Table 2.

Major characteristics of cardiovascular physiology in neonates and infants, and their anaesthetic implications

Physiologic characteristics	Anaesthetic implications
Persistent foetal circulation	Decreased peripheral tissue oxygen delivery. Prolonged inhalational induction/rapid iv induction with consequent cardio circulatory depression.
Vulnerable transitional circulation	Susceptible to revert to persistent foetal circulation, perioperatively.
Stiff myocardium/Less myocardial tension during contraction	Near static stroke volume/rate-dependent cardiac output.
Less functional cardiac reserve	Cannot tolerate increased pre- or after load, myocardial depression, hypovolaemia and arrhythmia.
Predominant parasympathetic control of heart	Prone to bradycardia in response to noxious and autonomic stimuli.
High basal endogenous catecholamines	Exogenous catecholamines are less effective.
Higher Foetal Haemoglobin in newborn	Prone to perioperative hypoxia