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

15 adult dogs fasted over night were used under Ketalar anesthesia. Experiments were undertaken during 3 months on 3 groups of animals vagotomized, splanchnicotomized and transected both extrinsic nerves. The intragastric pressure was measured by balloon-strain gauge method. The intragastric pressure was elevated in a way of filling with 200 ml of Ringer's solution within 1 minute every 2 minutes till a total of 800 ml. Following results were obtained: 1) The intragastric pressure at the initial period of gastric fullness and the average intragastric pressure during 2 minutes after filling of Ringer's solution in 3 groups were maintained in a higher level compared to that of the control dogs at every time after operation and every stage of gastric fullness. Their pressure gradients were shown sharp slopes compared to that of the control dogs. 2) The amplitude of the peristaltic movements in 3 groups was larger than that of the control dogs at every time after operation and every stage of gastric fullness. 3) The results in the chronic experiments were almost the same with that in the acute experiments of the present author (Ikeda, 1976 a b).
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PMID:[Chronic influences of transection of extrinsic nerves to dog's stomach on the fluctuations of intragastric pressure (author's transl)]. 91 40

Serial invasive and noninvasive (systolic time interval) measurements of left ventricular performance were obtained in six healthy volunteers during general anesthesia employing the following sequence: thiopental induction, succinylcholine (prior to endotracheal intubation), and halothane--100 per cent oxygen at 1.25 and 1.75 MAC. Heart rate (HR), mean pulmonary arterial "wedge" pressure (PAW) and mean systemic arterial pressure (MAP) were measured continuously; cardiac index and systolic time intervals (STI's) were measured during each intervention. At both levels of halothane, MAP and stroke work index decreased (both P less than 0.02), while HR and systemic vascular resistance did not change. At 1.25 MAC halothane PAW was unchanged, but at 1.75 MAC PAW increased from 8 +/- 4 (SD) to 11 +/- 5 torr (P less than 0.02). Preload was altered at 1.25 MAC by administration of 600-1,000 ml lactated Ringer's solution; PAW increased from 9 +/- 4 to 17 +/- 3 torr (P less than 0.01). At 1.75 MAC halothane, volume expansion increased PAW in a similar manner, but the resultant ventricular function curve was depressed compared with 1.25 MAC halothane. In additon, at each level of halothane anesthesia, the ventricular function curve was depressed compared with results obtained in awake normal subjects. Afterload was altered at 1.25 MAC halothane by infusion of phenylephrine sufficient to raise MAP by 30 per cent. This intervention resulted in a greater depression of cardiac performance than that observed at 1.75 MAC halothane alone. Although alterations in STI's were directionally similar to changes observed in invasive hemodynamic measurements, STI's were sensitive to acute alternations in loading conditions. It is concluded that the levels of halothane commonly employed for general anesthesia significantly depress left ventricular performance in normal subjects, as evidenced by abnormal responses to alterations in preload and afterload, and that STI's should not be employed for routine measurement of left ventricular performance during anesthesia unless both the afterload and the preload on the myocardium are known.
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PMID:Alterations of normal left ventricular performance by general anesthesia. 98 77

Twelve adult dogs fasted over night were used under Nembutal anesthesia. The intragastric pressure was measured by strain-gauge method with open tip cannula via duodenum. The stomach was filled through the cannula with 50 ml of Ringer's solution in a stepwise manner every two minutes until a total of 600 ml. Following results were obtained: 1) The intragastric pressure was more elevated on the vagotomized and the splanchnicotomized dogs than on the intact animals by a stepwise augmentation of Ringer's solution. 2) On the animals which were transected totally the extrinsic nerves, the increase of the intragastric pressure was the most. 3) It may be concluded that the elevation of intragastric pressure after denervation of the extrinsic nerves, due to the abolitions of vagal and splanchnic inhibitory reflexes.
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PMID:[The influence of transection of extrinsic nerves to stomach on the fluctuation of intragastric pressure in dog (author's transl)]. 98 90

