British journal of anaesthesia
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Accidental intrathecal injection of bupivacaine during epidural analgesia in labour remains a hazard, with the potential to cause total spinal anaesthesia and maternal collapse. Sacral block appears early after intrathecal injections compared with epidural ones, and we therefore used SI motor block to determine a safe and reliable test dose for epidural catheter misplacement. ⋯ We conclude that testing for SI motor block 10 min after epidural injection of bupivacaine 10 mg is a reliable test to detect accidental intrathecal injection in the obstetric population.
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Flow triggering in ventilators is an alternative to pressure triggering. Differences between these two trigger mechanisms may not be clinically significant in most patients. We report two patients with high spinal cord lesions in whom the use of flow triggering was unsuccessful. Severe muscle weakness in these patients made them sensitive to small changes in ventilator trigger characteristics.
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Vasovagal episodes occur frequently in young healthy patients undergoing venous cannulation and loco-regional anaesthesia. We report two cases of severe coronary vasospasm and non-Q-wave infarction in healthy young women after administration of ephedrine for vasovagal symptoms at the onset of spinal anaesthesia. In the light of unopposed vagal predominance pre-disposing patients to coronary vasospasm, even in young healthy patients, atrophine and not ephedrine should be the first line treatment for bradycardia with or without hypotension under spinal anaesthesia.
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Rapid defibrillation is the most important intervention required for a patient in cardiac arrest due to ventricular fibrillation or ventricular tachycardia. Isolated case reports of spurious asystole may have seen a change in practice, moving away from monitoring through defibrillator paddles and gel pads in favour of attaching electrocardiograph (ECG) leads for the initial monitoring of a collapsed patient. We surveyed current preferences for initial monitoring and estimated the difference in time taken to deliver the first shock with the following three monitoring techniques: defibrillator paddles and gel pads, ECG leads and hands-free adhesive pads. ⋯ The current practice of monitoring through leads delays the time to deliver the first shock. We recommend that initial monitoring through leads be discontinued in favour of hands-free adhesive pads or defibrillator paddles/gel pads.
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The inotropic effects of halogenated anaesthetics on diaphragmatic muscle remain a matter of debate. Their effects on its relaxation are poorly understood, although diaphragmatic relaxation is recognized as an important physiological process that may interfere with diaphragmatic performance, fatigue and arterial blood flow. ⋯ Halothane and isoflurane induced very moderate inotropic and lusitropic effects, suggesting that the decrease in diaphragm function observed in vivo is not related to a direct effect on diaphragmatic contractility.