Journal of clinical monitoring and computing
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J Clin Monit Comput · Aug 2018
Review Historical ArticleA technical review of the history, development and performance of the anaesthetic conserving device "AnaConDa" for delivering volatile anaesthetic in intensive and post-operative critical care.
There is a shift in critical care to adopt volatile anaesthetics as sedatives for certain patients using mechanical ventilation. Accompanying this shift is a growing body of literature describing the advantages or disadvantages of using isoflurane or sevoflurane for long term sedation. This practise requires a cost effective, efficient and safe means to deliver these drugs that can simultaneously operate with modern critical care ventilators and ventilation protocols while protecting the care environment and care workers from excessive exposure to the drugs. ⋯ This reflection reduces the total amount of anaesthetic needed, reducing that which is exhausted or scavenged upon exhalation. It can be used for 24 h of sedation, and fits into current critical care ventilator circuits almost without modifications. This article will describe the physical characteristics of the device, how it works, its development history and the performance parameters under which it can be used.
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J Clin Monit Comput · Aug 2018
Uncontrolled delivery of liquid volatile anaesthetic when using the anaesthetic conserving device.
During patient sedation with liquid volatile anaesthetic, some problems may occur through a process called auto-pumping, defined as an expansion of bubbles inside the syringe, which can lead to uncontrolled anaesthetic delivery. The study examined how the temperature of liquid volatile anaesthetics (sevoflurane and isoflurane) and the presence of gas bubbles in the syringe affect the occurrence of auto-pumping when using the anaesthetic conserving device (ACD, AnaConDa™, Sedana Medical, Uppsala, Sweden). Four different circumstances for each volatile anaesthetic were tested with a bench study: volatile anaesthetic at room temperature or precooled with and without the presence of gas bubbles in the syringe. ⋯ Furthermore, when the heat source was removed, a substantial decline in anaesthetic agent values below the baseline was observed with both anaesthetics. The presence of gas bubbles in the syringe, especially when exposed to a heat source, may provoke auto-pumping with uncontrolled excessive anaesthetic delivery. If auto-pumping is suspected, the syringe pump must be stopped and the ACD removed from the breathing circuit at once.
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J Clin Monit Comput · Aug 2018
Evaluating the efficiency of desflurane reflection in two commercially available reflectors.
With the AnaConDa™ and the MIRUS™ system, volatile anesthetics can be administered for inhalation sedation in intensive care units. Instead of a circle system, both devices use anesthetic reflectors to save on the anesthetic agent. We studied the efficiency of desflurane reflection with both devices using different tidal volumes (VT), respiratory rates (RR), and 'patient' concentrations (CPat) in a bench study. ⋯ Efficiency inversely correlates with the product of CPat and VT which can be imagined as the volume of anesthetic vapor exhaled by the patient in one breath, but not with the respiratory frequency. Efficiency of the AnaConDa™ was higher for each setting compared with the MIRUS™. Desflurane is reflected by both reflectors with efficiencies high enough for clinical use.
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J Clin Monit Comput · Aug 2018
Halving the volume of AnaConDa: initial clinical experience with a new small-volume anaesthetic reflector in critically ill patients-a quality improvement project.
AnaConDa-100 ml (ACD-100, Sedana Medical, Uppsala, Sweden) is well established for inhalation sedation in the intensive care unit. But because of its large dead space, the system can retain carbon dioxide (CO2) and increase ventilatory demands. We therefore evaluated whether AnaConDa-50 ml (ACD-50), a device with half the internal volume, reduces CO2 retention and ventilatory demands during sedation of invasively ventilated, critically ill patients. ⋯ Minute ventilation and end-tidal CO2 were significantly reduced with the ACD-50, respiratory rate remained unchanged, and tidal volume decreased by 66 ± 43 ml. End-tidal isoflurane concentrations were also slightly reduced while haemodynamic measures remained constant. The ACD-50 reduces the tidal volume needed to eliminate carbon dioxide without augmenting isoflurane consumption.