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Clinical evaluation of low‐flow sevoflurane anaesthesia for paediatric patients
Author(s) -
Igarashi M.,
Watanabe H.,
Iwasaki H.,
Namiki A.
Publication year - 1999
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1034/j.1399-6576.1999.430105.x
Subject(s) - nitrous oxide , medicine , sevoflurane , anesthesia , fresh gas flow , soda lime , significant difference , zoology , chemistry , organic chemistry , biology
Background: Sevoflurane expenditure, inspired gas humidity, temperature, soda lime temperature, and compounds A and B were measured during high and low fresh gas flow anaesthesia in paediatric patients. Methods: Sixty ASA 1 or 2 paediatric patients were randomly allocated to two groups: low‐flow circle anaesthesia (LFA) patient group (n=30) and high‐flow circle anaesthesia (HFA) patient group (n=30). Initial fresh gas flow (FGF) was 4 l · min −1 of nitrous oxide and 2 l · min −1 of oxygen in both groups. This FGF of 6 l · min −1 was maintained in the HFA group. After 10 min of HFA, the FGF was reduced to 600 ml · min −1 (nitrous oxide and oxygen 300 ml · min −1 each) in the LFA group. Results: Sevoflurane expenditure during LFA was about 1/7 of that during HFA (3.3±0.2 ml · h −1 · vol.% −1 compared to 22.8±0.6 ml · h −1 · vol.% −1 , mean±SEM, respectively). Absolute humidity in the LFA patients was 4 times higher than that in the HFA patients (22.8±2.4 g · m −3 , 5.6±3.4 g · m −3 respectively). There was no significant difference in the inspiratory gas temperature between the LFA (28.5±0.6°C) and HFA (26.9±1.3°C) groups. There was significant difference in the mean highest soda lime temperature between the LFA (35.5±1.2°C) and HFA (28.7±1.2°C) groups. The mean highest concentration of compound A was 12.2±3.8 ppm in the LFA group. The mean highest concentration of compound B was less than 1 ppm. Compounds A and B were below detectable level in the HFA group. Conclusion: In conclusion, sevoflurane used for paediatric patients in a circle system with a fresh gas flow of 0.6 l · min −1 resulted in a significantly reduced sevoflurane expenditure, higher inspired absolute humidity, but not temperature, compared to a fresh gas flow of 6 l · min −1 . Low levels of compounds A and B were detected.