British journal of anaesthesia
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Comparative Study
Neuroleptic malignant syndrome and malignant hyperthermia. In vitro comparison with halothane and caffeine contracture tests.
The in vitro halothane and caffeine contracture tests have been performed on muscle tissue from six survivors of the neuroleptic malignant syndrome. The results, which are expressed in accordance with the criteria of the European MH Group, defined five of the subjects as MHN and one patient as MHE. It is concluded that there is no common pathophysiological link between the neuroleptic malignant syndrome and malignant hyperthermia.
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This study investigated the possible analgesic effect of midazolam as a result of interruption of those spinal cord pathways taken by pain afferents. Experiments were performed on 15 male Wistar rats with chronically implanted lumbar subarachnoid catheters. ⋯ We also performed experiments on frog sciatic nerves which showed that midazolam did not have a local anaesthetic action. We conclude that intrathecal midazolam causes spinally-mediated analgesia by binding to benzodiazepine receptors in the spinal cord.
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Gas exchange was modelled by a Fortran program. Arterial blood-gas tensions have higher resolution than inert gas retentions in terms of distinguishing a single VA/Q compartment from a progressively broadening lognormal distribution. ⋯ The way in which the arterial blood-gas tensions vary with the variables of two and three-compartment distributions is described. Two- and three-compartment VA/Q distributions are derivable from either arterial blood-gas tensions or inert gas retentions.
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The influence of fresh gas flow (FGF) setting on rebreathing was investigated in 15 infants and children (weight 3.5-21.8 kg) during balanced anaesthesia with mechanically controlled ventilation using a T-piece (Mapleson E) system and a Nuffield ventilator 200. Tidal volume (VT), minute volume (VE), maximal inspired (PICO2) and end-tidal (PE'CO2) carbon dioxide tensions and airway pressure were measured. VE, set to produce a PE'CO2 of about 4.5 kPa and measured at a high FGF (minimal rebreathing), was unchanged throughout the study and the regression equation for VE and weight was: VE (ml min-1) = 146 x kg + 482, r = 0.92. ⋯ At FGF:VE ratios equal to 1.0, alveolar rebreathing was more pronounced and hypercapnoea occurred with a PE'CO2 (mean +/- 1 SD) of 5.89 +/- 0.53 kPa. At this FGF setting, change in I:E ratio from 1:2 to 1:1 did not influence the level of alveolar rebreathing. A minimal FGF (ml min-1) setting of 1.5 x VE (that is, 1.5 (146 x kg + 482), approximated to the expression (200 x kg + 1000) is recommended for controlled ventilation to avoid hypercapnoea when using the T-piece system in children weighing less than 20 kg.
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Randomized Controlled Trial Comparative Study Clinical Trial
Intrathecal sufentanil as a supplement to subarachnoid anaesthesia with lignocaine.
The combination of low-dose sufentanil with lignocaine for subarachnoid anaesthesia was studied in a double-blind comparative trial in 40 urological patients. Patients were allocated randomly to two groups and received 5% heavy lignocaine 1.5 ml together with either 1.5 ml of sufentanil 5 micrograms ml-1, or physiological saline 1.5 ml. ⋯ There was no significant difference in the number of patients requiring supplementary analgesics. Side-effects were similar in both groups.