Can the Effects of High Flow Nasal Cannula Oxygenation on Postoperative Atelectasis be Evaluated With Lung Ultrasound

In obese patients, lung compliance decreases by 25% and Functional Residual Capacity decreases by about one-third. As they consume about 25% more oxygen than non-obese individuals, postoperative pulmonary complications occur more commonly. POINT (Peri-Operative Insufflatory Nasal Therapy) provides humidified and heated high flow oxygen therapy in perioperative period. High-flow nasal oxygen (HFNO) facilitates oxygenation and ventilation of both the spontaneously breathing and apnoeic patient.High-flow nasal cannula oxygen came to prominence in anaesthesia when it was shown to prolong the time to oxygen desaturation in patients with a difficult airway.

Lung ultrasonography (LUS) has been used more frequently in the diagnosis of pulmonary pathologies than chest radiography. This prospective observational study is to evaluate the effects of high-flow nasal oxygen therapy on atelectasis in the perioperative period by lung ultrasound (LUS) in bariatric surgery patients.

Materials and Methods: Following the Ethics Committee approval and written informe consents, 100 adult bariatric surgery patients are include in this observational study. The patients are randomly distributed into two groups ; High Flow Nasal Cannula Oxygenation(HFNCO) made group(n:50); HFNCO not made group(n:50).

HFNCO is start at a flow rate of 20 L/min with 100% oxygen in the preoperative period. It is titrate up to 50 L/min and increase to 80 L/min under general anesthesia until tracheal intubation. Atelectasis evaluation with lung ultrasound is performe and score in 6 different areas before and after HFNCO.

Pulmonary function tests and blood gas parameters are compared.During the procedure, the patient's blood pressure, heart rate, oxygen saturation, any complications that may develop will be recorded.nduction of anesthesia; difficult airway management, difficult mask and / or difficult intubation incidence, Mallampati scores, the use of one of the difficult intubation techniques during intubation (such as FastTrack, videolaryngoscopy or fiberoptic intubation), perioperative mechanical ventilation parameters (ventilation mode, tidal volume, respiratory frequency, end of tidal CO2 (carbon dioxide) pressure, PEEP usage, SpO2 (saturation oxygen), airway peak pressure, urine volume, arterial blood gas parameters are recorded.Duration of operation, surgical method (laparotomy / laparoscopy), agents used in induction and postoperative analgesia, use of blood, blood product and vasopressor are recorded.

Inclusion criteria

• Above 18 years;
• Patients who have undergone obesity surgery;
• ASA 2-3 patients;
• Patients who have received written informed consent;

Exclusion criteria

• Patients under the age of 18;
• Patients refusing to participate in the study;
• Patients under emergency conditions;
• Earlier laryngeal and tracheal surgery;
• allergies to lidocaine;
• Patients with FEV1 / FVC below 60%