British journal of anaesthesia
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Metoclopramide has been used for almost 40 yr to prevent postoperative nausea and vomiting (PONV). We have reviewed the efficacy and safety of metoclopramide for the prevention of PONV. A systematic search (MEDLINE, EMBASE, manufacturers' databases, hand searching, bibliographies, all languages, up to June 1998) was performed for full reports of randomized comparisons of metoclopramide with placebo in surgical patients. ⋯ There was no significant late anti-vomiting effect. Minor drug-related adverse effects (sedation, dizziness, drowsiness) were not significantly associated with metoclopramide. There was one adult who experienced extrapyramidal symptoms with metoclopramide.
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It has been suggested previously that tramadol increases central nervous system activity and 'lightens' anaesthesia with volatile agents. We assessed the effects of tramadol on the minimum alveolar concentration (MAC) of isoflurane in 56 Wistar rats, instrumented chronically with an arterial and central venous catheter. The MAC of isoflurane was determined using the tail clamp method under three conditions: (1) after injection of saline (control); (2) after administration of tramadol 10 mg kg-1 i.v.; and (3) after administration of morphine 1 mg kg-1 i.v. ⋯ In contrast, after pretreatment with naloxone, tramadol (1.47 (0.04)%) or morphine (1.38 (0.07)%) did not cause a reduction in the MAC of isoflurane compared with controls (1.39 (0.06)%). We conclude that tramadol and morphine reduced the MAC of isoflurane to a small but significant extent. For both drugs, this effect was related to their action at opioid receptors.
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Case Reports Clinical Trial Controlled Clinical Trial
Continuous auditory monitoring--how much information do we register?
We have studied response times of 30 anaesthetists to a standardized episode of arterial oxygen desaturation in a simulated patient, randomized to the use of either a fixed or variable pitch pulse oximeter. We wished to determine if a variable auditory signal was important in detecting adverse events. A variable pitch pulse signal had a shorter time to recognition of desaturation (P < 0.0001), with a mean response time of 32 s, compared with 129 s for the fixed pitch signal.
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Randomized Controlled Trial Clinical Trial
Sevoflurane anaesthesia causes a transient decrease in aquaporin-2 and impairment of urine concentration.
Sevoflurane anaesthesia is occasionally associated with polyuria, but the exact mechanism of this phenomenon has not been clarified. Aquaporin-2 (AQP2) is an arginine vasopressin (AVP)-regulated water channel protein localized to the apical region of renal collecting duct cells and is involved in the regulation of water permeability. To elucidate the effect of sevoflurane anaesthesia on urine concentration and AQP2, we have compared serum and urinary concentrations of AVP, AQP2 and osmolar changes during sevoflurane and propofol anaesthesia. ⋯ Although urinary AQP2 excretion in the propofol group increased together with changes in plasma and urinary AVP, urinary AQP2 was significantly lower at 90 min in the sevoflurane group. Urine osmolality in the sevoflurane group also showed a transient but significant decrease in parallel with suppression of AQP2. Our data suggest that sevoflurane anaesthesia transiently produced an impaired AQP2 response to an increase in intrinsic AVP.