Cardiovascular effects of caffeine therapy in preterm infants
F. J. Walther, R. Erickson and M. E. Sims
Department of Pediatrics, University of Southern California School of Medicine, Los Angeles 90059.
Theophylline therapy increases left ventricular output in preterm infants
by a combination of positive inotropic and chronotropic effects. The
cardiovascular effects of caffeine were evaluated in 20 clinically stable
preterm infants. Ten infants received intravenous caffeine citrate with a
loading dose of 20 mg/kg and a maintenance dose of 5 mg/kg every 24 hours,
and 10 infants were control subjects. Left ventricular output, stroke
volume, and heart rate were measured by using a combination of
two-dimensional and pulsed Doppler echocardiography and mean arterial blood
pressure by oscillometry (Dinamap, Critikon, Division of McNeil
Laboratories, Irvine, Calif) before the start and on days 1, 2, 3, and 7 of
caffeine therapy and 7 days after discontinuation of therapy. Compared with
controls, left ventricular output and stroke volume were significantly
increased on days 1 to 7 of caffeine therapy. Caffeine led to an increase
in the mean arterial blood pressure on the first 3 days of therapy, but the
heart rate did not change. These data indicated that caffeine
administration leads to a significant increase in left ventricular output
in preterm infants and that this inotropic effect is accompanied by a
pressor effect.
