Correlation of Conjunctival Oxygen Tension with Carotid Artery Blood Flow During Hemorrhagic Hypotension

The palpebral conjunctiva is a very special tissue. The mucous membrane epithelium overlying the conjunctival capillaries is only two to four cell layers thick with minimum oxygen consumption, and this presents a unique opportunity to measure tissue oxygen tension atraumatically [1]. The transconjunctival oxygen monitor measures tissue oxygen tension, which reflects both the oxygen content of the arterial blood and the regional blood flow. If arterial oxygen content remains constant, then any change in tissue oxygen tension should be secondary to a change in the blood flow to that tissue. The purpose of this study was to examine the relationship between the conjunctival PO2 (PcjO2, in millimeters of mercury) and carotid artery blood flow (CaBF, in millimeters per minute) in the dog during hemorrhagic hypotension.