Articles: general-anesthesia.
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To evaluate the possible interaction between clonidine and ephedrine, the authors studied hemodynamic responses to intravenous ephedrine in 80 patients who received either clonidine pre-anesthetic medication of approximately 5 micrograms.kg-1 orally (n = 40) or no medication (n = 40). The patients were studied while they were either awake (n = 40) or anesthetized with enflurane and nitrous oxide in oxygen (n = 40). ⋯ The enhanced pressor responses to ephedrine observed in both awake and anesthetized patients in the presence of clonidine may be attributed to increased catecholamine storage at sympathetic nerve endings due to clonidine, enhanced sensitivity of tissue receptors to which ephedrine binds, potentiation of alpha-adrenoceptor mediated vasoconstriction of both agents, or all of these. It is concluded that oral clonidine preanesthetic medication of 5 micrograms.kg-1 does augment rather than attenuate the pressor responses to intravenous ephedrine in patients both prior to and during general anesthesia.
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We have studied the effects of anaesthesia on atelectasis formation and gas exchange in 45 patients of both sexes, smokers and nonsmokers, aged 23-69 yr. None of the patients showed clinical signs of pulmonary disease, and preoperative spirometry was normal. In the awake patient, partial pressure of arterial oxygen (PaO2) decreased with increasing age (P less than 0.001) and the alveolar-arterial oxygen partial pressure difference (PAO2-PaO2) increased with age (P less than 0.001). ⋯ Atelectasis and shunt did not increase significantly with age, whereas log SD Q and perfusion of regions with low VA/Q ratios did (r = 0.55, P less than 0.001 and r = 0.35, P less than 0.05, respectively). Awake, the major determinant of PaO2 was perfusion of regions of low VA/Q ratios, which increased with age. During anaesthesia shunt influenced PaO2 most, low VA/Q being a secondary factor which, however, was increasingly important with increasing age, thus explaining the well-known age-dependent deterioration of arterial oxygenation during anaesthesia.
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Rev Esp Anestesiol Reanim · Mar 1991
Historical Article[History of the introduction of ether anesthesia in Spain. A new contribution to its study].
Ether anesthesia was introduced in Spain on January 13, 1847. Dr. Diego de Argumosa y Obregón, from Madrid, was the first Spanish surgeon who operated with the help of sulphuric ether. ⋯ We have in some occasions defended that thesis; however, we were not satisfied with it and we decided to reinvestigate the facts. We had access to other sources and we concluded that anesthetics were really used a very early phase in Santiago de Compostela, but in the case of ether it was later than Argumosa and Oliverio Machechan used it in Madrid and Mendoza in Barcelona. In the present article we analyze these facts in detail, with emphasis on those that we consider historically relevant and that had not been previously dealt with by any other author addressing these issues.
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Comparative Study Clinical Trial Controlled Clinical Trial
Neuromuscular effects of pipecuronium bromide.
The neuromuscular effects of pipecuronium bromide have been evaluated in 90 adult patients anaesthetized with thiopentone, nitrous oxide in oxygen and intravenous fentanyl with or without halothane. Eighty patients received pipecuronium 45 micrograms kg-1 and the remaining ten 70 micrograms kg-1. A separate group of 10 patients received pancuronium in a dose of 60 micrograms kg-1 (equipotent to pipecuronium 45 micrograms kg-1). ⋯ The time to onset of complete block with 70 micrograms kg-1 of pipecuronium averaged 2.5 min and the duration to 25% recovery 95 min. There were no significant changes in heart rate and arterial pressure with the use of pipecuronium. The results show pipecuronium to be a drug resembling pancuronium in its neuromuscular effects when used in equipotent doses.