Abstract
Volatile agents are economically and ecologically acceptable only when administered via low-flow systems. However, sevoflurane degrades during low-flow anaesthesia to compound A, and a high carbon dioxide absorber temperature increases this degradation. This thesis suggests that there is a correlation between apparatus dead-space volume and absorber temperature during low- and minimal-flow sevoflurane anaesthesia. Increasing the dead-space volume reduces absorber temperature during low- and minimal-flow sevoflurane anaesthesia.
The main disadvantage of low-flow techniques is that inspired (In) and end-tidal (Et) anaesthetic agent concentrations are not directly related to the vaporiser setting. In the present studies, with desflurane and sevoflurane, there was a significant difference between Et and In concentrations at fresh gas flows (FGFs) of 1.0 and 2.0 l/min. However, the ratio of Et to In concentration remained fairly constant.
Excessive respiratory heat loss may lower body temperature. Artificial humidification of dry inspired gases reduces loss of body heat during anaesthesia, hence the popularity of heat and moisture exchangers (HMEs). In this study, HMEs improved the humidity of the anaesthetic gases at different FGFs, but did not improve maintenance of body temperature during low-flow anaesthesia in adults undergoing elective general or urologic surgery.
The main disadvantage of low-flow techniques is that inspired (In) and end-tidal (Et) anaesthetic agent concentrations are not directly related to the vaporiser setting. In the present studies, with desflurane and sevoflurane, there was a significant difference between Et and In concentrations at fresh gas flows (FGFs) of 1.0 and 2.0 l/min. However, the ratio of Et to In concentration remained fairly constant.
Excessive respiratory heat loss may lower body temperature. Artificial humidification of dry inspired gases reduces loss of body heat during anaesthesia, hence the popularity of heat and moisture exchangers (HMEs). In this study, HMEs improved the humidity of the anaesthetic gases at different FGFs, but did not improve maintenance of body temperature during low-flow anaesthesia in adults undergoing elective general or urologic surgery.
| Original language | English |
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| Qualification | Doctor |
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| Award date | 2003 Sept 26 |
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| ISBN (Print) | 91-628-5814-9 |
| Publication status | Published - 2003 |
Bibliographical note
Defence detailsDate: 2003-09-26
Time: 10:15
Place: Lecture room 3, University Hospital Lund
External reviewer(s)
Name: Stenqvist, Ola
Title: Professor
Affiliation: Avdelningen för Anestesiologi och Intensivvård, Sahlgrenska Universitetssjukhuset, Göteborg
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Article: Hans Henrik Luttropp and Anders Johansson.Soda lime temperatures during low-flow sevoflurane anaesthesia and differences in dead-space.Acta Anaesthesiol Scand 2002; 46: 500-505.
Article: Anders Johansson, Dag Lundberg and Hans Henrik Luttropp.Low-flow anaesthesia with desflurane; kinetics during clinical procedures.Eur J Anaesthesiol 2001; 18: 499-504.
Article: Anders Johansson, Dag Lundberg and Hans Henrik Luttropp.The quotient end-tidal/inspired concentration of sevoflurane in a low-flow system.J Clin Anesth 2002; 14: 267-270.
Article: Anders Johansson, Dag Lundberg and Hans Henrik Luttropp.The effect of heat and moisture exchanger on humidity and body temperature in a low-flow system.Acta Anaesthesiol Scand 2003; 47: 564-568.
Subject classification (UKÄ)
- Anesthesiology and Intensive Care
Free keywords
- Anestesiologi
- intensive care
- intensivvård
- Anaesthesiology
- humidity and temperature
- heat and moisture exchanger
- isoflurane
- desflurane
- sevoflurane
- anaesthetics volatile
- carbon dioxide absorber
- Low-flow
- re-breathing circle circuit