ORIGINAL ARTICLES   Free access

Minerva Anestesiologica 2015 January;81(1):28-32

Copyright © 2015 EDIZIONI MINERVA MEDICA

language: English

Factors of tidal volume variation during augmented spontaneous ventilation in patients on extracorporeal carbon dioxide removal. A multivariate analysis

Bein T. ¹, Müller T. ², Graf B. M. ¹, Philipp A. ³, Zeman F. ⁴, Schultz M. J. ⁵, Slutsky A. S. ^{6, 7, 8}, Weber-Carstens S. ⁹ ✉

¹ Department of Anesthesia and Operative Intensive Care, Regensburg University Hospital, Regensburg, Germany; ² Department of Internal Medicine II, Regensburg University Hospital, Regensburg, Germany; ³ Department of Cardiothoracic Surgery, Regensburg University Hospital, Regensburg, Germany; ⁴ Center for Clinical Studies, Regensburg University Hospital, Regensburg, Germany; ⁵ Department of Intensive Care and Laboratory of Experimental Intensive Care and Anesthesiology, Academic Medical Center at the University of Amsterdam, Amsterdam, The Netherlands; ⁶ Keenan Research Center of Biomedical Sciences, Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, ON, Canada; ⁷ Interdepartmental Division of Critical Care Medicine, University of Toronto, Toronto, ON, Canada; ⁸ Department of Medicine, University of Toronto, Toronto, ON, Canada; ⁹ Department of Anesthesia and Operative Intensive Care Medicine, Charité Universitary Medicine Berlin, Campus Virchow-Klinikum and Campus Charité Mitte, Berlin, Germany

BACKGROUND: Extracorporeal carbon dioxide removal (ECCO2-R) allows lung protective ventilation using lower tidal volumes (VT) in patients with acute respiratory failure. The dynamics of spontaneous ventilation under ECCO2-R has not been described previously. This retrospective multivariable analysis examines VT patterns and investigates the factors that influence VT, in particular sweep gas flow and blood flow through the artificial membrane.
METHODS: We assessed VT, respiratory rate (RR), minute ventilation (MV), and levels of pressure support (0-24 cm H2O), sweep gas flow (0-14 L/min) and blood flow through the membrane (0.8-1.8 L/min) in 40 patients from the moment they were allowed to breathe spontaneously. Modest hypercapnia was accepted.
RESULTS: Patients tolerated moderate hypercapnia well. In a generalized linear model the increase in sweep gas flow (P<0.001), a low PaCO2 (P=0.029), and an increased breathing frequency (P<0.001) were associated with lower VT. Neither blood flow through the membrane (P=0.351) nor the level of pressure support (P=0.595) influenced VT size.
CONCLUSION: Higher sweep gas flow is associated with low VT in patients on extracorporeal lung assist and augmented spontaneous ventilation. Such a technique can be used for prolonged lung protective ventilation even in the patient’s recovery period.