Xenon expenditure and nitrogen accumulation in closed‐circuit anaesthesia

Abstract

SummaryThe high price of xenon has prevented its use in routine, clinic anaesthetic practice. Xenon therefore has to be delivered by closed-circuit anaesthesia. The accumulation of nitrogen is a significant problem within the closed circuit and necessitates flushing, which in turn increases gas expenditure and costs. In previous investigations, nitrogen concentrations between 12% and 16% have been reported in closed-circuit anaesthesia. In order to avoid such nitrogen accumulation, we denitrogenised seven pigs using a non-rebreathing system and connected the animals to a system primed with a xenon/oxygen mixture. In comparison, seven pigs were anaesthetised with xenon using a standard low-flow anaesthetic procedure. Anaesthesia time was 2 h. Nitrogen concentrations in the closed system ranged from 0.08 to 7.04% and were not significantly different from those observed during low-flow anaesthesia. Closed-circuit anaesthesia reduced the xenon expenditure 10-fold compared with low-flow anaesthesia.

A practical rule for optimal flows for xenon anaesthesia in a semi-closed anaesthesia circuit

“…21 These techniques will reduce strange gas accumulation over time and thus limit the necessity to flush the system. Recycling of xenon is not an option for a reduction in overall consumption, because only 1-2 l will be exhaled during the short recovery from anaesthesia (3.6 min to extubation) 22 due to the long half-life of 97 min.…”

Xenon consumption during general surgery: a retrospective observational study

“…Previous studies repeatedly demonstrated that consumption and/or waste of xenon was remarkably elevated within the wash-in period aiming to remove accumulated nitrogen and accelerate time to target concentration of xenon [15], [22]. It`s important to note that a significant and irreducible part of xenon used during wash-in corresponds to the xenon volume needed to saturate the fast compartment of the patient`s body (several litres of xenon) as well as to saturate the respirator internal volume and tubes (estimated to 3l xenon).…”

“…However, time of pre-oxygenation (before intubation) and denitrogenation (after intubation) was comparable between the groups. While use of high-flow is frequently necessary during wash-in period, previous studies already supposed induction period to offer most potential to reduce waste of xenon [15], [22]. …”

Fokus – NarCO2se und Umwelt

“…Maßnahmen zur Reduktion des Xenonverbrauchs wurden daher angestrebt. Durch die Verwendung von geschlossenen Narkosesystemen liegt der Xenonverbrauch verglichen mit Low-Flow-Systemen bei einem Zehntel [57]. Zur Reduktion des Xenonbedarfs wurden in der Vergangenheit Ansätze zur i. v. Applikation einer Xenon-Lipidemulsion beschrieben [58].…”