British journal of anaesthesia
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The incidence of immediate postoperative hypoxaemia following general anaesthesia was studied using a pulse oximeter in 120 ASA category I and II patients during transport to the recovery room. Thirty-two percent of those not given oxygen during transport developed desaturation (SaO2 less than 90%) in spite of receiving 100% oxygen for 5 min before transport. ⋯ None of the patients given oxygen 2 litre min-1 via a nasopharyngeal catheter during transport exhibited an SaO2 less than 90%. The only variable which correlated with the development of desaturation was the duration of anaesthesia.
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Randomized Controlled Trial Comparative Study Clinical Trial
High- and low-dose fentanyl anaesthesia: hormonal and metabolic responses during cholecystectomy.
We have compared two groups of patients given low- or high-dose fentanyl anaesthesia. Arterial blood samples were collected for measurement of glucose, free fatty acids (FFA), glycerol, beta-hydroxy-butyrate, insulin, c-peptide, glucagon, human growth hormone (HGH), cortisol and adrenaline concentrations. After induction of anaesthesia, blood concentrations of most of these substances decreased. ⋯ In the group that received high-dose fentanyl anaesthesia the plasma concentrations of almost all the hormones and substances measured remained relatively low. The differences between the two groups during surgery were significant for adrenaline (P less than 0.001) and cortisol (P less than 0.001). High-dose fentanyl appears to block the trauma-induced stress response seen in patients anaesthetized with low dose fentanyl.
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Neostigmine 1.25 mg or 0.625 mg was used to antagonize neuromuscular blockade produced by either atracurium 0.5 mg kg-1 or vecuronium 0.1 mg kg-1 in four groups of patients (n = 45) when the first EMG response of the train-of-four (A') had recovered to 10% of control (A). The time for A'/A and the train-of-four ratio (D'/A') to reach 70% was recorded. ⋯ However, with neostigmine 0.625 mg after vecuronium, recovery of D'/A' (but not A'/A) was little faster than spontaneous. Neostigmine 1.25 mg appears to be almost as effective as neostigmine 5.0 mg or 2.5 mg in antagonizing considerable block (90% depression of twitch height) produced by either atracurium or vecuronium, but neostigmine 0.625 mg is not sufficient, especially after vecuronium.
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This study has examined the effects of inhaled nitrous oxide on the N1 and P2 components of the cortical auditory evoked potentials (AEP) in the latency interval 80-300 ms after the stimulus. The amplitudes, latencies and thresholds of the AEP were measured at a range of end-tidal nitrous oxide concentrations (0%, 10%, 20%, 40%) in 10 subjects with normal hearing. ⋯ A study of the effect of stimulus intensity on AEP amplitude showed that the amplitude change with nitrous oxide was accounted for largely by systematic increase in evoked potential threshold. Subjective pure tone thresholds were not affected by the concentrations of nitrous oxide used, indicating that the AEP changes were independent of subjective hearing level.
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A system for the non-invasive monitoring, recording and storing haemodynamic indices has been developed using an Apple II microcomputer, a Dinamap automatic arterial pressure monitor and a non-invasive cardiac output monitor based on bio-electrical impedance. This system was used during the induction and maintenance of anaesthesia. Numerical and graphical displays of heart rate, arterial pressure, cardiac output and systemic vascular resistance are available. A print-out of data can be produced for later analysis.