Table 1.

Infant Characteristics n = 92

	Mean (sd)	Range	N (%)
Birth weight (grams)	1280 (445)	500 - 2525
Gestational age at birth (weeks)	29 (2)	24 - 32
SNAP- II Day 1*	12 (10)	0 - 46
Ventilation (days)	8 (13)	0 - 50
Other respiratory support (days)	8 (9)	0 - 36
Pain exposure at 32 weeks PCA†	76 (58)	8 - 276
Intravenous morphine exposure at 32 weeks PCA‡	0.90 (2.1)	0-9.6
Grade III, IV Intraventricular hemorrhage or periventricular leukomalacia (n=82)§			6 (0.07)
Days of Dexamethazone	0.3(2)	0-19
Ethnicity (Caucasian)			63 (69)
Maternal age (years)	30 (6)	19-47

^*Score for Neonatal Acute Physiology (Richarson et al, 2001)

^†Number of invasive (skin breaking) procedures from birth to the test day

^‡Morphine exposure = daily average intravenous mg/kg) X days

^§Infants born weighing > 1250 grams did not receive head ultrasound scans (n=19).