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Query: UMLS:C0278134 (anesthesia)
 110,339 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We measured plasma endothelin-1 (ET) in 10 patients undergoing coronary artery bypass grafting under high dose fentanyl (107.0 +/- 11.9 micrograms.kg-1, mean +/- SD) anesthesia. Arterial blood samples were obtained: 1) before induction of anesthesia (control), 2) just before the start of cardiopulmonary bypass (CPB), and 3) just before the end of CPB. ET levels were analyzed by radioimmunoassay based on double antibody method using Silica ODS suspension. ET concentrations in period 1, 2, and 3 were 1.8 +/- 0.7, 3.4 +/- 1.1 and 3.1 +/- 1.3 pg.ml-1 (mean +/- SD), respectively. There were significant differences between the control value and the values obtained at periods 2 and 3 (P less than 0.05). The elevation in ET level before CPB suggests the existence of hidden coronary ischemia despite the absence of detectable sign indicating myocardial oxygen supply demand imbalance. It was also suggested that, under high dose fentanyl anesthesia, stress evoked by CPB might not affect plasma ET concentration.
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PMID:[Changes in endothelin in plasma in patients undergoing coronary artery bypass grafting under high dose fentanyl anesthesia]. 156 May 78

In recent years, the number of elderly patients who require operation has been increasing. We experienced three patients with perioperative brain infarction, occurring respectively, during the preoperative period, just after operation, and three days after operation. All three patients had more than one of the common risk factors for cerebrovascular accidents, including hypertension, advanced age, hyperfibrinogenemia, diabetes mellitus, and past history of cerebrovascular accident. On the basis of our experience with these three patients, we suggest the following: (1) Waiting period of elective surgery should be reconsidered in some cases with a past history of stroke. (2) Some high-risk patients may benefit from anticoagulative or antiaggregative drugs (e.g. low-molecular dextran or prostaglandin E1) to prevent brain ischemia. (3) Abrupt control of hypertension or diabetes mellitus status undoubtedly adversely affects the patient's general condition; and (4) A practical monitoring system to detect regional brain ischemia during operation under general anesthesia should be developed.
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PMID:[Three cases of perioperative brain infarction]. 156 May 89

Protection from and treatment of myocardial ischemia involves detection and recognition of early changes in myocardial function associated with ischemia, as well as use of techniques and agents designed to alleviate or ameliorate ischemia. However, decisions regarding which agent(s) to employ depend upon not only the effects of a particular therapy but also the interaction(s) among the therapeutic agents and anesthetics. All the drugs and treatments discussed above may have beneficial effects in conscious patients but variable degrees of effectiveness during anesthesia. The choice of agents to be used for myocardial protection ultimately depends upon clinical decisions regarding coronary blood supply and myocardial oxygen demand. The availability of several different classes of agents capable of altering specific physiological variables allows a wide variety of clinical situations to be effectively managed.
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PMID:Perioperative myocardial ischemia and infarction. Prophylaxis and treatment of ischemia. 157 37

Continuous ECG recording of ST segments can provide important insight into the effects of CAD in patients before, during, and after anesthesia and surgery. The stresses of anesthesia and surgery are particularly threatening to the patient with critical coronary disease and ischemia. ST-segment monitoring is a useful alternative to preoperative stress ECG in patients who are unable to exercise, particularly if radionuclide techniques are not readily available. Continuous ST-segment monitoring provides an additional and unique method of monitoring patients during and after surgery, and on-line analysis of such data provides the anesthesiologist with opportunities to recognize and promptly respond to ischemic episodes. Future studies will determine whether such aggressive strategies will alter the outcome for patients with perioperative myocardial ischemia.
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PMID:Perioperative myocardial ischemia and infarction. Detection of myocardial ischemia using continuous electrocardiography. 157 38

