Background and Goal of Study: 
Humidified high flow nasal cannula (HFNC) oxygen therapy delivers an air/oxygen blend with a concentration range between 21% to 100% and generating up to 60 L/min flow rates. Gas flow is humidified, heated (35° to 40°) and delivered to the patients trough a one-way circuit, connected to a large diameter nasal cannula. Aim of the study was to evaluate the effectiveness of Optiflow™ in patients with OSA, who underwent laparoscopic bariatric surgery, in the postoperative period.
Materials and Methods: 
45 mild and moderate OSA patients, with BMI≤ 45 (ASA≤ III) submitted to laparoscopic sleeve gastrectomy, were enrolled. The same intra- and postoperative anesthesiological protocol was administered to all patients: opioid-free anesthesia (OFA), using clonidine as intra-operative analgesic adjuvant and non-steroidal anti-inflammatory drugs (NSAID) for post-operative pain control. Optiflow™ was positioned in the immediate postoperative period and up to 48 hours postoperatively. Oximetry was monitored and recorded in continuous. Blood gas samples were taken at a distance of 1, 6, 12 and 48 h from the intervention. Authors monitored the incidence of hemoglobin saturation below 90% during sleep (T90), the O2 Desaturation Events Index (ODI), and the number of O2 desaturation events per hour of sleep, and hemogasanalytic parameters. In addition, post-operative analgesia was evaluated using 11 points NRS score (0=no pain, 10=maximum pain) and relative comfort for each patient (0=no comfort, 4=optimal comfort). All the patients have given their informed consent to participation in the research study. The study was approved by the Local Ethics Committee. 
Results and Discussion: 
The median duration of intervention was 70 ± 15min, recorded T90 values ≤30% and ODI ≤ 5. Global emogasanalytic parameters (expressed in mean values and standard deviation): PaO2 97.6 ± 10.9 mmHg, PaCO2 = 37.2 ± 5.5 mmHg, SaO2 = 92.5 ± 3.8%, pH 7.45 ± 0.04. The NRS mean values, evaluated at the end of the intervention and at 6-12-24 h, was 1 ± 3. Overall valued comfort using the device was 4 for all 45 patients. 
Conclusions: 
Based on our preliminary results, Optiflow™ was effective in the prevention of hypoxia and in postoperative respiratory complications and outcomes.


08 / Humidified high flow nasal for morbidly obese patients undergoing bariatric surgery: our experience in the prevention of postoperative respiratory complications