Preoxygenation is a critical step in the preparation for procedures such as intubation and surgery, where patients may experience periods of decreased oxygenation. The goal of preoxygenation is to maximize the oxygen reserves in the patient's lungs before the procedure begins, in order to prevent hypoxemia (low oxygen levels) during the procedure and minimize the risk of complications. Various techniques can be used for preoxygenation, such as providing high-flow oxygen to the patient through a mask, using positive pressure ventilation, or using non-invasive ventilation methods. The effectiveness of preoxygenation can vary depending on the patient's underlying health conditions and the specific procedure being performed. Overall, preoxygenation is a crucial step in ensuring patient safety during procedures that may compromise their respiratory function, and research in this area focuses on identifying optimal techniques and strategies to achieve adequate oxygen reserves in patients before such procedures.