Objective: To systematically evaluate the effect of high-flow nasal cannula oxygen (HFNC) on improving the atelectasis and respiratory function in adults after cardiac surgeries.
Methods: All randomized controlled trials (RCTs) about HFNC therapy for adults after cardiac surgeries published from January 2000 to March 2018 were searched through CNKI, CBM, VIP, Wanfang, PubMed, Springer Link, Embase, Web of Science, Cochrane Library. The references from relevant articles were searched. The experimental group was treated with HFNC while the control group treated with conventional oxygen therapy (COT). The outcome measurements included radiological atelectasis score (RAS), endotracheal reintubation rate and the length of intensive care unit (ICU) stay. Two researchers were responsible for literature screening, data extraction and quality evaluation respectively. Meta-analysis was performed with RevMan 5.2 software. Funnel plot was used to analyze the publication bias.
Results: A total of 4 RCTs were enrolled and 643 patients were included (325 in experimental group and 318 in control group). Meta-analysis showed that the tracheal reintubation rate in experimental group was lower than that in control group [odds ratio (OR) = 0.26, 95% confidence interval (95%CI) = 0.09-0.74, P = 0.01], but there was no significant difference in RAS [mean difference (MD) = -0.15, 95%CI = -0.50-0.21, P = 0.41] and the length of ICU stay (MD = 0.09, 95%CI = -0.09-0.26, P = 0.33) between experimental group and control group. Sensitivity analysis was performed in two trials with low risk of bias, which demonstrated that there was no significant difference in RAS between the two groups (MD = 0.06, 95%CI = -0.26-0.37, P = 0.73). It was shown by the funnel analysis that there was bias in the study of the length of ICU stay in the literature, while the bias of RAS and tracheal reintubation rate was low.
Conclusions: Compared with COT, HFNC could reduce the rate of tracheal reintubation in adults after cardiac surgeries, but no difference was found in improving atelectasis or reducing the length of ICU stay.