The differential Fick method was introduced in 1980 and the rebreathing approach in 1985.

(Gedeon A et al. : A new method for noninvasive bedside determination of pulmonary blood flow. Medical & Biological Engineering & Computing 18(4) 411-418 )

(Gedeon A. Noninvasive pulmonary blood flow for optimal PEEP. Clinical Physiology 5 (Suppl 3) 49-58.)

Below is an explanation how it works

Description of our work :

Video abstract:  https://youtu.be/-eqfO9gbsGE

Poster summary:

Poster Epbf Pdf
PDF – 1.4 MB 2 downloads

Full paper:

A Gedeon, J Jansson D Patrickson, M Wallin : A new method for non-invasive determination of effective pulmonary blood flow and cardiac output in spontaneously breathing subjects Experimental Physiology 1-6 2025

 http://doi.org/10.1113/EP093079

References:

Pulmonary embolism: 

  1. European Heart Journal (2020)   2019 ESC Guidelines for the diagnosis and management of acute pulmonary emboli  
  2. Eur Respir J (2010); 35: 735–741 Bedside end-tidal CO2 tension as a screening tool to exclude pulmonary embolism                                         AR Hemnes*, A.L. Newman*, B. Rosenbaum#, T.W. Barrett",  C.Zhou,T.W. Rice* and J.H. Newman*                                                       

Cardiac output:

       Paediatr Anaesth .(2022) Feb;32(2):255-261.  Capnodynamics-Measuring cardiac output via ventilation   Jacob Karlsson,  Per-Arne Lönnqvist 

 

History

The only commercially available device that employed the differential Fick method for calculating cardiac output was the NICO unit from Respironics - Philips. It operated with a disposable valve allowing rebreathing and was designed for patients on mechanical ventilation in the OR

This device, shown to the left, is no longer on the market.