“SOS” commonly means “if needed” or “as required.” So “SOS sleep study” usually means your doctor recommends a sleep study if symptoms or clinical suspicion warrant it, often to check for obstructive sleep apnea.

A sleep study can measure breathing pauses, oxygen level, heart rhythm, snoring, body position, and sometimes brain activity during sleep. It may be done at home or overnight in a sleep lab.

Common reasons include:

Please share the exact sentence from the report, with personal details removed, because “SOS” can be used differently by individual doctors. Seek earlier medical review if you have frequent choking at night, severe daytime drowsiness while driving, or low oxygen readings.