Plugged Ears--Blackout?

I recently took an extended Caribbean trip where I completed 25 dives.
Looking back, on the first 5 or 6 dives I was concerned that after first beginning my dives and in the process of equalizing my ears I had this sensation of beginning to blackout. On a scale of 1 to 10 with 10 a complete blackout the blackout sensation was about a 4. In looking for an explanation, I know that just before my trip I had been fighting flu/cold symptoms and my ears were plugged up with excess ear wax. After a few dives I bought some over the counter medication to clear my ears.
To the medical experts--Is it possible an ear infection/plugged ears while equalizing can cause someone to blackout?

Unlikely, but the answer is yes. The Valsalva maneuver that some people use to clear their ears increases intrathoracic and intraabdominal pressure. This has a dual effect of reducing venous return to the heart, and activating what is called the vagal reflex, which slows the heart rate. It is possible, if you are one of the people who is particularly sensitive to this effect, to get lightheaded from inadequate blood supply to the brain.

​:doctor: That scientifical explanation made my head spin.

TS&M, is that a zebra or a horse?

chillyinCanada:

TS&M, is that a zebra or a horse?

Click to expand...

A horse of course....