL/m2/min). Impaired oxygen consumption index increased (86 +/- 43 mL/m2/min vs. 153 +/- 58 mL/m2/min) after AD. In patients with severe burn injury, elevated IAP makes pulmonary artery wedge pressure and UO unreliable indices of preload or intravascular volume, and decreases abdominal perfusion in the resuscitation period. AD in these patients significantly improves the ventilation, hemodynamic parameters, and oxygen metabolism.

Contemporary strategies for the prevention of stress-related mucosal bleeding

The purpose of this review is to describe the clinical presentation and pathophysiology of stress-related mucosal bleeding and review the strategies to prevent bleeding. The mortality rate associated with clinically significant stress-related mucosal bleeding is high. Respiratory failure requiring mechanical ventilation for more than 48 hours and coagulopathy are two strong, independent risk factors for bleeding. Splanchnic hypoperfusion is the underlying etiology of stress-related mucosal injury and bleeding. Mucosal damage typically manifests as multiple superficial lesions without perforation, and bleeding often originates in superficial capillaries after the patient is admitted to the intensive care unit. Providing adequate visceral perfusion is vital to preventing bleeding. Gastrointestinal function should be taken into consideration before using enteral nutrition, and enteral nutrition should not be the sole stress ulcer prophylactic therapy. Acid-suppression therapy should be used to raise the intragastric pH above 3.5 because it reduces the incidence of stress-related mucosal bleeding. Proton pump inhibitors are at least as effective, and may be more effective than histamine H2-receptor antagonists in achieving this pH goal and preventing bleeding. The key to reducing mortality from stress-related bleeding in critically ill patients is to prevent mucosal damage. Providing adequate visceral perfusion and acid-suppression therapy can reduce the risk of stress-related mucosal damage and bleeding.

Pathochemical Toxicity of Perfluorocarbon-5070, a Liquid Test Performance Fluid Previously Used in Dialyzer Manufacturing, Confirmed in Animal Experiment

In the light of clustered deaths in late 2001 associated with hemodialysis (HD), this article analyzes the pathochemical toxicity of the perfluorocarbon-5070 (PF-5070), a liquid used as test performance fluid for detecting capillary leaks during dialyzer manufacturing. Residual PF-5070 in some Athane dialyzers of the involved brands was infused in the injured patients during hemodialysis. The clinical presentation was in contrast with other previously described severe reactions to HD. Foam material was discovered in the right ventricle and caval vein of the patients who underwent postmortem examination. Deaths were attributed to gas embolism without the external causes identified. To explore the pathochemical toxicity of the inert liquid PF-5070, an animal model was developed. In a rabbit model, single slug intravenous injections as bolus of increasing doses of PF-5070 were performed. In a first set of experiments, three groups of three rabbits were administered increasing doses of PF-5070 at 4, 40, or 160 microl/kg. After intravenous injection, the animals were observed for clinical signs of adverse effects and underwent autopsy after death. Doses were normalized to animal body weight to allow comparison with supposed patient exposure. Five of nine rabbits died soon after PF-5070 dosing: One rabbit died within 4 h in the 4 microl/kg group, one rabbit died within 30 min in the 40 microl/kg group, and three rabbits died within 30 min in the 160 mul/kg group. In a second set of experiments, six rabbits were injected with a lethal dose of PF-5070 to analyze clinical symptoms and pathophysiology. All rabbits died on the day of dosing and displayed neurologic disorders (paralysis, nystagmus, rigidity, convulsions), then breathing abnormalities (rapid breathing, salivation, dark mucous membrane), and fatal collapse. Autopsy of rabbits showed evidence of gas retention in the lung tissue and gas bubbles in the right cardiac cavities. Histologic findings included alveolar hemorrhage with pulmonary edema, cerebellum, and cortex patchy areas of infarction. Single-dose intravenous administration of PF-5070 reproduced in a rabbit model the pathophysiologic effects observed in the hemodialysis patients. Severity of the symptoms observed in the animals was dose-dependent. Clinical and pathologic findings can be explained by the capacity of perfluorocarbon to emulsify blood at body temperature, to increase partial pressure in the pulmonary capillary bed, and to form bubbles in the pulmonary capillary circulation, thus blocking lung and visceral perfusion. Such experimental findings indicate the toxicity of PF-5070 administered intravenously and make the pathochemical toxicity link with the hemodialysis-related deaths caused by the presence of residues of PF-5070 in the Althane dialyzers. We conclude, in light of this outbreak and the subsequent investigations, that liquid PF-5070 is a highly toxic compound when administered intravenously because of its emulsifying properties. The use of PF-5070 or any liquid fluorocarbon compounds in medical devices with blood contact and particularly in the dialyzer manufacturing should be considered with caution.

