Malnutrition is the main reason for infants and children mortality throughout the world [21, 22], and it is directly responsible for approximately 300,000 childhood deaths per year . Nutritional deficiency also increases the risk of mortality in an intensive care population. Protein-energy malnutrition significantly affects the human physiology and these effects include cardiac, renal, hepatic function, humoral, and cellular immunity . Gastrointestinal intolerance is frequently observed in critically ill children who receive insufficient calories and proteins. In addition to that, there is a restriction to fluid intake, and interruptions in enteral nutrition in order to administer medications resulting in a further decrease in protein and calories intake . In our sample population, we recognized 9.7% incidence of GERD and constipation in 12.7%.
Vaidyanathan et al. reported a prospective observational cohort that included 476 patients with CHD less than 16 months old who underwent cardiac surgery. Fifty-nine percent (weight), 26.3% (height), and 55.9% (weight/height) of patients had Z-scores of ≤ –2 at presentation, Z-scores of ≤–3 for weight, height, and weight/height were observed in 27.7%, 10.1%, and 24.2% patients, respectively. Three months follow-up post cardiac surgery showed statistically significant improvement in all parameters of weight P < 0.001, height P 0.04, weight/height and in-hospital mortality of 2.7% . Ratanachu-ek et al. conducted a prospective cohort study in 161 pediatric patients with CHD who underwent cardiac surgery. The nutritional status of the patients before surgery was defined as normal 57%, malnutrition 40%, and over-nutrition 3%. Malnutrition included underweight 28%, wasting 22%, and stunting 16%. Post-cardiac surgery, the means of Z-score of weight for age (WFA), weight for height (WFH), and height for age (HFA) were significantly increased and the prevalence of underweight and wasting were decreased to 17% and 6% respectively, which was statistically significant compared to the baseline (p < 0.05) . In our current study, we have 32.4% of the patients suffered from severe malnutrition pre-admission; the abnormality of weight and height of less than 5% of the sample were 48.2% and 36.3% respectively. Lower weight-for-age and weight-for-height have been reported to be associated with poor outcomes in pediatric critical care; these results correlate with our findings of increased risk of infection in patients who were kept NPO for long time, ventilation time, increased ICU LOS, and even risk of mortality. Okoromah and colleagues reported a 41% prevalence of “wasting” defined by WHO as weight-for-height Z score <−2. Among pediatric cardiac patients with CHD in Lagos, Nigeria, malnutrition has been linked to increased morbidity and mortality, as indicated by frequent hospitalization, poor surgical outcomes, persistent impairment of somatic growth, and increased mortality . Monique Radman et al. concluded in their study that there is a strong correlation between acute and chronic malnourishment and worse clinical outcomes post-cardiac repair in children undergoing surgery for CHD, specifically the ICU length of stay and the ventilation time, these findings strongly correlate with our findings in the current study . PNI is one of the reliable tools to assess the nutritional status of pediatric patients in the perioperative period. In our present study, PNI was significantly correlating with the ventilation time, and the PICU LOS; these results are correlating with Wakita and his colleagues who concluded in their study that preoperative PNI score is a predictor of the length of stay in the PICU for pediatric patients after cardiac surgery; patients with low PNI score had PICU stay 5 days more than patients with high PNI score. A cut-off point of 55 for the PNI score proved to be a reliable predictor which is the same cut-off point we used and confirmed the strong correlation with ICU length of stay and ventilation time . Buzby et al. proved in their PNI using albumin level, triceps skinfold thickness, serum transferrin level, and cutaneous delayed hypersensitivity reactivity predicts incidence of postoperative infectious complications, septicemia, and mortality, but this study was in adults , in our current study using the Onodera’s PNI we could not prove any correlation of PNI with the risk of infection. The relation between optimal delivery of enteral nutrition and clinical outcomes, including mortality, has been well described in multiple studies [29, 30], Manoj et al. demonstrated in their study the feasibility of early enteral nutrition for patients with congenital cardiac malformations, postoperatively with mother’s milk. Providing fortification in the form of a calorie dense expressed breast milk to these infants is tolerated and also benefits in better postoperative recovery with less incidence of infection and shorter ICU stay . In the current study, it was very obvious that patients who were kept NPO longer suffered more severe malnutrition, and there was a strong correlation between the NPO duration and the inadequate intake expressed as RDA less than 50% with the incidence of infection, ventilation duration, and postoperative mortality. Our study has many limitations that include single center experience. Also, late referral of some of our patients could have affected negatively their nutritional status and the results of our study. Furthermore, due to many confounding factors that include type of surgery, complexity of surgery, bypass time, presence of residual lesions, feeding tolerance, and difficulty to adapt a uniform pattern in initiating feeding in postoperative cardiac children that may affect the study result and conclusion. Though we attempt to introduce enteral feeding in majority of our cases as early as possible, on many occasions the feeding had to be interrupted or replaced with parenteral feeding in children with complex cardiac surgery or in neonates and small infants who frequently suffer from feeding intolerance or other complication such as necrotizing enterocolitis or chylothorax that can affect their ability to absorb or to be fed through normal gastrointestinal tract. We believe that multi-center with nutritional protocol-based study is recommended to minimize bias and limitation of small number of cases in single center study. Also, such multi-center study will verify the discriminatory PNI 55 finding that we proposed in our study based on analysis of our group of patients.