Yes, you're perfectly correct in layman terms.
They will hospitalised you for 1 day before the scheduled test. The
night before the test, they will not allow you to eat after 10pm or
12 Midnight, depending on the time-slot you've received. You will
be required to drink a PEG Solution, which is just clear liquid
with some laxative medication. It will have an awkward taste and
thus you may request for some Orange Syrup to be added (For SGH).
You will be requred to finish a 2L jug filled with it, from 9pm
onwards. After approximately 3 hours, you will start to move your
bowels which is very watery, loose. It will continue for around 10
times or more, depending on your body system. This will clear you
intestine thoroughly.
During the test for lower scope, they will give you light sedation
which makes you slighly drowsy through a drip inserted in your
hand. The doctors will insert the scope lens into your anus with
lubrication, nevertheless, it's painful in the process and when the
scope lens is in your intestine, you will feel the movement and
it's scary and slightly painful as the sedation relieve some of the
pain. For some people, before they could remove the scope lens, you
might already have been sedated fully.
They will have to observe you for approximately 2 hours, in which
during this time, you will definately fart alot and at times, some
liquid or lubrication will be passed out. You will feel slight pain
at the site for around 1 - 2 days. Light pain-killers might do the
job.
*These are personal experiences. For accuracies, check with
professionals.*