INVITED COMMENTARY

INVITED COMMENTARY

Pancreas Transplants From Donors Aged 45 Years or Older

Aims Since donor age of 45 years or more is considered a relative contraindication for pancreas transplantation (PTx), we herein report our experience with these donors. Methods Pancreases from donors aged 45 years or older were used in 16 of 147 PTx procedures (11%). The final decision to accept a graft for PTx was based mainly on the quality of visceral perfusion and the gross appearance of the pancreas and the vessels. There were 9 men and 7 women, ranging in age from 45 to 55 years (average, 48.9 years) who were donors, due to cerebrovascular accidents (n = 11; 68.7%). Among the donor group, 5 patients were receiving multiple vasopressor agents (31.2%), and 2 had a history of cardiac arrest (12.5%). Pancreases were transplanted either simultaneously with a cadaveric kidney (n = 6) or as solitary grafts (n = 10). Results After a mean period of cold preservation of 616 minutes (range, 475 to 844 min), delayed endocrine function occurred in 1 recipient (6%), who subsequently achieved insulin independence. Two recipients died suddenly, with functioning grafts. Two further grafts were lost due to portal vein thrombosis (6%) or late arterial thrombosis (6%). Three patients required repeat surgery (18.7%). After a mean follow-up period of 26.6 months, actuarial 1-year and 5-year patient survival rates were 87.5%, with insulin independence in 81.2% and 67.7%, respectively. Conclusions Meticulons donor selection and short preservation times allow the safe use of pancreases procured from donors aged 45 years or older, thus expanding the donor pool for PTx procedures.

Aneurisma toracoabdominal roto: modificação do circuito de perfusão visceral

Paciente portador de aneurisma toracoabdominal (ATA) tipo lV, roto, submetido a tratamento cirúrgico utilizando perfusão visceral assistida por bomba centrífuga e oxigenador de membrana neonatal. Este circuito permite a perfusão visceral com sangue oxigenado, durante o período de isquemia, e infusão de volume rápido via venosa após a retirada da pinça.

Epinephrine induces tissue perfusion deficit in porcine endotoxin shock: evaluation by regional CO2 content gradients and lactate-to-pyruvate ratios

Epinephrine is widely used as a vasoconstrictor or inotrope in shock, although it may typically induce or augment lactic acidosis. Ongoing debate addresses the question of whether hyperlactatemia per se is a sign of tissue perfusion deficit or aerobic glycolysis. We wanted to test the hypothesis that epinephrine has selective detrimental effects on visceral perfusion and metabolism. We performed rigorous regional venous blood gas analyses as well as intraperitoneal microdialysis. We used a mathematical model to calculate regional arteriovenous CO(2) content gradients and estimated the magnitude of the Haldane effect in a porcine model of prolonged hypotensive shock induced by endotoxin infusion (mean arterial blood pressure < 60 mmHg). Subsequently, vasopressors (epinephrine or norepinephrine) were administered and adjusted to maintain systemic mean arterial pressure > 70 mmHg for 4 h. Epinephrine caused systemic hyperlactatemia and acidosis. Importantly, both systemic and regional venous lactate-to-pyruvate ratios increased. Epinephrine was associated with decreasing portal blood flow despite apparently maintained total splanchnic blood flow. Epinephrine increased gastric venous-to-arterial Pco(2) gradients and CO(2) content gradients with decreasing magnitude of the Haldane effect, and the regional gastric respiratory quotient remained higher after epinephrine as opposed to norepinephrine infusion. In addition, epinephrine induced intraperitoneal lactate and glycerol release. We did not observe these adverse hemodynamic or metabolic changes related to norepinephrine with the same arterial pressure goal. We conclude that high CO(2) content gradients with decreasing magnitude of the Haldane effect pinpoint the most pronounced perfusion deficiency to the gastric wall when epinephrine, as opposed to norepinephrine, is used in experimental endotoxin shock.

