Hypoxemia refers to low blood oxygen levels, while hypoxia denotes low tissue oxygen levels. Both conditions pose life-threatening risks when precautions are not adequately taken or when risks are not effectively managed. Intubation represents a critical phase that can lead to a decrease in arterial oxyhemoglobin levels. Two frequently employed techniques for preoxygenation and ventilation during intubation are bag-valve mask (BVM) ventilation and noninvasive mechanical ventilation (NIMV). The aim of this study was to evaluate the efficacy and safety of BMV and the NIMV.

Ventilation and intubation challenges increase the risk of arterial desaturation, emphasizing the importance of careful management during this process. Throughout the intubation process, the oxygen reserves within the lung, plasma, hemoglobin, body mass index (BMI) play a critical role in meeting the tissue oxygen demand. Preoxygenation serves to extend the time window for intubation safely. The quantity of available oxygen reserve and the duration of the apneic period represent the primary determinants for the occurrence of hypoxemia during intubation.

Anticipating difficult intubation is crucial, as it often prolongs both the duration of intubation and the apneic period. The Intubation Difficulty Scale (IDS) is commonly utilized to predict the likelihood of encountering difficult intubation scenarios. It is imperative to select the appropriate preoxygenation technique, particularly in patients with a high IDS, to mitigate the risk of desaturation during the intubation process.

Two frequently employed techniques for preoxygenation and ventilation during intubation are BVM ventilation and NIMV. Preoxygenation, also referred to as denitrogenation, has the potential to induce atelectasis. However, this complication can be mitigated with positive pressure ventilation (PPV), which not only aids in maintaining oxygen levels but also exerts effects on the circulatory system. Hypotension is the most common symptom that occurs as a result of the interaction of the respiratory and circulatory systems.

The objective of this study was to evaluate and compare the impacts of preoxygenation with BVM and NIMV techniques on oxygenation and hemodynamic parameters specifically during the apneic period of endotracheal intubation.

Inclusion Criteria:

• Aged over 18 years
• Having a partial arterial oxygen pressure (PaO2)/fraction of inspired oxygen (FiO2) ratio exceeding 200
• Consented to participate

Exclusion Criteria:

• Patients with an American Society of Anesthesiologists (ASA) Physical Status Classification System Score 4
• Patients with a Mallampati Score greater than 3
• Patients with a history of difficult intubation
• Patients who are pregnancy
• Patients who have hypoxia (defined as a PaO2/FiO2 ratio less than 200)
• Patients with heart failure
• Patients with chronic obstructive pulmonary disease
• Patients who undergoing emergency surgeries