There is a risk of airway-related incidents during anaesthesia associated with obesity. High-flow nasal oxygen is advocated for perioperative preoxygenation in obese patients to reduce airway adverse reactions. However, there have been no reports on whether smoking behaviors have an impact on obese men's Apnoeic oxygenation with high-flow nasal.This study compared the effects of smoking on the duration of safe apnoea times in obese males.

All patients were were divided into two groups based on smoking status: smokers(S groups), and never smokers(NS groups). Those in the smoking group were current smokers, while those in the nonsmoking group had never smoked. Both groups of patients were induced with intravenous anesthesia and received 5 minutes of high flow nasal oxygen (60 L min) prior to induction.After induction of anaesthesia, the patients were apnoeic until peripheral oxygen saturation decreased to 95 %.

Inclusion Criteria:

1. Participants ranged in age from 18 to 80 with BMI≥30 kg/m2.
2. Participants are male obese patients undergoing elective non-thoracic surgery

Exclusion Criteria :

1. patients were kept awake during the intubation due to cervical spine pathology.
2. Patients with unstable hemodynamics.
3. Patients with airway inflammatory diseases, including asthma, chronic obstructive pulmonary disease (COPD), lung cancer, pulmonary fibrosis and cystic fibrosis.
4. Patients with upper respiratory infection and nasal blockage.
5. Patients with Hypersensitivity to the drug.

Male

A total of 60 male obese patients undergoing elective non-thoracic surgery were divided into two groups (n=30) based on smoking status: smokers(S groups), and never smokers(NS groups). Those in the smoking group were current or past smokers, while those in the nonsmoking group had never smoked.