A new device to reduce the consumption of a halogenated anaesthetic agent*

Abstract

SummaryWe report the first clinical application of a new anaesthetic agent-saving device. The principles of a heat±moisture exchanger have been further developed to create a device that reduces inhalational agent consumption. Sixteen patients were randomly allocated to receive isoflurane through either a vaporiser or through the agent-saving device. A coaxial Mapleson D system (Bain) was used in both groups. A standard ventilatory setting was used, aiming for normocapnia. Mean (SD) isoflurane consumption was 24.5 (2.8) ml.MAC-hour 21 with the vaporiser, compared with 15.2 (3.0) ml.MAC-hour 21 with the new device (p , 0.05). This corresponded to a 40% saving in the consumption of isoflurane. The amount of isoflurane that was scavenged to the atmosphere was reduced by an average of 55%.

Comparison of the Coaxial Circle Circuit with the Conventional Circle Circuit

“…In the present study, because of similarities in room moisture, room temperature, and, in particular, the warmth and moisture content of inspired fresh gas, there was no difference in core temperature between the groups. During general anesthesia, appropriate humidification is advised to ensure normal functioning of the ciliated epithelium of the respiratory tract in adults [22], and the loss of heat and moisture expected when using a coaxial circle system can be prevented [23]. The Universal F breathing system is a coaxial circle system.…”

Saving sevoflurane and hastening emergence from anaesthesia using an anaesthetic-conserving device

“…One more benefit of the AnaConDa is that we can anaesthetize patients with AnaConDa alone without using an anaesthesia machine, which might be quite useful in developing countries or in the field. Some studies [6][7][8] have compared anaesthetic consumption between the AnaConDa with high fresh gas flow and a conventional vaporizer with low fresh gas flow. However, no study has compared the AnaConDa and a conventional vaporizer in the same total gas flow and the AnaConDa has never been studied with a rebreathing circuit.…”

“…The AnaConDa is a single-use device including a heat and moisture exchanger with a dead space of 100 ml. The AnaConDa incorporates an activated carbon filter that retains and releases a major part of the expired anaesthetic agent back to the patient, and a second filter that limits particles and microorganisms from reaching the patient or the breathing system [6]. The AnaConDa is connected between the anaesthesia circuit and tracheal tube in the same way as a heat and moisture exchanger.…”

Sedation with Inhaled Anaesthetics in Intensive Care Units: Intravenous Route is not the Only Way

“…During the expiration phase, the anaesthetic is exhaled by the patient and is stored in the carbon layer, followed by a rerelease into the gas mixture during the next inspiratory cycle. More than 90% of the anaesthetic gas is recirculated in such a way [8].…”