What are the factors that influence the attainment of satisfactory energy intake in pediatric intensive care unit patients receiving enteral or parenteral nutrition?

ObjectiveChildren admitted to the intensive care unit (ICU) are at risk of inadequate energy intake. Although studies have identified factors contributing to an inadequate energy supply in critically ill children, they did not take into consideration the length of time during which patients received their estimated energy requirements after having achieved a satisfactory energy intake. This study aimed to identify factors associated with the non-attainment of estimated energy requirements and consider the time this energy intake is maintained.MethodsThis was a prospective study involving 207 children hospitalized in the ICU who were receiving enteral and/or parenteral nutrition. The outcome variable studied was whether 90% of the estimated basal metabolic rate was maintained for at least half of the ICU stay (satisfactory energy intake). The exposure variables for outcome were gender, age, diagnosis, use of vasopressors, malnutrition, route of nutritional support, and Pediatric Index of Mortality and Pediatric Logistic Organ Dysfunction scores.ResultsSatisfactory energy intake was attained by 20.8% of the patients, within a mean time of 5.07 ± 2.48 d. In a multivariable analysis, a diagnosis of heart disease (odds ratio 3.62, 95% confidence interval 1.03–12.68, P = 0.045) increased the risk of insufficient energy intake, whereas malnutrition (odds ratio 0.43, 95% confidence interval 0.20–0.92, P = 0.030) and the use of parenteral nutrition (odds ratio 0.34, 95% confidence interval 0.15–0.77, P = 0.001) were protective factors against this outcome.ConclusionA satisfactory energy intake was reached by a small proportion of patients during their ICU stay. Heart disease was an independent risk factor for the non-attainment of satisfactory energy intake, whereas malnutrition and the use of parenteral nutrition were protective factors against this outcome.     

Interleukin-2 and natural killer activity in acute type B hepatitis

Natural killer (NK) cell activity against K562 cell line, and interleukin-2 (IL-2) activity in supernatants from lectin-activated PBMC cultures from 17 patients with acute hepatitis B in the early phase of illness were studied. These patients showed enhanced NK cytotoxicity and higher levels of IL2 activity as compared with control subjects. There was a positive correlation between cytotoxicity values and levels of IL2 activity. Furthermore, in the recovery phase of illness there was a tendency towards normalization in both parameters. When patients were divided in accordance with markers of HBV replication, HBV-DNA positive patients showed increased NK cell activity and IL2 levels as compared with the control group, whereas in HBV-DNA-negative patients no differences were found. However, no differences were found between patients with HBeAg and patients with anti-HBe. These results suggest that natural cytotoxicity is increased early in the course of acute hepatitis B, while NK cell activity returns to normal later, during convalescence. Enhanced NK cell activity appears to be secondary, at least in part, to increased production of IL2. Natural cytotoxicity may be one mechanism that controls the HBV infection before other cytotoxic mechanisms become fully operative.     

Resistance to reinfection in experimental murine schistosomiasis: role of porto-hepatic hemodynamics

Experiments were conducted to evaluate critically, and independently of the immune system, the possible role of hemodynamic mechanisms in resistance to schistosomal reinfection. The effects of a challenge schistosomal infection were compared in groups of mice which were either previously infected with schistosomiasis, vaccinated with irradiated cercariae, or underwent partial portal vein ligation for the induction of portal hypertension and porto-systemic shunting. Following infection with 60 cercariae, the appearance of portal hypertension preceded by approximately 2 weeks the development of porto-systemic shunting, which reached maximal values 11 weeks postinfection. Such a primary infection conferred on C3H mice an estimated 90% protection to a 2nd infection, measured by the reduction of worm burden. Worm burdens were also reduced in vaccinated and ligated animals as compared to normal controls. The protection amounted to 30% and 56%, respectively, in the C3H strain and 63% and 75-85%, respectively, in the C57Bl/6 strain. Reduction in worm burden in the ligated animals is believed to be due to the extrahepatic porto-systemic vascular shunts. Hemodynamic as well as immunological factors may account for the resistance to reinfection observed in chronic murine schistosomiasis.     

Fecal lactate and short bowel syndrome

In patients with short bowel syndrome (SBS), the carbohydrate overload to the colon may disturb the normal pattern of colonic fermentation with production ofd-lactic acid and subsequent development of a metabolicd-lactic acidosis. We measuredd-lactic acid in blood, urine, and feces, as well as the composition of fecal water and fecal reducing substances from 11 patients with SBS, comparing the results with those from normal subjects. The fecal water from patients with SBS was characterized by low pH, potassium, and volatile fatty acids, high osmotic gap, and high concentration ofl- andd-lactic acid. Five of 11 had abnormal amounts of fecal reducing substances. Fecald-lactic acid was increased in nine of 11 patients. However, none of these patients showedd-lactic acid in urine, and only one had a very low concentration in plasma. These results show thatd-lactic acid was overproduced in the colon of most of the patients with SBS. However, other factors such as absorption or impairedd-lactic acid metabolism may be necessary for a plasmatic increase ofd-lactic acid.Unidad de Terapia Nutricional, Hospital de Niños Sor Maria Ludovica, La Plata, Provincia de Buenos Aires, Argentina.Part of this work was presented at the International Symposium on Short Chain Fatty Acids, Strasbourg, France, September 1993.