Preterm neonates (those born at a gestational age <37 weeks) have very delicate skin, and skin quality varies dramatically by gestational age at birth. Skin care for this population is very important because preterm infants lack a fully developed skin barrier, which can lead to infections.1–3 Because physiologic maturity of the stratum corneum is achieved during the third trimester, preterm newborns are prone to imbalances in stratum corneum hydration (SCH).4,5 Even routine care, such as changing and bathing, can provoke skin irritation because of this compromised skin barrier function.6
Currently, there are no evidence-based guidelines to standardize skin care for preterm infants.2 However, natural oils are increasingly used for neonatal skin care in developing and developed countries to support skin barrier maturation.3,7–9 Part of the appeal of these oils is easy availability readily at low cost.10–12 Therefore, evidence-based research on the effect of natural oils is extremely valuable for the development of cost-effective skin care for preterm infants.7
In developing countries where oil massage for infants and children is traditional, topically applied natural oils such as sunflower seed oil (SSO), coconut oil, and almond oil (AO) have been reported to positively affect infant skin and may prevent the development of some skin conditions.3,7–9,12 These topically applied plant-derived oils potentially improve skin condition, reduce skin irritation, moisturize, reduce transepidermal water loss (TEWL), conserve heat, promote weight gain, decrease the length of neonatal ICU (NICU) stay, and prevent infections.9,13,14
Based on this body of research, it is reasonable to conclude that regular use of natural oils may positively affect preterm infant skin. In accordance with this information, this randomized controlled trial was designed to evaluate the effectiveness of SSO and AO on the SCH and Neonatal Skin Condition Scores (NSCS) of infants born between 32 and 37 weeks of gestation. This study aimed to answer the following research questions:
- (1) Does SSO or AO have an effect on SCH in preterm infants?
- (2) Does SSO or AO have an effect on skin integrity among preterm infants (as measured by NSCS)?
- (3) Which oil is more useful for preterm infant skin care?
This monocentric, prospective, randomized controlled trial was designed to investigate the effect of the use of SSO and AO on SCH and NSCS levels in the skin care of preterm infants born between 32 and 37 weeks of gestation who were hospitalized in the NICU of the Dr Sadi Konuk Training and Research Hospital between September 2016 and September 2017.
The inclusion criteria were infants whose age was 48 hours or less and who were medically stable, born between 32 and 37 weeks’ gestation, and who were hospitalized for at least 5 days. Infants were excluded from the study if they had a life-threatening medical condition (eg, sepsis, serious congenital problems, birth asphyxia, hypoxic-ischemic condition, or intracranial bleeding), an immune deficiency, a skin disease known to affect the skin barrier function (eg, congenital ichthyosis or congenital candidiasis), maceration or inflammation on the skin (eg, epidermolysis bullosa or herpes simplex), and/or an acute or a chronic disease.
The sample size of the study was calculated using G*Power version 22.214.171.124 (Heinrich Heine University Düsseldorf, Germany). Accordingly, given repeated measurements for an effect size of f = 0.30 (ie, the applied oil will be at least 0.3 or more effective compared with the control group), α = .05 (type 1 error probability), and power = 0.80 (1-β error probability), the minimum number of participants required was 84 infants (28 infants in each study group). Study authors decided to include 30 infants in each group to accommodate any losses.
Groups were assigned by a computer-based random number generator program. For every new infant who came into the NICU, a researcher assessed the health condition of the infant and gave the necessary information about the study to the family to obtain informed consent. A flow diagram of patient enrollment, allocation, and analysis is shown in the Figure.
Ethical approval was obtained from the Clinical Trials Ethics Committee of Dr Sadi Konuk Training and Research Hospital (institutional review board no. 2015/231) before starting the study. Before any intervention, the parents of infants meeting the inclusion criteria were informed about the objective, content, and method of the study; written and verbal permission was obtained from those who voluntarily agreed to participate. Participants were informed that they could leave the study at any stage. Because the administration of natural oils is common and traditional in Turkey, parents typically agreed to participate in the study.
