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![Schematic diagram of MADM TM in-line vaporizer. This vaporizer is interposed on the inspiratory limb of a circular circuit. It senses the input flow [1] and volatile anaesthetic (VA) concentration [2]. The data processor and device controller [3] compare the input mass of VA with the target output designated by the dial [8]. It instructs the pump [4] to transfer VA from the anaesthetic reservoir [5] to the vaporization chamber [6] and the vapour pump [7] to top up the inspired gas with the appropriate mass of VA to meet the target as concentration. Sensor [1b] is attached to the endotracheal tube and monitors inspired and end-tidal anaesthetic concentrations.](profile/Marcin-Wasowicz/publication/320639152/figure/fig4/AS:668471100702727@1536387338465/Schematic-diagram-of-MADM-TM-in-line-vaporizer-This-vaporizer-is-interposed-on-the.png)
Schematic diagram of MADM TM in-line vaporizer. This vaporizer is interposed on the inspiratory limb of a circular circuit. It senses the input flow [1] and volatile anaesthetic (VA) concentration [2]. The data processor and device controller [3] compare the input mass of VA with the target output designated by the dial [8]. It instructs the pump [4] to transfer VA from the anaesthetic reservoir [5] to the vaporization chamber [6] and the vapour pump [7] to top up the inspired gas with the appropriate mass of VA to meet the target as concentration. Sensor [1b] is attached to the endotracheal tube and monitors inspired and end-tidal anaesthetic concentrations.
Source publication
Background:
A volatile anaesthetic (VA) reflector can reduce VA consumption (VAC) at the cost of fine control of its delivery and CO2 accumulation. A digital in-line vaporizer and a second CO2 absorber circumvent both of these limitations. We hypothesized that the combination of a VA reflector with an in-line vaporizer would yield substantial VA c...
Contexts in source publication
Context 1
... vapor- izer 8 (http://thornhillresearch.com/mobile-anesthe sia-madm/). Deadspace is limited by the separation of inspiratory and expiratory limbs in a secondary circuit. CO 2 accumulation is avoided by placing a CO 2 absorber in the inspiratory limb. We name this configuration the Reflector-In-line-Vaporizer Anaesthesia AppLication, or RIVAL (Fig. 1). We hypothesized that RIVAL would reduce VA con- sumption compared to semi-closed circuits, even at very low FGF. Indeed, efficiency should be main- tained independent of ...
Context 2
... in a separate secondary circuit (RIVAL) as described by Perhag et al. 9 RIVAL is intended to be inter- posed between the endotracheal tube and a pri- mary ventilator circuit. In this study, we used the standard circle system available in most operating rooms as the primary ventilator cir- cuit. RIVAL and the experimental setup are shown in Fig. 1; it consisted of a Y-piece with inspiratory and expiratory valves. The inspira- tory limb contained the in-line vaporizer and a CO 2 absorber. The inspiratory and expiratory limbs were attached by a Y-piece connected to the pig's endotracheal tube. The ventilator cir- cuit consisted of a standard circle anaesthetic system with a ...
Citations
... All patients receive lung protective ventilation strategies (4-6 mL/kg), which limited using volatile delivery systems in smaller patients (i.e., < 60 kg). Since completion of this pilot trial, the risk of rebreathing has been reduced with recent availability of smaller in-line vaporizers (e.g., AnaConDa-S) with a lower dead space and tidal volume requirement (minimum 200 mL) and alternate vaporizing systems (e.g., Mobile Anesthesia Delivery Module) (21). Concerns surrounding malignant hyperthermia were raised in ICU patients showing an acute deterioration and hypermetabolic state. ...
Objectives: Assess feasibility, barriers to recruitment, and safety of volatile-based sedation in longer term sedation patients in North American ICUs with limited or no experience with volatile sedation.
Design: Open-label, pilot randomized clinical trial performed between October 2013 and September 2018.
Setting: Four Canadian ICUs across two academic tertiary and quaternary hospitals. Patients: Sixty adults anticipated needing sedation and invasive ventilation beyond 48 hours with tidal volumes greater than 350 mL, expected 6-month mortality risk less than 50%, no evidence of high intracranial pressure, or drug contraindications (malignant hyperthermia, allergy).
Interventions: 2:1 randomization to inhaled volatile sedation using isoflurane or standard midazolam and/or propofol IV sedation.
Measurement and Main Results: Primary outcome of safety and feasibility was assessed by staff satisfaction scores using a five-point Likert scale and serum fluoride measurements. Secondary clinical outcomes included time to extubation, quality of sedation, opioid use, cardiorespiratory parameters, vasopressor and antipsychotic drug use, and 3-month cognitive outcome measured using telephone interview for cognitive status. From 2,210 screened patients, 308 met eligibility criteria secondary to many not requiring sedation, extubation planned within 48 hours, high risk of death, or low tidal ventilation. Of 308 patients, 60 were randomized to isoflurane (n = 41) or IV (n = 19) sedation secondary to lack of substitute decision-maker or physician consent. Duration of inhaled isoflurane and IV sedation were median of 114 and 88 hours, respectively. Nine isoflurane patients crossed into the IV arm secondary to mainly hypercarbia from low tidal ventilation. Nursing and respiratory therapy staff satisfaction scores were quantitatively similar between both sedation approaches. Serum fluoride levels rose with duration of isoflurane sedation but were not associated with altered kidney function. There were no significant differences in secondary clinical outcomes.
