The ductus arteriosus remains patent beyond 3 days after birth in up to 60% of very preterm infants. Treatments to close a patent ductus arteriosus (PDA) are medications such as indomethacin or surgical ligation. Vocal cord injury (VCI) is a known complication of PDA ligation, and may lead to difficulties with feeding, breathing, speech and achievement of developmental milestones. The true incidence of vocal cord injury and the relationships between vocal cord injury and outcomes in very preterm infants are unknown.
Hypothesis and Aims
We hypothesized that the incidence of VCI after PDA ligation in very preterm infants is at least 40%. Further, we hypothesized that a rigorous, long-term multicenter evaluation of VCI is both feasible and necessary. Therefore, we launched a pilot cohort study with the following aims:
Specific Aim 1: To estimate the incidence and describe the natural history of VCI after PDA ligation.
Specific Aim 2: To evaluate between-center variation in the incidence of VCI after PDA ligation.
Specific Aim 3: To demonstrate the feasibility of a large multicenter study of the incidence and consequences of VCI after PDA ligation in very preterm infants.
This pilot study will generate data essential for the design of a larger multicenter study in which we will test the hypothesis that VCI increases risk for neurodevelopmental impairment at 24 months of age.
In this multicenter prospective cohort study, flexible nasal laryngoscopy, the gold standard method for diagnosis of VCI, will be performed by an experienced otorhinolaryngologist (ENT) within one week after the first post-ligation extubation. The safety of this intervention has been demonstrated in several recent single center studies. All patients will undergo routine neonatal follow-up until 24 months corrected age. Patients with VCI will be followed by ENT until 24 months or res