British journal of anaesthesia
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The "K-type" designation is used to describe a patient being investigated for malignant hyperthermia (MH) when concurrent administration of caffeine and halothane induces muscle contracture (rigidity, spasm) in vitro, but when halothane and caffeine given separately produce a normal response. It is accepted in some centres that K-type individuals are susceptible to malignant hyperthermia (MHS). In this paper, the K-type is shown not to correlate with the MH susceptible (MHS) status as accepted by the European MH group.
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Randomized Controlled Trial Comparative Study Clinical Trial
Comparison of hypertonic saline (5%), isotonic saline and Ringer's lactate solutions for fluid preloading before lumbar extradural anaesthesia.
We have compared the haemodynamic effects of fluid preloading performed before lumbar extradural anaesthesia with isotonic saline (NS), 5% hypertonic saline (HS) and Ringer's lactate (RL) solutions in 30 ASA I patients undergoing minor orthopaedic surgery, allocated randomly to the three groups. All patients received an equal amount of sodium (2 mmol kg-1). After fluid preloading, lumber extradural anaesthesia was performed (2% lignocaine 6 mg kg-1) and ephedrine was administered in order to maintain mean arterial pressure (MAP) > 80% of its control value. ⋯ MAP was not affected by any fluid preload and its maximal decrease after lumbar extradural anaesthesia was similar in all groups. Infusion of 5% HS 2.3 ml kg-1 was tolerated well and produced a significant (P < 0.05) but moderate hypernatraemia lasting 90 min after the end of fluid preloading. We conclude that HS may be useful when rapid fluid preloading is desired, in situations where excess free water administration is not desired.
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Randomized Controlled Trial Comparative Study Clinical Trial
Mechanism of extension of spinal anaesthesia by extradural injection of local anaesthetic.
We have examined the effect of extradual injection of 0.5% bupivacaine or normal saline on the progression of spinal anaesthesia in 28 patients undergoing Caesearean section. Three groups were studied. Subarachnoid anaesthesia was established in all patients. ⋯ Sensory levels were compared at 5-min intervals and extension of the block was found to be similar in groups B and C and significantly faster than the control (P < 0.05). The quality of anaesthesia and incidence of adverse effects was similar for all three groups. We conclude that the mechanism of extension of spinal anaesthesia by extradural injection of local anaesthesia is largely a volume effect.
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We have studied the immediate and long term (up to 28 days) effects of short and long bevelled needle impalement of the rat sciatic nerve. Three techniques were used to assess neural trauma and its consequences: stained longitudinal nerve sections were assessed by light microscopy and scored for injury; the extravasation of Evan's Blue dye, after antidromic electrical nerve stimulation, was used as a test of unmyelinated fibre function; the flexion withdrawal times from a noxious stimulus were measured. ⋯ Nerve injury induced by short bevelled needles was associated with persisting signs of injury 28 days after the injury. These results suggest that the current practice of using short bevelled needles to prevent nerve injury complicating regional anaesthesia be reassessed.