Sevoflurane-based Anaesthesia Research Articles

Comparison of the effects of sevoflurane and propofol on cooling and rewarming during deliberate mild hypothermia for neurosurgery

Because the time available for cooling and rewarming during deliberate mild hypothermia is limited, studies of the rate of the cooling and rewarming are useful. The decrease in core hypothermia caused by heat redistribution depends on the anaesthetic agent used. We therefore investigated possible differences between sevoflurane and propofol on the decrease and recovery of core temperature during deliberate mild hypothermia for neurosurgery. After institutional approval and informed consent, 26 patients were assigned randomly to maintenance of anaesthesia with propofol or sevoflurane. Patients in the propofol group (n=13) received propofol induction followed by a continuous infusion of propofol 3-5 mg kg(-1) h(-1). Patients in the sevoflurane group (n=13) received propofol induction followed by sevoflurane 1-2%. Nitrous oxide and fentanyl were also used for anaesthetic maintenance. After induction of anaesthesia, patients were cooled and tympanic membrane temperature was maintained at 34.5 degrees C. After surgery, patients were actively rewarmed. There was no difference in the rate of decrease and recovery of core temperature between the groups. There was also no difference in skin surface temperature gradient (forearm to fingertip), heart rate and mean arterial blood pressure between the groups. Sevoflurane-based anaesthesia did not affect cooling and rewarming for deliberate mild hypothermia compared with propofol-based anaesthesia.

Differential effects of vecuronium on the thumb and great toe as measured by accelography and electromyography

We evaluated possible differential effects of vecuronium on the thumb and great toe using two types of neuromuscular transmission monitor. Train-of-four stimuli were simultaneously applied to the ulnar nerve and tibial nerves using cutaneous electrodes. The responses were quantified with accelographs (thumb and left great toe) and an electromyograph (right great toe). Twenty ASA 1 or 2 patients received, by random allocation, one of two types of anaesthesia: neuroleptanaesthesia or sevoflurane-based anaesthesia. With both techniques, the shortest time to maximum block after vecuronium 0.1 mg.kg-1 occurred in the thumb as measured by accelography. The average (SD) values with neuroleptanaesthesia were: 173(23) s for thumb using accelography; 220(16) s for great toe using accelography; 205(44) s for great toe using electromyography. The average (SD) value(s) with sevoflurane-based anaesthesia were: 137(15) for thumb using accelography; 179(21) for great toe using accelography; 153(23) for great toe using electromyography. The differences between the thumb and great toe were statistically significant during both types of anaesthesia when measured with the accelograph (p < 0.01). The time from completion of maximal block to 25% recovery of twitch height in the thumb was significantly longer than that of the great toe as measured by accelography during both types of anaesthesia (p < 0.05). In contrast, there were no statistically significant differences between time to maximum block and 25% recovery of twitch height of the thumb as measured by accelography compared to the values measured for the great toe using electromyography during either anaesthetic technique.(ABSTRACT TRUNCATED AT 250 WORDS)

Differential effects of vecuronium on the thumb and great toe as measured by accelography and electromyography

We evaluated possible differential effects of vecuronium on the thumb and great toe using two types of neuromuscular transmission monitor. Train-of-four stimuli were simultaneously applied to the ulnar nerve and tibial nerves using cutaneous electrodes. The responses were quantified with accelographs (thumb and left great toe) and an electromyograph (right great toe). Twenty ASA 1 or 2 patients received, by random allocation, one of two types of anaesthesia: neuroleptanaesthesia or sevoflurane-based anaesthesia. With both techniques, the shortest time to maximum block after vecuronium 0.1 mg.kg-1 occurred in the thumb as measured by accelography. The average (SD) values with neuroleptanaesthesia were: 173(23) s for thumb using accelography; 220(16) s for great toe using accelography; 205(44) s for great toe using electromyography. The average (SD) value(s) with sevoflurane-based anaesthesia were: 137(15) for thumb using accelography; 179(21) for great toe using accelography; 153(23) for great toe using electromyography. The differences between the thumb and great toe were statistically significant during both types of anaesthesia when measured with the accelograph (p < 0.01). The time from completion of maximal block to 25% recovery of twitch height in the thumb was significantly longer than that of the great toe as measured by accelography during both types of anaesthesia (p < 0.05). In contrast, there were no statistically significant differences between time to maximum block and 25% recovery of twitch height of the thumb as measured by accelography compared to the values measured for the great toe using electromyography during either anaesthetic technique.(ABSTRACT TRUNCATED AT 250 WORDS)