Anaesthesia
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Molecular sieves are used in industry to 'scrub' industrial gases. We examined, during simulated low-flow closed system anaesthesia, (1) the carbon dioxide adsorbing potential of molecular sieves and (2) the reactivity of the sieves compared to soda lime using sevoflurane as an indicator. A low-flow anaesthetic system containing 13X molecular sieves was connected to a model lung. ⋯ No increase in compound A was observed when molecular sieves were used for carbon dioxide removal. The highest mean (SD) temperature of the molecular sieves was 41.5 (3.2) degrees C. Molecular sieves are effective adsorbents of carbon dioxide when used in a simulated low-flow, closed anaesthetic system.(ABSTRACT TRUNCATED AT 250 WORDS)
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Randomized Controlled Trial Comparative Study Clinical Trial
A comparison of diclofenac with ketorolac for pain relief after knee arthroscopy.
We performed a double-blind controlled trial to compare the analgesic effect of two nonsteroidal anti-inflammatory drugs. We compared rectal diclofenac 100 mg given 1 h before induction of anaesthesia with intravenous ketorolac 10 mg given immediately before anaesthesia in 40 patients undergoing arthroscopy of the knee as day cases. ⋯ There was no difference in the pain parameters, sleep disturbance, or restriction of activity between groups. We suggest that ketorolac 10 mg intravenously and diclofenac 100 mg rectally provide comparable postoperative analgesia in the first 24 h after arthroscopy of the knee.
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Randomized Controlled Trial Comparative Study Clinical Trial
The effect of cerebrospinal fluid dilution of isobaric 0.5% bupivacaine used for spinal anaesthesia.
A prospective study was conducted to see the effect on spinal anaesthesia of the dilution of isobaric 0.5% bupivacaine with cerebrospinal fluid. Sixty patients were randomly allocated to three groups. In group 1, patients received 3 ml isobaric 0.5% bupivacaine intrathecally without aspirating cerebrospinal fluid. ⋯ The only statistical difference was the time to reach complete motor block, which was shorter in group 1 as compared to groups 2 and 3 (6.9 SD 1.4 min versus 11.3 SD 3.0 and 13.5 SD 3.9 min respectively). The mean value of maximum decrease in systolic blood pressure was small, being less than 15% of the pre-operative value for each group. In conclusion, the effect of diluting isobaric 0.5% bupivacaine with cerebrospinal fluid, 1 ml and 2 ml, is minimal and it is an unnecessary procedure with limited clinical effect.
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Increased duration of anaesthetic administration has implications for recovery from anaesthesia, has cardiovascular effects, and potential for toxicity through metabolism and breakdown of the anaesthetics. Recovery of function after desflurane or sevoflurane anaesthesia, because of the low blood gas and tissue solubilities of these agents, is more rapid than after halothane, isoflurane or enflurane, with recovery being most rapid after desflurane. Increased duration of anaesthesia amplifies the differences in rate of recovery because of the additional anaesthetic (greater with more soluble agents) dissolved in tissues. ⋯ Sevoflurane undergoes considerable metabolism, producing free fluoride ion, with plasma concentrations proportional to dose and duration of anaesthesia exceeding 50 microM in approximately 7% of patients. In rats, the effects of a toxic breakdown product of sevoflurane, CF2 = C(CF3)OCH2F (compound A), are also dose- and duration-dependent, with lower concentrations producing toxic effects as duration of exposure increases. The clinical importance of the metabolism and in vitro breakdown of sevoflurane has still to be adequately tested.
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Desflurane is a new volatile, inhaled anaesthetic that differs significantly from presently available inhaled agents in being halogenated solely with fluorine. This fluorination produces a lower solubility and increased resistance to biodegradation. ⋯ Limitations include a lesser potency and greater pungency at concentrations exceeding 1 minimum alveolar concentration (MAC). Other pharmacological properties are similar to those of isoflurane.