Data Collection and Instruments
Various patient demographic characteristics were collected for all groups, including sex, delivery method, gestational age, and weight. Although studies have shown that SSO and AO oils have positive effects on infants’ skin and adverse reactions are rare, contact dermatitis, atopic dermatitis, and candida infection or other local reactions such as dryness, erythema, vesicles were monitored.15–17
Skin Moisture Meter
The DMM Skin Moisture Meter (Beijing, China) was calibrated and used to measure SCH. (The device does not have published validity and reliability data.) The product shows the moisture level (0%-99.9%) on contact with the skin but does not damage it. The moisture meter weighs 40 g and operates effectively at ambient temperatures between 5° and 40° C.18
Neonatal Skin Condition Score
The NSCS was developed for clinical nurses to use to evaluate infant skin condition daily. The scale was developed by Lund and Osborne,19 and a validity and reliability study using the score was carried out in 2004. The reliability of the NSCS for each of the three subscales and for the total score was adequate (68.7%-85.4% [intrarater] and 65.9%-89% [interrater]).19 The scale evaluates skin dryness, erythema, and eruption. The best and worst possible scores are 3 and 9, respectively. The scale does not have a cutoff value. High scores indicate poor skin condition, and low scores indicate normal skin condition.
Researchers administered SSO (natural supplements suitable for medical use; cold extracted, medium concentration, saturated fat content 15%, unsaturated fat 85%, oleic 14%-43%, linoleic 44%-75%, palmitic 7.16%, and linolenic acid 0.7%) to the first intervention group and AO (natural supplements suitable for medical use; cold-pressed, saturated fat 9%, unsaturated fat 91%, oleic 64%-82%, linoleic 8%-28%, linolenic 1%, and palmitic acid 6%-8%) to the second. The control group received standard NICU skin care (AO is applied to the skin of the babies only when dryness is observed based on NSCS scoring). To ensure blinding, identical dark-colored glass bottles containing colorless and odorless SSO and AO were marked as X and Y, respectively. The nurse researcher conducting the application did not know which bottle contained which oil.
The aforementioned nurse researcher evaluated SCH and NSCS as soon as the newborn was admitted to the unit (within 48 hours after birth). The nurse researcher was instructed to apply the appropriate oil to the whole body of each infant in the intervention groups (except for the head and face) four times a day (4 mL/kg) for 5 days.7,20 Before beginning administration, she washed her hands and warmed them under a radiant warmer. Then, the nurse squeezed 4 mL of oil from the bottle onto her hands and applied the oil to the infant with gentle strokes without massage and with medium pressure for 2 to 3 minutes. The same nurse applied the oils to all of the babies in the SSO and AO groups during the day shift every 3 hours at routine care times.
After 5 days and 6 hours after the last oil application, the research nurse reobtained the NSCS and measured the SCH of each participant on his/her abdomen (sides of the belly), lateral surface of the upper leg, and upper outer quadrant of the thigh.7 After this, routine care procedures resumed for all babies.
Humidity in each NICU incubator is regulated according to infant weight. Ambient humidity in the unit is between 35% and 40%, and the ambient temperature is maintained between 24° and 27° C.
The data were analyzed using SPSS for Windows version 21.0 (IBM Corp, Armonk, New York). The data were evaluated by using the number, percentage, mean, SD, and median in descriptive statistics. Homogeneity of the descriptive characteristics of the groups was tested with the Pearson χ2 test and independent-sample variance analysis. The difference between the mean values of SCH with respect to time (before and after the study period) was evaluated with a dependent-sample t test, and the difference between mean scores of skin identification was evaluated with the Wilcoxon test because the data did not show a normal distribution. Before and after the intervention, the mean SCH levels among the three groups were compared and evaluated with independent-sample variance analysis (advanced Tukey analysis), and NSCS was evaluated with the Kruskal-Wallis (KW) analysis (advanced Mann-Whitney U test using a Bonferroni correction). The significance level was P < .05.
A total of 90 infants who met the study criteria were recruited to participate (30 in each group). Almond oil was not applied to the babies in the control group during the study period because no dryness was noted.
Baseline characteristics for each group are described in Table 1. There were no statistically significant differences by sex (χ2 = 0.089, P = .957), delivery method (χ2 = 2.411, P = .300), or gestational age (F2 = 2.610, P = .079); however, there was a significant difference in birth weight (F2= 3.829, P = .025), which was significantly higher for infants in the control group than the AO group (F2= 32.043, P = .000).
There were no significant differences in mean SCH of the abdomen (F2 = 2.715, P = .072) or lateral surface of the upper leg (F2 = 3.080, P = .051) among groups prior to the study; however, these levels were significantly different after the intervention (abdomen, F2 = 16.280, P = .000; upper leg, F2 = 10.917, P = .000; Table 2). After advanced analysis, it was determined that these levels in the SSO and AO groups were significantly higher than in the control group (P = .000); that said, the difference between the SSO and AO groups was not significant (P > .05). Further, there was a significant difference among groups in mean SCH for the upper outer quadrant of the thigh before the study (F2 = 4.131, P = .019). Advanced analysis showed that thigh SCH in the SSO group was significantly lower than that of infants in the control group. There was no significant thigh SCH difference between the other two groups (P > .05). In addition, infants in the control group had lower mean thigh SCH than the other two groups after the study, but the difference between the groups was not significant (F2 = 2.127, P = .125; Table 2).
