Anaesthesia and intensive care
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Anaesth Intensive Care · Dec 2002
Reflex responses to insertion of the intubating laryngeal mask airway, intubation and removal of the ILMA.
We studied 21 patients (ASA 1 or 2) to investigate the skin vasomotor reflex (SVmR) and haemodynamic responses to insertion of an intubating laryngeal mask airway (ILMA), tracheal intubation using the ILMA and removal of the ILMA. Anaesthesia was induced with fentanyl, midazolam, vecuronium and nitrous oxide. A size 4 ILMA was inserted using the standard technique, and a silicone reinforced tracheal tube (7.5 mm, ID) was passed through it. ⋯ The mean amplitudes of the SVmR were 0.46 (SD 0.29), 0.54 (0.32) and 0.68 (0.21) respectively. The magnitude of the SVmR and the haemodynamic changes induced by removal of the ILMA were significantly larger than those accompanying the other two procedures. Use of the ILMA for intubation and removal of the ILMA produces three stimuli and the removal of the ILMA produces the greatest response.
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Anaesth Intensive Care · Dec 2002
Comparative StudyAppropriate size of laryngeal mask airway for children.
The aim of this crossover study was to determine the optimal size of laryngeal mask airway in children weighing 10 to 20 kg. In each of 67 apnoeic anaesthetized children, the size 2 and size 2 1/2 laryngeal mask airways were inserted consecutively by a skilled user and the cuff inflated to 60 cmH2O. Each LMA was assessed for the ease of insertion (by the number of attempts), oropharyngeal leak pressure, anatomical position (assessed fibreoptically) and the volume of air required to achieve intracuff pressure of 60 cmH2O. ⋯ The fibreoptic bronchoscope scores were not significantly different between the two sizes of LMAs. The volume of air to achieve intracuff pressure of 60 cmH2O was much lower than the maximum recommended volume (5.1 ml for size 2 and 6.2 ml for size 2 1/2). We conclude that the size 2 1/2 LMA provides a better fit than size 2 in children 10 to 20 kg.
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Anaesth Intensive Care · Dec 2002
Transient lumbar pain after 5% hyperbaric lignocaine spinal anaesthesia in patients having minor vascular surgery.
Transient lumbar pain has been reported to occur frequently in patients having surgery using 5% hyperbaric lignocaine for spinal anaesthesia. The incidence of transient lumbar pain is highest with this agent in patients having surgery in the lithotomy position and in outpatients. The aim of this audit was to determine the incidence of transient lumbar pain in patients having minor surgery for the complications of peripheral vascular disease, a group of patients in whom short duration spinal anaesthesia is desirable. ⋯ All patients had 5% hyperbaric lignocaine spinal anaesthesia and were followed up postoperatively utilizing a standardized questionnaire to determine the incidence of transient lumbar pain. The condition was found to occur in 4% of patients. This low incidence of transient lumbar pain justifies the continued use of 5% hyperbaric lignocaine for spinal anaesthesia in this group of patients.
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Anaesth Intensive Care · Dec 2002
The cerebrovascular effects of adrenaline, noradrenaline and dopamine infusions under propofol and isoflurane anaesthesia in sheep.
Infusions of catecholamines are frequently administered to patients receiving propofol or isoflurane anaesthesia. Interactions between these drugs may affect regional circulations, such as the brain. The aim of this animal (sheep) study was to determine the effects of ramped infusions of adrenaline, noradrenaline (10, 20, 40 micrograms/min) and dopamine (10, 20, 40 micrograms/kg/min) on cerebral blood flow (CBF), intracranial pressure (ICP), cerebrovascular resistance (CVR) and cerebral metabolic rate for oxygen (CMRO2). ⋯ Under propofol and isoflurane anaesthesia, the cerebrovascular effects of catecholamines were significantly different from the awake, physiological state, with dopamine demonstrating the most pronounced effects, particularly under propofol. Dopamine-induced hyperaemia was associated with other cerebrovascular changes. In the presence of an equivalent effect on mean arterial pressure, the exaggerated cerebrovascular effects under anaesthesia appear to be centrally mediated, possibly induced by propofol- or isoflurane-dependent changes in blood-brain barrier permeability, thereby causing a direct influence on the cerebral vasculature.
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Anaesth Intensive Care · Dec 2002
The impact of intraoperative transoesophageal echocardiography on an unselected cardiac surgical population: a review of 2343 cases.
Although intraoperative transoesophageal echocardiography (TOE) has an established role in the management of some cardiac surgical procedures, there is little data on its impact on coronary artery bypass graft (CABG) cases that are stratified for clinical risk. This is a retrospective review of the surgical impact of intraoperative TOE on 2,343 unselected cardiac cases. The surgical impact of TOE findings were rated E (essential)--resulted in changes to the proposed surgical procedure or V (valuable)--the surgical technique for the planned surgery was altered. ⋯ The commonest E-impact in CABG patients was unscheduled valve surgery (2.6% of high-risk patients). The complication rate attributable to TOE was 0.09%. These findings provide indirect evidence for a potential patient benefit from the routine use of TOE in cardiac surgery.