Russian to English Medical Medical: Health Care Medical questionnaire

There isn't much context to go on here. These acronyms are from instructions for a patient to follow in completing a calendar. The purpose is to assess the patient's alcohol use. Here are the acronyms I'm having trouble with. I'm not sure any of the expansions I found are correct — they don't seem to be something a patient would know about.

I'll ask about one at a time:

ВСК – Multitran glosses this as "время свёртывания крови.
or "blood clotting/coagulation time," (BCT)
ПОН – I found "полиорганная недостаточность," or "multiple organ dysfunction syndrome" (MODS) for this one.
ВТР – ?
СРД – I found "вариабельность сердечного ритма," or "heart rhythm variability" (HRV)
ЧТВ – I found "частное тромбопластиновое время, "partial thromboplastin time" (PTT)
ПТН – ?
СБТ – ?
СЕН – ?