Hui-Ping Wang, Chang-De Jin

1 Graduate College, Tianjin University of Traditional Chinese Medicine, Tianjin, 301617, China;

2＊ School of Nursing, Tianjin University Traditional Chinese Medicine, Tianjin, 301617, China.

Abstract Objective:The meta-analysis is to objectively evaluate the efficacy of swaddling in neonates.Methods:Randomized controlled trials (RCTs) and Randomized cross-over design (RCD) about the effects of swaddling in neonates from multiple electronic databases(PubMed, Web of Science, the Cochrane Library, MBAS, CINAL,CNKI, Wanfang and VIP)until January 2019. Two investigators independently screened eligible studies, extracted data, and assessed the methodological quality by using the quality evaluation criteria for RCTs recommended by Cochrane andbook. Then data were analyzed by Rev Man 5.3.Results:A total of 6 papers (4 randomized controlled trials and 2 Randomized cross-over design) with 318 participants were included. The meta-analysis indicated that there was a significant difference on Body Temperature, eart Rate, crying time, incidence of open eyes and incidence of closed eyes (P＜0.05); There was no significant difference in Spo2 level between the two groups (p＞0.05).Conclusion:Swaddling bath has little influence on the Body Temperature, eart Rate, and behavioral response of newborn. And it has no significant effect on maintaining Spo2 level. owever it can reduce the stress behavior of the newborn. Due to the limitations of the quality of studies included, multi-centered randomized controlled trial large sample size are needed in the future to evaluate the effects of prone position ventilation on neonatal respiratory distress syndrome.

Keywords:swaddling bath; Neonate; Meta-analysis

Background

Bathing is an important primary nursing procedure for newborns [1-2]. It can relax the muscles of the newborn, regulate Body Temperature and reduce pain [3], but it may also lead to deterioration of the newborn’s vital signs, such as: increase or decrease in heart rate and respiratory rate, temporary decrease in oxygen saturation and hypothermia [4-5]. There is evidence that swaddling bath can reduce the newborn physiological signs and movement behavior, save energy and improve state control (such as reduce tears and incitement), it also keeps newborns calm, increases self-regulation and reduces Body Temperature loss[6]. Therefore, this study systematically evaluates the relevant literature and performs a meta-analysis to evaluate the effect of swaddling in neonates and provide strong evidence for clinical care.

1 Materials and methods

1.1 Search strategy

We carried on a comprehensive search of the literature in five English databases: PubMed, Web of Science,the Cochrane Library, EMBASE and CINALHL, and four Chinese databases: CBM, CNKI, Wanfang and VIP databases, which have been searched from their establishment to January 2019.

Search strategy: Chinese search strategy: “Newborn/preterm/very low birth weight”. English search strategy: “Infant*/Neonate*/Newborn*” AND“swaddle/swaddling”. We used following subject words, free words when searching. The language was restricted to Chinese and English. Computer retrieval is the main method, supplemented by manual retrieval. In the retrieved literatures, the second extended retrieval is carried out to avoid the omission of literatures, and the quality evaluation of the included literatures is carried out.

1.2 Inclusion and exclusion criteria

Inclusion criteria: Randomized controlled trials(RCTs) or Randomized cross-over design (RCD);term infants or premature infants who were born in the hospital; Vital signs are stable; Voluntary participation of parents.

Exclusion criteria: Newborns with contraindications to bathing; Having a congenital disease; Abnormal or pathological development of the brain and nerves.

1.3 Data extraction

Two reviewers screened these studies independently according to the inclusion and exclusion criteria.The data in each included study was extracted independently by two reviewers using a pre-designed data extraction form. The following information was extracted: study characteristics (eg, author and year),study design, sample size, description of interventions,and indexes of assessed outcomes. During the processes above, disagreements between the two reviewers were resolved through consulting, if the consensus could not be reached, the third reviewer was consulted for a final decision.

1.4 Data analysis

Meta-analysis was conducted using the RevMan 5.3 software. When meta-analysis was conducted for continuous variables, data were described and expressed as mean difference (MD) or standard mean difference (SMD) with 95% confidence interval (CI).If significant heterogeneity did not exist among studies(I2≤50%, P≥0.1), a fixed effect model was established in the meta-analysis. If significant heterogeneity existed among studies (I2 ＞ 50%, P ＜ 0.1), the source of the heterogeneity was analyzed. If only statistical heterogeneity was observed among the studies, without clinical heterogeneity, and will not affect result, a randomized effect model was constructed. Descriptive analysis was conducted if the heterogeneity was too obvious and the source could be not determined.

2 Results

For the first time, 1412 related literatures were detected, including 98 in Chinese and 1314 in English.Repeated literatures were removed by EndNote software, and literatures that obviously did not meet the inclusion criteria were excluded after reading the title and abstract, 9 in English and 1 in Chinese were selected for the first time. After further reading the full text, it was excluded to obtain the full text, which was 2.2.2 Effect of swaddling bath on Heart Rate

3 articles [9, 10, 11] reported the effect of swaddling bath on heart rate. The results showed no heterogeneity between studies (P=0.14, I2=48%), so we used a fixedeffect model for Meta-analysis. Compared with the control group, the Heart Rate of newborns in swaddling bath group was more stable, and the difference was statistically significant [Z=2.12, 95%CI (-6.61,-0.25),P=0.03], in Fig.1.

