Management of the surgical newborn: physiological foundations and practical considerations.
The unique physiological changes that occur at birth and the adaptations that come in the first weeks of life profoundly affect the clinical management of the surgical newborn patient. The newborn has adaptive challenges that have to be met at birth: (a) establish a functional residual capacity and breathe; (b) change from a fetal to a newborn circulatory circuit; (c) change from fetal hemoglobin to hemoglobin A; (d) sustain a heart rate dependent cardiac output; (e) maintain normal body temperature; establish renal function and regulate postnatal body fluid composition; (f) establish hepatic function; and (g) maintain normal vital signs. Classical physiological studies of the last century describe the physiological basis of these adaptive tasks, and support practical considerations that we follow in clinical practice.