None. Plethysmography is a noninvasive diagnostic manometric study used to measure changes in the size of blood vessels by determining volume changes in the blood vessels of the eye, extremities, and neck or to measure gas volume changes in the lungs.
1. countable noun [usually with poss] A guardian is someone who has been legally appointed to look after the affairs of another person, for example a child or someone who is mentally ill. 2. countable noun. The guardian of something is someone who defends and protects it.
A guardian angel is an angel assigned to protect and guide a particular person, group, kingdom, or country. Belief in guardian angels can be traced throughout all antiquity.The concept of tutelary angels and their hierarchy was extensively developed in Christianity in the 5th century by Pseudo-Dionysius the Areopagite.his guardian angel is not only a friend and a protector, who preserves from evil and who sends good thought; the image of God is reflected in the creature--angels and men--in such a way that angels are celestial prototypes of men.