This study was a retrospective analysis of prospectively collected data on all live newborn infants with birth weights in the range of 400 to 1500 g who required life support immediately after birth and who were admitted to the neonatal intensive care unit (NICU) at the King Faisal Specialist Hospital and Research Centre, from January 2006 to December 2008. Infants were identified through the NICU database and then followed by a careful review of their medical records to obtain the required data. Demographic data included maternal history, maternal age, parity, use of antenatal steroids, gestational age, birth weight, sex, mode of delivery, Apgar score, as well as need for resuscitation, mechanical ventilation, and surfactant administration.
Complications of prematurity included intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), RDS, pneumothorax, PDA, NEC, spontaneous intestinal perforation, ROP, BPD, sepsis, and surgical intervention during NICU admission. The study was approved by the Research Advisory Council of King Faisal Specialist Hospital and Research Centre.
Gestational age was determined from the date of the mother's last menstrual period and/or from details of earliest available ultrasound scans (at least before 20 weeks). Immediate life support was defined as administration of respiratory support to infants immediately after birth; this support included suctioning, oxygen supply, continuous positive airway pressure, endotracheal intubation, mechanical ventilation, and surfactant therapy when appropriate. Small for gestational age was defined as birth weight below the 10th percentile for age, based on the United States Vital Statistics natality data sets for 2001 and 2002.20
IVH was detected routinely by head ultrasound performed during the first 4 weeks of life, and IVH was graded according to Papile's classification, from 0 to 4.21
If multiple ultrasounds were done in the first 4 weeks, then the worst grade was recorded. PVL refers to periventricular echogenecity detected on head ultrasound done at any time during the NICU stay. RDS was considered to be present if the infant needed supplemental oxygen and a chest radiograph was consistent with RDS. Pneumothorax was considered to be present if the infant had extrapleural air diagnosed by chest radiograph or needle aspiration. PDA was considered to be present if it was detected by echocardiography with evidence of left-to-right shunting. NEC was diagnosed clinically with abdominal distension and intolerance to food or bloody stool, in addition to an abdominal radiograph showing pneumatosis intestinalis, pneumoperitoneum, or gas in the biliary tree.22
Bell classifications were used for staging.23
Spontaneous intestinal perforation refers to gut perforation without NEC. In case of ROP, only the worst grade of ROP detected on retinal exam was recorded utilizing the International Classification of ROP.24
BPD was defined as requiring oxygen at 36 weeks corrected age, with total oxygen duration of 28 days or more.25,26
Sepsis was considered if a blood culture or a cerebrospinal fluid culture was positive with a bacterial pathogen.
Outcomes that included complications of prematurity, were assessed by descriptive analysis. Continuous variables are summarized by median and range; categorical variables are summarized as frequency and percentages.
The results were compared with data from the NICHD Neonatal Research Network published in 20075
after obtaining permission from the authors and the publisher. The NICHD data included short-term outcome data of infants weighing 501 to 1500 g who were born from January 1990 through December 2002 at 16 participating centers of the NICHD Neonatal Research Network. To facilitate the comparison, a range was created for our data by adding and subtracting the standard error.