1. Lancet. 2018 Apr 28;391(10131):1693-1705. doi: 10.1016/S0140-6736(18)30479-3.
Epub 2018 Apr 26.

Mortality and morbidity in acutely ill adults treated with liberal versus
conservative oxygen therapy (IOTA): a systematic review and meta-analysis.

Chu DK(1), Kim LH(1), Young PJ(2), Zamiri N(1), Almenawer SA(3), Jaeschke R(4),
Szczeklik W(5), Schünemann HJ(4), Neary JD(1), Alhazzani W(6).

Author information: 
(1)Department of Medicine, McMaster University, Hamilton, ON, Canada.
(2)Medical Research Institute of New Zealand, Wellington, New Zealand; Intensive 
Care Unit, Wellington Regional Hospital, Wellington, New Zealand.
(3)Division of Neurosurgery, McMaster University, Hamilton, ON, Canada.
(4)Department of Medicine, McMaster University, Hamilton, ON, Canada; Department 
of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, 
ON, Canada.
(5)Department of Medicine, McMaster University, Hamilton, ON, Canada; Department 
of Intensive Care and Perioperative Medicine, Jagiellonian University Medical
College, Krakow, Poland.
(6)Department of Medicine, McMaster University, Hamilton, ON, Canada; Department 
of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, 
ON, Canada. Electronic address: alhazzaw@mcmaster.ca.

Comment in
    Lancet. 2018 Apr 28;391(10131):1640-1642.
    Lancet. 2018 Dec 8;392(10163):2436-2437.
    Lancet. 2018 Dec 8;392(10163):2436.
    Lancet. 2018 Dec 8;392(10163):2437.

BACKGROUND: Supplemental oxygen is often administered liberally to acutely ill
adults, but the credibility of the evidence for this practice is unclear. We
systematically reviewed the efficacy and safety of liberal versus conservative
oxygen therapy in acutely ill adults.
METHODS: In the Improving Oxygen Therapy in Acute-illness (IOTA) systematic
review and meta-analysis, we searched the Cochrane Central Register of Controlled
Trials, MEDLINE, Embase, HealthSTAR, LILACS, PapersFirst, and the WHO
International Clinical Trials Registry from inception to Oct 25, 2017, for
randomised controlled trials comparing liberal and conservative oxygen therapy in
acutely ill adults (aged ≥18 years). Studies limited to patients with chronic
respiratory diseases or psychiatric disease, patients on extracorporeal life
support, or patients treated with hyperbaric oxygen therapy or elective surgery
were excluded. We screened studies and extracted summary estimates independently 
and in duplicate. We also extracted individual patient-level data from survival
curves. The main outcomes were mortality (in-hospital, at 30 days, and at longest
follow-up) and morbidity (disability at longest follow-up, risk of
hospital-acquired pneumonia, any hospital-acquired infection, and length of
hospital stay) assessed by random-effects meta-analyses. We assessed quality of
evidence using the grading of recommendations assessment, development, and
evaluation approach. This study is registered with PROSPERO, number
CRD42017065697.
FINDINGS: 25 randomised controlled trials enrolled 16 037 patients with sepsis,
critical illness, stroke, trauma, myocardial infarction, or cardiac arrest, and
patients who had emergency surgery. Compared with a conservative oxygen strategy,
a liberal oxygen strategy (median baseline saturation of peripheral oxygen [SpO2]
across trials, 96% [range 94-99%, IQR 96-98]) increased mortality in-hospital
(relative risk [RR] 1·21, 95% CI 1·03-1·43, I2=0%, high quality), at 30 days (RR 
1·14, 95% CI 1·01-1·29, I2=0%, high quality), and at longest follow-up (RR 1·10, 
95% CI 1·00-1·20, I2=0%, high quality). Morbidity outcomes were similar between
groups. Findings were robust to trial sequential, subgroup, and sensitivity
analyses.
INTERPRETATION: In acutely ill adults, high-quality evidence shows that liberal
oxygen therapy increases mortality without improving other patient-important
outcomes. Supplemental oxygen might become unfavourable above an SpO2 range of
94-96%. These results support the conservative administration of oxygen therapy.
FUNDING: None.

Copyright © 2018 Elsevier Ltd. All rights reserved.

DOI: 10.1016/S0140-6736(18)30479-3 
PMID: 29726345  [Indexed for MEDLINE]