Comparison of invasive and noninvasive saturation monitoring in prescribing oxygen during exercise in COPD patients

M. Carone, A. Patessio, L. Appendini, A. Purro, E. Czernicka, S. Zanaboni, C. F. Donner

Research output: Contribution to journalArticlepeer-review


The aim of this study was to determine whether it is possible using ear-oximetry to prescribe the correct oxygen flow rates during exercise in chronic obstructive pulmonary disease (COPD) patients on long-term oxygen therapy (LTOT). Twenty COPD patients on LTOT, with exercise desaturation breathing oxygen at resting flow rates, performed a series of 6-min treadmill walking tests, with a progressive increase in oxygen flows until oxygen saturation measured by ear- or pulse-oximetry (Sp,O2) was above 90%. The exercise studies were repeated the next day, saturation being measured both noninvasively by ear-oximetry (Sp,O2) and invasively by CO-oximeter (Sa,O2). The exercise studies continued until both Sa,O2 and Sp,O2 were above 90%. Reproducibility and agreement of the results were analysed according to Bland and Altman. Sp,O2 was significantly lower than Sa,O2 by, on average, 0.7% (p2 reproducibility between the two days was good. The invasive and noninvasive oxygen flow prescriptions agreed in only 10 subjects; in six subjects ear-oximetry overestimated the oxygen supply (p2 target had been raised to 93%, there would have been hardly any underestimations of Sa,O2 p=NS). We concluded that noninvasive measurement of oxygen saturation is not adequate for estimating arterial saturation in chronic obstructive pulmonary disease. We suggest, as a working solution, that a new cut-off limit of 93% oxygen saturation measured by pulse oximetry should be used as the value below which exercise-induced desaturation should be corrected in order to allow oxygen to be properly prescribed during activities of daily life.

Original languageEnglish
Pages (from-to)446-451
Number of pages6
JournalEuropean Respiratory Journal
Issue number2
Publication statusPublished - Feb 1997


  • exercise
  • lung disease (obstructive)
  • oximetry
  • oxygen inhalation therapy

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine


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