Anaesthesia
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Randomized Controlled Trial
Effect of magnesium sulphate on bleeding during lumbar discectomy.
We assessed the effect of magnesium on the amount of bleeding, coagulation profiles and surgical conditions during lumbar discectomy under general anaesthesia. Forty patients, of ASA physical status 1-2 and aged 18-65 years, undergoing single-level microscopic lumbar discectomy, were randomly assigned to magnesium sulphate (50 mg.kg(-1) in 100 ml saline over 10 min followed by a continuous infusion of 20 mg.kg.h(-1) ) or saline. The mean (SD) estimated blood loss was 190 (95) and 362 (170) ml in the magnesium and saline groups, respectively (mean difference = 172 ml; 95% CI 84-260 ml). ⋯ The activated partial thromboplastin time was prolonged in the magnesium group immediately postoperatively and at 6 h after surgery. After the bolus of magnesium, the heart rate was higher and the mean arterial pressure lower in the magnesium group. The use of magnesium sulphate during lumbar discectomy decreases blood loss, and provides better surgical conditions without marked haemodynamic effects.
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Airway management is primarily designed to avoid hypoxia, yet hypoxia remains the main ultimate cause of anaesthetic-related death and morbidity. Understanding some of the physiology of hypoxia is therefore essential as part of a 'holistic' approach to airway management. ⋯ This enables us to think of ways in which we might manipulate the cellular and molecular responses to confer greater protection against hypoxia-induced tissue injury. This article reviews some of those aspects.
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We discuss the relevance of finding a patient's lungs difficult to ventilate by facemask during the course of anaesthetic induction. In particular, we discuss the issue of whether it is advisable or unnecessary to check the ability to ventilate by facemask before administering a neuromuscular blocking agent. ⋯ Similarly, the development of videolaryngoscopes and rapidly acting drugs such as rocuronium have raised the possibility of earlier, and possibly more successful, tracheal intubation, with the potential result that mask ventilation becomes redundant. However, we conclude by reaffirming its value in airway management strategies.
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Clinical Trial
Effect of weight gain during pregnancy on heart rate variability and hypotension during caesarean section under spinal anaesthesia.
The purpose of this study was to assess the effect of antenatal weight gain on baseline heart rate variability and incidence of hypotension in singleton parturients with a normal pre-pregnancy body mass index, presenting at term for elective caesarean section under spinal anaesthesia. Sixty-six parturients, of ASA physical status 1-2, were allocated to one of three groups according to their weight gain during pregnancy: < 11 kg; 11-16 kg; and > 16 kg. ⋯ The incidence of hypotension in the < 11 kg group (17/22; 77%) was significantly higher than in the 11-16 kg group (7/22; 32%) (p = 0.006) and the > 16 kg group (8/22; 36%) (p = 0.01). We conclude that weight gain < 11 kg during pregnancy is associated with increased baseline heart rate variability and a higher incidence of hypotension at the time of elective caesarean section under spinal anaesthesia.
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We applied the C-MAC videolaryngoscope in 52 consecutive patients who were found to have an unexpected Cormack and Lehane grade-3 (n = 49) and grade-4 (n = 3) laryngeal view with the Macintosh laryngoscope. The glottic view improved in 49 (94%) patients using the C-MAC. ⋯ In one patient, tracheal intubation failed using the C-MAC despite the presence of a Cormack and Lehane grade-2. These results suggest that the C-MAC videolaryngoscope has a role as a rescue device in cases of an initially difficult laryngeal view.