The effect of oxygen application via double nasal cannula on respiratory complications in gastrointestinal endoscopies

Objective: In our study, we aimed to investigate the effect of oxygen therapy with double nasal cannula on desaturation and respiratory complications in patients scheduled for gastrointestinal endoscopy. Materials and Methods: After obtaining the written and verbal consent of the faculty ethics committee and the patients, a total of 300 patients aged 18-65 years with ASA I-II who were scheduled for gastrointestinal endoscopy (upper, lower or both) were included in the study. OSA scores were determined preoperatively with the STOP BANG questionnaire. A second nasal cannula oxygen delivery device was available in the intervention room. Following routine monitoring, the patients were randomly divided into 3 groups using the envelope method. Group TK5 (n=100): 5 minutes preoxygenation with nasal oxygen cannula at 5 L/min and 5 L/min oxygen during and after the procedure, Group TK15 (n=100): 5 minutes preoxygenation with nasal oxygen cannula at 15 L/min, 15 L/min oxygen during and after the procedure, Group TK30 (n=100): 5 minutes preoxygenation with nasal oxygen cannula at 30 L/min, 30 L/min oxygen was administered during and after the procedure. Entry saturation and the time until 99-100 saturation were recorded in all patients. Sedation was provided with 1 mg/kg propofol and additional fentanyl 0.5 µg/kg in colonoscopies. These doses were repeated if necessary. Peripheral oxygen saturation falling below 92 was considered desaturation, falling below 90 was considered advanced desaturation, and falling below 85 was considered severe desaturation. In all patients, the duration of endoscopy, duration of sedation, amounts of propofol and fentanyl used, number of desaturation episodes, recovery time of desaturation, side effects such as bradypnoea, hypotension, bradycardia, burning sensation in the nose, and desaturation in the recovery unit were recorded. Results: The incidence of desaturation was statistically significantly lower in GCT15 (7%) and GCT30 (2%) compared to GCT5 (31%) (p<0.05). The incidence of desaturation was not different between GCT30 and GCT15 (p>0.05). Advanced desaturation was not observed in any patient in GCT15 and GCT30, whereas it was observed in 18% in GCT5 group (p<0.05). Severe desaturation was found in 11% of the GTK5 group, whereas there was no severe desaturation in the other groups (p<0.05). Desaturation time was 16±32 sec in GTK5, which was longer than the other groups (3±10 sec, 1±5 sec). Saturation 99 time was 47±24 sec in G15, 35±23 sec in G30 and 72±43 sec shorter than G5 (p<0.05). In GTK30, this period was significantly shorter than in GTK15 (p<0.05). However, 30 % of the patients had a burning sensation in the nose during double nasal cannula oxygen applications (p<0.05). Conclusion: Oxygen administration with a double nasal cannula has similar effectiveness to a single nasal cannula with 15 L flows in preventing respiratory complications in sedation applications for gastrointestinal system endoscopies; we found that respiratory complications were significantly reduced at both flow rates compared to the 5-liter flow rate. We observed that a single cannula of 15 L is better in terms of patient comfort. Keywords: Gastrointestinal endoscopy, sedation, respiratory complications, oxygen administration