Researchers at the University of Texas has found that caffeine is often used to treat and prevent sleep apnea in preterm infants. Sleep apnea is a condition characterized by cessation in breathing and sometimes occurs in premature infants. However, there is a growing concern over caffeine's effects on a baby's circulatory system.
Researchers in Texas analyzed the effects of caffeine on cardiac output, specifically studying the effects on arteries in the brain and intestines. Researchers gave 20 preterm infants an initial dose of 25 milligrams of caffeine over a period of 10 to 15 minutes. They presented various studies to collect data, immediately before doctors administered the dosage as well as one and two hours after the administration. Of these included ultrasound and echocardiograms (EKGs).
They found that blood flow velocity in a major brain artery decreased by 18 percent an hour after caffeine administration and 25 percent after two hours. Within the intestinal arteries, the BFV decreased to 10 percent after an hour, but showed no major changes two hours after caffeine administration. An artery supplying blood through most of the small intestine had a 22 percent decrease in BFV at one hour and a 32 percent decrease at two hours. Researchers also observed blood pressure, heart rate, and left ventricle output, but found no changes.
Thus they conclude an initial dose of 20 milligrams of caffeine reduces BFV in brain and intestinal arteries, while cardiac output remains constant. The decrease in BFV is attributable to vasoconstriction, the constriction of blood vessels leading to reduced blood flow, associated with the caffeine.
Reduction of blood flow to the brain potentially increases the risk of hemorrhage and periventricular leukomalacia, a disease in premature infants characterized by swelling of cerebral blood vessels and tissue death due to lack of oxygen in the brain. Decreased blood flow to the intestines potentially causes inflammation, which can later result in narrowing of the intestinal track.
Based on results, doctors recommend smaller doses of caffeine to treat apnea, rather than larger doses like those used in the study. However, smaller doses may not be sufficient to decrease the number of apneas in infants. If this frequency remains high, doctors recommend a subsequent smaller dose a few hours following the initial administration.