The cerebral protective effects of etomidate were evaluated in a model of incomplete forebrain ischemia. Fourteen Wistar-Kyoto rats were anesthetized with halothane. After preparation, the rats were alloted to either the control group (halothane anesthesia, n = 7) or the etomidate group (n = 7). In the etomidate group, immediately before and during the period of ischemia, the animals received etomidate in sufficient concentration to achieve electroencephalogram burst suppression (loading dose, 7.5 mg/kg; infusion, 0.3-0.5 mg/kg/min). Both groups were subjected to a 10-minute ischemic insult accomplished by bilateral carotid artery occlusion and simultaneous hypotension (mean arterial pressure, 35 mm Hg). Histological evaluation of the brain was performed after a 4-day recovery period. Injury was evaluated in coronal brain sections in five structures: neocortex, striatum, reticular nucleus of the thalamus, and the CA1 and CA3 areas of the hippocampus. The location of the sections in the rostral-caudal axis was chosen to encompass anterior areas within the core of the ischemic territory as well as more posterior regions within the anticipated "watershed" zone between the occluded anterior and the intact posterior circulations. In the animals that received etomidate, statistically significant (P less than 0.05) reduction in the severity of the ischemic injury was observed in the CA3 area and in the ventral portion of the CA1 area of the hippocampus in the more posterior sections. There was an apparent trend toward protection in other structures in both rostral and caudal sections, but these changes were not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:An assessment of the cerebral protective effects of etomidate in a model of incomplete forebrain ischemia in the rat. 158 52

Raynaud's phenomenon is mainly linked with cold provoked vasomotor perturbations, but also with rheological alterations since blood viscosity is enhanced by lowering temperature. Several methods are available for studying distal vascularization: peri-ungual capillaroscopy, digital plethysmography and laser-Doppler. Digital arteriography must be reserved to serious ischemia regarding the general anesthesia needed to avoid spasm. All these methods explore especially the vessel wall. Conservely, blood viscosity which has been developed for 25 years investigates the content of the vessel. Since 1965, numerous hemorheological studies pointed out the rheological disorders, especially those concerning plasma and blood viscosity. The most usual viscometry abnormalities revealed erythrocyte hyperaggregation, red cell hypodeformability, blood and plasmatic hyperviscosity. In a comparative study, 46 patients with Raynaud's phenomenon were studied: we performed peri-ungual capillaroscopy, plethysmography and viscosity measurements. The results demonstrated a link between capillaroscopy and thixotropy. Both investigations are never normal at the same time in connectivites and never abnormal at the same time in Raynaud's disease (primary Raynaud's phenomenon). In conclusion hemorheological studies showed nearly normal rheological parameters in Raynaud's disease, but abnormal rheological parameters in secondary Raynaud's phenomenon.
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PMID:[Raynaud's phenomenon and blood viscosity]. 160 50

During carotid endarterectomy (CEA), phenylephrine infusions are commonly used to induce hypertension during carotid clamping in an attempt to increase collateral cerebral blood flow and prevent cerebral ischemia. Although this practice appears to increase the incidence of intraoperative myocardial ischemia during CEA when general anesthesia is employed, whether the limited use of phenylephrine infusions in specific instances of cerebral ischemia, as shown on an electro-encephalogram, results in low perioperative rates of both myocardial infarction (MI) and cerebral infarction remains unclear. We studied 171 CEAs done under general anesthesia performed with selective shunting based on the identification of cerebral ischemia by a two-channel computerized electroencephalographic monitor. The use of a phenylephrine infusion was restricted to the following instances of cerebral ischemia: 1) ischemia associated with hypotension that did not resolve within 2 minutes of decreases in anesthetic administration and treatment with fluid and/or colloid; 2) ischemia poorly or slowly responsive to shunt placement, accompanied by either hypo- or normotension; and 3) ischemia poorly or slowly responsive to removal of the carotid clamp, accompanied by either hypo- or normotension. Two non-Q wave MIs (1.2%) occurred, both nonfatal. There were two cerebral infarctions (1.2%) and three deaths not related to MI (1.8%). Based on these findings, in order to decrease the incidence of both MI and cerebral infarction after general anesthesia for CEA, we recommend the restrictive use of phenylephrine-induced hypertension for specific instances of slowly or poorly reversible cerebral ischemia, as shown on the electroencephalogram.
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PMID:Computerized electroencephalographic monitoring and selective shunting: influence on intraoperative administration of phenylephrine and myocardial infarction after general anesthesia for carotid endarterectomy. 161 84

