COMMENTARY |
Department of Pediatrics, University of Arkansas for Medical Sciences, Little Rock, Arkansas
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Accurate pain assessment is a key and central issue that confronts clinicians at the bedside of preterm neonates or researchers who study nonverbal subjects.1 Although many validated methods for pain assessment are available,2 none of them are widely accepted or clearly superior to others. Consequently, no "gold standard" can be recommended for broad adoption in clinical practice because of 2 problems that are common to all assessment methods.
First, these methods were developed from studies of neonates who underwent acute painful procedures (heel stick, venipuncture, circumcision). Physiologic or behavioral parameters chosen for inclusion in these methods were those that changed most acutely in response to tissue injury and subsided after painful stimulation was over. These responses were thought to be "specific" for neonatal pain. Subsequent research, however, noted that many infants do not produce "specific" responses when exposed to invasive, skin-breaking procedures.3 Preterm newborns who were more immature, asleep, or exposed to previous painful procedures were less likely to demonstrate specific responses to pain,3 whereas previous physical handling accentuated their responses to acute pain.4
Second, these behavioral and physiologic responses require the subjective evaluation of a clinical observer.5 Significant interobserver variability occurs6,7 and can be reduced but not eliminated by training or greater experience. The need for training creates a significant obstacle for the routine use of these methods. Because physicians or nurses who rotate temporarily through the unit are not trained, most neonates are not assessed for pain, which greatly reduces their likelihood of receiving analgesia.8,9
Most pain
Address correspondence to K.J.S. Anand, MBBS, DPhil, Arkansas Children's Hospital, 800 Marshall St, Little Rock, AR 72202. E-mail: anandsunny@uams.edu