Preventing Renal Failure in Thoracoabdominal Aortic Aneurysm Repair

In our cumulative experience of 1004 thoracoabdominal and descending thoracic aortic aneurysm repairs, approximately 20% of patients have suffered from some form of postoperative renal dysfunction. Although slightly lower than rates in the era of cross-clamp-and-go, the contemporary incidence of renal failure and consequent morbidity and mortality remain significant. Between January 1991 and February 2003, we used and appraised many different forms of renal protection. After September 1992, we began to routinely use the adjuncts of distal aortic perfusion and cerebrospinal fluid drainage for all thoracoabdominal and descending thoracic aortic aneurysm repairs. The methods we examined for renal protection included aortic perfusion, followed by warm blood visceral perfusion, antegrade cold blood visceral perfusion, retrograde cold blood perfusion, and the perioperative use of a renal protective pharmacologic agent, fenoldopam. The results were not overly promising. We are currently testing a method of split perfusion in which the renal arteries receive cold lactated Ringer's solution while the visceral arteries are perfused with cold blood. The major predictors of postoperative renal dysfunction are preoperative renal function, cross-clamp time, and repair extending to the renal arteries. Distal aortic perfusion is protective, but only for aortic repair that does not directly involve the renal arteries. Evidence shows that patients with cold perfusion have superior survival and recovery rates, but none of the adjuncts clearly prevent acute renal failure. The current mortality rates associated with postoperative renal failure remain high, and the pursuit of the optimal method of renal protection is a top priority.

Cold visceral perfusion improves early survival in patients with acute renal failure after thoracoabdominal aortic aneurysm repair

Introduction Despite advances in organ protection during thoracoabdominal aortic aneurysm (TAAA) repair, acute renal failure (ARF) remains a significant clinical problem, associated with increased morbidity and mortality. We studied outcome of ARF after TAAA repair in patients who underwent either warm or cold visceral perfusion. Method Between 1991 and 2001 657 TAAA repairs were performed, of which 359 (55%) had either warm or cold visceral perfusion. Twelve patients with renal failure who had undergone preoperative dialysis were excluded from the study. Of the remaining 347 patients, ARF developed in 81 (23%) after TAAA repair. Forty-four (54%) of the 81 patients with ARF received cold visceral perfusion, and 37 (46%) patients received warm visceral perfusion. ARF was defined as either an increase of 1 mg/dL in serum creatinine (SCr) concentration per day for 2 consecutive days or dialysis requirement. Patient records were reviewed through hospital discharge. Results Twenty six (32%) of the 81 patients in whom ARF developed died, 17 of 37 (46%) patients in the warm perfusion group versus 9 of 44 (21%) patients in the cold perfusion group ( P < .02). Median onset of ARF was on postoperative day 1 in both groups. Twenty-six of 81 (32%) patients recovered renal function, 10 of 37 (27%) patients in the warm perfusion group versus 16 of 44 (36%) patients in the cold perfusion group. Preoperative SCr concentration was predictive of recovery of renal function (odds ratio, 4.5 per mg/dL increase; P < .03) in patients who received either warm or cold visceral perfusion. Conclusions ARF after TAAA repair remains a significant clinical problem. Recovery of renal function occurred in approximately one third of patients. Preoperative SCr concentration was the only significant determinant of recovered renal function. While cold visceral perfusion did not alter renal recovery, it significantly reduced hospital mortality.

