Index of Palta et al for Scoring Baseline Respiratory Disease in a Very Low Birth Weight Neonate

Baseline lung disease is any acute respiratory insufficiency or failure in the first few days of life.

 

Exclusion:

(1) birthweight > 1,500

(2) PaO2 > 85 mm Hg

 

Parameters:

(1) ventilator pressure in mm Hg (PIP)

(2) FIO2

(3) PaO2 in mm Hg

(4) birthweight in grams

(5) Apgar score at 5 minutes

(6) Edwards score for the chest radiograph taken at 12 hours after birth

(7) pneumothorax

(8) pulmonary hemorrhage

(9) pulmonary interstitial emphysema

 

Parameter	Finding	Points
PIP	no ventilation	0
	CPAP only	10
	10	16.7
	12.5	23.2
	15	31
	17.4	39.8
	20	50.7
	25	68
	30	83
	35	90.7
	40	95.4
	45	98.1
	>= 50	100
FIO2	0.21 (room air)	0
	0.25	2.7
	0.30	6.5
	0.40	18.7
	0.50	42.2
	0.60	59
	0.70	75.3
	0.80	90.8
	0.85	93.3
	0.90	96.2
	0.95	98.6
	1.00	100
PaO2 in mm Hg	<= 45 mm Hg	5.3
	59	0
	79	0
	80	-0.6
	85	-1.6
birthweight	500 grams	100
	700 grams	63
	900 grams	21.7
	>= 1,100 grams	0
Apgar score at 5 minutes	0	100
	1	76.2
	2	67.8
	3	36.6
	4	31
	5	22.8
	6	2
	7 - 10	0
Edwards score	0 (or none taken)	0
	1	13.7
	2	36.2
	3	52.7
	4	71.7
	5	100
pneumothorax in 1st 72 hours	absent	0
	present	100
pulmonary hemorrhage in 1st 72 hours	absent	0
	present	100
pulmonary interstitial emphysema in 1st 72 hours	absent	0
	present	100

 

When the data is examined in Mini-Tab the following equations are derived.

 

points for PIP from 10 to 16 =

= (2.373 * (PIP)) - 6.825

 

points for PIP from 16 to 50 =

= (0.001340 * ((PIP)^3)) - (0.2087 * ((PIP)^2)) + (11.03 * (PIP)) - 97.13

 

points for birthweight if a single equation is used =

= (0.000096 * ((weight)^2)) - (0.3237 * (weight)) + 239.1

 

points for birthweight from 500 to 700 grams =

= 192.5 - (0.185 * (birthweight))

 

points for birthweight from 500 to 700 grams =

= 207.55 - (0.2065 * (birthweight))

 

points for birthweight from 900 to 1100 grams =

= 119.35 - (0.1085 * (birthweight))

 

points for PaO2 from 45 to 59 =

= (-0.3786 * (PaO2)) + 22.337

 

points for PaO2 from 81 to 85 =

= (-0.2 * (PaO2)) + 15.4

 

points for FIO2 from 0.21 to 0.40 =

= (251 * ((FIO2)^2)) - (55.28 * (FIO2)) + 0.628

 

points for FIO2 from 0.40 to 0.80 =

= (-117.9 * ((FIO2)^2)) + (318.7 * (FIO2)) - 89.25

 

points for FIO2 from 0.80 to 1.00 =

= (-77.14 * ((FIO2)^2)) + (186.3 * (FIO2)) - 8.98

 

lung function component =

= (0.60 * (points for PIP)) + (0.40 * (points for FIO2)) + (points for PaO2)

 

"other component" if Edwards score available =

= (0.06 * (points for birthweight)) + (0.08 * (points for Apgar)) + (0.48 * (points for Edward score)) + (0.09 * (points for pneumothorax)) + (0.14 * (points for pulmonary hemorrhage)) + (0.15 * (points for pulmonary interstitial emphysema))

 

"other component" if Edwards score cannot be scored due to poor radiograph  =

= (0.12 * (points for birthweight)) + (0.15 * (points for Apgar)) + (0.17 * (points for pneumothorax)) + (0.27 * (points for pulmonary hemorrhage)) + (0.29 * (points for pulmonary interstitial emphysema))

 

where:

• Each factor in the formula for when the Edwards score is unreadable is twice that when it is readable.

• According to the footnote to Table 1 a score of 0 is given if a chest X-ray was not done at 12 hours. In the implementation the absence of a chest X-ray will be scored as if unreadable.

 

severity index =

= (0.97 * (lung function component)) + (0.33 * (other component)) - (0.0031 * (lung function component) * (other component))

 

LOG10(days in hospital) =

= 3.604 * (0.009 * (points for birthweight)) + (0.014 * (severity index))

 

days in hospital =

= 10^ (3.604 * (0.009 * (points for birthweight)) + (0.014 * (severity index)))

 

where:

• The formula in the paper involved "log" with the base not specified. Using base e resulted in values incompatible with the text description.

 

X =

= (0.07 * (severity index)) + (0.06 * (points for birthweight)) -3.94

 

probability oxygen dependency at 30 days =

= 1 / (1 + EXP((-1) * X))