Awakening arterial blood and end-tidal concentrations of isoflurane in female surgical patients

Abstract

Delayed extubation occurs after isoflurane anesthesia, especially following prolonged surgical duration. We aimed to determine the arterial blood concentrations of isoflurane and the correlation with end-tidal concentrations for predicting emergence from general anesthesia.Thirty-four American Society of Anesthesiologists physical status class I–II gynecologic patients were included. General anesthesia was maintained with a fixed 2% inspiratory isoflurane in 6 L/minute oxygen, which was discontinued after surgery. One milliliter of arterial blood was obtained for the determination of isoflurane concentration by gas chromatography at 20 and 10 minutes before and 0, 5, 10, 15, and 20 minutes after discontinuation, in addition to the time of eye opening to verbal command, defined as awakening. Inspiratory and end-tidal concentrations were simultaneously detected by an infrared analyzer.The mean awakening arterial blood concentration of isoflurane was 0.20%, which was lower than the simultaneous end-tidal concentration 0.23%. The differences between arterial and end-tidal concentrations during emergence fell into an acceptable range (±1.96 standard deviation). After receiving a mean time of 108-minute general anesthesia, the time to eye opening after discontinuing isoflurane was 18.5 minutes (range 11–30, median 18 minutes), without statistical significance with anesthesia duration (P = 0.078) and body mass index (P = 0.170).We demonstrated the awakening arterial blood concentration of isoflurane in female patients as 0.20%. With well-assisted ventilation, the end-tidal concentration could be an indicator for the arterial blood concentration to predict emergence from shorter duration of isoflurane anesthesia.

Quantitative myocardial first‐pass perfusion imaging of CO2‐induced vasodilation in rats

“…Alternatively, the actual in vivo isoflurane levels could be monitored (e.g. using blood testing) 58 . In the current study, during one scanning session, only a single perfusion scan (either rest, PCO 2 or regadenoson) was measured to circumvent any potential bias effects of prolonged anesthesia (as observed in intrasession repeated rest measurements).…”

“…using blood testing). 58 In the current study, during one scanning session, only a single perfusion scan (either rest, PCO 2 or regadenoson) was measured to circumvent any potential bias effects of prolonged anesthesia (as observed in intrasession repeated rest measurements). Moreover, all measurements were carried out using healthy animals.…”

Discrepant End-Tidal Concentrations of Sevoflurane at the Same A-Line Autoregressive Index Level during Induction of General Anesthesia: An Observational Study

“…For inhalational anesthetics, however, a time lag between end-tidal and brain concentrations has been identified and physiologically modelled through measurement of the inspiratory, end-tidal, and jugular bulb concentrations [ 6 , 7 , 8 ]. Accordingly, the body’s uptake and elimination [ 9 ] of anesthetics across the alveolar membrane and blood–brain barrier depend on the partition coefficient [ 10 , 11 , 12 ], ventilation [ 13 ], and cardiac output [ 7 ]. Sevoflurane requires nearly 40 min to achieve a pharmacokinetic equilibrium between arterial and jugular bulb concentrations, indicating that no further brain uptake of inspiratory 3.5% sevoflurane occurs after general anesthesia induction [ 7 ].…”

Discrepant End-Tidal Concentrations of Sevoflurane at the Same A-Line Autoregressive Index Level During Induction of General Anaesthesia: An Observational Study

“…(5) For inhalational anaesthetics, however, a time lag between end-tidal and brain concentrations has been identi ed and physiologically modelled through measurement of the inspiratory, end-tidal, and jugular bulb concentrations. (6)(7)(8) Accordingly, the body's uptake and elimination (9) of anaesthetics across the alveolar membrane and blood-brain barrier depend on the partition coe cient, (10)(11)(12) ventilation, (13) and cardiac output. (7) Sevo urane requires nearly 40 min to achieve a pharmacokinetic equilibrium between arterial and jugular bulb concentrations, indicating that no further brain uptake of inspiratory 3.5% sevo urane occurs after general anaesthesia induction.…”