Early Experience with the Minimal Extracorporeal Circulation System (MECC®) During Thoracoabdominal Aortic Aneurysm Repair

Aim. The purpose of this report is to describe our early experience with a minimal extracorporeal circulation system (MECC), a compact closed heparin coated system consisting of a centrifugal pump and a membrane oxygenator, during thoracoabdominal aortic aneurysm (TAAA) repair.Methods. Between January and December 2002 the MECC system was employed in seven consecutive patients (four TAAA type II, two TAAA type I and one TAAA type III according to the Crawford classification). In all patients distal aortic, selective renal and visceral perfusion was performed with this compact closed heparin coated system consisting of a centrifugal pump and a membrane oxygenator.Results. The MECC system was used in all cases with no technical malfunctions. Six out seven patients were discharged from the unit. One patient developed paraplegia after TAAA repair and died on the third post-operative day from multi-organ failure. In this case the total spinal ischaemic time was 120 min and the distal aortic perfusion pressure was <50 mmHg. No cardiac, cerebral, renal, hepatic or bleeding complications were recorded in the remaining six patients.Conclusion. Our early experience with MECC during TAAA repair showed that it is feasible for distal aortic spinal and visceral selective perfusion. Further large clinical trials are required to determine the efficacy of this technique.

Emergency Repair of Type IV Thoracoabdominal Aneurysm with the Use of a Singular Shunt to Maintain Visceral Perfusion

Surgical intervention for thoracoabdominal aneurysm (TAA) is associated with a high rate of perioperative complications arising from visceral and/or distal hypoperfusion. Despite a variety of intraoperative strategies reported in the literature, – 4 there is a lack of an effective procedure that provides a quick method to maintain visceral perfusion during TAA repair, particularly in emergency cases. In this report, we present a patient with a ruptured type IV TAA, who had previously undergone infrarenal aortic repair in a different hospital and subsequently, because of a prosthetic infection, graft removal and axillobifemoral bypass. In this particular case, visceral and renal perfusion has been supported with a singular shunt realized simply during operation and inserted in axillobifemoral bypass.

Comparison of gastric mucosal pH and clinical judgement in critically ill patients.

To compare gastric tonometry (pHi) with estimates of pHi in ill injured patients, and to correlate pHi with haemodynamic variables. Prospective, non-interventional study. ICU of Level I trauma centre, USA. 154 gastric tonometry measurements were compared with physicians' estimates of adequacy of resuscitation. Resuscitation was categorised as inadequate (pHi < 7.35) or adequate (pHi> or = 7.35). Measured and estimated pHi were also compared with oxygen delivery, oxygen consumption, cardiac index, mixed venous O2 saturation, and critical illness scores. Estimated pHi was often higher than measured pHi in the judgement of all four surgical intensive care physicians. Measured pHi correlated positively with mixed venous O2 tension (r = 0.21). There were significant negative correlations between measured pHi and both oxygen delivery (r = -0.25) and oxygen consumption (r = 0.28). Estimated pHi correlated positively with mean arterial pressure (r = 0.21) and hospital day (r = 0.26); it correlated negatively with pulmonary arterial elastance (r = -0.35). Experienced intensive care physicians tended to overestimate visceral perfusion, which suggests that gastric tonometry adds useful information over and above routine haemodynamic indices. Arterial blood pressure and mixed venous oxygen saturation correlated better with measured pHi than with other indices of perfusion.

