A premature infant is born with a patent ductus aeriosus. Its closure can be stimulated by administration of-

Ans. is 'd' i.e. Prostaglandin inhibitors Management of PDA o After bih ductus arieriosus constricts within a few hours producing functional closure. o Permanent anatomic closure follows in the next 10-21 days due to extensive intimal thickening. o The mechanism producing the initial constriction is not completely understood, but the increase in aerial 02 tension plays an impoant role. o One more factor which helps in closure of the ductus aeriosus is the decrease in concentration of prostaglandins at the time of bih o In the intrauterine period the concentration of prostaglandin PGF2 a is very high. This prostaglandin has a vasodilatory effect which keeps the ductus open. o The synthesis of these vasodilator is inhibited at bih by the inhibition of the enzyme cycloxygenase at bih. o Cycloxygenase is an impoant enzyme in the synthetic pathway of prostaglandin. o In many premature infants the ductus fail to close spontaneously. In these cases the closure can be produced by infusion of drugs that inhibit cyclooxygenase. o Indomethacin is a potent inhibitor of prostaglandin synthesis. It inhibits prostaglandin synthesis by inhibiting the enzyme cvclooxvgenase. o Indomethacin is routinely used to close the PDA in premature infants, it does not close the PDA of full term infants or children. The success of indomethacin therapy is as high as 80-90% in premature infants with bih weight over 1200 g. o If indomethacin is not successful and the ductus remains hemodynamically significant, surgical ligation should be performed without hesitation. o Recent studies from Europe indicate that ibuprofen may be as effective as indomethacin for the medical closure of preterm PDA.