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

The variations in QRS-T configurations in both standard and precordial leads from control rat electrocardiograms are analysed in this study. The durations of the above mentioned QRS complex, T and Q waves and the QT interval are also described. Many of the observed differences in rat electrocardiograms are due to a series of factors that may include recording equipment, anaesthesia used, dorsal or ventral position of the animal, age weight, sex and litter. The influence of all these parameters has been taken into account in the course of this research work. The electrocardiograms shown in this work were carried out as part of a project in which these patterns would later be compared with those obtained from rats in which ischemia has been induced by means of isoproterenol.
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PMID:[Variations in electrocardiogram QRS-T (author's transl)]. 74 Oct 57

Since sub-endocardial ischemia is the consequence of a discrepancy between the blood demand and supply of oxygen at this level, the study of the myocardial performance by the measurement of the endocardial viability ratio (E.V.R.) is both useful and possible during anesthesia. E.V.R. is the ratio between the oxygen supply and demand of the myocardium. It is equal to the diastolic pressure time index (D.P.T.I.) over the tension time index (T.T.I.). Measurements are made at different times, by means of the arterial pressure and the left atrial pressure, as well as with the Datascope-E.V.R. Computer. During gradual morphine administration (0.5-1-1.5 mg/kg) and if no major surgical stress occurs, E.V.R. remains excellent and stable (1.46 - 1.48 - 1.43). It deteriorates more or less (1.29 - 1.09) during tachycardia or hypertension. Within the hour following the end of extracorporeal circulation, E.V.R. significantly improves (1.04 - 1.06 - 1.09 - 1.23). Although E.V.R. measurement is easy during cardiac surgery, it is impossible to carry out in case of arrhythmia. While morphine anesthesia induces no variation in E.V.R., tachycardia or hypertension require the addition of therapeutic drug. Within one hour following the end of extra-corporeal circulation, E.V.R. measurement shows improved endocardial viability, although the hemodynamic parameters undergo no significant change.
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PMID:Measurement of endocardial viability ratio (E.V.R.) during anesthesia for cardiac surgery. 75 39

The physiology and pathophysiology of the cerebral circulation have been discussed in relation to treatment of the cerebral hemodynamic crisis. Data are presented to show how cerebral vascular resistance, the intracranial compartments, and brain metabolic demand may be manipulated to effect internal decompression and raise local perfusion pressures. It is quite apparent that irreversibility occurs rapidly in cases of complete ischemia and therapeutic success is often limited by this fact. Application of sound therapeutic principles will limit the extent of cellular destruction. Of particular importance to the general surgeon treating the multiply injured patient, is the effect of anesthesia on intracranial pressure in patients with compromised intracranial volume reserve.
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PMID:Cerebral hemodynamic crisis. Physiology, pathophysiology, and approach to therapy. 76 84

If good anesthesia is to be provided to the patient undergoing surgery for an expanding intracranial lesion, certain principles should be borne in mind. These principles include: 1. Careful preoperative assessment of the patient 2. Awareness of abnormal intracranial dynamics in the presence of an intracranial mass lesion 3. The importance of a smooth induction of anesthesia 4. Adequate depth of anesthesia and complete muscle paralysis before laryngoscopy and intubation 5. The choice of a maintenance technique that does not increase ICP and allows adequate CPP. Failure to adhere to these principles may lead to sudden increases in intracranial pressure, decreased cerebral perfusion pressure, and regional ischemia. In the closed skull, internal herniation of brain tissue through the tentorial notch or the foramen magnum may occur. External brain herniation, with increased bleeding and rupture of cerebral cortex, may occur after the dura mater has been opened if these anesthetic parameters are not controlled. Neuroanesthesia, therefore, plays an important role in the reduction of morbidity and mortality in the surgery of intracranial lesions of all types, including neoplasms - not only in the operating room, but also in the pre- and postoperative care of the neurosurgical patient.
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PMID:Anesthesia for intracranial surgery with particular reference to surgery for neoplasms. 77 21

Regional cerebral blood flow (CBF) was measured (intra-arterial injections of 133Xe) and electroencephalograms (EEG) were recorded periodically before, for two hours during, and for one and one-fourth hours after middle cerebral artery (MCA) occlusion in 20 squirrel monkeys (Saimiri sciureus). A CBF-Paco2 response curve for these animals under barbiturate anesthesia was created from CBF values prior to MCA occlusion and during the time a steady state was being achieved. The animals were subdivided into four groups (five monkeys in each) on the basis of Paco 2 values: 20, 36, 40, and 60 mm Hg. CBF values from this study were compared to previous results obtained with 85Kr. The phenomenon of "look through" and the importance of recognizing this artifact and its significance in analyzing CBF results in areas of focal ischemia are discussed. The present results were correlated with cerebral ATP and lactate concentrations in ischemic regions determined in previous studies using this preparation at these Paco2 values and at comparable time intervals before, during, and after MCA occlusion. The EEG appears to reflect the state of ischemic brain accurately. However, CBF measured by the 133Xe method can be misleading in regard to the true degree of ischemia resulting from occlusion of an intracranial vessel and cannot be relied on to demonstrate accurately "steal" or "reverse steal" due to changes in Paco2.
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PMID:Blood flow measurements and the "look through" artifact in focal cerebral ischemia. 80 30

