A total of 574 patients scheduled for gastroscopy under
intravenous anesthesia were enrolled and randomly assigned to receive either a nasal mask or a traditional
nasal cannula for oxygenation. The primary outcome was the incidence of
hypoxemia. The secondary outcomes included the incidence of severe
hypoxemia, duration of
hypoxemia, minimum oxygen saturation, the proportion of emergency
airway management, length of procedure, recovery time, and the satisfaction of the anesthetist and gastroenterologists as well as other adverse events (including
cough,
hiccups,
nausea and
vomiting, reflux, aspiration, and
laryngospasm).
RESULTS: A total of 565 patients were included in the analysis: 282 patients in the
nasal cannula group and 283 patients in the nasal mask group. The incidence of
hypoxemia was lower in the nasal mask group (18.0%) than in the
nasal cannula group (27.7%; relative risk [RR] = 0.65; 95% confidence interval [CI], 0.48-0.89; P = .006), and the
hypoxemia lasted a median of 18.0 seconds (interquartile range, 10.0-38.8) in the nasal mask group and 32.5 seconds (20.0-53.5) in the
nasal cannula group (median difference -14.50; 95% CI, -22.82 to -1.34; P = .047). The proportion of patients requiring emergency
airway management was significantly lower in the nasal mask group (8.8%) than in the
nasal cannula group (19.1%; RR, 0.46; 95% CI, 0.30-0.73; P < .001). No difference was found in the overall incidence of other adverse events between the 2 groups (nasal mask 20.8%;
nasal cannula 17.0%; RR, 1.23; 95% CI, 0.87-1.73; P = .25). Satisfaction was higher with the nasal mask than with the
nasal cannula from the perspective of anesthetists (96.1% for nasal mask versus 84.4% for
nasal cannula; RR, 1.14; 95% CI, 1.08-1.20; P < .001) and gastroenterologists (95.4% for mask versus 81.9% for
cannula; RR, 1.17; 95% CI, 1.10-1.24; P < .001). There were no significant differences in the incidence of severe
hypoxemia, minimum oxygen saturation, length of procedure, or recovery time between the 2 groups.
CONCLUSIONS: