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PubMed · 3768229

A microprocessor-controlled anaesthetic vaporizer.

C E Hahn·E Palayiwa·B R Sugg·D Lindsay-Scott
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Abstract

A microprocessor-controlled anaesthetic vaporizer is described. Fresh gas is mixed in the correct proportions using two pulsed solenoid valves and a proportion of this passes through a third pulsed solenoid valve and is bubbled through liquid halothane. The temperature of the liquid agent is measured and the pulse frequency is modified to give the correct vapour concentration for the set flow rate and measured temperature. Initially, the vapour was produced by bubbling fresh gas through the agent in a conventional halothane bottle. However, because of the large liquid volume available, nitrous oxide was found to dissolve in large quantities in the halothane. A small volume vaporizer which was continually replenished from a reservoir was designed. Measurements of the vapour concentrations emerging from such a vaporizer were made and were found to agree with the set values +/- 0.1% v/v.

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Anesthesia, InhalationComputersEquipment DesignMicrocomputersNebulizers and VaporizersJournal Article

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C E Hahn, E Palayiwa, B R Sugg, D Lindsay-Scott. 1986. A microprocessor-controlled anaesthetic vaporizer.. https://doi.org/10.1093/bja%2F58.10.1161

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The effects of isoflurane, sevoflurane, and desflurane anesthesia on neurocognitive outcome after cardiac surgery: a pilot study.

BACKGROUND: Inhalation anesthetics such as isoflurane, sevoflurane, and desflurane are widely used in clinical practice; however, there is no study for comparing these drugs in cardiac surgery with respect to postoperative cognitive outcome and S100 beta protein (S100 BP) levels. In this study, we evaluated the effect of sevoflurane, isoflurane, and desflurane anesthesia on neuropsychological outcome and S100 BP levels in patients undergoing coronary artery bypass grafting (CABG) surgery with cardiopulmonary bypass (CPB). MATERIALS AND METHODS: Forty-two male patients were prospectively randomized and classified into 3 groups according to the volatile agents used; isoflurane, sevoflurane, desflurane. All patients had a sufficient education level to participate in neuropsychological testing and a normal carotid Doppler ultrasonography. Blood samples for analysis of S100 BP were collected before anesthesia (T1), before heparinization (T2), 15 minutes into CPB (T3), following protamine administration (T4), postoperatively (T5), 24 hours after the operation (T6), postoperative day 3 (T7), and postoperative day 6 (T8). The neuropsychological tests, including Mini-Mental State Examination (MMSET) and visual-aural digit span test (VADST), were administered 1 day prior to surgery and on the third and sixth postoperative days. RESULTS: The postoperative third and sixth day MMSET scores and third day visual-written subtest scores in the sevoflurane group were significantly lower than in the isoflurane and desflurane groups (P < .05). S100 BP levels increased with the beginning of anesthesia in the sevoflurane and desflurane groups. Although S100 BP decreased to baseline levels on postoperative day 1 in the sevoflurane group, this was significantly higher on the third and sixth days postoperatively in the desflurane group (P < .05). In the isoflurane group, the S100 BP level was significantly higher than the baseline level only after CPB (P < .05). CONCLUSION: Our study suggests that isoflurane is associated with better neurocognitive functions than desflurane or sevoflurane after on-pump CABG. Sevoflurane seems to be associated with the worst cognitive outcome as assessed by neuropsychologic tests, and prolonged brain injury as detected by high S100 BP levels was seen with desflurane.

Anesthesia, Inhalation↗