The Effect of Breast Milk, 10% and 20% Dextrose on Pain and Physiological Variables During Heel Puncture in Infants

Aim: This study aims to determine the primary effect of oral breast milk, 20% dextrose, and 10% dextrose solutions-administered alongside supportive positioning methods during routine heel lancing blood sampling (within the Neonatal Screening Program)-on pain scores in premature newborns admitted to the NICUs. Secondarily, it aims to evaluate the effects of these interventions on heart rate and oxygen saturation variables.

Hypotheses: The research hypothesizes that there is a statistically significant difference between the oral breast milk, 20% dextrose, and 10% dextrose solution groups (applied with supportive positioning) regarding pain scores (H1a), heart rate (H1b), and oxygen saturation levels (H1c) during the heel lancing procedure.

Study Design: The study will be conducted using a single-center, parallel-group, randomized controlled trial design.

Study Location: The research will take place in the Neonatal Intensive Care Unit of Mersin University Hospital.

NICUs Characteristics: The unit features a traditional open-bay design comprising two wards. It provides level 4a care and has a total incubator capacity of 27.

Work Environment and Care Approach: As a tertiary referral center, the NICUs operates on two shifts (08:00-16:00 and 16:00-08:00), with a nurse-to-infant ratio ranging from 1:1 to 1:3. The unit adopts a family-centered individualized developmental care approach. The Turkish version of the Neonatal Pain, Agitation, and Sedation Scale (N-PASS) is routinely used to evaluate and record pain scores during shift changes and interventional procedures.

Study Population: The study population will consist of premature newborns admitted to the Mersin University Hospital NICU who are scheduled for routine heel prick blood sampling.

Sample Size: The sample size was determined via a priori power analysis using G*Power 3.1.9.4. Based on the effect size (d=0.92) from Brovedani et al. (2007), a minimum of 26 infants per group is required to detect a statistically significant difference with a 5% type I error margin (α = 0.05) and 90% power (1-β = 0.90).

Attrition Allocation: To account for potential dropouts and confounding variables, the sample size was increased by 20%. Consequently, the study will include a total of 96 premature newborns, with 32 infants assigned to each of the three intervention groups.

Data Collection Tools and Forms

• Infant Information and Observation Form: Developed by the researcher based on the literature, this 11-item form records demographic and clinical data such as gestational age, birth weight, procedure duration, heart rate, oxygen saturation, and N-PASS scores.
• N-PASS Scale: A valid and reliable tool for the multidimensional assessment of pain, incorporating both physiological (heart rate, saturation, respiratory rate) and behavioral (crying, facial expression, muscle tone) components. To compensate for the limited behavioral responses of premature infants, gestational age-based points are added. The clinical goal is to maintain a score below 3.
• Physiological Measurement Tools: A monitor and a compatible pulse oximeter sensor will be placed on the infant's right hand (palmar/preductal area) to measure the average heart rate and capillary oxygen saturation before, during, and after the procedure.
• Camera: A tablet will be used to record the infant's facial expressions, behavioral responses, and monitor readings. Recording will start 3 minutes prior to the procedure and end 2 minutes after its completion.
• Heating and Puncture Devices: A radiant heater will be used to warm the nurse's hands, monitored by an infrared thermometer. A disposable mechanical/automatic lancet specifically designed for preemies (0.85 mm depth, 1.75 mm width) will be utilized for the puncture.

Study Implementation Steps

• Preparation: Following ethical committee and institutional approvals, informed written consent will be obtained from the parents. The Infant Information Form will be filled out 30 minutes before the procedure. To ensure standardization, a single researcher-nurse will perform the blood collections while another records the video.
• Positioning (15 minutes prior): The infant will be swaddled in a supine facilitated flexion position (trunk flexed, limbs in midline, head and shoulders elevated 30-45°) to provide postural support (nesting).
• Pre-procedure Intervention (2 minutes prior): 1 mL of the assigned oral solution will be slowly administered to the anterior part of the infant's tongue using a PPD syringe. Non-nutritive sucking will be initiated, and the puncture site (heel) will be warmed in the nurse's palm.
• The Procedure: The oral solution will be administered once more immediately before the puncture. The site will be cleaned with an antiseptic, punctured, and the first drop of blood wiped away before collecting the sample on Guthrie paper. An injection bandage will then be applied.
• Evaluation Process: Video recordings will be evaluated at four distinct time points: 2 minutes before (T0), during (T1), 1 minute after (T3), and 2 minutes after (T4) the procedure. The N-PASS scoring will be conducted independently by the nurse performing the procedure and an external certified neonatal nursing expert using the video footage.

Information regarding the duration of the procedure, the duration of the baby's crying, and heart rate and saturation before, during, and after the procedure will be obtained from camera recordings.

Analysis of Research Data: A statistical software package will be used to analyze the research data. The statistical significance level has been set at 0.05. Kolmogrow-Smirnov and Shapiro-Wilk tests will be used for normality analysis of dependent variables. Chi-square and mean comparison tests will be used to determine the similarity of groups. Appropriate parametric or non-parametric tests will be used to compare intra-group and between-group means, depending on whether the distribution is normal. In case of differences in between-group means, the appropriate effect size will be used according to the test family. Agreement and correlation analyses will be performed between N-PASS score evaluators. Additionally, post-hoc power analysis will be used to test whether the study was conducted with an adequate sample size. Effect Size: Cohen's d coefficient will be calculated to determine the strength of the difference between the groups.

Inclusion criteria

• Parental consent for the baby's participation in the study
• Admission to Mersin University Hospital NICU between July 16, 2026 and December 30, 2026,
• Gestational age at birth between 33 weeks and 37 weeks,
• Postnatal age less than 7 days,
• Heel prick blood test planned within the scope of NTP,
• Stable clinical condition,
• Absence of genetic or metabolic problems,
• Developed sucking-swallowing and breathing coordination,
• Having been fed at least 30 minutes before the procedure,
• No experience with invasive procedures in the last 6 hours before the procedure,
• No administration of non-opioid analgesics in the last 4 hours before the procedure,
• No administration of opioid analgesics and sedative agents in the last 24 hours before the procedure,
• Spontaneous respiration at 21% FiO2,
• Absence of neurological problems (e.g., asphyxia, hypoxic ischemic encephalopathy, intraventricular hemorrhage, periventricular leukomalacia, spinal cord injury…),
• Absence of contraindications to oral glucose/breast milk administration (e.g., necrotizing enterocolitis or suspicion thereof, feeding intolerance, tracheoesophageal fistula, absence of esophageal atresia…),
• Absence of endocrine problems (e.g., hypoglycemia, hyperglycemia, large for gestational age, absence of a diabetic mother…),

Exclusion criteria

• Parental disapproval of infant's participation in the study
• No hospitalization at Mersin University Hospital NICUs between July 16, 2026 and December 30, 2026,
• Gestational age at birth less than 33 weeks or greater than 37 weeks,
• Postnatal age greater than 7 days,
• Heel prick blood test not planned within the scope of NTP,
• Clinical condition not stable,
• Lack of developed sucking-swallowing and breathing coordination,
• Having been fed within 30 minutes of the procedure,
• Having had invasive procedures experience in the last 6 hours before the procedure,
• Having received non-opioid analgesics in the last 4 hours before the procedure,
• Having received opioid analgesics and sedative agents in the last 24 hours before the procedure,
• Genetic or metabolic problem The following are contraindications:
• Being on invasive or non-invasive mechanical ventilation support,
• Having a neurological problem,
• Oral glucose/breast milk administration being contraindicated,
• Having an endocrine and metabolic problem.