Intraoperative transcranial Doppler monitoring of cerebral ischemia during carotid clamping under general anesthesia was done in 238 carotid artery operations, mostly endarterectomy. Depending on the severity of reduction of middle cerebral artery mean velocity, patients were classified as no, mild, or severe ischemia at clamping. With a carotid shunt, velocity was always in the "no ischemia" category during shunting. For patients with no ischemia, stroke was significantly lower without a shunt (2/175 no shunt versus 2/12 shunt). For mild ischemia, shunting did not affect the stroke rate (1/20 no shunt versus 0/9 shunt). For severe ischemia, strokes were less frequent with a shunt (4/9 no shunt versus 0/13 shunt). Intraoperative electroencephalogram predicted most, but not all severely ischemic cases. Carotid back pressure correlated with Doppler velocity, but transcranial Doppler was more helpful. Transcranial Doppler is a new and valuable technique in carotid surgery.
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PMID:Carotid endarterectomy monitored with transcranial Doppler. 161 88

Hemorrhage, ischemia and ischemic edema are among the complications which may occur following neurosurgery and they represent the most frequent cause of neurological deterioration. The mechanisms predisposing vascular complications (hemorrhage, ischemia) are described and discussed in relation to systemic alterations associated with surgery and anesthesia. In addition, the physiopathology of these complications is discussed in the various pathologies: cancer, vascular malformations, trauma and the intra-operative diagnostic possibilities which prevent their onset.
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PMID:[Postoperative complications in neurosurgery]. 162 Apr 39

The normal control of coronary blood flow is through alterations in the resistance of the intramyocardial arterioles (R2). Myocardial cellular hypoxia causes increased breakdown of ATP (or decreases synthesis) resulting in increased concentrations of the purine metabolite, adenosine. This potent endogenous, vascular smooth muscle relaxant vasodilates the R2 arterioles increasing coronary blood flow and myocardial O2 delivery. This mechanism autoregulates coronary blood flow according to myocardial O2 needs. Myocardial hypertrophy (from chronic hypertension) or coronary atherosclerosis interfere with this process and result in myocardial ischemia which may cause symptoms (angina), signs (ECG changes, regional muscle dysfunction) or tissue death (myocardial infarction). In addition, coronary atheroma disrupt endothelial function in the large R1 coronary arteries predisposing to vasoconstriction, platelet aggregation and thrombosis. Therapeutic measures for controlling ischemia may include decreasing oxygen demand (especially heart rate) and maintaining supply (R1 vasodilators and anti-thrombotic drugs such as non-steroidal anti-inflammatories). Intravenous, most inhalational and regional anesthesia appear to interfere minimally in the control of both the normal and ischemic coronary circulation. Thus optimizing myocardial oxygen balance (maintaining supply and decreasing demand) during anesthesia protects the ischemic myocardium. High doses of isoflurane, sevoflurane or desflurane are potent R2 coronary vasodilators which may cause redistribution of collateral blood flow away from ischemic regions (coronary steal). However, if tachycardia and hypotension are avoided, such an effect has not been shown experimentally or clinically. Preliminary evidence suggests that halothane may preferentially dilate R1 arteries and/or interfere with platelet aggregation. If these effects are confirmed, then halothane may prove to be the anesthetic of choice in the non-failing ischemic heart.
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PMID:Physiology, pathophysiology and pharmacology of the coronary circulation with particular emphasis on anesthetics. 164 43


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