A Study Of The Prevalence And Clinical Correlates Of Haemodynamically Significant Patent Ductus Arteriosus In Low Birth Weight Preterm Infants At The Kenyatta National Hospital
Background: Haemodynamically significant patent ductus arteriosus (hsPDA) is a common condition in preterm infants and is associated with considerable morbidity and mortality. Although amenable to both medical and surgical treatment, a limited number of patients are treated at KNH because of under diagnosis in the absence of routine timed echocardiography for preterm infants. At the KNH-NBU, preterm infants who undergo echocardiographic evaluation for PDA are selected based on presence of suggestive clinical signs. The prevalence of hsPDA at the unit is therefore not known. Objective: To determine the prevalence of haemodynamically significant PDA and its clinical correlates among low birth weight preterm infants. Design: cross sectional descriptive study. Setting: The newborn unit of the Kenyatta National Hospital Methods: Over a three-month period 156 consecutive eligible low birth weight preterm infants aged at least 3 days were recruited into the study. A perinatal history was taken and physical examination done to determine the presence of tachypnea, chest indrawing, and tachycardia, bounding pulses, hyperactive precordium, murmur and hepatomegaly. Echocardiographic evaluation was subsequently done to determine the presence of hsPDA. A haemodynamically significant patent ductus arteriosus (hsPDA) was considered present if a PDAwas associated with a LA: AO ratio of > 1.5: 1. Those with hsPDA were compared to those without hsPDAwith regard to clinical correlates. Results: Eighty-one (51.9%) preterm infants had a PDA diagnosed by echocardiography. Thirty of those infants with PDA had LA: AO ratio of > 1.5: 1 giving a prevalence of hsPDA among low birth weight preterm infants of 19.2%. The male to female ratio was 1.5: 1, mean birth weight 1635 (1233-2047) g, mean gestational age 31.5 (29.3-33.7) weeks and median postnatal age of 5 days (IQR 4-11). Of the 30 infants with hsPDA, 10 (33.3%) had clinically diagnosed PDA. Clinical signs had low positive predictive values with the most predictive signs being hyperactive precordium 46.2%, murmur (systolic or continuous) 43.8% and bounding peripheral pulses, 40.5%. Conclusion: The echocadiographic prevalence of hsPDA was 19.2% with only a third of these diagnosed clinically. Therefore, although haemodynamically significant PDA is common in this unit, reliance on clinical signs alone leads to underdiagnosis. Improved availability and utilization of echocardiography in the unit will enhance the diagnosis and management of patients with hsPDA.