الفهرس 
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Abstract
The ductus arteriosus is a large vascular channel connecting the pulmonary trunk to the descending aorta. During fetal life, the ductus arteriosus diverts a major proportion of right ventricular output away from the lungs to the descending aorta Closure of the ductus arteriosus (PDA) is a crucial part of normal circulatory adaptation to extra-uterine. Ductus arteriosus constricts in response to high oxygen level and DROP in circulating or locally produced prostaglandins.
Its persistence after preterm birth is associated with an increased risk of morbidity, including necrotising enterocolitis, bronchopulmonary dysplasia and neurodevelopmental impairment. These morbidity characteristics relate to pulmonary hyperperfusion with steal phenomena from the systemic circulation.
The incidence of Patent Ductus Arteriosus (PDA) in preterm is far greater than full term neonates, with reports ranging from 20%-60%. The increased incidence of PDA in the preterm infant is attributable to the lack of normal closure mechanisms due to immaturity.
Treatment of PDA thus remains one of the most debated topics in neonatal medicine with no consensus on whether to treat, and when and how to treat. Treatment options for PDA include surgical and pharmacological modalities. Conservative management includes fluid restriction and high positive end-expiratory pressure (PEEP) during mechanical ventilation. Restricted fluid regimens and high PEEP are most difficult to follow in extremely low gestational ages. Pharmacological therapy is thus the mainstay for treatment of PDA. Surgical therapy is often used as a last resort for treatment of PDA.
Indomethacin and ibuprofen act by blocking the conversion of arachidonic acid to prostaglandins, and have been adequately studied for ductal closure. However, due to their adverse effects, paracetamol came up into clinical practice as a new and promising treatment option for PDA.
The aim of the present study was evaluate safety and efficacy of early intravenous paracetamol administration as a prophylaxis of hemodynamically significant PDA.
To achieve this goal, 155 preterm infants who fulfilled our inclusion criteria were enrolled in this study. Those preterm infants were randomly divided into two groups: group I (perfalgan group), group II (control group)). Intravenous paracetamol was given for perfalgan group in dose of 15 mg/kg/6h for 5-7 days. The differences among the two study groups in terms of clinical and imaging evidence of PDA, complications of PDA, and side effects of perfalgan prophylactic treatment, were evaluated.
The two groups enrolled in this study were subjected to thorough history taking, full physical examination, laboratory investigations, ABG, chest radiographs, echocardiography, and cranial U/S.
No significant statistical differences regarding the sex, gestational age, birth weight, mode of delivery, maternal intake of antenatal steroid, resuscitation needs, and admission diagnosis were found among the studied groups in our study.
In our study Echocardiogram, the gold standard tool for diagnosis of PDA, was performed onDOL5 and 14.The closure rate was significantly higher in Perfalgan group than the control group on DOL5 and 14(p< .05).
We used 2 sensitive and specific echocardiographic markers for determination of hemodynamicaly significant duct. They were transductal diameter (TDD) and Left atrial to aortic root ratio (LA:Ao). The DA diameter can be related to the infant’s weight, a DA diameter >1.4 mm/kg indicates hs-PDA. In our study there were no statistically significant differences between mean value of TDD and LA /Ao ratio between cases with open ducts in both study groups. However, taking in consideration closed cases, paracetamol significantly affected occurrence of hs PDA.
Relying on clinical signs leads to a mean diagnostic delay of 2 days, with a range of 1 to 4 days. In our study we recorded the clinical signs of PDA including tachycardia (HR>170b/min), murmur, pericardial pulse, bounding pulse, hepatomegaly, frequent apnea, metabolic acidosis and oliguria on DOL1, DOL5-7 and DOL14. The clinical signs were more in cases of control group but the difference did not reach the level of clinical significance except for murmurs. Systolic murmurs on DOL5-7 and DOL 14 were significantly more in control group.
There were no statistically significant differences between the two groups as regard ventilator support, pulmonary hemorrhage, BPD, IVH, PVL, NEC, time to reach full feeds, and renal impairment. This means that prophylactic perfalgan is like ibuprofen and indomethacin at this point as they do increase closure rates but did not improve the secondary outcome of PDA. Logistic regression analysis of factors affecting duct closure revealed that iv paracetamol intake and lack of surfactant administration significantly affected the duct closure.
Finally, Paracetamol, as a prophylactic treatment, proved to be safe and effective in reducing the incidence of Patent ductus arteriosus and hs PDAon Day of life 5 and 14 and consequently the need for rescue treatment with other pharmacotherapy and need for surgical closure. Thus, Paracetamol may be accepted as a prophylactic treatment for PDA in preterm infants However, it did not significantly reduce patent ductus associated morbidities and mortality.