The haemodynamic effect of enflurane has been examined in two groups of geriatric patients, one with and the other without preanaesthetic administration of 15 mg/kg of 1,8% dextran in lactated Ringer's solution. All the patients have been immobilized for 2 to 3 days before they were operated for an orthopaedic procedure. The administration of the colloidal solution led only to minor cardiovascular alterations: a rise of central venous pressure by 6 +/- 1 (+/- S.E.M.) cm H2O, an increase of mean arterial pressure by 6 +/- 2%, an increase of cardiac output by 10 +/- 4%. Heart rate decreased by 5 +/- 4% and total peripheral resistance by 12 +/- 5%. The cardiovascular depressant effect of enflurance was markedly attenuated by the preanaesthetic volume administration. Mean arterial pressure decreased during anaesthesia by only 16 +/- 3%, as compared with a decrease of 25 +/- 7% in the control group, cardiac output remained virtually unchanged (-3 +/- 9% vs. -37 +/- 5% in the controls) and total peripheral resistance decreased not significantly by 10 +/- 12%, while it rose in the controls by 20 +/- 8%. These findings support the hypothesis that the particular sensitivity of geriatric patients towards the depressant effects of anaesthetics is at least partially due to a compensated hypovolaemia which occurs as a physiological adaptation to immbolization. Enflurane appears as a suitable anaesthetic for geriatric patients, if proper measures for preanaesthetic volume substitution are taken.
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PMID:[Effect of volume substitution with dextran on the haemodynamics under enflurane anaesthesia in geriatric patients (author's transl)]. 100 39

The effects of acute normovolemic hemodilution on lung water, blood volume, hemodynamics, and oxygen transport were studied. The subjects were six patients undergoing major operations, with prebleeding and hemodilution under fluoroxene and nitrous oxide anesthesia. The menatocrit was reduced form 43 to 25 percent in one step, with simultaneous infusion of Plamanate and lactated Ringer's solution. Blood volume was expanded by 5 percent by the hemodilution. The major compensation was a striking rise in cardiac output to 161 percent. Systemic oxygen transport (CO times arterial O2 content) increased despite the marked fall in oxygen-carrying capacity, and the arteriovenous O2 content difference decreased. Lung water the aveolararterial (A-a) oxygen differences were reduced. The procedure was well tolerated by this group of selected patients and homologous blood utilization was reduced.
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PMID:Intraoperative prebleeding in man: effect of colloid hemodilution on blood volume, lung water, hemodynamics, and oxygen transport. 115 56

The authors studied the effects of varying Na+ and Ca++ concentrations and of replacing H2O with D2O in Ringer's solution upon the actions of general and local anesthetics on isolated frog sciatic nerves. This experimental model was used to study whether general anesthetics affect excitable membranes in a manner similar to that of typical membrane stabilizers (local anesthetics). Procaine (2.5-7.5 mM), halothane (9, 18, and 36 mM), enflurane (8 mM), and ketamine (0.15 and 0.73 mM) raised threshold and lowered spike amplitude, and their effects were facilitated by reducing Na+ concentration in the Ringer's solution. The local anesthetic effects of procaine (2.5-7.5 mM) and ketamine (0.73 mM) were antagonized by Ca++, while the axonal depressant effect of halothane was facilitated by increasing Ca++ concentration in the Ringer's solution, indicating a different mode of action. General anesthetics also differed from local anesthetics in their interaction with water: replacement by D2O of H2O in the Ringer's solution selectively increased the axonal depressant effects of halothane and enflurane but not those of ketamine or procaine. Since D2O differs from H2O in its greater ice-likeness, these results are consistent with the view that general anesthetics stabilize excitable membranes via stabilization of the water-biopolymer lattice, as predicted by the hydrate-microcrystal theory of anesthesia. In contrast, local anesthetics may stabilize excitable tissues by binding to the same fixed negative charges of the membrane to which Ca++ is normally bound. (Key words: Theories of anesthesia, hydrate-microcrystal; Nerve, mode of action of anesthetics; Anesthetics, volatile, halothane; Anesthetics, volatile, enflurane; Anesthetics, local, procaine; Anesthetics, intravenous, ketamine.)
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PMID:Differential membrane effects of general and local anesthetics. 119 May 39

