Capnodynamic assessment of effective lung volume during cardiac output manipulations in a porcine model.

Journal: Journal of clinical monitoring and computing
PMID: 26377022

Abstract

A capnodynamic calculation of effective pulmonary blood flow includes a lung volume factor (ELV) that has to be estimated to solve the mathematical equation. In previous studies ELV correlated to reference methods for functional residual capacity (FRC). The aim was to evaluate the stability of ELV during significant manipulations of cardiac output (CO) and assess the agreement for absolute values and trending capacity during PEEP changes at different lung conditions. Ten pigs were included. Alterations of alveolar carbon dioxide were induced by cyclic reoccurring inspiratory holds. The Sulphur hexafluoride technique for FRC measurements was used as reference. Cardiac output was altered by preload reduction and inotropic stimulation at PEEP 5 and 12 cmHO both in normal lung conditions and after repeated lung lavages. ELV at baseline PEEP 5 was [mean (SD)], 810 (163) mL and decreased to 400 (42) mL after lavage. ELV was not significantly affected by CO alterations within the same PEEP level. In relation to FRC the overall bias (limits of agreement) was -35 (-271 to 201) mL, and percentage error 36 %. A small difference between ELV and FRC was seen at PEEP 5 cmHO before lavage and at PEEP 12 cmHO after lavage. ELV trending capability between PEEP steps, showed a concordance rate of 100 %. ELV was closely related to FRC and remained stable during significant changes in CO. The trending capability was excellent both before and after surfactant depletion.

Authors

  • Caroline Hällsjö Sander
    Department of Anesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden. caroline.hallsjo-sander@karolinska.se.
  • Per-Arne Lönnqvist
    Paediatric Anesthesia and Intensive Care Astrid Lindgrens Children's Hospital, Karolinska University Hospital, Stockholm, Sweden.
  • Magnus Hallbäck
    Maquet Critical Care AB, Solna, Sweden.
  • Fernando Suarez Sipmann
    Hedenstierna Laboratory, Department of Surgical Sciences, Section of Anesthesiology and Critical Care, Uppsala University, Uppsala, Sweden.
  • Mats Wallin
    Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
  • Anders Oldner
    Department of Anesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden.
  • Håkan Björne
    Department of Anesthesiology, Surgical Services and Intensive Care Medicine, Karolinska University Hospital, 171 76, Solna, Stockholm, Sweden.

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