Which rule regarding positional asphyxia is essential for ensuring lung expansion?

The essential rule regarding positional asphyxia that focuses on ensuring lung expansion is allowing for lung expansion. When an individual is in a position that restricts their ability to breathe easily, such as being face down or in a position that compresses the chest, it can lead to serious respiratory issues. Ensuring that there is adequate space for the lungs to expand is crucial for maintaining oxygen flow and avoiding asphyxia, which can be life-threatening.

This means that any intervention should prioritize the individual’s ability to take deep breaths and not restrict their thoracic movement. Proper positioning, along with monitoring the person's respiratory status, becomes vital in avoiding complications like positional asphyxia, especially during restraint situations.

Other options, although relevant to the safe management of an individual, focus on specific actions or techniques that may also contribute to preventing positional asphyxia but do not directly address the core principle of enabling lung expansion during restraint.