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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Acute mesenteric ischemia is extremely difficult to diagnose because peritoneal signs are absent until the bowel becomes necrotic and irretrievably damaged. So far the only reliable diagnostic procedure has been mesenteric angiography. The present study verifies that significant elevations of serum inorganic phosphate concentrations occur in dogs after mesenteric occlusion; the authors' initial clinical studies in humans support these experimental findings. Detailed analysis of body fluid and soft tissue phosphate content shows that the high phosphate load originates in the sloughing intestinal mucosa; if this phosphate escapes filtration by the liver it enters the systemic circulation. Simple measurement of the inorganic phosphate concentrations of the serum and peritoneal fluid may lead to earlier diagnosis of acute intestinal ischemia and a successful revascularization procedure to prevent its progression to infarction.
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PMID:Preinfarction diagnosis of acute mesenteric ischemia by simple measurement of inorganic phosphate in body fluids. 44 38

Acute intestinal ischemia is a pathology which is relatively often encountered in elderly patients where the concomitance of other diseases make its prognosis more severe, especially since diagnosis is usually late. Laboratory tests and imaging techniques are not of great value to diagnosis since they do not provide pathognomonic data, but together with a careful anamnesis they contribute a series of findings which, taken as a whole, lead to the diagnosis of intestinal ischemia. The sole therapy is surgery--when still possible and the best results are obtained when surgery is performed at an early stage. The authors report a series of 12 cases of acute intestinal ischemia and underline the difficulty of diagnosing this subtle pathology and the advantages of aggressive surgical techniques.
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PMID:[Acute intestinal ischemia. Our experience]. 147 Apr 5

Acute mesenteric ischemia is an uncommon but catastrophic event after cardiopulmonary bypass. From 1980 to 1990, 16,951 cardiac procedures requiring cardiopulmonary bypass were performed at Emory University Hospital in Atlanta, Ga. Eighteen patients (0.1%) had acute mesenteric ischemia that resulted in intestinal infarction. Emergency cardiac surgery had been performed in 16 of the 18 patients, and all 18 patients were vasopressor dependent for hemodynamic support after surgery. Diagnostic difficulties resulted in the diagnosis of intestinal infarction an average of 9 1/2 days after cardiopulmonary bypass. Nonocclusive mesenteric arterial ischemia was the determined cause in all cases. Statistically significant risk factors associated with acute mesenteric ischemia after cardiopulmonary bypass surgery included (1) emergency cardiac surgery (p less than 0.0001), (2) the use of an intraaortic balloon pump (p less than 0.0001), (3) failed angioplasty requiring emergency surgery (p = 0.0074), (4) prolonged pump time (p = 0.0093), and (5) advanced age (p = 0.0016). A high index of suspicion for mesenteric ischemia after cardiopulmonary bypass in patients with identified risk factors may decrease the diagnostic delay and lead to an improvement in the 67% mortality rate seen in this series.
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PMID:Acute mesenteric ischemia after cardiopulmonary bypass. 152 41

Acute mesenteric ischemia is highly lethal and therefore a serious problem for surgery and intensive care medicine; accordingly its pathophysiology warrants further study. Oxygen free radicals (OFR) play a role in the intestinal mucosal damage that develops during reperfusion after ischemia. Histamine (H) is generally released in various types of tissue ischemia. The link between H release and OFR has only been studied in in vitro systems. We tested the hypothesis that OFR may be involved in H release following reperfusion of the ischemic gut. The artery supplying a segment of the ileum was occluded for 1 or 2 h in anesthetized dogs. On reperfusion, a release of H into the venous effluent of the segment was demonstrated. Pretreatment of the animals with allopurinol (an inhibitor of xanthine oxidase), or with MTDQ-DA [6,6'-methylene-bis(2,2-dimethyl-4-methanesulfonic acid sodium-1,2-dihydroquinoline)], a superoxide anion scavenger, or with a combination of allopurinol and MTDQ-DA resulted in an inhibition of H release. We conclude that OFR may play a role in the local H release following intestinal ischemia.
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PMID:Oxygen free radical-induced histamine release during intestinal ischemia and reperfusion. 248 33

Acute mesenteric ischemia is becoming an increasing cause of death in old patients with generalized atherosclerosis. Pathogenetically, this condition presents as poor splanchnic perfusion, with or without occlusion of the major visceral vessels. Because the patient manifests such nondescript abdominal pain and the physical examination reveals few abdominal signs, it is therefore extremely difficult to make an accurate diagnosis in the early stage of the disease. Furthermore, laboratory studies and X-ray examinations are usually noncontributory. It is therefore necessary to keep this lesion in mind, whenever examining the old patient with severe unexplained abdominal pain. Selective arteriography is essential for differentiating occlusive ischemia from non-occlusive, however, the recent advances in medical imaging and minute flowmetry make it possible to detect intestinal lesions and the state of visceral perfusion, transcutaneously, in the early stage of the disease. Emergency revascularization is mandatory for an occlusive lesion, but it is not indicated in the early stage of non-occlusive disease, and requires support of cardiac failure, hypovolemia, septic shock and lowered splanchnic perfusion.
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PMID:Acute mesenteric ischemia. 324 74

