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

In 21 patients undergoing ear operations associated with minimal bleeding plasma renin activity and plasma aldosterone concentration were studied before and during surgical procedure, and in the postoperative state. Studies were performed in two groups, one without (n=9) and one with beta-adrenergic blockade by Practolol (n=12). Plasma renin activity increased significantly during halothane anaesthesia alone whereas the surgical manipulations did not further influence mean values significantly. Thus, it seems to be established that anaesthesia per se influences renin secretion. On the other hand Practolol does not show an inhibiting effect. The plasma renin increase following anaesthesia is due to the hemodynamic including renal hemodynamic, changes as well as to activation of the sympatho-adrenal system. Changes in plasma aldosterone are variable. For the greater part of patients with beta-adrenergic blockade an increase during the operative procedure was found. However, in some patients especially in the control group, plasma aldosterone was unchanged or decreased in spite of increasing renin values. Significantly lower plasma potassium concentration in these cases seems to indicate the important contributing role of potassium for the short-term regulation of aldosterone secretion. Plasma sodium concentration remained unchanged for the periods studied.
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PMID:[Plasma renin activity and plasma aldosterone during anaesthesia and operative stress and beta-adrenergic blockade (author's transl)]. 0 27

Hyperventilation of patients during surgical anesthesia is a common practice in the United States. The results obtained in the present study re-emphasize serum potassium concentration is directly proportional to arterial carbon dioxide tension, and that for every 10 torr decrease in PaCO2 there is a concomitant 0.5 mEq/L decrease in potassium. Therefore sudden and significant levels of hypokalemia may occur during the course of a general anesthetic, and since hypokalemia is known to be capable of producing serious cardiac arrhythmias, hyperventilation should be avoided during surgical anesthesia, particularly in patients on drugs which produce electrophysiologic changes similar to those resulting from hypokalemia.
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PMID:Acute hypocapneic hypokalemia: an latrogenic anesthetic complication. 2 72

In pentobarbital (35.0 mg/kg) anaesthetised dogs, bolus injections of prazosin into the femoral artery (3.0--300.0 microgram) provoked a dose-related fall in the vascular resistance of the innervated hind limb. In contrast to papaverine, prazosin failed to produce the same effect in dogs under spinal anaesthesia even when the intrinsic femoral vascular tone was increased with vasopressin. However, vasodilator effects of prazosin were again observed when the tone of the limb was elevated by either stimulating the sympathetic lumbar chain or by infusing alpha-adrenoceptor agonists. A significant reduction of both aortic blood pressure and pressor response to bilateral carotid artery occlusion was noted in a group of normotensive dogs anaesthetised 12 h after the last dose of prazosin given twice daily at 0.5 mg/kg, p.o., for 3 day period. This short-term treatment modified neither the resting heart rate nor the positive chronotropic effect induced by either intravenous noradrenaline or electrical stimulation of pre- and post-ganglionic nerve fibres of the right stellate ganglion. However, it prevented the larger increase in heart rate in response to bilateral carotid occlusion in placebo-treated dogs after section of the vagi. A decrease in baseline sympathetic tone of the perfused hind limb as well as vasoconstrictor effects produced by i.a. injections of several alpha-adrenoceptor agonists and electrical stimulation of the lumbar sympathetic chain was observed in prazosin-treated animals. The dose--pressor response profiles to these alpha-adrenoceptor stimulants after prazosin were not parallel to those obtained in the control group. The vasoconstrictor response to angiotensin II was not changed by prazosin. In rabbit aortic strips, prazosin (0.1--3.0 micrometer) produced competitive antagonism of the contractile responses induced by cirazoline, noradrenaline and phenylephrine. In contrast to papaverine, prazosin in concentrations up to 100.0 micrometer neither relaxed the aortic strips contracted by potassium ions nor modified the concentration-response curve to calcium ions. These studies indicate that blood pressure lowering effects of prazosin given acutely or for three days can be accounted for by a clear-cut functional impairment of vascular postsynaptic alpha-adrenoceptors. No evidence for a direct myorelaxant property of prazosin could be obtained in these studies.
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PMID:Studies on the mechanism of the vasodilator effects of prazosin in dogs and rabbits. 2 80

In summary, one should be aware that hyperventilation and hypokalaemia occur frequently in the operating room under ordinary clinical conditions. An awareness of the rapidity with which these changes occur, and their extent as well as their potential hazards, should cause consideration of more aggressive attempts to maintain normocarbia and to use supplemental potassium during anaesthesia, particularly in patients with cardiac disease.
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PMID:Dynamics of serum potassium change during acute respiratory alkalosis. 3 68

