Hormonal and Metabolic Response to Operative Stress in the Neonate

Abstract

It is evident from this review that newborns, even those born prematurely, are capable of mounting an endocrine and metabolic response to operative stress. Unfortunately, many of the areas for which a relatively well-characterized response exists in adults are poorly documented in neonates. As is the case in adults, the response seems to be primarily catabolic in nature because the combined hormonal changes include an increased release of catabolic hormones such as catecholamines, glucagon, and corticosteroids coupled with a suppression of and peripheral resistance to the effects of the primary anabolic hormone, insulin.

Phenylalanine and Tyrosine Kinetics in Critically Ill Children with Sepsis

“…h-' for phenylalanine hydroxylation in healthy newborns (7) might be lower than the actual rates, although that is speculative and a matter for further study. The values for Prots and Prot,, in our patients with sepsis are somewhat higher than the 7 and 6 g.kg-'.d-', respectively, reported for healthy infants (25,33), although perhaps they are not as high as might be anticipated for hypermetabolic or acute catabolic states (34).…”

“…Critically ill newborns and infants with sepsis who receive limited parenteral protein and energy intakes, as dictated by routine clinical practice (34,42), are unable to maintain phenylalanine homeostasis, and because of the link between phenylalanine and tyrosine metabolism, it is to be expected that a deterioration in tyrosine homeostasis will occur. Indeed, tyrosine may become a "conditionally" indispensable amino acid under these circumstances despite an apparently generous supply of phenylalanine.…”

Endogenous Distress in Ventilated Full-Term Newborns with Acute Respiratory Failure

“…During the last years documented evidence is available regarding the unfavorable effects of life-threatening distress and painful stimuli on sick neonates, based on the numerous physiological, vegetative and endocrine-metabolic changes which they engender [1][2][3]. Aside from the acutely raised morbidity due to distress, some authors also postulate irreversible negative long-term effects of postnatal distress on later neuronal development [4,5].…”

Endocrinopathies in the Cardiac ICU

“…Neonates and infants are more sensitive to acute pain than older children or adults because they have lower thresholds for the cutaneous flexor reflex, 21 –23 delayed maturation of descending noxious inhibitory controls, 24,25 excitatory effects of the classical inhibitory neurotransmitters (γ-aminobutyric acid [GABA], glycine), 26,27 often leading to prolonged windup and hyperalgesia 23,28 and accentuated metabolic stress responses. 1,2,29 –33…”