Patient selection: premature infant
Parameters:
(1) weeks of gestational age
(2) days of mechanical ventilation
(3) number of disc diameters of avascular area of the retina
A =
= (0.461 * (weeks GA)) + 11.417
B =
= 2.571 - (0.078 * (days of mechanical ventilation))
C =
= 4.64 - (0.746 * (disc diameters of avascular area))
D =
= 5.251 - (0.686 * (disc diameters)) - (0.064 * (days on mechanical ventilation))
probability of ROP requiring (? see below) treatment =
= 1 / (1 + EXP((-1) * (A or B or C or D)))
Implementation:
(1) The equation using gestational age gave unacceptable results.
(2) The data shown in Table 5 (percent of patients requiring treatment, using D equation) can be seen as 1 - (result of the probability equation).
(3) If the (-1) is removed from the probability equation then values in Table 5 are returned.
