The Efficacy of the Automatic Lancet Use Measured by Near-Infrared Spectroscopy for Relief of Heel Stick Pain in Neonates

Introduction: Newborns are exposed to many painful procedures at hospital conditions for a variety of reasons. Heel sticks are one of the most common painful procedures during neonatal hospitalization. Exposure to pain may change pain responses such as pain hypersensitivity in short-term period, as well as cognitive functions may be affected in school age due to abnormalities in brain development. The purpose of this study was to evaluate the efficacy of the automatic lancet use instead of standard lancet for the relief of pain during heel sticks in neonates measured by neonatal infant pain scale (NIPS) and to show its impact on cerebral perfusion via near-infrared spectroscopy (NIRS).

Materials and Methods: Term neonates (i.e., born after 37 weeks of gestation) who met the inclusion criteria, without previous pain experience were enrolled into the study between June and October 2017 and were divided into two groups according to a random numbers table. Two milliliter of 20% glucose was given and a standard lancet was used in the first group (Group 1), and 2 ml of 20% glucose was given and an automatic lancet was used for the heel stick in the second group (Group 2). Heel stick test was performed to draw the blood required for the “National Newborn Screening Program,” not any other heel blood sampling was performed. All the patients were monitorized by Nellcor Covidien Pulse oxymeter with a probe placed on the right hand wrist for heart rate (HR) and arterial oxygen saturation (SaO₂), and via INVOS 5100, Somanetics with a probe placed on the forehead for near-infrared spectroscopy (NIRS) values. Each HR, SaO₂, and NIRS values were recorded for four times: before heel stick, on the second minute after glucose administration, on the time of heel prick and on the second minute after the prick. NIPS was used as pain evaluation criterion, and each video recording taken during the procedure was watched by two different researchers to try to optimize scoring. Sampling size and power analysis was performed in G * Power 3.1.9.2 and statistical evaluation of data was performed in the package program of the Statistical Package for the Social Sciences (SPSS) version 15.0 (SPSS Inc, Chicago, IL).

Results: According to the inclusion criteria, some 41 newborns were enrolled into the study. There was no differences in demographic characteristics (gestational age, birth weight, gender) between Group 1 (n = 21) and Group 2 (n = 20). There was no statistically significant difference between the two groups as for concerns the measurements of HR and NIRS on four different evaluation periods. However, oxygen saturation values of Group 1 before, during, and 2 minutes after the procedure were lower than Group 2. NIPS scores were significantly lower on the time of heel prick and on the second minute after the prick in Group 2. There was no statistically significant difference between the two groups in NIRS assessments.

Conclusion: This study shows that there is a significant analgesic effect of automatic lancet use for heel stick in infants who have never experienced pain before. This may be caused by the fact that the glucose given before the procedure has increased cortical activation in the brain. Beside the use of glucose as a nonpharmacological analgesic agent, the use of automatic lancet instead of standard lancet for heel sticks in neonates may be important to have better pain control.

Keywords: neonate, pain, neonatal infant pain scale, near infrared spectroscopy, automatic lancet