title: [A Problem with Flow Indicators of Anesthesia Machine].
abstract: Some anesthesia machines indicate both analog and digital flow volumes of oxygen, air and nitrous oxide. We have noticed that there are discrepancies in the flows between analog and digital flow indicators of two anesthesia machine models (Dräger ; Fabius GS premium and Fabius Tiro). When oxygen or air flow is low, the analog indicator shows higher flows than the digital indicator. In contrast, when oxygen or air flow is high, the analog indicator shows lower flows than the digital indicator. This discrepancy is comparatively small when total gas flow is within the range of 2-5 l x min(-1). We contacted the manufacturer, which replied that the digital indicator is correct and the analog indicator should be regarded as an adjunctive, in case of a power failure when the digital indicator does not function. But this discrepancy may cause practical problems. When we cannot use a digital indicator and have to perform ventilation using a supporting gas cylinder, we may misjudge the available time for oxygen. In addition, when we use only analog indicator, insufficient volume of oxygen may be delivered, leading to the grave hypoxia.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Tanada
authors.forename: Akira
authors.initials: A
authors.lastname: Kawashima
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Kuremoto
authors.forename: Motonari
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D000758:Anesthesia; D000776:Anesthesiology / Q000295:instrumentation*; D018685:Anesthetics, Inhalation
chemical_list: D018685:Anesthetics, Inhalation