HOW DO pH INDICATORS WORK? pH indicators detect the presence of H+ and OH-. They do this by reacting with H+ and OH-: they are themselves. weak acids and bases. If an indicator is a weak acid and is coloured and its conjugate base has a different. colour, deprotonation causes a colour change.
Have varicose veins, which are a common cause of superficial thrombophlebitis. Have a pacemaker or have a thin, flexible tube (catheter) in a central vein, for treatment of a medical condition, which may irritate the blood vessel wall and decrease blood flow. Are pregnant or have just given birth.
A thrombus itself (even if it does not completely block the blood vessel) can lead to an embolic stroke (see below) if the thrombus breaks off and travels in the bloodstream, at which point it is called an embolus. Two types of thrombosis can cause stroke: Large vessel disease involves the common and internal carotid arteries, the vertebral artery, and the Circle of Willis.