Duration effect of desflurane anesthesia and its awakening time and arterial concentration in gynecologic patients

Abstract

OBJECTIVES:To determine the awakening arterial blood concentration of desflurane and its relationship with the end-tidal concentration during emergence from various durations of general anesthesia.METHOD:In total, 42 American Society of Anesthesiologists physical status class I-II female patients undergoing elective gynecologic surgery were enrolled. General anesthesia was maintained with fixed 6% inspiratory desflurane in 6 l min-1 oxygen until shutoff of the vaporizer at the end of surgery. One milliliter of arterial blood was obtained for desflurane concentration determination by gas chromatography at 20 and 10 minutes before and 0, 5, 10, 15, and 20 minutes after the discontinuation of desflurane and at the time of eye opening upon verbal command, defined as awakening. Concentrations of inspiratory and end-tidal desflurane were simultaneously detected by an infrared analyzer.RESULTS:The mean arterial blood concentration of desflurane was 1.20% at awakening, which correlated with the awakening end-tidal concentration of 0.96%. The mean time from the discontinuation of desflurane to eye opening was 5.2 minutes (SD = 1.6, range 3-10), which was not associated with the duration of anesthesia (60-256 minutes), total fentanyl dose, or body mass index (BMI).CONCLUSIONS:The mean awakening arterial blood concentration of desflurane was 1.20%. The time to awakening was independent of anesthetic duration within four hours. Using well-assisted ventilation, the end-tidal concentration of desflurane was proven to represent the arterial blood concentration during elimination and could be a clinically feasible predictor of emergence from general anesthesia.

Arterial blood and end-tidal concentrations of sevoflurane during the emergence from anesthesia in gynecologic patients

“…In this study, the end-tidal concentrations of sevoflurane decreased more prominently in the initial 5 minutes after discontinuation, indicating a rapid alveolar washout, and then became consistently close to the arterial concentrations. Our previous study demonstrated that the end-tidal concentrations of desflurane are generally lower than the arterial blood concentrations during elimination in gynecologic patients 8 ; this effect is related to the lower blood-gas partition coefficient of 0.42 and tissue/blood partition coefficients of desflurane 5 . By determining the arterial blood concentration, we therefore identified that the end-tidal concentration of sevoflurane, which is close to 0.36%, is a reliable indicator for predicting emergence from general anesthesia.…”

“…During the elimination phase, sevoflurane washout progresses from the brain and body to the alveolar space and can be detected by the end-tidal concentration. Clinically, the end-tidal concentration of inhalation anesthetics has been a feasible indicator for predicting the emergence from general anesthesia, especially after desflurane anesthesia 8 . However, irregular respiration before awakening usually results in fluctuations of the end-tidal concentrations of inhalation anesthetics.…”

Transcranial motor evoked potentials during anesthesia with desflurane versus propofol – A prospective randomized trial

“…Additionally, the wider range of MEP amplitudes at T2 with propofol, compared to any measurement in the control group, may indicate a persistent desflurane effect. However, based on data regarding the time frame of desflurane elimination, desflurane blood concentrations should reach clinically irrelevant levels after 20 min (Lin et al, 2013;Lu et al, 2013). Moreover, the protocol requires a maximum MAC of 0.6, which suggests even faster elimination.…”

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.…”