1 The effects of high pressures of helium and of nitrogen on acetylcholine release were tested using the guinea-pig ileum as a model preparation. A superfusion system was designed in which this tissue could be maintained under physiological conditions in a high pressure chamber.2 Helium, at a pressure of 136 atm slightly increased the spontaneous output of acetylcholine but produced no significant changes at 68 atm (136 atm is close to the lethal pressure for small mammals).3 The acetylcholine release evoked by electrical stimulation or by 55 mM potassium was not altered by 136 atm of helium. Effects on tetrodotoxin-treated tissues were not consistent.4 Nitrogen, which in contrast to helium possesses general anaesthetic properties, caused considerable increases in spontaneous and in electrically evoked acetylcholine output at pressures which produce anaesthesia. These increases were not changed when helium was used to increase the total pressure to 136 atm, although this reverses the general anaesthetic actions of nitrogen in vivo.5 The increases in rate of acetylcholine release produced by nitrogen were observed in tetrodotoxintreated tissues and in tissues from reserpine-treated animals. In a calcium-free medium the increases were considerably smaller.6 The conclusions from these results are that while high pressures of helium caused little or no change in acetylcholine release rates, nitrogen produced large changes, which were not due to effects on axonal conduction. The effect of nitrogen is not apparently related to its general anaesthetic actions. Differences such as these in transmitter release would be likely to contribute to the differing physiological effects of these two gases.
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PMID:The effects of high pressure helium and nitrogen on the release of acetylcholine from the guinea-pig ileum. 4 Jun 48

1. Pentobarbitone anaesthesia, in rabbits, produces (i) hypokalaemia, (ii) increased intracellular potassium and reduced intracellular sodium in cardiac and skeletal muscle. 2. These changes suggest that the hypokalaemia which accompanies anaesthesia results from movement of potassium between the extracellular and intracellular compartments.
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PMID:The effect of pentobarbitone on plasma and intracellular sodium, potassium and pH in rabbit cardiac and skeletal muscle. 4 7

In rats, the sleeping time induced by overdosage with eight steroid anesthetics--alfathesin, 3-(3-oxo-17beta-hydroxy-19-nor-4-androsten-17alpha-yl)-propionic acid-lactone (SC-8109), 21-hydroxy=5alpha-pregnane-3,20-dione (P-234), 4-pregnene-3,11,20-trione (Bio.66), 17-hydroxy-3-oxo-4-androstene-17alpha-propionic acid-gamma-lactone(SC-5233),3alpha-hydroxy-5beta-pregnane-11,20-dione, 5beta-pregnane-3,11,20-trione (U-1373), and hydroxydione--was abolished or considerably reduced by a variety of catatoxic compounds, particularly 3beta-hydroxy-20-oxo-5-pregnene-16alpha-carbonitrile (PCN), 9alpha-fluoro-11beta,17-dihydroxy-3-oxo-4-androstene-17alpha-propionic acid potassium salt (CS-1), prednisolone, ethylestrenol and spironolactone. Phenobarbital and diphenylhydantoin, two non-steroidal stimulators of hepatic microsomal drug metabolism, were also highly effective. In contrast, triamcinolone, estradiol,progesterone, desoxycorticosterone and hydroxydione, which exert little or no catatoxic activity, failed to significantly diminish anesthesia or sedation.
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PMID:Inhibition of the effects of alfathesin and other steroid anesthetics by catatoxic steroids in rats. 5 71

The levels of total calcium, inorganic phosphorus, magnesium, sodium, potassium, and chlorides in the blood plasma, and the osmolality of the plasma, were determined in bovine foetuses (n = 20) and the dams (n = 20) in the third trimester of gravidity. The cows of the Bohemian Spotted breed were 2.5 to 7 years old. The foetuses were taken from the uterus by the Caesarean section with local anaesthesia. The foetuses were of both sexes (nfemale = 12, n male = 8). Only the level of total calcium and inorganic phosphorus in the blood plasma was much higher in the foetuses than in the dams and this difference was highly significant. The levels of other minerals showed no statistically significant differences in the two categories of animals tested. The osmolality of the blood plasma of the foetuses was almost the same as in the cows. The higher calcaemia and phosphoraemia of the foetuses ensues from the function of osteotrophic minerals in the process of quick growth and ossification in the third trimester of intrauterine life. The closeness of the levels of sodium, potassium and chlorides as well as the very similar osmolality of the blood plasma in the foetuses and the dams prove the "stability" of the dynamic balance of these parameters between the foetus and the dam in the internal environment of the womb.
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PMID:[The levels of various mineral substances in the blood plasma of bovine fetuses and their mothers in the third trimester of pregnancy]. 9 44

Studies in patients undergoing peritoneal laparoscopy, in which carbon dioxide was used as insufflating gas, showed that artificial hyperventilation was an effective means of preventing serious hypercapnia. The hypercapnia caused a rapid hyperkalaemia and there was a linear relationship between the two. Reversal of the hypercapnia caused the serum potassium to fall towards normal but the speed of this fall did not match the speed of reduction in Paco2. It is suggested that the changes in serum potassium following changes in Paco2 may have some clinical relevance in potassium-depicted patients.
Anaesthesia 1979 Oct
PMID:Hypercapnia and hyperkalaemia. 16 Nov 43

The plasma potassium, sodium, pH and haemoglobin of stored acid dextrose blood were measured after various periods of storage and after passage through a Fenwall R 4301 dry heat blood warmer. No significant changes were observed except a slight rise in plasma haemoglobin concentration.
Anaesthesia 1975 Mar
PMID:The effects of a dry heat blood warmer on some components of stored blood. 23 79


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