The effects of lidocaine infusion on the ultrastructural damage induced in cardiac muscle by normothermic cardiopulmonary bypass were assessed in 15 dogs. Six dogs received no medication other than sodium pentobarbital (25 mg/kg, intravenously) while 9 dogs were treated with lidocaine after anesthesia. Lidocaine was given as a 2-mg/kg loading dose 10 minutes prior to ischemic arrest and a 2-mg/min continuous infusion during the entire experimental period. Biopsy samples of the left ventricular apex were taken 15 and 45 minutes after the start of ischemic arrest and 5 minutes after resumption of coronary blood flow. Biopsy samples were also obtained from 4 animals after thoracotomy to serve as controls for experimental procedures. Myocardial ultrastructure in the 4 control animals was comparable to that reported by other investigators. Five of 6 of the nontreated dogs and 8 of 9 lidocaine-treated dogs survived the entire period of ischemia and 5 minutes of coronary reperfusion. However, the extent of ultrastructural damage varied considerably between the two groups. In the experimental dogs receiving no lidocaine, mitochondria were swollen, cristae were absent, the mitochondrial matrix was cleared, and sarcomeres were disrupted. Myelin figures and contraction bands were also observed. None of the surviving lidocaine-treated animals had ultrastructural changes comparable to the worst ones in nontreated dogs. Damage was limited to some swelling of mitochondria with focal clearing of matrix. Most cristae remained intact. There were no myelin figures and few contraction bands. The results suggest that lidocaine protects the integrity of ischemic myocardium. It is suggested that this protection resulted from stabilization of plasma and/or mitochondrial membranes. (Am J Pathol 87:399-414, 1977).
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PMID:Reduction of ischemic myocardial damage in the dog by lidocaine infusion. 85 Nov 72

Selective renal angiograms and xenon washout curves were performed under general anesthesia with pentobarbital in hydrated or dehydrated dogs weighing 22-27 kg. Compared to the hydrated animals a significant overall decrease in the angiographic cortical perfusion was found in the dehydrated dogs which was reversible with the infusion of 200 ml isotonic saline. The total renal blood flow, the rapid flow component and the percent of total flow to the first compartment assessed with the xenon washout technique was however not significantly different in hydrated and dehydrated animals. It is suggested that temporary cortical ischemia might occur in dehydration which differs from the well known pathologic condition of cortical ischemia since total renal blood flow appears to be normal in the former and there is a fast recovery with isotonic saline infusion. The observed findings in dehydration could be explained with redistribution of blood away from the outer cortex to the inner cortex and to the medulla.
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PMID:Comparison of renal cortical perfusion assessed with angiography and xenon washout technique in hydrated and dehydrated dogs: a preliminary observation. 88 92

The yield of infarcted hemispheres following unilateral carotid ligation in gerbils under ketamine anesthesia substantially exceeded that occurring under pentobarbital anesthesia. In addition to increasing the gerbil stroke model's efficiency, ketamine provided a shorter recovery period, thus allowing earlier observation of clinical signs of brain injury. These results support the contention that anesthetic agents may modify the response of central neuronal tissues to acute ischemia.
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PMID:Modification of cerebral ischemic damage by anesthetics. 90 64

The present experiments were undertaken to measure postischemic regional cerebral blood flow (rCBF) and oxygen utilization rate (CMRo2) in rats anesthetized with either 70% N2O or phenobarbital (150 mg x kg-1). In previous studies we have found that extensive restitution of cerbral energy metabolites occurs after 30 min of complete cerebral ischemia irrespective of the type of anesthesia used. Following 30 min of pronounced, incomplete ischemia, however, a comparable restitution of cerebral energy state was obtained in deeply anesthetized (phenobarbital 150 mg x kg-1) but not in superfically anesthetized (70% N2O) rats. The objectives of the present investigation were (1) to study whether postischemic cerebral blood flow was higher in barbiturate-anesthetized animals during the initial recirculation period, and (2) to investigate if the protective effects of phenobarbital previously observed could be attributed to a decrease in CMRo2. In both groups of animals a considerable variability in postischemic rCBF was observed between different animals. However, no signs of gross inhomogeneity in blood flow were found and no consistent differences in flow values between the two groups of animals were observed. Since the measured postischemic CMRo2 were identical in both groups of animals and since cerebral venous oxygen contents were above normal the results leave little support to the assumption that, in the present model of transient, incomplete cerebral ischemia, failure of recovery of cerebral metabolism (N2O group) is primarily due to impaired recirculation, nor do they indicate that the protective effects of barbiturates is due to their ability to reduce rate of cerebral energy utilization.
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PMID:Postischemic cerebral blood flow and oxygen utilization rate in rats anesthetized with nitrous oxide or phenobarbital. 92 Feb 15

Angioplasty of the profunda femoris should be the primary approach to revascularization of the limb whenever it is feasible. Claudication distance can be significantly improved in almost all patients and prolonged limb salvage achieved in the majority of patients. In some high risk patients, the entire procedure can be accomplished expeditiously and atraumatically under local anesthesia, using a single groin incision. When the pattern of distribution of atherosclerosis provides the surgeon with the choice of performing either angioplasty of the profunda femoris or femoral popliteal bypass, the former option should be tried initially with resort to the latter if ischemia is not adequately relieved. In many instances when distal bypass is not possible or is unlikely to function effectively, angioplasty of the profunda femoris may provide the only opportunity to relieve ischemic symptoms. Operative blood flow measurements support the thesis that the collateral function of the profunda femoris artery is able to compensate for extensive obstructive disease in both the superficial femoral and popliteal segments.
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PMID:The role of angioplasty of the profunda femoris artery in revascularization of the ischemic limb. 93 26


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