The integumentary system protects the underlying body from the external environment, such as shocks, temperature, ultraviolet radiation, chemicals, and other threats. There is a considerable body of clinical evidence highlighting the importance of the stratum corneum and its barrier functions, which are especially beneficial for newborns. Given the dramatic transition from the aqueous womb to the dry terrestrial environment at birth, studies describing adaptations made by the skin barrier within the first month of life assume greater importance. The skin of the baby is morphologically and functionally different from the skin of adults. Neonatal skin is thinner, more fragile, and drier than adult skin; it is difficult to maintain fluid-electrolyte balance and temperature regulation. Notwithstanding, structure and function of skin continues to improve during the first months and even years of life. Special care procedures are nonetheless necessary to ensure healthy development, to protect the skin from irritation and reddening, and to help the newborn feel well. Therefore, this study, taking the form of a randomized controlled trial, aims to examine the effectiveness of tub bathing and sponge bathing on the physiological parameters (heart rate, respiration rate, oxygen saturation, body temperature) and comfort of late preterm infants. Increasing comfort and physiological stabilization in premature infants during neonatal care improves their neurophysiological development. Bathing procedures that support this development and will not expose the newborn to stress should be preferred.

Increasing comfort and physiological stabilization in premature infants during neonatal care improves their neurophysiological development. Bathing procedures that support this improves and will not expose the newborn to stress should be preferred.This study aimed to examine the effectiveness of tub bathing and sponge bathing methods on the comfort and physiological parameters of late preterm infants. The study was conducted in the Neonatal Intensive Care Unit of a university hospital in Turkey, between November 2015 and November 2016. Skin care is routinely performed between 08.00 and 09.00 in the form of sponge bathing. This research study sampled 120 stable, late preterm infants being cared for in the NICU. This sample was deemed adequate based on a sample size calculation conducted in PS Power and Sample Size Calculations (Version 3.0). Information concerning allocation was available only to the principal investigator. Participants were assigned a sequential number that was placed in an opaque, sealed envelope by the researcher who received the signed parental informed consent. When the participant was scheduled to be bathing, the envelope was opened by the researcher who then performed the test. The nurses could not be blinded to the allocation because of the nature of the intervention. However, the outcome assessment of the participants was blinded. Participats were randomly assigned to either sponge bathing or tub bathing groups. Bathing was performed anywhere from 6 to 48 hours post-birth, based on individual participant needs. Participants were subsequently placed in a preheated incubator, which varied according to the participant's weight and age. In order to compensate for such differences, the heads of all participants were placed at a height of 30 degrees in a right lateral position after bathing and they were monitored. The participants were not dressed during the observation period. After bathing, participants were left without intervention or contact for approximately 10 minutes or until settled before being assessed. The data collection instrument, the Preterm Infant Bathing Study Record, was designed specifically for this study. The instrument incorporates a number of scales for the measurement of outcome variables, physiological parameters, and demographic information (age, gender, type of delivery, gestational age, birth weight, body weight at study time, etc.). Outcome measures include neonatal comfort behavior and physiological parameters (body temperature, heart rate, oxygen saturation, respiratory rate). Those responsible for data collection were blinded as to the allocation of participants they were assessing. The ComfortNeo scale was used to measure newborns' comfort and pain intensity. Comfort was inferred based on infant behavior, which was evaluated on two separate occasions, 10 minutes before bathing and 10 minutes after bathing. Measurement took approximately 1-2 minutes. Internal consistency was measured by way of Cronbach's alpha coefficient, which was 0.94 before bathing, 0.93 after bathing for the second researcher, and 0.92 after bathing for the nurse. Kappa coefficients were approximately 0.84 for each sub-item. Thus, there was harmony between the two observers. Infant physiological parameters (heart rate, respiratory rate, oxygen saturation, and body temperature) were evaluated on three separate occasions (10 minutes before bathing, 15 minutes and 30 minutes after bathing).Statistical analysis was performed using SPSS 20.0 and SAS (ver.9.3), with statistical significance set at p<0.05.

Data was presented as means and standard deviations for continuous variables, and frequencies for categorical variables. For participant characteristics, such as the type of delivery and sex, a Chi-square test was applied to determine whether there were significant between-group differences. participant characteristics, such as birth weight and body weight at the time of the study, were evaluated for significant between-group differences using a one way ANOVA test. For a comparison of the different phases, measurement parameters (comfort score, heart rate, oxygen saturation, respiratory rate, body temperature) through the baths were averaged separately. Repeated measurement analysis of variance was performed to analyze both between and within-group differences, followed by the Bonferroni post-hoc test.

Inclusion Criteria:

• All inborn infants with a gestational age of 34 weeks and 0 days to 36 weeks and 6 days (late preterm) were eligible to participate in this study.

Exclusion Criteria:

• Participants were excluded from the study if they were connected to
• a mechanical ventilator,
• if they had bathed in the last 12 hours,
• if within the first 78 hours of the postoperative period,
• had a central catheter,
• had received either a sedative and/or muscle relaxant,
• if they did not fulfill the inclusion criteria.

The data sharing plans for the current study are unknown and will be made available at a later date

Physiological data was collected by nurses trained by the lead researcher. Data on neonatal comfort behavior was collected by a second researcher and by research nurses who had been trained by the lead researcher. Those responsible for data collection were blinded as to the allocation of infants they were assessing.