During surgery, right after anesthesia is given, the first step to help the patient breathe is to provide breathing support with a mask. This step is very important because if there is a problem with mask ventilation, the anesthesia team must quickly use other methods to help the patient breathe.

For some people, mask ventilation can be more difficult. Factors such as older age, having a beard, missing teeth, being overweight, sleep apnea, or certain facial shapes can make this process harder.

To make mask ventilation easier, special devices placed in the mouth are used. The most common one is called the Guedel airway. In recent years, a new device called the Tulip airway has also been introduced. The shape and features of the Tulip airway are designed to make breathing support easier.

In this study, we will compare the Tulip airway and the Guedel airway in patients who are expected to have more difficult mask ventilation. Our goal is to find out which device makes it easier and safer to help patients breathe.

The first step in airway management following anesthesia induction is the period of bag-mask ventilation. This step is the most critical phase of airway management because, if mask ventilation fails, the anesthesiologist must make a life-saving decision for the patient. Bag-mask ventilation is a technical skill acquired over time; therefore, difficulty in mask ventilation may be related to either the provider or the patient. According to the literature, the incidence of difficult mask ventilation varies between 0.08% and 15% in different studies.

The American Society of Anesthesiologists (ASA) defines difficult mask ventilation as inadequate mask or supraglottic airway (SGA) ventilation, excessive air leakage, or excessive resistance to airflow during inspiration or expiration. Signs of inadequate ventilation include, but are not limited to, absent or insufficient chest movement, absent or diminished breath sounds, auscultatory signs of severe obstruction, cyanosis, gastric insufflation or distension, decreased or inadequate oxygen saturation (SpO₂), absence or inadequacy of end-tidal carbon dioxide (EtCO₂), absence or inadequacy of expiratory gas flow on spirometry, and hemodynamic changes associated with hypoxemia or hypercarbia (e.g., hypertension, tachycardia, arrhythmia).

Predictors of difficult mask ventilation include age over 55 years, the presence of a beard, poor mask fit due to secretions, edentulism, a history of snoring or obstructive sleep apnea syndrome (OSAS), and obesity. In anesthesia practice, when faced with difficult mask ventilation, various maneuvers, two-hand techniques, and adjunct airway devices are employed. Among these devices are various oral airways, the most common of which is the Guedel airway.

In recent years, new oral airway devices have been introduced as alternatives to the Guedel airway. The Tulip airway is a novel oral airway that is longer than the Guedel airway, equipped with a cuff, and features a connector that allows attachment to the breathing circuit. These characteristics enable it to be secured within the oral cavity via its cuff, and connection to the breathing circuit allows for airway management that may be more comfortable for the anesthesiologist compared to two-handed mask control.

The superiority of the Tulip airway over the Guedel airway has been demonstrated in patients with cervical spine injury, in edentulous manikins, and in patients undergoing general anesthesia. However, it has not been studied in patients with anticipated difficult mask ventilation. The aim of our study is to investigate whether the Tulip airway provides superior performance to the classical Guedel airway during the mask ventilation phase in patients with anticipated difficult mask ventilation. We hypothesize that the use of the Tulip airway in such patients will improve respiratory parameters and reduce the risk of complications during mask ventilation.

Inclusion Criteria:

• Patients aged between 18 and 75 years
• Patients scheduled for elective surgery under general anesthesia
• Patients with at least two risk factors for difficult mask ventilation, including:
• Age over 55 years
• Presence of beard
• Edentulism (missing teeth)
• Obesity (Body Mass Index (BMI) ≥ 30 kg/m²)
• History of obstructive sleep apnea syndrome (OSAS) or snoring
• Neck circumference > 43 cm
• Retrognathia (small jaw structure)
• Patients classified as American Society of Anesthesiologist (ASA) physical status 1, 2, or 3
• Patients who provide informed consent

Exclusion Criteria:

• Pregnant or breastfeeding women
• Patients with a history of airway surgery (e.g., tracheostomy, maxillofacial surgery)
• Patients with severe cardiopulmonary diseases (e.g., advanced Chronic obstructive Pulmonary Disease (COPD), pulmonary hypertension, severe heart failure)
• Patients with craniofacial anomalies or significant anatomical airway deformities
• Patients requiring emergency surgery
• Patients with gastroesophageal reflux disease (GERD) and high risk of aspiration
• Patients with active upper respiratory tract infection
• Patients with a history of difficult intubation

Individual participant data (IPD) underlying the findings of this study will be available upon reasonable request from qualified researchers, after de-identification, beginning 6 months following publication and ending 5 years later. Data will be shared for academic purposes with appropriate ethical approval and a signed data access agreement."