2.2.3 Effect of swaddling bath on SPO2

3 literatures [9, 10, 11] reported the effect of swaddling clothes on Spo2. The results showed that there was heterogeneity between studies (P=0.03,I2=72%), so we used a random-effect model for Metaanalysis. The results showed that Spo2 in swaddling bath group was higher than that in control group, and the difference was not statistically significant [Z=1.23,95%CI (-0.19, 0.85) , P=0.22], in Fig.2.

2.2.4 The effect of swaddling bath on crying time Five articles [8, 10, 11, 12, 13] reported the influence of swaddling bath on crying time. The results showed that there was significant heterogeneity among the studies,so only descriptive analysis was conducted. The results showed that swaddling bath can reduce the crying time of newborns in all 5 studies, and the difference was statistically significant (P＜0.05).

3.2.5. The effect of swaddling bath on the incidence of open eyes

The results showed no heterogeneity between studies(P=0.34, I2=0%), so we used a fixed-effect model for Meta-analysis. The results showed that the incidence of open eyes in swaddling bath group was lower than that in control group, and the difference was statistically significant [Z=3.71, 95%CI (-27.84, -8.58), P=0.22], in Fig 3.inconsistent with the study design, outcome indicators and other literatures. Finally, 6 papers (5 in English and 1 in Chinese) with 318 patients were included.

2.1 Basic characteristics and methodological quality evaluation of included studies

The basic characteristics of the included studies are shown in table 1. This study included 4 RCTS and 2 RCDs. 6 papers (5 in English and 1 in Chinese) with 318 participants. All the included literatures were evaluated strictly according to the Cochrane 5.1.0 systematic evaluation manual quality standard and the quality grade was assessed. Among the 6 included literatures, 1 was of A quality, and 5 were of B quality.Among them, 3 studies [8, 9, 11] were grouped by random number table, 1 study [10] was grouped by computer-generated random sequence, and the other 2 studies [12, 13] were grouped by random block grouping; 1 study [9] used allocation hiding; 3 studies[9, 12, 13] blinded those who assessed the results.In addition, the baseline included in the study was comparable.

2.2 Meta-analysis results

2.2.1 Effects of swaddling bath on Body Temperature

5 articles [8, 9, 10, 11, 13] reported the effect of swaddling bath on Body Temperature. The results showed significant heterogeneity between studies, so only descriptive analysis was performed. Freitas [9]et al. found that swaddling bath could not maintain the stability of neonatal Body Temperature, and the difference was not statistically significant (P＞0.05).The results of Chen and Ceylan[8, 10, 11, 13] et al.showed that the neonatal Body Temperature loss in the intervention group was lower than that in the control group, and the difference was statistically significant(P＜0.05).

Fig 1. Forest plot of Heart Rate

Table 1. Basic characteristics and methodological quality evaluation of included studies

Fig 2. Forest plot of SPO2

Fig 3. Forest plot of the incidence of open eyes

3 Discussion

3.1 The effect of swaddling bath on physical signs

The neonatal skin care association's women's health guide, obstetric and neonatal nurses and neonatal nurses association (2013) recommends: Once the umbilical cord is cut, premature babies and newborns are swaddled bath [14]. This study shows that swaddling bath can promote the stability of heart rate and body temperature, but it has no significant effect on the stability of SPO2 level. Swaddling can help reduce pain in newborns [15-16], effectively reduce their behavioral stress and reduce the stress response during bathing. At the same time it can maintain a stable Heart Rate.

Bathing affects the lungs and gastrointestinal tract,increasing evaporation and expanding blood vessels around the skin. The poor regulation of neonatal body temperature increases the possibility of hypothermia.When swaddling is performed, the baby is covered by swaddling cloth and warm water during the bathing process, which reduces the change of heat and ensures the stability of body temperature [17]. Short bath time or weak bath stimulation may be the reason why swaddling bath has no effect on newborn SPO2 level stability. In addition, the depth and temperature of the water bath, as well as the bath environment and time are important factors affecting SPO2 levels[9], however, it has not been unified in the literature included in this study. This may also be the reason why swaddling bath at the SPO2 level is not effective.

3.2. The effects of swaddling on behavioral responses

Swaddling bath can reduce newborn crying time,reduce the incidence of open eyes and improve the incidence of closed eyes. After the birth of a newborn,swaddling bath can simulate the uterine environment.This familiar environment provides the newborn with a calm and stress-free bath experience, which promotes a state of calm in the newborn [18-19]. Crying is the most obvious response to pain and stress [20].After the environment of newborn babies’ changes,swaddling bath can wrap newborn babies in water to soak, providing them with a strong sense of security"package", which provides newborn babies with greater comfort and satisfaction and reduces pressure [20]. The swaddling bath significantly increased the newborn's self-regulation ability to open and close eyes, and significantly reduced the duration of crying. After the newborn leaves the intrauterine environment, it is more difficult to adapt to the external environment, the baby may feel every touch is pain, and will make behavioral response. Gently wrap a blanket, soft cloth or a mother's hand around the baby to help it feel as safe as if it were in the womb [21], this swaddling method can relieve pain in newborns [22] and reduce the incidence of crying.

4 Conclusions

Swaddling bath has a good effect on maintaining the physiological signs and behavioral responses of newborn, but the application of swaddling in neonates is still at the initial stage and lack of multi-center and large-sample RCTS. At the same time, we found that the evaluation indicators were relatively limited, so later studies could take weight, sleep quality, the impact on parental pressure, maternal and infant attachment,parental satisfaction and participation as indicators to evaluate the effectiveness of swaddling clothes. In this study, only published Chinese and English literatures were retrieved and the number of some index literatures was small, which would affect the accuracy of the research conclusion to some extent.