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25-04-2024 | Sevoflurane | Original Research

Comparison of automated and manual control methods in minimal flow anesthesia

Authors: Rezan Şerefoğlu, Havva Kocayiğit, Onur Palabıyık, Ayça Taş Tuna

Published in: Journal of Clinical Monitoring and Computing

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Abstract

Purpose

New-generation anesthesia machines administer inhalation anesthetics and automatically control the fresh gas flow (FGF) rate. This study compared the administration of minimal flow anesthesia (MFA) using the automatically controlled anesthesia (ACA) module of the Mindray A9 (Shenzhen, China) anesthesia machine versus manual control by an anesthesiologist.

Methods

We randomly divided 76 patients undergoing gynecological surgery into an ACA group (Group ACA) and a manually controlled anesthesia group (Group MCA). In Group MCA, induction was performed with a mixture of 40–60% O2 and air with a 4 L/min FGF until the minimum alveolar concentration (MAC) reached 1. Next, MFA was initiated with 0.5 L/min FGF. The target fraction of inspired oxygen (FiO2) value was 35–40%. In Group ACA, the MAC was defined as 1, and the FiO2 was adjusted to 35%. Depth of anesthesia, anesthetic agent (AA) consumption, time to achieve target end-tidal AA concentration, awakening times, and number of ventilator adjustments were analyzed.

Results

The two groups showed no statistically significant differences in depth of anesthesia or AA consumption (Group ACA: 19.1 ± 4.9 ml; Group MCA: 17.2 ± 4.5; p-value = 0.076). The ACA mode achieved the MAC target of 1 significantly faster (Group ACA: 218 ± 51 s; Group MCA: 314 ± 169 s). The number of vaporizer adjustments was 15 in the ACA group and 217 in the MCA group.

Conclusion

The ACA mode was more advantageous than the MCA mode, reaching target AA concentrations faster and requiring fewer adjustments to achieve a constant depth of anesthesia.
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Metadata
Title
Comparison of automated and manual control methods in minimal flow anesthesia
Authors
Rezan Şerefoğlu
Havva Kocayiğit
Onur Palabıyık
Ayça Taş Tuna
Publication date
25-04-2024
Publisher
Springer Netherlands
Keyword
Sevoflurane
Published in
Journal of Clinical Monitoring and Computing
Print ISSN: 1387-1307
Electronic ISSN: 1573-2614
DOI
https://doi.org/10.1007/s10877-024-01163-0