amnion. the innermost fetal membrane, which forms a sac filled with amniotic fluid that surrounds the embryo and later the fetus; as it enlarges it gradually obliterates the chorionic cavity and enfolds the umbilical cord. Called also bag of waters.
cluster breathing. cluster breathing. a breathing pattern in which a closely grouped series of respirations is followed by apnea. The activity is associated with a lesion in the lower pontine region of the brainstem. See also Biot's respiration, Cheyne-Stokes respiration.
High Oxygen Flow Rates for Cluster Headache. Use of oxygen therapy in cluster headache patients. Cluster headache patients require effective abortive therapy due to the extreme intensity of their pain. The two most effective cluster abortives are injectable sumatriptan and inhaled oxygen.