Continuous monitoring of membrane lung carbon dioxide removal during ECMO: experimental testing of a new volumetric capnometer

Alice Montalti, Mirko Belliato, Sandro Gelsomino, Sandro Nalon, Francesco Matteucci, Orlando Parise, Monique de Jong, Maged Makhoul, Daniel M. Johnson, Roberto Lorusso

Research output: Contribution to journalArticle

Abstract

Background: Extracorporeal membrane oxygenation constitutes a complex support modality, and accurate monitoring is required. An ideal monitoring system should promptly detect ECMO malfunctions and provide real-time information to optimize the patient–machine interactions. We tested a new volumetric capnometer which enables continuous monitoring of membrane lung carbon dioxide removal (V′CO 2 ML), to help in estimating the oxygenator performance, in terms of CO 2 removal and oxygenator dead space (VDsML). Methods: This study was conducted on nine pigs undergoing veno-arterial ECMO due to cardiogenic shock after induced acute myocardial infarction. The accuracy and reliability of the prototype of the volumetric capnometer (CO 2 RESET , by Eurosets srl, Medolla, Italy) device was evaluated for V′CO 2 ML and VDsML measurements by comparing the obtained measurements from the new device to a control capnometer with the sweep gas values. Measurements were taken at five different levels of gas flow/blood flow ratio (0.5-1.5). Agreement between the corresponding measurements was taken with the two methods. We expected that 95% of differences were between d − 1.96s and d + 1.96s. Results: In all, 120 coupled measurements from each device were obtained for the V′CO 2 ML calculation and 40 for the VDsML. The new capnometer mean percentage bias (95% confidence interval limits of agreement) was 3.86% (12.07-4.35%) for V′CO 2 ML and 2.62% (8.96-14.20%) for VDsML. A negative proportional bias for V′CO 2 ML estimation with the new device was observed with a mean of 3.86% (12.07-4.35%). No correlations were found between differences in the coupled V′CO 2 ML and VDsML measurements and the gas flow/blood flow ratio or temperature. Coupled measurements for V′CO 2 ML showed strong correlation (r s = 0.991; p = 0.0005), as did VDsML calculations (r s = 0.973; p = 0.0005). Conclusion: The volumetric capnometer is reliable for continuous monitoring of CO 2 removal by membrane lung and VDsML calculations. Further studies are necessary to confirm these data.

Original languageEnglish
JournalPerfusion (United Kingdom)
DOIs
Publication statusPublished - Jan 1 2019

Keywords

  • capnometer
  • ECLS
  • ECMO
  • extracorporeal membrane oxygenation monitoring
  • membrane lung carbon dioxide removal
  • membrane lung function
  • oxygenator performance
  • V′CO

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging
  • Safety Research
  • Cardiology and Cardiovascular Medicine
  • Advanced and Specialised Nursing

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