Skin conductance and the stress response from heel stick in preterm infants.

AIM To evaluate whether spontaneous skin conductance activity is an objective method for measuring the stress response to painful stimuli in premature infants. The number and amplitude of the waves and the baseline increase with the activity of the sympathetic nervous system. METHODS In 20 preterm infants of gestational age >/= 29 weeks, behavioural state and spontaneous skin conductance activity variables were measured for three minutes before, during, and for three minutes after heel stick. RESULTS The number of waves (p < 0.001), the amplitude of the waves (p = 0.001), and the level of the behavioural state (p < 0.001) increased during heel stick, and then decreased to levels found before the procedure. The baseline increased both during (p < 0.001) and after heel stick (p < 0.001), compared with levels before. CONCLUSION Spontaneous skin conductance activity reflects the stress response to heel stick in premature infants from at least 29 weeks of gestational age.