Thirteen patients were studied during two hours of anaesthesia for abdmonial operations and for an hour post-operatively. Serial venous blood samples were taken for determination of plasma total and ionized calcium, acid-base variables, Na, K, Mg, PO4 total proteins and parathyroid hormone. One group of patients received 5 per cent dextrose/water and the other 5 per cent dextrose in Ringer's solution, at 250 ml per hour. Total and ionized calcium levels decreased toward the end of operation and an hour later, associated with respiratory alkalosis. Parathyroid hormone increased at the end of operation, as an effect of the decreased ionized calcium. The general effect was mild haemodilution with all the other electrolytes decreasing, as did total protein concentration.
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PMID:Patterns of total and ionized calcium and other electrolytes in plasma during and after general surgery. 124 24

Pressure injections of a Ringer's solution containing glutamate (10 or 20 mM) into the nucleus basalis of Meynert inhibited the tonic firing of reticular thalamic (RT) neurones which were recorded in rats under deep urethane anaesthesia. When the inhibition was strong enough to stop the discharges, a burst firing mode was induced in RT cells before the recovery of tonic discharges. This glutamate-induced inhibition of RT cells was completely abolished following the systemic administration of the muscarinic antagonist, scopolamine (150 micrograms kg-1, i.v.). These results indicate that the cholinergic cells of the nucleus basalis of Meynert can control the mode of discharges of RT neurones through the activation of muscarinic receptors.
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PMID:Muscarinic inhibition of reticular thalamic cells by basal forebrain neurones. 136 97

Lactated Ringer's solution is frequently used to avoid metabolic acidosis during fluid resuscitation. The standard lactated Ringer's solution contains racemic lactate, an equal mixture of the D- and L-stereoisomers. We investigated whether sodium L-lactate or sodium racemic lactate (DL-lactate) is more effective for increasing buffering capacity in body fluids. For the purpose of this comparison, Ringer's solutions containing no lactate, sodium L-lactate, or racemic lactate at a concentration of 84 mEq/L (three times more than the ordinary level) were infused in patients under general anesthesia during tympanoplasty. Although differences occurred among the three groups in blood concentrations of L-lactate, D-lactate, and the L-lactate/pyruvate ratio, no differences occurred between the two lactate groups in either bicarbonate ion concentration or base excess. The amount of buffering capacity increased significantly in both lactate groups, compared with preinfusion levels, and was more than the values in the nonlactated Ringer's solution group. We conclude that sodium racemic lactate is metabolized at nearly the same rate as that of sodium L-lactate.
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PMID:Effects of sodium L-lactate and sodium racemic lactate on intraoperative acid-base status. 141 21

A new method of selective cooling of the brain was studied under profound hemodilution in 17 dogs. The carotid and vertebral arteries were bilaterally exposed, and the right vertebral artery was destroyed to provide an infusion route for cold solution for brain cooling. After the other three cerebral arteries were clamped simultaneously in the neck under low-dose heparinization, cold Ringer's lactate solution was immediately perfused into the right vertebral artery. Brain temperatures fell gradually in two dogs, and the experiments were terminated. In 10 dogs, the brain temperature fell to 28 degrees C within 4.4 +/- 1.5 minutes and was maintained at 27.0 +/- 1.0 degrees C for 60 minutes. During this interval, the body temperature was 33.9 +/- 1.6 degrees C, the stump pressure of the vertebral artery was 58 +/- 15 mm Hg, and the hematocrit value of cerebral venous blood was 7.2 +/- 4.2%. Inspection of the brain during infusion revealed paleness of the cortical vessels and no evidence of swelling. All animals survived in good condition until the time of death at 10 weeks. Histological examination of the brain revealed no evidence of ischemic injury. In a control study of five dogs, Ringer's solution at 38 degrees C was infused in the same manner as the cold solution. None of these dogs recovered from anesthesia. It is concluded that selective cooling of the brain under profound hemodilution has a protective effect on cerebral ischemia and provides a relatively bloodless operative field.
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PMID:Selective cooling of brain using profound hemodilution in dogs. 147 Mar 15


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