The Validity of Skin Conductance for Pain Assessment in Hospitalized Infants

Abstract

Background Measuring pain in infants is important but challenging for researchers and health care professionals. The measurement of skin conductance (SC) is considered as a measure of stress and a surrogate indicator of pain. Purpose This dissertation provides insight on the validity of SC for pain measurement in infants and consists of two studies: 1) a scoping review synthesizing the methods and findings of previous studies on validating or using SC for measuring pain in infants; 2) a primary study evaluating the validity of SC for measuring pain in mechanically ventilated infants. Methods Arksey and O’Malley’s framework informed the methods of the scoping review. Nine electronic databases were searched. Data were analyzed and presented descriptively. The primary study used a prospective cross-sectional observational design. Eligible infants were those up to 12 months of age, hospitalized in intensive care units, who were mechanically ventilated, and required painful and non-painful procedures. Results Scoping review: Twenty-eight studies with 1061 infants were included, including 23 cross-sectional observation studies and five interventional studies. The validity evidence of SC was tested in relation to referent pain measures (13 variables), stimuli (13 variables), age (2 variables) and other contextual variables (11 variables). Fifteen studies evaluated the validity evidence in relation to phase of painful procedure, and SC increased significantly during painful procedures in most studies (n=14/15). However, inconsistent findings on other validity evidence and wide variation in methods existed across studies. Primary study: SC showed good validity in relation to the category of procedure, the phase of procedure and the referent pain measures in critically ill mechanically ventilated infants. The findings from diagnostic test accuracy showed that SC had good capacity of detecting moderate to severe pain. However, the values of SC need to be used with caution, due to the imperfect correlations with the referent pain measures and imperfect positive predictive value. Conclusions SC is a promising approach to measuring pain in critically ill infants. Further research testing the validity of SC in relation to pain treatments and advancing the technology of measuring and analyzing SC is needed before it can be recommended for clinical use.