Nitrogenous content in parenteral nutrition: a four-year experience in a general hospital. Critically-ill patient specificity

Introduction: There have been several studies focusing on caloric intake during the last years, while protein content relevance has been underestimated. Some recent evidence has shown that protein deficiency has also an impact on patient outcomes. We have studied the nitrogen (N) content in parenteral nutrition (PN) bags administered to adult patients in a Spanish tertiary level hospital for four years. Material and methods: Patients who received parenteral nutrition in the general ward and Intensive Care Unit (ICU) were recorded. Caloric and protein content were registered and adjusted to weight and length of stay. Data were compared among three group of patients: those in the general ward, those in the ICU and those requiring renal replacement therapy (RRT). The one-factor analysis of variance (ANOVA) test was used after checking data normality and homoscedasticity. Results: There was an increase in the mean g N/stay year after year (p < 0.01) from 14 to 15.5 g, with a decrease in non-protein caloric content (p < 0.001) from 111.6 to 101.8 kcal/g N. The range was established from 4.1 to 32.6 g. PN diets with ≥ 18 g N% ranged from 12.8% (2010) to 19.6% (2013). There were significant differences among the groups when comparing the variable g N/stay (p < 0.0001): 13.5 general ward vs15.9 ICU patients vs17.6 ICU with RRT, also when referring to adjusted weight. Conclusions: According to most recent recommendations nitrogen has been provided in higher amounts than previously, especially in critical care patients with RRT.