Canadian journal of anaesthesia = Journal canadien d'anesthésie
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of hyperbaric solutions of bupivacaine and tetracaine during continuous spinal anaesthesia.
The aim of this study was to compare two equipotent solutions of hyperbaric bupivacaine and tetracaine in 30 elderly patients undergoing elective hip surgery under continuous spinal anaesthesia. With the patient in the supine position, 2 ml (8 mg) of either hyperbaric solution (density 1.030) were administered in a double-blind and randomized fashion. The median maximum sensory and temperature discrimination levels (T5 and T4) were similar with both solutions. ⋯ The haemodynamic changes and vasopressor requirements were comparable. The plasma catecholamine levels measured at four different times remained unchanged and were not different between the two groups at any time. The authors conclude that, during continuous spinal anaesthesia, equipotent hyperbaric solutions of bupivacaine and tetracaine have similar anaesthetic and haemodynamic effects.
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The hypothesis that histamine H2 receptor blockade adversely affects neuromuscular function was tested, in vivo, in rats anaesthetised with urethane during mechanical pulmonary ventilation. Succinylcholine was administered as a bolus and constant-rate infusion to maintain 49.2% (+/- 1.5 SEM) twitch suppression in 19 rats. Cimetidine iv, 3.2, 7.5, 10, 17.8, 23.7, 31.6, or 56.2 mg.kg-1 was then administered in groups of two to three rats. ⋯ There was a good relationship between peak potentiation and serum cimetidine concentration with 50% potentiation occurring at 46.5 (+/- 4.6) micrograms.ml-1. Potentiation at steady-state was not correlated to serum cimetidine concentration but there was a weak relationship between reversal and serum cimetidine concentration. These results support reports from patients of an interaction between cimetidine and succinylcholine.
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Randomized Controlled Trial Clinical Trial
Amrinone before termination of cardiopulmonary bypass: haemodynamic variables and oxygen utilization in the postbypass period.
One hundred patients were randomly allocated to receive saline or amrinone, 0.75 mg.kg-1, ten minutes before separation from cardiopulmonary bypass (CPB) after elective coronary artery bypass grafting, in order to determine the effects of this agent on haemodynamic variables and O2 utilization. Anaesthesia and CPB were managed in a standard fashion. Before induction of anaesthesia, at pericardiotomy, then at 1, 10, 20 and 30 min after CPB, haemodynamic profiles, haematocrit, and O2 saturation of arterial and mixed venous blood were measured. ⋯ Haemodynamic measurements were similar between groups at all times; however, a higher dose of phenylephrine was given immediately before weaning from CPB in the amrinone group, and more patients in this group received phenylephrine in the first 30 min after CPB. Mixed venous saturation (SvO2) was higher in the amrinone patients at all times after CPB, leading to lower calculated oxygen consumption (VO2) (P less than 0.05). Insufficient dosage may explain the lack of haemodynamic effect, while possible reasons for the higher SvO2 and lower VO2 are either reduced whole body VO2 or peripheral shunting.
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Randomized Controlled Trial Comparative Study Clinical Trial
Epidural fentanyl and caesarean section: when should fentanyl be given?
Epidural fentanyl is often added to epidural local anaesthetic agents to improve the quality of anaesthesia obtained during Caesarean section. Fentanyl may be given either before or after delivery of the infant. When given before delivery, fentanyl has not been reported to cause neonatal depression, although this remains a concern. ⋯ Neonates were assessed by umbilical arterial blood pH and Apgar scores. No differences were detected in either group with respect to maternal or neonatal outcome. We recommend using only epidural local anaesthetic agents before delivery, and giving epidural fentanyl following delivery of the infant.
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Randomized Controlled Trial Comparative Study Clinical Trial
Supplemental maternal oxygen therapy during caesarean section under epidural anaesthesia: a comparison of nasal prongs and facemask.
Forty healthy parturients at term, undergoing elective Caesarean section, were divided into two groups to receive supplemental oxygen by either simple facemask (Group FM, 8 L.min-1) or nasal prongs (Group NP, 4 L.min-1) during the procedure. Anaesthesia was provided by epidural block to equivalent dermatomal levels in all patients. Maternal oxygen saturation was measured continuously with pulse oximetry and supplemental oxygen was provided to the mother after administration of the epidural test dose and continued until the end of the procedure. ⋯ There was no difference in the clinical condition of the neonates, as assessed by Apgar scores, or in the acid-base and oxygenation status, as assessed by blood gas analyses between the two groups. Mean umbilical vein oxygen saturation, a measure of fetal oxygen delivery, was 46 +/- 18% (95% confidence interval 39% to 54%) for Group NP and 54 +/- 17% (95% confidence interval 46% to 62%) for Group FM, again not different. We conclude that when the clinical condition, acid-base and oxygenation status of neonates, delivered by elective Caesarean section to healthy, low-risk parturients with normal placental function under epidural anaesthesia, are evaluated, it makes no difference whether the mothers received supplemental oxygen by nasal prongs or simple facemask.