No statistically significant difference was found in NSCS (dryness, redness, breakdown) of the infants among groups before the study (KW2 = 2.046, P = .360). However, there was a highly significant difference among group scores after the study (KW2 = 44.193, P = .000). Advanced analysis showed that infants in the control group had significantly higher scores than the infants in either the SSO or AO group (Table 3). The Cronbach α for the NSCS was .33 for the whole group and .29 for the control group after the study.
There has been a recent increase in clinical studies comparing different skin care products for newborn infants. The results are important for generating a standard skin care guideline. Studies examining the effect of plant-derived oils in neonates generally focus on clinical findings, skin condition, infection, and mortality.3,8,9,14
For example, in a study of 115 term newborns, Cooke et al21 applied sunflower oil to one group and olive oil to another, and did not apply any oils to a control group. No significant difference was observed in the skin scores of the infants at the end of the intervention period. In another study with 74 newborns, coconut oil was applied to one group, and no oil was applied to the control group. At the end of the study, TEWL reduction was achieved without increasing bacterial colonization in the intervention group.14 Another study with coconut oil found that the skin status scores of premature babies in the experimental group were better than the control group.8 The results of this study are consistent with extant literature. However, to ensure that topical oils are useful for infant skin health, further evidence-based and randomized controlled trials are needed.
Up to 48 hours from birth, skin hydration may vary according to endogenous (sex, age) and exogenous factors (environmental humidity and exposure); SCH for different body areas may vary anywhere from 30% to 80%.4,22 A study conducted with healthy, term infants found that on the third day of life, in general, SCH was between 50% and 80%.23 Further, SCH is known to increase in the 2 weeks after birth; another study of premature infants found that their SCH levels were between 32.7% and 33.9% after 7 days but increased to 36.4% by the 15th day.24 A third study showed that infant SCH during their first day of life was between 20% and 60%, but after 2 weeks, SCH levels varied by around 30%.4 These findings are consistent with those in this study; preterm infant SCH varied by group, body area, and before and after the study (minimum, 29%; maximum, 38%).
Considering that infants in the control group had a statistically higher birth weight than the other two groups, infants in the control group could also be expected to have high SCH levels. However, the SCH increase in infants in the control group was not as high as in the other groups. These findings suggest that AO and SSO may have positive effects on infant skin. This is in accordance with previous studies that determined SSO had a significant effect on skin moisture.7,21 Another study reported that AO was an effective moisturizer in preterm infants and improved dermatologic problems rapidly.25 However, no study proves the superiority of either SSO or AO. More evidence-based studies are needed to compare different natural oils.
These researchers noted that the NSCSs of infants for whom SSO and AO were applied were similar, whereas those of the control group were statistically significantly higher at the end of the study. Because higher mean scores indicate poorer skin condition, it can be concluded that the natural oils had a positive effect on the general condition of participants’ skin. That said, the mean NSCS of all infants evaluated remained within the reference range throughout the study. It is important to note that even though NSCS is a widely used and practical method for evaluating infant skin condition, it is not as sensitive as biophysical measurements. Therefore, NSCS values do not necessarily correlate with significant findings in skin functional parameters.7,19
This study did not examine certain quantitative parameters such as pH and TEWL. Further, the impact of birth weight and gestational week on SCH and NSCS was not examined. Ultimately, it is not possible to generalize these results because of the limited sample and short intervention period (5 days). Further studies involving longer intervention periods with larger groups and that evaluate quantitative parameters such as pH and TEWL are recommended.
In this study, mean SCH levels were significantly increased in infants in the SSO and AO groups over the control group. Further, there was no significant difference in NSCS between the SSO and AO groups before and after the application, whereas scores were significantly higher in the control group at the end of the study. It is therefore likely that AO and SSO had positive effects on the skin of preterm infants in this study. Researchers found no evidence of the superiority of SSO over AO.
Based on these results, it is likely that NICU nurses can safely use natural oils such as SSO and AO to promote skin integrity and increase SCH among preterm infants. Nurses should be familiar with natural oils such as olive, sunflower seed, almond, and coconut oils to advise parents in their use, although no oil can be recommended definitively.15,16 They also should inform parents and caregivers that infant skin is more sensitive and drier than adult skin and requires moisturization.
Further evidence-based, methodologically appropriate studies of the benefits and drawbacks of topical plant-derived oils on newborn infants are necessary to support the development of standard skin care recommendations and special products for preterm infants.
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