Effectiveness of non-nutritive sucking for pain relief in newborns during calcaneal puncture: a randomized clinical trial

INTRODUCTION: Newborns (NB), to monitor their health, need procedures that cause pain, such as heel puncture. This procedure is used to monitor blood glucose in premature, small-for-gestational-age, macrosomic newborns, children of diabetic mothers or those with some physiological disorder. The heel puncture causes pain and for its relief it is possible to use non-pharmacological methods, such as non-nutritive sucking (NNS). The hypothesis of the study is that NNS is an effective non-pharmacological method to relieve pain in full-term newborns during calcaneal puncture. AIM: To evaluate the effectiveness of NNS in relieving pain in full-term newborns during calcaneal puncture. METHOD: An open, parallel, randomized clinical trial developed at the Obstetric Unit of the Hospital de Clínicas de Porto Alegre (HCPA) during the months of April to August 2022. The population consisted of NBs in rooming-in, at term, who presented stable vital signs, who had a medical prescription for glycemic control, who were pain free before the procedure, as assessed by the Neonatal Infant Pain Scale (NIPS), and who completed the 8th or 12th hour of life between 6 am and 10 pm. NBs with congenital malformations, who underwent hospitalization or observation in the Neonatology Unit, who received pharmacological analgesia or whose technique for performing the calcaneal puncture did not comply with the Standard Operating Procedure for Checking Capillary Glycemia were excluded. Based on a pilot study with 20 NBs, considering a significance level of 5%, power of 80%, a minimum difference of 50% in the proportion of pain during the procedure between the groups and an increase of 10% for possible losses, obtained a minimum of 21 NBs in the Control Group (CG) and 21 in the Intervention Group (IG). The CG did not receive any method for pain relief and the IG received the SNN. The procedure of the 8th or 12th hour of life of the NB was observed, applying the NIPS, as well as checking the heart rate (HR) and oxygen saturation (SatO2). Data were recorded in a structured instrument for observation and information was collected from the electronic medical record regarding the characterization of postpartum women and newborns. Quantitative variables were described as mean and standard deviation or median and interquartile range. Categorical variables were described by absolute and relative frequencies. To compare means, the T-Student test was applied and in case of asymmetry, the Mann-Whitney test. In comparing proportions, Pearson's chi-square or Fisher's exact tests were used. The terms of Resolution No. 466/12 and the General Data Protection Law were complied with. The study was approved by the Research Ethics Committee of the HCPA under protocol number 5.335.648. RESULTS: At the time of puncture, there was a difference between the groups in terms of facial expression (p=0.045), arms (p=0.005) and NIPS score (p<0.001), with a greater proportion of facial muscles and relaxed arms in GI and lower NIPS score. Regarding HR and SatO2, there was no difference between the groups during puncture [HR (p=0.656); SatO2 (p=0.361)]. CONCLUSION: The NNS was effective in reducing the pain of the NB during the calcaneal puncture, considering that the NIPS scale score for the GI was < 4. It is recommended that other studies be carried out in order to assess how long the life of the NB the SNN is effective in relieving pain during procedures, aiming to contribute to the adoption of non-pharmacological methods to relieve pain also in outpatient care situations. The limitations of the study were the sample size, the presence of few articles that study non-pharmacological methods for pain relief in full-term newborns and the size of the research data collection team.