Skip to main content

Volume 3 Supplement 1


Automation of oxygen titration in patients with acute respiratory distress at the emergency department. A multicentric international randomised controlled study


Oxygen therapy is commonly administered in critical care and emergency medicine. Its benefits are well known but potential side-effects may be underestimated. Compliance to recommendations remains dependent on staff workload. We developed FreeO2, an innovative device that automatically titrates oxygen flow delivered through nasal cannulas or masks to maintain the patients in the SpO2 target set by the clinician1.


To compare FreeO2 with oxygen manual adjustment, in patient admitted to the emergency department (ED) for acute respiratory failure (ARF).


We conducted a multicentre randomized controlled study. Inclusion criteria were: admission to ED for ARF requiring O2≥3L/min. Main exclusion criteria were: O2≥15 L/min, immediate need for ventilatory support. After inclusion, patients were randomized to either FreeO2 or conventional O2 manual adjustment during 3 hours. The randomization was web-based and stratified for the type of respiratory failure (hypoxemia/hypercapnia) and for the centre. Primary outcome was the % of time with SpO2 within the predefined target (92-96% for hypoxemic patients; 88-92% for hypercapnic patients). Secondary endpoints were: frequency of severe hypoxemia (SpO2 < 85%) and hyperoxia (SpO2> 98%), partial or complete oxygen weaning at the ED, total O2 duration, ventilator support use, ICU admissions, ICU and hospital LOS.


187 patients were randomized (93 FreeO2 and 94 Manual). Baseline physiological characteristics were similar in the 2 groups: age = 76 ± 12 yrs., 35% of COPD patients; mean O2 flow at inclusion was 5.8 ± 3.1 L/min. No serious adverse events related to the protocol or device was recorded. The percentage of time within the SpO2 target was 81 ± 21% in the FreeO2 arm and 51 ± 30% in the Manual arm (P < 0.001). Percentage of time with severe hypoxemia and with hyperoxia were significantly lower with FreeO2 (P < 0.001). The percentage of patients with O2 flow reduction of more than 50% during the 3 hours of the study was 39% with FreeO2 vs 19% in the Manual arm (P = 0.011). Percentage of O2 weaning at the end of the study (3h) was 4.3% in the FreeO2 arm vs. 14.1 % in the Manual arm; p < 0.001. Significantly less patients in the hypercapnic subgroup were transferred in the ICU, overall O2 administration and hospital LOS were significantly reduced in the non-adjusted analysis (9.2 ± 6.9 vs 11.1 ± 7.0, P = 0.01).


The automation of oxygen therapy with FreeO2 at the ED improves the oxygenation parameters with more time in the specified SpO2 target, less desaturation and less hyperoxia. FreeO2 may reduce staff workload and improve the compliance to recommendations for oxygen administration with potential related clinical benefits

Grant Acknowledgment

PHRC National 2010 FreeO2 Hypox #08-12

Grant PSR-SIIRI-MDEIE (Ministry of Finances, Québec)


  1. Lellouche F, L’her E: Automated oxygen flow titration to maintain constant oxygenation. Respir Care. 2012, 57 (8): 1254-1262.

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations


Rights and permissions

Open Access  This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

L'Her, E., Dias, P., Gouillou, M. et al. Automation of oxygen titration in patients with acute respiratory distress at the emergency department. A multicentric international randomised controlled study. ICMx 3 (Suppl 1), A424 (2015).

Download citation

  • Published:

  • DOI: