High-flow versus conventional nasal cannula oxygen supplementation therapy and risk of hypoxia in gastrointestinal endoscopies: Α systematic review and meta-analysis.

BACKGROUND AND AIMS Gastrointestinal endoscopy (GIE) represents a mainstay diagnostic and therapeutic procedure in modern clinical practice. Hypoxemia and respiratory failure during endoscopy constitute major complications and concerns for endoscopists. Emerging evidence supports the utilization of high-flow nasal cannula (HFNC) over conventional nasal cannula (CNC) for oxygen supplementation and avoidance of hypoxemia. Aim of our study was to compare the risk of hypoxemia in patients undergoing GIE with HFNC versus CNC oxygen supplementation recruited by randomized controlled trials (RCTs). METHODS We conducted an electronic literature search in established medical databases i.e. PubMed, EMBASE and Cochrane to identify RCTs investigating the abovementioned association. The enrolled studies were evaluated for risk of bias and inserted into a random effects model for meta-analysis; sub-group analyses and publication bias were also assessed. RESULTS Out of 271 initially retrieved articles, five RCTs were eligible for meta-analysis with totally 2656 recruited patients (1299 HFNC and 1357 CNC). A statistically significant reduced relative risk (RR) of hypoxemia among HFNC patients was revealed (RR=0.18, CI95%: 0.05-0.61), whilst with high heterogeneity (I2:79.94%, p<0.01). Patients undergoing upper GIE with HFNC displayed a significantly lower risk of hypoxemia (96%, p