Preventing Prolonged Times to Awakening While Mitigating the Risk of Patient Awareness: Gas Man Computer Simulations of Sevoflurane Consumption From Brief, High Fresh Gas Flow Before the End of Surgery

Franklin Dexter; Richard H Epstein; Anil A Marian; Carlos E Guerra-Londono

doi:10.7759/cureus.55626

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Preventing Prolonged Times to Awakening While Mitigating the Risk of Patient Awareness: Gas Man Computer Simulations of Sevoflurane Consumption From Brief, High Fresh Gas Flow Before the End of Surgery

Journal article

Open access

Peer reviewed

Preventing Prolonged Times to Awakening While Mitigating the Risk of Patient Awareness: Gas Man Computer Simulations of Sevoflurane Consumption From Brief, High Fresh Gas Flow Before the End of Surgery

Franklin Dexter, Richard H Epstein, Anil A Marian and Carlos E Guerra-Londono

Curēus (Palo Alto, CA), Vol.16(3), e55626

03/2024

DOI: 10.7759/cureus.55626

PMCID: PMC10995762

PMID: 38586680

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Abstract

Prolonged times to tracheal extubation are associated with adverse patient and economic outcomes. We simulated awakening patients from sevoflurane after long-duration surgery at 2% end-tidal concentration, 1.0 minimum alveolar concentration (MAC) in a 40-year-old. Our end-of-surgery target was 0.5 MAC, the Michigan Awareness Control Study's threshold for intraoperative alerts. Consider an anesthetist who uses a 1 liter/minute gas flow until surgery ends. During surgical closure, the inspired sevoflurane concentration is reduced from 2.05% to 0.62% (i.e., MAC-awake). The estimated time to reach 0.5 MAC is 28 minutes. From a previous study, 28 minutes exceeded ≥95% of surgical closure times for all 244 distinct surgical procedures (N=23,343 cases). Alternatively, the anesthetist uses 8 liters/minute gas flow with the vaporizer at MAC-awake for 1.8 minutes, which reduces the end-tidal concentration to 0.5 MAC. The anesthetist then increases the vaporizer to keep end-tidal 0.5 MAC until the surgery ends. An additional simulation shows that, compared with simulated end-tidal agent feedback control, this approach consumed 0.45 mL extra agent. Simulation results are the same for an 80-year-old patient. The extra 0.45 mL has a global warming potential comparable to driving 26 seconds at 40 kilometers (25 miles) per hour, comparable to route modification to avoid potential roadway hazards.

Global Warming

Industrial Engineering

Management Science

inhalational anesthesia

pharmacokinetics (pk)

volatile anesthetic

case duration

computer simulation

sevoflurane

hospital engineering

Details

Title: Subtitle: Preventing Prolonged Times to Awakening While Mitigating the Risk of Patient Awareness: Gas Man Computer Simulations of Sevoflurane Consumption From Brief, High Fresh Gas Flow Before the End of Surgery
Creators: Franklin Dexter - University of Iowa
Richard H Epstein - University of Miami
Anil A Marian - University of Iowa
Carlos E Guerra-Londono - Henry Ford Health System
Resource Type: Journal article
Publication Details: Curēus (Palo Alto, CA), Vol.16(3), e55626
DOI: 10.7759/cureus.55626
PMID: 38586680
PMCID: PMC10995762
NLM abbreviation: Cureus
ISSN: 2168-8184
eISSN: 2168-8184
Language: English
Date published: 03/2024
Academic Unit: Anesthesia
Record Identifier: 9984585057702771

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