Ballard Exam Flashcards
Why is the estimation of GA important?
knowledge of the neonate’s age and growth patterns aid in the identification of neonatal risks and in the development of a management plan, especially if on the edge of viability
What are the three general methods of determining GA in the newborn?
1) calculation of dates based on LMP
2) evaluation of OB parameters obtained in pregnancy
3) physical exam of the neonate
What is the average gestation of the human?
280 days, 40 weeks from the onset of the LMP
Why can calculation based on reported LMP be potentially misleading?
if MOB menstrual cycles are irregular, h/o recent contraception use, patient with medically induced ovulations, limited prenatal care
What is the most accurate guide to GA?
the combination of menstrual dates and ultrasound measurements
What are the 2 methods used to determine GA based on physical assessment?
1) assessment of the anterior vascular capsule of the lens
2) assessment of neuromuscular and physical criteria by inspection and palpation
What is the basis for the anterior vascular capsule exam as a determinant of GA?
the hyaloid system and the tunica vasculosa lentis are transient embryologic vascular systems that invade the developing eye to nourish the eye during periods of active growth.
When can the anterior vascular capsule be appreciated?
appears at 27 wk GA and then atrophies progressively until it is gone after wk 34
When should the anterior vascular capsule be evaluated?
performed within the first 24 to 48h of life because the vascular system atrophies rapidly after that period
What maternal conditions are thought to influence the anterior vascular capsule?
chronic HTN accelerates atrophy of this system; chronic intrauterine stress may influence the maturation of this vascular structure
What can primitive reflexes and active muscle tone evaluation reveal?
indicator of illness or wellness
What is the definition of passive muscle tone?
the slight constant tension of healthy muscles which contributes a slight resistance of passive displacement of a limb
What is the progression of development?
caudo-cephalad direction
What is the difference between extensor and flexor tone?
flexor tone is the resistance to extensor tone, as seen by positioning the limb midlined and with small angle between limbs
How does flexor tone change over the course of development?
passive flexion overcomes passive extension as CNS maturation progresses
What are tests of passive flexor tone?
square window, angle of recoil, arm recoil, resistance to extension, scarf sign, popliteal angle, heel to ear
How do eyes begin to develop in utero?
wide open; develops from the outer canthus ~48d progressing to the inner canthus ~51d
When do eyes close in utero?
close from canthi to center (~57 d); fusion then persists until 7th mo (26-28wk GA)
How is the posture of a newborn evaluated?
remove restrictive clothing and nesting materials, place infant supine, observe preferred attitude at rest; assign score based on the degree of flexion of the arms, knees and hips
What is the square window an assessment of?
passive flexion at the wrist
How is the square window test completed?
Apply gentle pressure of dorsum of baby’s hand at metacarpal-phalangeal joint; measure the angle between the forearm and the palm
When conducting the square window test, how are the results affected by GA?
the angle decreases with advancing GA
What is the arm recoil an assessment of?
passive flexor tone of biceps muscle