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

Reperfusion following lower-torso ischemia in humans leads to respiratory failure manifest by pulmonary hypertension, hypoxemia, and noncardiogenic pulmonary edema. The mechanism of injury has been studied in the sheep lung lymph preparation, where it has been demonstrated that the reperfusion resulting in pulmonary edema is due to an increase in microvascular permeability of the lung to protein. This respiratory failure caused by reperfusion appears to be an inflammatory reaction associated with intravascular release of the chemoattractants leukotriene B4 and thromboxane. Histological studies of the lung in experimental animals revealed significant accumulation of neutrophils but not platelets in alveolar capillaries. We conclude that thromboxane generated and released from the ischemic tissue is responsible for the transient pulmonary hypertension. Second, it is likely that the chemoattractants are responsible for leukosequestration, and, third, neutrophils, oxygen-derived free radicals, and thromboxane moderate the altered lung permeability.
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PMID:Reperfusion pulmonary edema. 221 74

A previous article (Part I) described the patient population and operative management of 666 patients who had surgery for nonruptured abdominal aortic aneurysms. This article details the perioperative complications and, by chi-square and logistic regression analysis, identifies the variables that are associated with each complication. In summarizing the results (below) the incidence of each complication is listed, along with the predictive risk factors in parentheses that have significance levels less than 0.05. Vascular morbidity data are as follows: intraoperative bleeding, 4.8%; postoperative bleeding requiring transfusion, 2.3% or repeat operation, 1.4% (large volume of blood transfusion and/or use of an autotransfusion device); intraoperative limb ischemia, 3.5%; graft thrombosis, 0.9% (femoropopliteal disease and/or distal anastomosis at the femoral level); distal thromboembolism, 3.3% (male sex, femoral popliteal disease, and/or intraoperative graft thrombosis); amputation, 1.2%; graft infection, 1 case. General morbidity data are as follows: cerebrovascular event, 0.6%; paraplegia, 1 case; cardiac event, 15.1% (age, previous episode of congestive heart failure, and/or electrocardiogram [ECG] evidence of a previous myocardial infarction); myocardial infarction, 5.2% (advancing age, angina, and/or prolonged aortic cross-clamp time); congestive heart failure, 8.9% (previous history of congestive heart failure, ECG evidence of ischemia, and/or chronic obstructive lung disease); arrhythmia requiring treatment, 10.5% (preoperative ventricular premature beats and/or respiratory failure requiring ventilation for more than 48 hours); new arrhythmia, 8.4% (angina and/or chronic obstructive lung disease); respiratory failure, 8.4% (chronic obstructive lung disease, large volume of blood transfused, and/or occurrence of postoperative bleeding, cerebrovascular accident, congestive heart failure, or myocardial infarction); renal damage with rise in creatinine or blood urea nitrogen, 5.4% and/or renal failure requiring dialysis, 0.6% (elevated preoperative creatinine, suprarenal aortic cross-clamping, and/or renal vein ligation); diarrhea without evidence of ischemia colitis, 7.1% and ischemic colitis, 0.6% (pelvic flow interrupted); prolonged ileus, 11.0% (aortoiliac occlusive disease, deterioration of renal function, prolonged ventilation, and/or preoperative history of angina); superficial wound infection, 1.5% and deep infection, 0.5% (femoral anastomosis and/or female sex); coagulopathy, 1.1% (large volume of blood transfused).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Multicenter prospective study of nonruptured abdominal aortic aneurysm. Part II. Variables predicting morbidity and mortality. 264 60

The role of prostanoids in respiratory failure during circulatory shock of intestinal origin was investigated in anesthetized, non-ventilated dogs by measuring PGF2 alpha thromboxane B2 (TXB2) and 6-keto prostaglandin F1 alpha (PGF1 alpha) in arterial and mixed venous (right ventricle) blood samples during superior mesenteric artery occlusion-induced (SMAO) shock. Release of the SMAO caused a dramatic decrease in mean arterial blood pressure (MABP), arterial and mixed venous pO2, hyperventilation and a more than 2 fold increase in levels of prostanoid studied within 5 min. At the same time, arterial and mixed venous pCO2 and pH remained unchanged. Thereafter, 6-keto PGF1 alpha concentration decreased so that at 60 min post release it was not significantly different from that of control values. PGF2 alpha and TXB2 levels rose continuously during shock. Respiratory failure which occurred after declamping was characterized by low pO2 and oxygen saturation and hyperventilation throughout the experiment. Pulmonary metabolism of PGF2 alpha was significantly reduced in shock. Indomethacin significantly attenuated the magnitude of postocclusion hypotension and respiratory failure, furthermore reduced prostanoid production. The present results suggest that PGF2 alpha and thromboxane A2 released by intestinal tissues might play an important role in the development of respiratory failure in shock caused by intestinal ischemia.
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PMID:Role of prostanoids in respiratory failure during circulatory shock of intestinal origin in dogs. 278 Jul 63

