Conservative versus Liberal Oxygenation Targets for Mechanically Ventilated Patients. A Pilot Multicenter Randomized Controlled Trial.
BACKGROUND
There are no randomized controlled trials comparing different oxygenation targets for intensive care unit (ICU) patients.


OBJECTIVE
To determine whether a conservative oxygenation strategy is a feasible alternative to a liberal oxygenation strategy among ICU patients requiring invasive mechanical ventilation (IMV).


METHODS
At four multidisciplinary ICUs, 103 adult patients deemed likely to require IMV for greater than or equal to 24 hours were randomly allocated to either a conservative oxygenation strategy with target oxygen saturation as measured by pulse oximetry (SpO2) of 88-92% (n = 52) or a liberal oxygenation strategy with target SpO2 of greater than or equal to 96% (n = 51).


RESULTS
The mean area under the curve and 95% confidence interval (CI) for SpO2 (93.4% [92.9-93.9%] vs. 97% [96.5-97.5%]), SaO2 (93.5% [93.1-94%] vs. 96.8% [96.3-97.3%]), PaO2 (70 [68-73] mm Hg vs. 92 [89-96] mm Hg), and FiO2 (0.26 [0.25-0.28] vs. 0.36 [0.34-0.39) in the conservative versus liberal oxygenation arm were significantly different (P < 0.0001 for all). There were no significant between-group differences in any measures of new organ dysfunction, or ICU or 90-day mortality. The percentage time spent with SpO2 less than 88% in conservative versus liberal arm was 1% versus 0.3% (P = 0.03), and percentage time spent with SpO2 greater than 98% in conservative versus liberal arm was 4% versus 22% (P < 0.001). The adjusted hazard ratio for 90-day mortality in the conservative arm was 0.77 (95% CI, 0.40-1.50; P = 0.44) overall and 0.49 (95% CI, 0.20-1.17; P = 0.10) in the prespecified subgroup of patients with a baseline PaO2/FiO2 less than 300.


CONCLUSIONS
Our study supports the feasibility of a conservative oxygenation strategy in patients receiving IMV. Larger randomized controlled trials of this intervention appear justified. Clinical trial registered with Australian New Zealand Clinical Trials Registry (ACTRN 12613000505707).
1 Intensive Care Unit, John Hunter Hospital, Newcastle, Australia.|2 School of Medicine and Public Health, University of Newcastle, Newcastle, Australia.
Rakshit
R
Panwar
1 Intensive Care Unit, John Hunter Hospital, Newcastle, Australia.
Miranda
M
Hardie
3 Department of Intensive Care, Austin Hospital, The University of Melbourne, Melbourne, Australia.|4 Australian and New Zealand Intensive Care Research Centre, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
Rinaldo
R
Bellomo
5 Critical Care Unit, University Hospital Besançon and University of Franche-Comté, Besançon, France.
Loïc
L
Barrot
3 Department of Intensive Care, Austin Hospital, The University of Melbourne, Melbourne, Australia.|4 Australian and New Zealand Intensive Care Research Centre, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
Glenn M
GM
Eastwood
6 Intensive Care Unit, Wellington Hospital, Wellington, New Zealand; and.|7 Medical Research Institute of New Zealand, Wellington, New Zealand.
Paul J
PJ
Young
4 Australian and New Zealand Intensive Care Research Centre, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.|5 Critical Care Unit, University Hospital Besançon and University of Franche-Comté, Besançon, France.
Gilles
G
Capellier
1 Intensive Care Unit, John Hunter Hospital, Newcastle, Australia.|2 School of Medicine and Public Health, University of Newcastle, Newcastle, Australia.
Peter W J
PW
Harrigan
4 Australian and New Zealand Intensive Care Research Centre, School of Public Health and Preventive Medicine, Monash University, Melbourne, Australia.
Michael
M
Bailey
D005260:Female; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D010102:Oxygen Inhalation Therapy / Q000379:methods*; D010865:Pilot Projects; D012121:Respiration, Artificial / Q000379:methods*
D010100:Oxygen
critical illness; intensive care; mechanical ventilation; oxygen inhalation therapy; targets