During suctioning of an intubated patient, oxygen saturation drops suddenly. What should be the immediate nursing action?

Correct option is B

If desaturation occurs during suctioning, the correct step is to stop suction immediately and provide 100% oxygen before resuming if needed.
Explanation of options: (a) ✘ Continuing suction worsens hypoxia. (b) ✔ Correct; stop suction + reoxygenate first. (c) ✘ Increasing suction pressure increases mucosal injury, not oxygenation. (d) ✘ Removing ETT is not indicated unless tube blocked.