continuous non-invasive monitoring of tidal volumes by measurement of tidal impedance in neonatal piglets连续的非侵入性的监视测量潮汐潮汐卷的阻抗在新生儿的小猪.pdfVIP

Continuous Non-Invasive Monitoring of Tidal Volumes by Measurement of Tidal Impedance in Neonatal Piglets Florian Kurth, Fabienne Zinnow, Alexandra Prakapenia, Sabrina Dietl, Stefan Winkler, Sascha Ifflaender, ¨ Mario Rudiger*, Wolfram Burkhardt Department of Neonatology and Paediatric Intensive Care, University Hospital Carl Gustav Carus, Dresden, Germany Abstract Background: Electrical Impedance measurements can be used to estimate the content of intra-thoracic air and thereby give information on pulmonary ventilation. Conventional Impedance measurements mainly indicate relative changes, but no information concerning air-volume is given. The study was performed to test whether a 3-point-calibration with known tidal volumes (VT) during conventional mechanical ventilation (CMV) allows subsequent calculation of VT from total Tidal- Impedance (tTI) measurements using Quadrant Impedance Measurement (QIM). In addition the distribution of TI in different regions of the thorax was examined. Methodology and Principal Findings: QIM was performed in five neonatal piglets during volume-controlled CMV. tTI values at three different VT (4, 6, 8 ml/kg) were used to establish individual calibration curves. Subsequently, each animal was ventilated with different patterns of varying VT (2–10 ml/kg) at different PEEP levels (0, 3, 6, 9, 12 cmH2O). VT variation was repeated after surfactant depletion by bronchoalveolar lavage. VT was calculated from tTI values (VTcalc) and compared to the VT delivered by the ventilator (VTPNT). Bland-Altman analysis revealed good agreement between VTcalc and VTPNT before (bias 20.08 ml; limits of agreement 21.18 to 1.02 ml at PEEP = 3 cmH2O) and after surfactant depletion (bias 20.17 ml; limits of agreement 21.57 to 1.22 ml at PEEP = 3 cmH2O). At higher PEEP levels VTcalc was lower than VTPNT, whe