Acute intestinal ischemia remains a catastrophic event even with the advent of modern diagnostic and vascular surgical techniques. An early noninvasive test would be valuable since early operation yields better survival rates. We have used an in vivo rat model to study acute intestinal ischemia after occlusion of the superior mesenteric artery (SMA). 31Phosphorus magnetic resonance spectroscopy (MRS), a noninvasive nondestructive technique, can detect the phosphorus metabolites most likely to be altered in ischemia: adenosine triphosphate, phosphocreatine (PCr), inorganic phosphate (Pi) and phosphomonoesters and phosphodiesters. Furthermore, intracellular pH can be estimated from the pH dependent position of the Pi spectral line relative to PCr. A tourniquet was loosely placed around the SMA in five Wistar rats through a transabdominal approach to the retroperitoneum. The abdomen was immediately closed. A 20 millimeter MRS surface coil was placed on the abdomen and 31Phosphorus spectra were accumulated. The SMA was then occluded and additional 31Phosphorus spectra were taken for the next 75 minutes. Significant (p less than 10(-4) changes in the position and magnitude of the spectra lines occurred within 20 minutes; the Pi position indicates severe intracellular acidosis and rapidly increases to three times its original magnitude. The PCr line decreases in magnitude. In a similar experiment, occlusion of the superior mesenteric vein (SMV) produced equivalent results. Occlusion of vessels other than the SMA or SMV not accompanied by transmural ischemia resulted in spectra unaltered from control. These findings support the application of phosphorus MRS to clinical studies.
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PMID:In vivo noninvasive observation of acute mesenteric ischemia in rats. 357 17

Acute intestinal ischemia and infarction remain serious clinical problems despite early operative intervention. An accurate and reproducible method of assessing ischemic tissue is critical to determine the precise limits of resection. The purpose of this study was to compare the utility of infrared photoplethysmography, intravenous fluorescein, and Doppler ultrasound in assessing intestinal ischemia in an operative canine model. After five segmental mesenteric arterial ligations in each of six conditioned dogs, the detection threshold for the limits of arterial perfusion of each modality was determined and correlated with the respective histopathologic specimens. Infrared photoplethysmography proved to be 100% sensitive for ischemia when its waveform amplitudes were 50% or greater of matched reference waveforms, whereas both intravenous fluorescein and Doppler ultrasound were 88% sensitive. All were comparably specific. We conclude that infrared photoplethysmography is comparable to intravenous fluorescein and Doppler ultrasound in the assessment of ischemic intestinal segments.
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PMID:The use of infrared photoplethysmography in identifying early intestinal ischemia. 382 70

Acute mesenteric ischemia represents one to two percent of all gastrointestinal illnesses. There are three possible causes of acute arterial mesenteric ischemia: embolism, thrombosis, and nonocclusive mesenteric insufficiency. The key to early diagnosis is a high index of suspicion. The classic clinical picture of obvious cardiac disease, sudden onset of severe abdominal pain and gastrointestinal emptying, is not always present. Serum markers and plain films are often nondiagnostic but may suggest acute arterial mesenteric ischemia. Angiography establishes the diagnosis and allows for planning of aortomesenteric bypass, if indicated. Papaverine is immediately instilled to decrease splanchnic vasoconstriction. Embolic and thrombotic disease is treated by laparotomy with re-establishment of visceral perfusion. Only after blood flow is restored is nonviable bowel resected. Clinical methods of assessing intestinal viability include Doppler scanning, intravascular dyes, and tissue oximetry. The decision to perform a second-look laparotomy is made prior to closure of the abdomen. Pharmacologic treatment is the mainstay of nonocclusive ischemia. Surgery is reserved for clinical deterioration. Survival is dependent on the cause and extent of occlusion as well as the rapidity of diagnosis and therapy. Bowel necrosis results in mortality rates between 80 percent and 95 percent.
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PMID:Mesenteric ischemia. Acute arterial syndromes. 760 44

Acute mesenteric ischemia is a potentially life-threatening vascular disorder affecting the gastrointestinal tract. The prognosis depends on early recognition, accurate diagnosis, and timely intervention to prevent extensive tissue necrosis and the onset of sepsis and multi-organ complications. Identifying the patient at risk, evaluating physical findings and laboratory data, maintaining adequate cardiac output and perfusion pressure, and implementing medical interventions are nursing care measures essential to patient survival. Future directions for the management of acute mesenteric ischemia are focused on identifying early markers of ischemia and mucosal injury to diagnose the condition accurately and reliably before the onset of systemic consequences.
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PMID:Acute mesenteric ischemia. 844 95

Acute mesenteric ischemia is a rare and often fatal event after cardiopulmonary bypass. We describe a diagnostic and therapeutic algorithm and present a patient with nonocclusive intestinal ischemia who had a successful conservative treatment.
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PMID:Mesenteric ischemia after a cardiac operation: conservative treatment with local vasodilation. 865 91


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