Effect of conservative and conventional oxygen therapy on the prognosis of critically ill patients: a Meta-analysis

Abstract

To compare the efficacy and safety of conservative and conventional oxygen therapy in critically ill patients. Relevant literature and randomized controlled trials (RCTs) about the effect of conservative oxygen therapy and conventional oxygen therapy on the prognosis of intensive care unit (ICU) critically ill patients was searched from CNKI, VIP, Wanfang Data, Chinese Clinical Trial Registry, PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov by using the keywords "critically ill patients, conservative oxygen therapy, liberal oxygen therapy, conventional oxygen therapy, mortality" until October 30th in 2018. The main outcome indicators were short-term mortality (28-day mortality or ICU mortality); secondary indicators were 90-day mortality, duration of mechanical ventilation, the length of ICU stay, total hospitalization time, new infection rate in ICU and incidence of new organ dysfunction in ICU. In the conservative oxygen therapy group, the aim of pulse oxygen saturation (SpO2) was 0.90-0.92 or the arterial partial oxygen pressure (PaO2) was 70-100 mmHg (1 mmHg = 0.133 kPa), while in conventional oxygen therapy group SpO2 > 0.96 or PaO2 > 150 mmHg. Literature search, quality evaluation and data extraction was conducted independently by the two authors. The quality of these study was evaluated using Cochrane risk deviation assessment tool, and the relevant data were analyzed using RevMan 5.3 software. Four studies were included in the analysis, these studies were assessed as moderate to high quality studies. A total of 1 076 patients were enrolled, with 539 in the conservative oxygen therapy group and 537 in the conventional oxygen therapy group. Compared with conventional oxygen therapy group, short-term mortality [odds ratio (OR) = 0.66, 95% confidence interval (95%CI) = 0.50-0.87, P = 0.003] and the incidence of new organ dysfunction in ICU (OR = 0.64, 95%CI = 0.41-0.99, P = 0.04) were significantly decreased in conservative oxygen therapy group, duration of mechanical ventilation was significantly prolonged [standardized mean difference (SMD) = 17.17, 95%CI = 7.14-27.21, P = 0.000 8]. But there was no significantly difference in 90-day mortality (OR = 0.83, 95%CI = 0.59-1.17, P = 0.28), new infection rate in ICU (OR = 0.90, 95%CI = 0.66-1.21, P = 0.47), the length of ICU stay (SMD = -0.22, 95%CI = -1.02-0.59, P = 0.60) and total hospitalization time (SMD = 1.44, 95%CI = -1.43-4.31, P = 0.32) between the two groups. Compared with conventional oxygen therapy, conservative oxygen therapy can reduce short-term mortality and the incidence of organ dysfunction in critically ill patients, but cannot decrease the length of ICU stay and total hospitalization time.