The use of inhaled sevoflurane during operative hysteroscopy is associated with increased glycine absorption compared to intravenous propofol for maintenance of anesthesia.

Study Objective: To compare the effects of anesthesia maintenance drugs (inhaled sevoflurane versus intravenous propofol) used in general anesthesia on the absorption of glycine 1.5% solution during hysteroscopy.
Design: Prospective comparative study.
Setting: Tertiary care university hospital.
Patients: One hundred fifteen women undergoing hysteroscopy.
Interventions: Women were assigned to receive general anesthesia with inhaled sevoflurane (n = 77) or intravenous propofol (n = 38) to maintain anesthesia.
Measurements: The primary endpoint was clinically relevant glycine 1.5% absorption (>1000 mL), while secondary endpoints were the median of glycine absorption, operative time, complications and the incidence of discontinuation of the hysteroscopic procedure due to excessive glycine 1.5% absorption.
Main Results: Maintenance with sevoflurane produced significantly increased absorption of glycine 1.5% solution compared to intravenous anesthesia (264 vs 202 mL, P = .007). Clinically relevant absorption rates (>1000 mL) were observed in the sevoflurane group (P = .04) while none of the women receiving intravenous anesthesia reached this absorption level. No cases of severe post-operative hyponatremia (Na(1+)<125 mmol/L) or adverse events derived from glycine 1.5% absorption were reported. No major complications (such as perforations, severe hemorrhage or infection) were presented during the interventions.
Conclusions: The results of the present study show that the use of inhaled sevoflurane is associated with significantly increased glycine 1.5% absorption compared to intravenous propofol for the maintenance of anesthesia. However, further randomized controlled trials are needed to assess the possible mechanisms and risk factors involved in the higher absorption induced by sevoflurane.
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