British journal of anaesthesia
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Randomized Controlled Trial Clinical Trial
Influence of nitrous oxide on induction of anaesthesia with sevoflurane.
Nitrous oxide is often used during inhalation induction of anaesthesia with sevoflurane. Although the value of using nitrous oxide during inhalation induction with other volatile anaesthetics has been studied, the popularity of sevoflurane induction and the different characteristics of this agent make a study of the combination of nitrous oxide with this agent of interest. We compared induction times, oxygenation, and excitatory events during inhalation induction of anaesthesia using sevoflurane, with and without nitrous oxide. ⋯ Mean time to induction of anaesthesia (fall of an outstretched arm) was 102 s in both groups, but excitation (limb or head movement) was more frequent in those receiving nitrous oxide (10 patients) than in those receiving oxygen only (five patients) (P<0.05). Oxygenation was similar in both groups. We conclude that nitrous oxide confers no advantage when anaesthesia is induced with sevoflurane in this way.
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The determination of susceptibility to malignant hyperthermia (MH) by genetic investigation is a controversial issue because of the genetic heterogeneity of this disorder. The requirement for such an approach in MH diagnosis is a strong correlation between MH-associated genetic abnormalities and phenotypic findings in the in vitro contracture test (IVCT). After a severe clinical MH crisis during general anaesthesia a patient was diagnosed by the IVCT in which susceptibility to MH was confirmed. ⋯ Of these, 10 were heterozygous (including both parents) and one was homozygous (sister). Further IVCTs were subsequently performed on the parents of the index patient, the homozygous sister and all relatives who did not carry the Arg614Cys in order to determine the genotype/phenotype correlation. After analysing these data, and because of the strong correlation between clinical, phenotypic, and genetic results in the index patient, we assigned the diagnosis 'MHS' to all the remaining Arg614Cys mutation carriers of that family without performing the IVCT.
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Case Reports
Ipsilateral thoraco-lumbar anaesthesia and paravertebral spread after low thoracic paravertebral injection.
We report ipsilateral thoraco-lumbar anaesthesia and paravertebral spread of contrast after injection through a thoracic paravertebral catheter that was placed at the right T8-9 spinal level for pain management in a patient with multiple fractured ribs. We review the literature and describe the subendothoracic fascial communication between the thoracic paravertebral space and the retroperitoneal lumbar paravertebral region, which we propose, is the anatomical basis for ipsilateral thoraco-lumbar anaesthesia and paravertebral spread of contrast in our patient.
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Perioperative levels of jugular bulb oxyhaemoglobin saturation (Sj(O(2))) and lactate concentration (Lj), and postoperative duration of Sj(O(2))<50% were compared between patients undergoing coronary artery bypass grafting (CABG) (n=86), heart valve (n=14) and abdominal aortic (n=16) surgery. Radial artery and jugular bulb blood samples were aspirated after induction of anaesthesia, during re-warming on cardiopulmonary bypass (CPB) (36 degrees C), on arrival in the intensive care unit (ICU) and, subsequently, at 1, 2 and 6 h after ICU admission. Most patients having heart surgery were hypocapnic at 36 degrees C on CPB. ⋯ Following correction for La, there were no postoperative effects on Lj. No significant differences (P=0.2) in duration of Sj(O(2))<50% existed between patients undergoing CABG (1054 (82) min), abdominal aortic (893 (113) min) and heart valve (1073 (91) min) surgery. The lack of significant reciprocal effects on Lj combined with the frequency of hypocapnia and strong influence of Pa(CO(2))()on Sj(O(2)), suggest that Sj(O(2))<50% during CPB and after cardiac surgery represents hypoperfusion as a consequence of hypocapnia rather than cerebral ischaemia.
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The effect of sepsis on the minimum alveolar concentration of desflurane (MAC(DES)) in humans and other animals has not been reported previously. The aim of this study was to test the hypothesis that sepsis might alter MAC(DES) in a normotensive septic porcine model. Twenty-four young healthy pigs were premedicated with ketamine 10 mg kg(-1 )i.m and then anaesthesia was established with propofol 3 mg kg(-1) and the trachea was intubated. ⋯ Significant increases in heart rate, cardiac output, mean pulmonary artery pressure and pulmonary vascular resistance occurred in the sepsis group. MAC(DES) was 9.2% (95% confidence interval (CI) 6.8-10.6%) for the saline group and 6.7% (95% CI: 4.7-10.4) for the sepsis group (P<0.05). These data indicate that MAC(DES) is significantly decreased in this normotensive hyperkinetic septic porcine model.