title: Asynchrony Between Ventilator Flow and Pressure Waveforms and the Capnograph on Dräger Anesthesia Workstations: A Case Report.
abstract: Modern anesthesia workstations display capnography, flow-time, and pressure-time waveforms in real time. We observed that at certain ventilator settings (10 breaths/min) on Dräger workstations, the expiratory phase of the capnograph overlaps both the inspiratory and the expiratory phases of ventilation. This discrepancy disappears at respiratory rates of 16 breaths/min. This synchronous respiratory monitoring display at respiratory rates 16 breaths/min is not physiologically correct, because it implies a synchronization of waveforms that is not actually present. This again becomes asynchronous once the respiratory rate is increased to >18 breaths/min. Such an artifact may not affect the patient's safety in most cases but may mislead clinicians when synchrony between flow/pressure and capnography is needed for diagnostic purposes. We wish to share this discrepancy with clinicians and notify the manufacturer so that potential solutions may be found.
authors.affiliation: From the *Department of Anesthesiology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow; †Ursila District Hospital, Kanpur; ‡Emergency Medicine, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
authors.forename: Mukesh
authors.initials: M
authors.lastname: Tripathi
authors.forename: Nilay
authors.initials: N
authors.lastname: Tripathi
authors.forename: Mamta
authors.initials: M
authors.lastname: Pandey
mesh_terms: D000768:Anesthesia, General; D019296:Capnography / Q000295:instrumentation; D017081:Cholecystectomy, Laparoscopic; D005260:Female; D006801:Humans; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000295:instrumentation*; D012122:Ventilators, Mechanical