British journal of anaesthesia
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Randomized Controlled Trial Comparative Study Clinical Trial
Cardiovascular and catecholamine responses to laryngoscopy with and without tracheal intubation.
The catecholamine and cardiovascular responses to laryngoscopy alone have been compared with those following laryngoscopy and intubation in 24 patients allocated randomly to each group. Following induction with fentanyl and thiopentone, atracurium was administered and artificial ventilation undertaken via a face mask for 2 min with 67% nitrous oxide in oxygen. Following laryngoscopy, the vocal cords were visualized for 10 s. ⋯ Arterial pressure, heart rate and plasma noradrenaline and adrenaline concentrations were measured before and after induction and at 1, 3 and 5 min after laryngoscopy. There were significant and similar increases in arterial pressure and circulating catecholamine concentrations following laryngoscopy with or without intubation. Intubation, however, was associated with significant increases in heart rate which did not occur in the laryngoscopy-only group.
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Randomized Controlled Trial Comparative Study Clinical Trial
Subarachnoid analgesia for caesarean section. A double-blind comparison of plain and hyperbaric 0.5% bupivacaine.
Equal volumes (2.5 ml, 12.5 mg) of plain 0.5% bupivacaine (glucose-free) and hyperbaric 0.5% bupivacaine (in 8% glucose) were compared in a randomized double-blind study of 40 patients undergoing Caesarean section under subarachnoid anaesthesia. There were no differences in the rate of onset, maximum spread, number of patients with high cervical levels, duration of anaesthesia or incidence of post-spinal headaches between the two solutions. ⋯ Thirteen patients in the hyperbaric group and 10 in the isobaric group required i.v. ephedrine to treat hypotension. Nine patients (23%) developed a post-spinal headache, and three were treated with an extradural blood patch.
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Randomized Controlled Trial Comparative Study Clinical Trial
Anaesthesia for evacuation of retained products of conception. Comparison between alfentanil plus etomidate and fentanyl plus thiopentone.
Forty-four patients presenting for evacuation of retained products of conception were anaesthetized with either fentanyl and thiopentone, or alfentanil with etomidate, along with 70% nitrous oxide in oxygen. There was no difference between the two techniques in indices of immediate recovery (time to opening eyes and obeying a simple command), but the rate of return of higher mental functions (assessed by a coin counting test) was significantly better using the alfentanil-etomidate technique. There was no statistically significant difference between the techniques for apnoea or abnormal movements during anaesthesia, but alfentanil with etomidate was associated with significantly more pain on injection and a higher frequency of postoperative vomiting (40%).
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Randomized Controlled Trial Comparative Study Clinical Trial
Effect of gravity on the spread of extradural anaesthesia for caesarean section.
The effect of gravity on the spread of extradural anaesthesia was evaluated in a series of parturients undergoing elective Caesarean section. Following placement of an extradural catheter, 25 patients were placed 30-40 degrees head-up for 20 min during the administration of the local anaesthetic drug; 25 additional patients remained supine during injection. ⋯ There were no differences in the rate of onset of sacral blockade or in the extent of neural blockade between the two groups. The semi-upright position was not necessary to ensure adequate sacral anaesthesia for Caesarean section.
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Comparative Study
Differential nerve blockade: esters v. amides and the influence of pKa.
The in vitro sensitivities to local anaesthetic blockade of A, B and C fibres in rabbit vagus nerves were examined using a series of structurally similar amide agents, which varied in lipid solubility and anaesthetic potency. The actions of these drugs were compared with one another, and with those of a series of amino-ester local anaesthetics studied previously. The results demonstrated that A fibres are the most, and C fibres the least, sensitive to blockade by local anaesthetic agents. ⋯ As the latter increased, so did the rate of A fibre blockade. Combining the results of the two studies suggests that an agent of low lipid solubility and high pKa might be used to produce differential C fibre blockade. Comparison of the results obtained with the two different classes of drug indicates that the ester structure may have an inherently more potent action than the amide.