risk factors for post-cardiac surgery diaphragmatic paralysis in children with congenital heart disease

background: injured phrenic nerve secondary to cardiac surgeries is the most common cause of diaphragmatic paralysis (dp) in infants. the aim of this study was to determine the risk factors for dp caused by congenital heart defect corrective surgeries in pediatrics. methods: this cross-sectional study, conducted in a 2-year period (2006 – 2008), included 451 children with congenital heart diseases admitted to the pediatric cardiac surgery ward of imam khomeini hospital. the diaphragmatic function was examined via fluoroscopy, and the frequency of dp and its relevant parameters were evaluated. results : of the 451 patients, comprising 268 males and 183 females at an age range of 3 days to 204 months ( 28.2 ± 33.4 months), 25 (5.5%) infants (60% male and 40% female, age range = 15 days to 132 months, 41.2 ± 28.1 months) had dp as follows: 48% unilateral right-sided and 36% unilateral left-sided. additionally, 68% had cyanotic congenital heart disease and 84% had dp following total correction surgery.  the highest prevalence rates of dp resulting in phrenic hemiparesis were observed after arterial switch operation, fontan procedure, and blalock–taussig shunt surgery, respectively. thirteen (52%) of the 25 dp patients underwent surgical diaphragmatic plication because of severe respiratory distress and dependency on mechanical ventilation, and most of the cases of plication underwent arterial switch operation. the rate of mortality was 24% (6 patients). conclusion: dp with a prevalence of 5.5% was one of the most common complications secondary to cardiac surgeries in the infants included in the present study. effective factors were age, weight, cyanotic congenital heart defects, and previous cardiac surgery. diaphragmatic plication improved prognosis in severe cases.