The cardiopulmonary effects of ventilatory support were studied in 12 patients with an acute myocardial infarction complicated by respiratory failure. At constant end-expiratory pressure, controlled mechanical ventilation, intermittent mandatory ventilation with 50 percent mechanical support, and spontaneous breathing all resulted in acceptable blood gas values. Intermittent mandatory ventilation offered hemodynamic advantages over controlled mechanical ventilation, as evidenced by a higher cardiac index and a lower arteriovenous oxygen content difference. Electrocardiographic evidence of myocardial ischemia was observed in one patient during controlled mechanical ventilation, in one during partial ventilatory support, and in five patients during spontaneous breathing. Myocardial ischemia should be one of the major determinants of mechanical ventilation when a patient with ischemic heart disease is subjected to ventilator treatment. The total withdrawal of ventilatory support carries a risk of marked ischemia and is not recommended until the patient can be extubated.
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PMID:Acute myocardial infarction complicated by respiratory failure. The effects of mechanical ventilation. 636 May 72

Two patients who were both 62-year-old males, also with various complications fully recovered from profound circulatory and respiratory failure. Both patients had experienced cardiac arrest one week or three months previously. Ischemic insult of brain produced from the prior cardiac arrest may be related to these excellent outcomes, because induction of tolerance to brain ischemia was demonstrated in animals which had undergone prior sublethal brain ischemia.
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PMID:[Two patients who recovered fully from profound circulatory and respiratory failure after cardiac arrest]. 747 13

We report two patients with bleeding stomal varices following total colectomy and ileostomy. The varices were demonstrated by superior mesenteric angiography and percutaneous transhepatic mesenteric venography; dilated ileal veins drained via the stomal varices into abdominal wall veins. Bleeding from the stomal varices was treated by transhepatic embolization. The first patient required three transhepatic embolizations after recurrent bleeding due to recanalization of the embolized ileal vein and the development of collaterals from the adjacent ileal veins over a one-year period. The second patient died of respiratory failure 1 week after embolization. Neither patient developed mesenteric or stomal ischemia.
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PMID:Percutaneous transhepatic embolization as treatment for bleeding ileostomy varices. 764 95

Aortic surgery results in ischemia/reperfusion of the lower body. This may liberate inflammatory mediators that activate neutrophils, and may result in lung microvascular changes with increased permeability and respiratory failure. We studied circulating inflammatory mediators and the pulmonary leak index (PLI) of 67Ga, a measure of transvascular transferrin transport and permeability, in patients scheduled for elective aortic and peripheral vascular surgery, before and after surgery. Aortic surgery patients in Groups 1 (n = 10) and 2 (n = 7) were studied before and at a median of 2.5 and 21.0 h after surgery, respectively. A control Group 3 (n = 6) was studied before and at a median of 2.9 h after peripheral vascular surgery. The PLI (median) increased from a median of 9.1 (range, 6.6 to 14.7) before to a median of 23.4 (range, 18.7 to 86.4) x 10(-3)/min after surgery in Group 1 but not in the other groups (p < 0.001). The postoperative increase in circulating neutrophils and elastase-alpha 1-antitrypsin, a marker of neutrophil activation, was similar among the groups. Plasma levels of activated complement 3a and tumor necrosis factor (TNF-alpha) did not change in any of the groups. In contrast, plasma levels of interleukin-8 (IL-8) increased in Group 1 from < 3 (range, < 3 to 37) before to 324 (range, 36 to 868) pg/ml after surgery, but did not change in the other groups (p < 0.005). The decrease in plasma levels of angiotensin converting enzyme (ACE) was greater in Group 1 than in the other groups (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Transient increase in interleukin-8 and pulmonary microvascular permeability following aortic surgery. 788 59

