Overfeeding-associated hyperglycemia and injury-response homeostasis in critically ill neonates

The Effect of Various, Everyday Practices on Glucose Levels in Critically Ill Children

BACKGROUND

To evaluate the effect of various, everyday intensive care unit (ICU) practices on glucose levels in critically ill pediatric patients with the use of a continuous glucose monitoring system.

METHODS

Seventeen sensors were placed in 16 pediatric patients (8 male). All therapeutic and diagnostic interventions were recorded and 15 minutes later, a flash glucose measurement was obtained by swiping the sensor with a reader. Glucose difference was calculated as the glucose value 15 minutes after the intervention minus the mean daily glucose value for each individual patient. Additionally, the consciousness status of the patient (awake or sedated) was recorded.

RESULTS

Two hundred and five painful skin interventions were recorded. The mean difference of glucose values was higher by 1.84 ± 14.76 mg/dL (95% CI: -0.19 to 3.87 mg/dL, P = .076). However, when patients were categorized regarding their consciousness level, mean glucose difference was significantly higher in awake state than in sedated patients (4.76 ± 28.07 vs -2.21 ± 15.77 mg/dL, P < .001). Six hundred forty-nine interventions involving the respiratory system were recorded. Glucose difference during washings proved to be significantly higher than the ones during simple suctions (4.74 ± 14.18 mg/dL vs 0.32 ± 18.22 mg/dL, P = .016). Finally, glucose difference in awake patients was higher by 3.66 ± 13.91 mg/dL compared to glucose difference of -2.25 ± 21.07 mg/dL obtained during respiratory intervention in sedated patients.

CONCLUSIONS

Diagnostic and therapeutic procedures in the ICU, especially when performed in an awake state, exacerbate the stress and lead to a significant rise in glucose levels.

Endogenous Glucose Production in Critical Illness

Regulation of endogenous glucose production (EGP) by hormonal, neuronal, and metabolic signaling pathways contributes to the maintenance of euglycemia under normal physiologic conditions. EGP is defined by the generation of glucose from substrates through glycogenolysis and gluconeogenesis, usually in fasted states, for local and systemic use. Abnormal increases in EGP are noted in patients with diabetes mellitus type 2, and elevated EGP may also impact the pathogenesis of nonalcoholic fatty liver disease and congestive heart failure. In this narrative review, we performed a literature search in PubMed to identify recently published English language articles characterizing EGP in critical illness. Evidence from preclinical and clinical studies demonstrates that critical illness can disrupt EGP through multiple mechanisms including increased systemic inflammation, counterregulatory hormone and catecholamine release, alterations in the hypothalamic-pituitary axis, insulin resistance, lactic acidosis, and iatrogenic insults such as vasopressors and glucocorticoids administered as part of clinical care. EGP contributes to hyperglycemia in critical illness when abnormally elevated and to hypoglycemia when abnormally depressed, each of which has been independently associated with increased mortality. Increased EGP may also promote protein catabolism that could worsen critical illness myopathy and impede recovery. Better understanding of the mechanisms and factors contributing to dysregulated EGP in critical illness may help in the development of therapeutic strategies that promote euglycemia, reduce intensive care unit-associated catabolism, and improve patient outcomes.

The Use of Visceral Proteins as Nutrition Markers: An ASPEN Position Paper

Serum albumin and prealbumin, well-known visceral proteins, have traditionally been considered useful biochemical laboratory values in a nutrition assessment. However, recent literature disputes this contention. The aim of this document is to clarify that these proteins characterize inflammation rather than describe nutrition status or protein-energy malnutrition. Both critical illness and chronic illness are characterized by inflammation and, as such, hepatic reprioritization of protein synthesis occurs, resulting in lower serum concentrations of albumin and prealbumin. In addition, the redistribution of serum proteins occurs because of an increase in capillary permeability. There is an association between inflammation and malnutrition, however, not between malnutrition and visceral-protein levels. These proteins correlate well with patients' risk for adverse outcomes rather than with protein-energy malnutrition. Therefore, serum albumin and prealbumin should not serve as proxy measures of total body protein or total muscle mass and should not be used as nutrition markers. This paper has been approved by the American Society for Parenteral and Enteral Nutrition Board of Directors.

Assessment of Energy and Protein Requirements in Relation to Nitrogen Kinetics, Nutrition, and Clinical Outcomes in Infants Receiving Early Enteral Nutrition Following Cardiopulmonary Bypass

BACKGROUND

Nutrition therapies in children with congenital heart disease (CHD) after cardiopulmonary bypass (CPB) is crucial, but energy and protein requirements remain undefined. We assessed energy and protein requirements, with nitrogen kinetics and clinical outcomes, in infants with complex CHD following CPB.

METHODS

Infants were randomized to control (1.3 g/kg/d), moderate protein (MP, 2.5 g/kg/d), or high protein (HP, 4 g/kg/d) groups. Resting energy expenditure (REE) was measured 6 hours post-CPB and then at 24-hour intervals, using indirect calorimetry to formulate energy intakes. Enteral formula feeding was initiated 6 hours post-CPB and continued for 5 days. Nitrogen balance (NB); urea nitrogen waste and nitrogen retention; serum prealbumin level; and hepatic, renal, and cardiac function were measured daily. Mid-upper arm circumference and triceps skinfold were measured preoperatively and 5 days after CPB. Adverse outcomes (bacterial infection, reintubation, and cardiac intensive care unit (CICU) stay > 8 days) were recorded.

RESULTS

REE was not different across the 3 groups (P = .37). It declined from 62 ± 6 to 57 ± 7 kcal/kg/d over 5 days post-CPB (P = .02). NB and nitrogen retention became positive by day 3 in the HP group but remained negative in the other 2 groups (P = .045-.003), despite higher urea nitrogen waste in the HP group (P < .0001). The HP group had a greater increase in serum prealbumin level and anthropometric measures (P = .009-.03). Other measures were not significantly different across the 3 groups.

CONCLUSIONS

In infants with complex CHD in the first 5 days post-CPB, protein and energy intakes of ≈4 g/kg/d and 60 kcal/kg/d, respectively, led to improved nutrition outcomes without increased adverse events.