Skin conductance variability between and within hospitalised infants at rest

Abstract

Background Various methods of pain assessment in infants have been trialled in the search for objective, specific, physiologic measures of responses to pain. Skin conductance (SC) measured in the palm of the hand or on the plantar aspect of the foot may be one such measure. SC in these sites reflects the emotional sweating due to sympathetic nerve activity. The skin conductance response (SCR), which results from filling and reabsorption of sweat in the sweat glands, has previously been suggested to be the most sensitive SC parameter of sympathetic nerve activity in response to painful stimulation. Aim To study SCRs within and between medically stable hospitalised infants while at rest. Methods SCRs were measured in infants during at least six periods of monitoring in a maximum 48-h period. Behavioural state was recorded throughout the data collection periods. Results SC recordings ( n = 91) from 15 infants during sleep showed that frequency of SCRs varied between 0 and 0.04 SCRs per second (SCRs/s), median 0.002 SCRs/s. 73% of the total variation was within-infant variation, with the remaining 27% of variation due to variation between the mean SCR values of different infants. Conclusion This pilot study contributes to establishing baseline phasic SC activity in hospitalised infants at rest by measuring SCRs. These data can be used as a reference for future studies to determine the validity and reliability of SC measurement in infants exposed to painful or stressful interventions within a neonatal unit.