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. Ten patients participated in this cross-over protocol. After sedation with isoflurane via ACD-100 for 24 h, the 5-h observation period started. During the first hour, ACD-100 was used; for the next 2 h, ACD-50; and for the last 2 h, ACD-100 was used again. Sedation was titrated to Richmond Agitation and Sedation Scale (RASS) score - 3 to - 4 and a processed electroencephalogram (Narcotrend Index, Narcotrend-Gruppe, Hannover, Germany) was recorded. Minute ventilation, CO2 elimination, and isoflurane consumption were compared. All patients were deeply sedated (Narcotrend Index, mean ± SD: 38 ± 10; RASS scores - 3 to - 5) and breathed spontaneously with pressure support throughout the observation period. Infusion rates of isoflurane and opioid, either remifentanil or sufentanil, as well as ventilator settings were unchanged. 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.
['Bomberg|Hagen|H|http://orcid.org/0000-0001-9778-0119', 'Meiser|Franziska|F|', 'Zimmer|Sarah|S|', 'Bellgardt|Martin|M|', 'Volk|Thomas|T|', 'Sessler|Daniel I|DI|', 'Groesdonk|Heinrich V|HV|', 'Meiser|Andreas|A|']
D000368:Aged D000769:Anesthesia, Inhalation D018685:Anesthetics, Inhalation D016638:Critical Illness D018592:Cross-Over Studies D054810:Deep Sedation D004867:Equipment Design D005260:Female D006801:Humans D007530:Isoflurane D008297:Male D008875:Middle Aged D058996:Quality Improvement D012189:Retrospective Studies
Inhalation sedation Dead space Isoflurane Anaesthesic reflection Carbon dioxide reflection