Total arch replacement for thoracic aortic aneurysm via median sternotomy with or without left anterolateral thoracotomy

Background Thoracic aneurysms involving the ascending aorta, arch, and descending aorta are usually approached in a series of operations. Here, we report our clinical experience with total arch replacement through a median sternotomy with or without left anterolateral thoracotomy, using a technique that preserves the anterior wall of the distal arch to avoid injuring the left recurrent and phrenic nerves. Methods Between March 1999 and February 2001, 32 consecutive patients underwent total arch replacement through a median sternotomy alone (median group, n = 23) or in combination with a left anterolateral thoracotomy (LAT group, n = 9). In all cases, antegrade hypothermic selective cerebral perfusion was used in conjunction with mild hypothermic visceral perfusion (cool head–warm body perfusion). Results There were no in-hospital deaths and two late deaths. One patient in the median group had permanent neurological dysfunction postoperatively. There were no significant differences between the two groups in bypass time, cardiac ischemic time, respiratory assist time, beginning peroral intake, hospital stay, or postoperative respiratory function. The distal anastomosis level was significantly lower in the LAT group (thoracic vertebra level 7.1 ± 1.5 vs 5.6 ± 0.5, p = 0.0015). Conclusions Preservation of the anterior wall in the distal arch may decrease in-hospital mortality and perioperative neurological dysfunction after total arch replacement. Total arch replacement through a median sternotomy with left anterolateral thoracotomy allowed expeditious and extended replacement of the aorta without increasing postoperative respiratory complications.

Thoracoabdominal Aortic Aneurysm Repair: Reducing Adverse Outcome with Left Heart Bypass, Selective Visceral Perfusion and Renal Protection

Objective: To report our experience with left heart bypass and selective visceral perfusion for prevention of permanent spinal cord injury and distal organ failure in patients undergoing thoracoabdominal aortic aneurysm repair. Methods: From April 2001 to March 2002 seven patients were electively operated on with left heart bypass and selective perfusion of the visceral and renal organs at the University Clinic of Vienna, Austria. There were four males (57%) and two females (43%) with a mean age of 70 ± 6 years. Etiology of the aneurysm was a chronic dissection in one patient and athereosclerotic in the remaining five. Crawford classification was I in one patient (14%), II in five patients (86%) and III in one patient (14%). Existing comorbidities were hypertension in all seven patients, coronary artery disease in two patients (29%), chronic pulmonary obstructive disease in two patients (29%), and lung cancer resection and peripheral artery occlusive disease in one patient (14%) each. Two patients had a history of prior aortic aneurysm repair, namely elective repair of the ascending thoracic aorta 2 months before the thoracoabdominal aortic aneurysm repair, and replacement of the infrarenal aorta 12 years previously in another patient. Results: All patients survived the operation and were discharged after a mean hospital stay of 25 ± 13 days. Adverse outcome occurred in three out of seven patients. One patient with Crawford classification 11 developed acute renal insufficiency, and two patients with class 11 and III showed signs of transient paraparesis, respectively. Mean intraoperative blood loss was 3315 ± 701 ml. On average, 6.7 ± 2.8 units of packed red cells, 10 units of fresh frozen plasma, and 1 unit of platelets were given during the operation. Intensive care unit stay ranged from 2 to 16 days. Conclusions: The combined usage of left heart bypass, selective visceral perfusion, and renal protection can be recommended as a useful and effective technique in order to minimize adverse outcome in patients undergoing repair of the thoracoabdominal aorta.

Endovascular Repair of Recurrent Thoracoabdominal Aortic Aneurysm

To report the endovascular repair of a complicated, recurrent thoracoabdominal aortic aneurysm (TAAA) using stacked, customized stent-grafts. A 75-year-old man was evaluated for an enlarging 7-cm suprarenal abdominal aortic aneurysm. The patient had repair of a distal TAAA in the past, as well as multiple visceral revascularizations from the infrarenal aorta. A 3-segment aortic endograft with proximal and distal extensions was delivered with the aid of a prosthetic conduit from the right common iliac artery to the end of the right renal artery; spinal fluid drainage was performed to mitigate paraplegia. The stent-graft components were serially deployed from the level of the left common carotid artery and ended with the bare springs of the distal extension covering the renal arteries. The patient was discharged but returned within a month for drainage of a purulent retroperitoneal hematoma. He has since resumed his preoperative activities and remains well with documented exclusion of the aneurysm and satisfactory visceral and distal perfusion at 21 months. This case illustrates that aortic endografting can be a viable option for the treatment of recurrent thoracoabdominal aortic aneurysms.

