Nutritional status and its relationship with infection-related complications in children after cardiac surgery

Abstract

There is little high-quality evidence investigating the relationship between preoperative nutritional status and clinical outcomes in children. Children with congenital heart disease are reported to be at increased nutritional risk. As healthcare associated infection, specifically surgical site infection (SSI), is a common postoperative complication, nutritional status prior to surgery may be one of few modifiable risk factors open to intervention in this patient group.
In this thesis, three interlinked studies explored links between nutritional status, with an emphasis on undernutrition, and postoperative infection-related complications in children after cardiac surgery. Firstly, existing evidence of this relationship following surgery in children < 18 years was systematically reviewed: 12 low-quality studies suggested a tentative association between undernutrition and postoperative infection-related complications, but lack of evidence on SSI.
A retrospective cohort study of 666 children undergoing cardiac surgery then explored whether undernutrition at time of surgery (weight-for-age z-scores (WAZ) less than two standard deviations below mean) was an independent risk factor for SSI. No relationship between undernutrition and SSI was found but neonatal age, preoperative Staphylococcus aureus carriage (OR 1.88, CI 1.01 – 3.07) and third or more cardiac reoperation (OR 5.41, CI 1.30 – 22.56) were independent risk factors. Furthermore, neonates who experienced the highest SSI rates, had low incidence of undernutrition. Consequently, a case study of 19 neonates explored postoperative feeding patterns and postoperative complications, including infection, during hospitalization following cardiac surgery. Four feeding patterns were identified. Those with more interrupted feeding patterns had more infections but less SSI and increased length of stay.
In conclusion, Staphylococcus aureus carriage should be targeted prior to surgery and during subsequent hospitalisation. There should be more research undertaken on the role of postoperative feeding in improving outcomes following neonatal cardiac surgery. Current methods of measuring SSI do not take into account competing risks from other infections potentially leading to erroneous conclusions about surgical performance.