Assessment of infant pain is a pressing concern, especially within the
context of neonatal intensive care where infants may be exposed to pr
olonged and repeated pain during lengthy hospitalization. In the prese
nt study the feasibility of carrying out the complete Neonatal Facial
Coding System (NFCS) in real time at bedside, specifically reliability
, construct and concurrent validity, was evaluated in a tertiary level
Neonatal Intensive Care Unit (NICU). Heel lance was used as a model o
f procedural pain, and observed with n = 40 infants at 32 weeks gestat
ional age. Infant sleep/wake state, NFCS facial activity and specific
hand movements were coded during baseline, unwrap, swab, heel lance, s
queezing and recovery events. Heart rate was recorded continuously and
digitally sampled using a custom designed computer system. Repeated m
easures analysis of variance (ANOVA) showed statistically significant
differences across events for facial activity (P < 0.0001) and heart r
ate (P < 0.0001). Planned comparisons showed facial activity unchanged
during baseline, swab and unwrap, then increased significantly during
heel lance (P < 0.0001), increased further during squeezing (P < 0,00
3), then decreased during recovery (P < 0.0001). Systematic shifts in
sleep/wake state were apparent, Rise in facial activity was consistent
with increased heart rate, except that facial activity more closely p
aralleled initiation of the invasive event. Thus facial display was mo
re specific to tissue damage compared with heart rate. Inter-observer
reliability was high. Construct validity of the NFCS at bedside was de
monstrated as invasive procedures were distinguished from tactile. Whi
le bedside coding of behavior does not permit raters to be blind to ev
ents, mechanical recording of heart rate allowed for an independent so
urce of concurrent validation for bedside application of the NFCS scal
e. (C) 1998 International Association for the Study of Pain. Published
by Elsevier Science B.V.