Importance of blood pressure regulation in maintaining adequate tissue perfusion during cardiopulmonary bypass.

Patients undergoing surgery with the aid of cardiopulmonary bypass (CPB) have an incidence of end-organ dysfunction, caused by embolization, regional hypoperfusion, or some combination of the two. In this article, we attempt to define the effect of mean arterial pressure (MAP) during CPB on postoperative end-organ function. Although early studies reported that cerebral perfusion during hypothermic CPB is independent of MAP, recent laboratory and clinical reports have shown a positive slope in the MAP versus cerebral blood flow relationship. In clinical studies, patients who had higher MAPs during CPB had a lower incidence of cardiac and neurologic complications, as well as late neurocognitive abnormalities compared with patients with lower MAPs. Improving collateral flow in the setting of cerebral embolization has been postulated as the main mechanism for the improved neurologic outcomes in the high MAP groups. Higher perfusion pressure during CPB affects regional blood flow to the kidneys and visceral organs. However, the lower autoregulatory limits of perfusion to abdominal organs differ from the limits to the brain. Enhanced visceral perfusion during CPB is best achieved by increasing perfusion pressure via increases in perfusion flow rates rather than by using peripheral vasoconstriction alone. In conclusion, it is clear that maintenance of a high MAP during CPB may have a significant impact in protecting the brain and abdominal organs, particularly in the subset of patients at high risk for embolization and end-organ dysfunction.

Alternate venous drainage and return of warmed blood combined with continuous hypothermic visceral perfusion. A new adjunct of thoracoabdominal aortic aneurysm repair.

As a new adjunct to surgical repair for a thoracoabdominal aortic aneurysm, we have devised and used visceral perfusion in combination with alternate venous drainage and return of warmed blood in 4 patients. Surgical repair of a thoracoabdominal aortic aneurysm of Crawford type III (n = 1) or type IV (n = 3) was performed. During visceral branch reconstruction, hypothermic blood (30-32 degrees C) was perfused continuously to each visceral and renal artery at a total flow rate of 300 ml/min, in combination with alternate venous drainage and return of warmed blood to the inferior vena cava. The visceral and renal perfusion time was 115 +/- 55 (with a range from 52 to 190) minutes. All 4 patients recovered uneventfully. Alternate venous drainage and return of warmed blood combined with continuous hypothermic visceral perfusion were a useful adjunct to thoracoabdominal aneurysm repair during reconstruction of visceral and renal arteries.

Damage control: collective review.

Damage control: collective review.

Deterioration of visceral perfusion caused by intra-abdominal hypertension in pigs ventilated with positive end-expiratory pressure.

Experimental studies and clinical experience suggest that the combination of positive end-expiratory pressure (PEEP) ventilation and intra-abdominal hypertension might alter splanchnic hemodynamics to a significantly greater degree than the effect of either of them alone. Therefore, we assessed the intestinal and hepatic hemodynamics in two steps of PEEP ventilation, adding tense pneumoperitoneum in a pig model. The hepatic artery, portal vein, and superior mesenteric artery blood flow, as well as the hepatic and intestinal mucosal microcirculation, and the hepatic pO2 and intestinal mucosal pH, were assessed before, then with 5 cmH2O and 10 cmH2O PEEP alone, and in combination with a 12-mmHg pneumoperitoneum, in ten domestic pigs. Statistical analysis of the hepatic and intestinal measurements revealed a significant decrease (P = 0.001) in all parameters in relation to the baseline, during the 5-cmH2O and 10-mmH2O PEEP ventilation period. The addition of 12 mmHg intra-abdominal pressure led to an extreme deterioration in all parameters (P = 0.001), in relation to both the baseline and the 10-cmH2O PEEP measurement. These findings demonstrate that PEEP and intra-abdominal hypertension act cumulatively on the abdominal viscera, producing conditions of extremely low hypoperfusion and ischemia.