Nutrition In Critically Ill Infants

Question 1

Defining the critically ill infant: gestational age of <34 weeks, any newborn requiring surgery

Answer 1

• gestational age of <34 weeks: immaturity of swallowing and poor tolerance of enteral feeds, jaundice, anaemia, immaturity of the immune system (increased risk of sepsis)
• any newborn requiring surgery: intestinal atresia (blockage of bowel), nectrotizing enterocolitis (emergency, gut necrotic), gastroschisis (intestines and liver outside body)

Question 2

When adaptation to the outside world doesnt work: hypoglycaemia

Answer 2

• defined at <2.6 mmol/L
• when adaptation from continuous supply (placenta) to discontinuous supply
• hypoglycaemia is deleterious to the newborn brain, and can cause white matter injury with poor neurodevelopment outcomes
• infants heavily rely on ketogenesis during starvation and glycogen breakdown
• preterm infants have greater variability in blood glucose and lower NEFA (lower ketone substrates) due to lower reserve

Question 3

Monitoring infant growth

Answer 3

• using z scores

- monitor to see if having catch up growth or failure to thrive

Question 4

Energy requirements in the preterm neonate

Answer 4

• need to supply enough for BMR, growth and cost of growth
• at least 125 kcal/kg/day (>65 kcal of these need to be from non-protein sources)
• no hypometabolic state seen post-surgery (unlike adults) therefore in acute phase of illness need at least REE, in stable phase REE1.3, in recovery phase REE1.7
• ESPEN protein requirements for preterm neonates at least 1.5g/kg/day immediately then increase to 2.5-3.5g/kg/day for anabolism (for term critically ill infants ok to begin 1 week later, and then have 1.5g/kg/day then increase up to 3g/kg/day for anabolism)

Question 5

Macronutrient interactions in preterm neonates

Answer 5

• CHO: can be stored at glycogen or metabolised to fat. If have less than 18g/kg/day will have far oxidation. Greater glucose intake will have greater VCO2
• FAT: lower CO2 production than CHO (lower RQ). May be beneficial to supplement infants with this as lower CO2 so dont need to ventilate as aggressively
• PROTEIN: more kcal consumed, more protein stored. At least 65 kcal/kg/day needed for positive N balance. PRO retention is better if supplement with fat too