Extracorporeal membrane oxygenation (ECMO) has had promising results in life-threatening respiratory failure and postcardiotomy cardiogenic failure. From October 1994 to October 1995, 18 patients received 19 ECMOs at National Taiwan University Hospital for severe cardiogenic shock after cardiac surgery. They included patients receiving cardiac massage or repeated bolus injections of norepinephrine to maintain blood pressure (n = 10), patients who could not be weaned off cardiopulmonary bypass after several attempts despite intraaortic balloon pumping and maximal doses of catecholamine (n = 7), and patients with progressive intractable cardiogenic shock after cardiac surgery. Venoarterial ECMO was set up via femoral artery (17 or 19 Fr cannula) and vein (19 or 21 Fr) in all patients except 2 infants. No left heart drainage was performed in any of the patients. The heparin-coated circuit (with Carmeda Bio-active Surface) was used in the last 13 patients to reduce bleeding. Ten (52.6%) of the 19 cases could be smoothly weaned off ECMO, and 6 (33.3%) of the 18 patients were discharged from the hospital in good condition. Four (80%) of the 5 patients after valvular surgery and all 3 heart transplant patients could be weaned off ECMO successfully with the survival rate being 60% and 67%, respectively. Complications included leg ischemia (n = 3), bleeding (n = 4), renal failure (n = 3), and tube rupture (n = 1). The inability to wean off ECMO was caused by multiple organ failure (n = 5), sepsis (n = 2), tube rupture (n = 1), and dysfunction of the ECMO system (n = 1). The major cause of multiple organ failure was hesitation to set up ECMO. Our preliminary results confirmed the effect of ECMO in postoperative cardiogenic shock.
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PMID:Extracorporeal membrane oxygenation support for postcardiotomy cardiogenic shock. 894 49

In choosing a pharmacologic agent for stress testing, the clinician must keep a number of things in mind, such as the diagnostic utility of the agent or in what situations a vasodilator or catecholamine will be the better choice. Although all stress agents produce similar diagnostic accuracy for CAD, vasodilators have a higher cardiac uptake than catecholamines, and the addition of exercise improves the heart/background contrast ratios. With regard to physiologic comparisons, exercise or dobutamine will double coronary perfusion compared with baseline flow, but vasodilators produce a threefold or fourfold increase. The clinician should also keep in mind that adenosine will produce the shortest duration of hyperemia, whereas dobutamine and arbutamine produce a longer effect, and dipyridamole has the longest duration. If electrophysiologic considerations are important, exercise and catecholamines accelerate sinoatrial and atrioventricular conduction and are not typically associated with heart block. In contrast, adenosine can cause transient atrioventricular block, but this rarely occurs with dipyridamole. Clinical factors also must be considered. Although clinical utility of pharmacologic stress agents in the first 24 hours after infarction has not been demonstrated, the prognostic utility of vasodilators in the subsequent 2- to 4-day period has been shown. With patients with pulmonary disease (asthma) who do not have wheezing, dipyridamole can be used, but dobutamine or arbutamine should be used in patients with recent respiratory failure or bronchospasm before testing. In patients with left bundle branch block, vasodilators are the preferred stress agents rather than synthetic catecholamines or dynamic exercise. In the first crossover thallium imaging, there was good overall agreement in segmental perfusion comparing adenosine and dipyridamole, but there was a tendency for adenosine to detect more ischemia. The clinical significance (if any) for these findings has yet to be determined.
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PMID:Comparison of pharmacologic stress agents. 898 83

Adequate prehospital care of the severely traumatised patient is important to prevent or attenuate early as well as late life threatening complications, such as tissue hypoxia, ischemia/reperfusion injury and finally multiple organ failure. A mismatch of oxygen supply and oxygen demand is a hallmark in the pathophysiology of multiple trauma. Oxygen supply may be diminished by the following factors: shock-related decrease of cardiac output, anemia and hypoxia. On the other hand, oxygen demand may be increased by pain, panic, and agitation. Hence, it is a central point in prehospital care to reduce this supply-demand imbalance by identification and prompt reversal of the underlying causes. Most often, shock is caused by hypovolaemia and tissue injury ("traumatic-hemorrhagic shock"). However, shock may also be a result of central nervous system injury (neurogenic shock as a special form of distributive shock) or circulatory obstruction, e.g tension pneumothorax or cardiac tamponade (obstructive shock). Volume resuscitation by means of crystalloid or colloid solutions is an essential part in the therapy of the traumatic-haemorrhagic shock. In addition, catecholamines may be necessary in order to achieve an adequate arterial pressure. However, if bleeding cannot be controlled in the prehospital setting, only moderate volume support and permissive hypotension as well as rapid transportation into the next hospital may be preferable. This may be the case in penetrating thoracic or abdominal injuries as well as in traumatic amputations of the proximal limb. On the contrary, in patients with severe head injury, hypotension must be avoided by all means. Obstructive shock has to be treated urgently by insertion of a chest drain or drainage of the pericardium, respectively. Under all circumstances, it is an essential part of prehospital therapy to provide sufficient analgesia as soon as possible. Prehospital anesthesia, combined with artificial ventilation may be necessary for optimal patient management. Furthermore, ventilatory support is indicated when respiratory failure, loss of consciousness, or severe shock are present. Additional oxygen should be given whenever possible, even in the absence of an overt hypoxic state. Important additional measures are cervical spine immobilisation and reposition as well as splinting of long bone fractures or luxations, in order to avoid secondary injury of the spinal cord or ongoing tissue and vascular damage.
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PMID:[Emergency management of polytrauma patients]. 902 49


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