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High volatile anaesthetic conservation with a digital in‐line vaporizer and a reflector
Author(s) -
Mashari A.,
Fedorko L.,
Fisher J. A.,
Klein M.,
Wąsowicz M.,
Meineri M.
Publication year - 2018
Publication title -
acta anaesthesiologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.738
H-Index - 107
eISSN - 1399-6576
pISSN - 0001-5172
DOI - 10.1111/aas.13017
Subject(s) - vaporizer , medicine , fresh gas flow , reflector (photography) , anesthesia , line (geometry) , sevoflurane , surgery , optics , physics , light source , geometry , mathematics , pathology
Background A volatile anaesthetic (VA) reflector can reduce VA consumption (VAC) at the cost of fine control of its delivery and CO 2 accumulation. A digital in‐line vaporizer and a second CO 2 absorber circumvent both of these limitations. We hypothesized that the combination of a VA reflector with an in‐line vaporizer would yield substantial VA conservation, independent of fresh gas flow (FGF) in a circle circuit, and provide fine control of inspired VA concentrations. Method Prospective observational study on six Yorkshire pigs. A secondary anaesthetic circuit consisting of a Y‐piece with 2 one‐way valves, an in‐line vaporizer and a CO 2 absorber in the inspiratory limb was connected to the patient's side of the VA reflector. The other side was connected to the Y‐piece of a circle anaesthetic circuit. In six pigs, an inspired concentration of sevoflurane of 2.5% was maintained by the in‐line vaporizer. We measured VAC at FGF of 1, 4 and 10 l/min. Results With the secondary circuit, VAC was 55% less than with the circle system alone at FGF 1 l/min, and independent of FGF over the range of 1–10 l/min. Insertion of a CO 2 absorber in the secondary circuit reduced P et CO 2 by 1.3–2.0 kpa (10–15 mmHg). Conclusion A secondary circuit with reflector and in‐line vaporizer provides highly efficient anaesthetic delivery, independent of FGF. A second CO 2 absorber was necessary to scavenge the CO 2 reflected by the anaesthetic reflector. This secondary circuit may turn any open circuit ventilator into an anaesthetic delivery unit.