Validity of Hemodynamic Monitoring Using Inert Gas Rebreathing Method in Patients With Chronic Heart Failure and Those Implanted With a Left Ventricular Assist Device

J Card Fail. 2021 Apr;27(4):414-418. doi: 10.1016/j.cardfail.2020.09.479. Epub 2020 Oct 7.

Abstract

Objective: The present study assessed agreement between resting cardiac output estimated by inert gas rebreathing (IGR) and thermodilution methods in patients with heart failure and those implanted with a left ventricular assist device (LVAD).

Methods and results: Hemodynamic measurements were obtained in 42 patients, 22 with chronic heart failure and 20 with implanted continuous flow LVAD (34 males, aged 50 ± 11 years). Measurements were performed at rest using thermodilution and IGR methods. Cardiac output derived by thermodilution and IGR were not significantly different in LVAD (4.4 ± 0.9 L/min vs 4.7 ± 0.8 L/min, P = .27) or patients with heart failure (4.4 ± 1.4 L/min vs 4.5 ± 1.3 L/min, P = .75). There was a strong relationship between thermodilution and IGR cardiac index (r = 0.81, P = .001) and stroke volume index (r = 0.75, P = .001). Bland-Altman analysis showed acceptable limits of agreement for cardiac index derived by thermodilution and IGR, namely, the mean difference (lower and upper limits of agreement) for patients with heart failure -0.002 L/min/m2 (-0.65 to 0.66 L/min/m2), and -0.14 L/min/m2 (-0.78 to 0.49 L/min/m2) for patients with LVAD.

Conclusions: IGR is a valid method for estimating cardiac output and should be used in clinical practice to complement the evaluation and management of chronic heart failure and patients with an LVAD.

Keywords: cardiac output; heart failure; inert gas rebreathing; thermodilution.

MeSH terms

  • Cardiac Output
  • Heart Failure* / diagnosis
  • Heart Failure* / therapy
  • Heart-Assist Devices*
  • Hemodynamic Monitoring*
  • Humans
  • Male
  • Thermodilution