Conclusions: We showed adequate preliminary safety and acceptability of inhaled volatile anesthetics for long-term sedation.
... 41 Another reflection system, RIVAL, has been described in an animal study by a Canadian group. 42 In their set-up, a reflector is interposed between an anaesthesia ventilator and a second (!) circle system, in which a carbon dioxide absorber as well as an inline (!) vaporizer are integrated. With this arrangement, the authors were able to reduce the consumption of anaesthetics even at higher fresh gas flows. ...
The increasing number of published studies on inhaled sedation from groups all over the world as well as the sales figures of AnaConDa (personal communication) indicate that inhaled sedation is used in some hospitals in everyday practice worldwide. This is remarkable, as there is no explicit approval for long-term ICU sedation with volatile anaesthetic by any authority and this application differs considerably from that in the operating theatre. A multicentre study with the title “a randomized controlled open-label study to confirm the efficacy and safety of sedation with isoflurane in invasively ventilated ICU patients using the AnaConDa administration system” (Acronym: Isoconda; EudraCT number: 2016-004551-67) is now under way to put things straight.
... These are currently used for sedation in medical intensive care units (Kim et al. 2017). Digitally controlled in-line reflectors are under investigation, which may improve precision in delivery of anaesthetic agents and reduce agent consumption by 55% at FGF of 1 L minute e1 (Mashari et al. 2018). Any such systems have the potential to increase patient dead space and potentially retain other gases such as carbon dioxide (Sturesson et al. 2015). ...
Objective:
Attention is drawn to the potential of global warming to influence the health and wellbeing of the human race. There is increasing public and governmental pressure on healthcare organisations to mitigate and adapt to the climate changes that are occurring. The science of anaesthetic agents such as nitrous oxide and the halogenated anaesthetic agents such as greenhouse gases and ozone-depleting agents is discussed and quantified. Additional environmental impacts of healthcare systems are explored. The role of noninhalational anaesthetic pharmaceuticals is discussed, including the environmental life-cycle analyses of their manufacture, transport, disposal and use. The significant role of anaesthetists in recycling and waste management, resource use (particularly plastics, water and energy) and engagement in sustainability are discussed. Finally, future directions for sustainability in veterinary anaesthesia are proposed.
Conclusions:
Veterinary anaesthetists have a considerable opportunity to drive sustainability within their organisations through modification of their practice, research and education. The principles of sustainability may help veterinary anaesthetists to mitigate and adapt to our environmental crisis. Due to their particular impact as greenhouse gases, anaesthetic agents should be used conservatively with the lowest safe fresh gas flow possible. Technologies for reprocessing anaesthetic agents are described.
... An anesthetic reflection system has also been used in a different way: interposed between two (!) circle systems (Fig. 48.7) [18]. The primary circle system was part of a common anesthesia ventilator; the secondary contained an in-line vaporizer as well as a second carbon dioxide absorber. ...
Volatile anesthetics are increasingly frequently used to sedate intensive care unit (ICU) patients who are receiving invasive mechanical ventilation. The AnaConDa™ (Sedana Medical, Stockholm, Sweden) is the most frequently used administration system. It is intended for use in a single patient for up to 24 h. Up to now, 2.3 million devices have been sold globally [1]. There is a growing body of literature showing advantages of volatile anesthetics over intravenous sedatives [2, 3] and inhaled sedation has been adopted by the German, British and Spanish sedation guidelines [4–6].
... In volume control mode, all modern ventilators have settings and self-performed tests of circuit compliance that allow them to compensate for differences in tubing length and chest compliance from patient to patient. 1 The system's very high efficiency and low pollution make it ideal for long term use, such as sedation in the ICU. A study in six (50 kg) pigs in our laboratory (Mashari et al. [11]) showed anesthetic consumption to be reduced to half of that with a circle circuit even at a low fresh gas flow of 1 L/ min (Fig. 4). This level of consumption remained constant and was independent of the fresh gas flow up to 10 L/min. ...
... The Sevoflurane concentration selection dial was set from 1 to 2.5% at the arrow. The figure illustrates that it took five breaths to reach the set inspired Sevoflurane concentration (data from Mashari et al.[11])Fig. 4Sevoflurane consumption as a function of fresh gas flow in a circle anesthetic circuit. The circle anesthetic circuit is attached to a secondary circuit illustrated inFig. ...
... The circle anesthetic circuit is attached to a secondary circuit illustrated inFig. 1. Error bars are standard deviation; study in six 50 kg pigs (data from Mashari et al.[11]) ...
As the clinical advantages of vapor anesthesia (VA) for sedation of patients in ICU become more apparent, the ergonomics, economy and safety issues need to be better addressed. Here we describe the use of a new commercial digital in-line anesthetic vaporizer that can be attached to the inspiratory limb of a ventilator. If used with a simple, and easily assembled secondary circuit and anesthetic reflector, the circuit remains remote from the patient, the VA consumption approaches a physical minimum, VA level is controlled and monitored, and the tidal volume size is not limited.
... This system recently has been tested in a pig animal model at gas flow rates up to 10 L/min and demonstrated good efficiency in volatile use with no accumulation of carbon dioxide. 43 A potential and important advantage of this system for clinical use is no restriction in tidal volume requirements, thus allowing for low and ultra-low tidal volume lung protective ventilation strategies. ...
