Premature births account for 11.1% of the total number of births worldwide. In Brazil, the percentage is slightly higher, at 11.9% (World Health Organization (WHO), 2012; Blencowe and Cousens, 2013; UNICEF, 2014). As a result of the demands often associated with prematurity, the preterm infant generally requires hospitalisation, in many cases for prolonged periods. In addition, the preterm infant's system and organ immaturity can lead to difficulty in adapting to life in its neuropsychomotor development, which may cause delays and extrauterine alterations in the long term (Ministério da Saúde, 2011a).
According to the synactive theory of newborn behavioural organisation and development (Als, 1982), the adaptation of the preterm infant to the neonatal intensive care unit (NICU) environment varies according to his or her ability to change their behaviour in response to a stimulus; to achieve a well-regulated balance; and to maintain the energy required to sustain life. This theory is divided into five subsystems: physiological, motor, behavioural state, attention, and interaction and regulatory (Ministério da Saúde, 2011a). Neuropsychomotor development is the result of a number of factors inherent to the preterm infant and his or her environment, which influence behaviour (Rodrigues and Bolsoni-Silva, 2011).
In this context, the hospital environment, along with the preterm infant's clinical conditions, can influence physiological and behavioural responses, both during hospitalisation, and after discharge from the NICU. Studies show that preterm infants' motor skills improve when early stimulation is received (Rodrigues and Bolsoni-Silva, 2011; Madlinger-Lewis et al, 2014). As the musculoskeletal system of the newborn infant is responsible for the positioning of the body during hospitalisation, the movements that the preterm infant performs, as well as the postures adopted, contribute to the formation of the spine, joints and skull. The NICU team is therefore responsible for the preterm infant's alignment, posture and movement (Rodrigues and Bolsoni-Silva, 2011).
Usual procedure in the NICU is that the infant should be positioned in alternate postures throughout the day, to prevent pressure lesions and postural deformities, and to improve respiratory rate and infant relaxation. Changing an infant's position is therefore recommended every 4 hours, or according to the infant's need (Gomella et al, 2004; Olmedo et al, 2012).
When positioning is not properly carried out, damage can be caused due to the immaturity of the musculoskeletal system, which can generate body alignment complications, such as neonatal hypertonia. The maintenance of a proper positioning can, however, provide control of sleep and wakefulness state, improve cardiorespiratory function and promote energy conservation. Positioning also improves an infant's self-regulation, which results in fewer stressful episodes to the newborn infant (Cândia et al, 2014). When the infant is able to achieve periods of deep sleep without interruption, the creation of permanent neural circuits takes place, stimulating the sensory-motor development (Liaw et al, 2012).
During positioning, attention should be paid to maintain the posture and movements, in order to improve skeletal development and body alignment, and to provide tactile and visual proprioceptive stimuli, keeping newborn behaviour comfortable, and conserving energy to prioritise vital functions (Sweeney and Gutierrez, 2002). Changing positioning and performing an appropriate placement affects motor development by positive stimulation of joints and muscles, which influences the mechanoreceptors, in order to improve and adapt the movements. As well as this, change promotes improved respiratory mechanics and a greater chance of relaxation for the preterm infant (Olmedo et al, 2012).
As a result, the preterm infant should therefore be handled holistically in the NICU, which is responsible for all aspects of the infant's medical care, besides appropriate positioning. Although positioning is a routine procedure in the NICU, and there is a standardised way in which this should be carried out, it is not always applied in the NICU in Brazil (toso et al, 2015).
Study setting
In the NICU where this study was developed, the health team did not have a standardised way of positioning preterm infants. As part of a separate study (Toso et al, 2015), the authors developed a standardised way of positioning to be used in the NICU to fill this need. This study presented here set out to apply this protocol, comparing this standard operating procedure with usual positioning in the NICU.
Study aims
This study was therefore developed to show NICUs the importance of following standrard operating procedures that concern preterm infant positioning. It is necessary to provide evidence that shows the influence of postural maintenance on the behavioural and physiological state of the preterm infant during hospitalisation in the NICU. Health professionals should understand the consequences of preterm infant positioning during NICU hospitalisation and after hospital discharge.
The aim of this study was to compare the different positions (lateral, prone and supine) performed as a standard operating procedure (Toso et al, 2015) and to examine whether there are differences related to pain, behavioural and physiological responses of preterm infants hospitalised in the NICU.
Materials and methods
Study design
This was a quantitative, quasi-experimental study that took place in a university hospital in southern Brazil, from June 2015–March 2016.
The study population was composed of preterm infants admitted to the NICU during the study period. The criteria for inclusion in the study sample were infants of a gestational age ≤ 32 weeks, with no congenital anomalies. Preterm infants whose parents or legal guardians did not give consent; or infants with a clinical diagnosis or treatment that would make it impossible to change position, such as an umbilical arterial catheter in situ, were excluded from the study. Sample calculation was performed by the program GPower 3.1, with a sample power of 0.94, with a size effect of 0.25 and a significance level of 0.05. The sample consisted of 24 preterm infants, who were randomised anonymously with a simple draw, by throwing a dice. Six preterm infants were allocated to each position: right side position, supine position, left side position and prone position. After randomisation, participants were distributed in ascending order according to bed availability in the NICU.
Data collection
Data were collected at birth to characterise the sample, although the intervention did not begin until 72 hours after birth. During the procedure, the variables evaluated referred to the proposed synactive theory of newborn behavioural organisation and development (Als, 1982), which corresponded to physiological subsystem responses (vital functions such as heart rate, respiratory rate and peripheral oxygen saturation); the neurological motor subsystem (involving muscle tone, posture, and voluntary and involuntary movements); and the behavioural state subsystem, which comprises six states of consciousness: deep sleep, light sleep, sleepy, awake, awake with activity, and cry (Liaw et al, 2012).
‘Usual procedure in the NICU is that the infant should be positioned in alternate postures throughout the day, to prevent pressure lesions and postural deformities, and to improve respiratory rate and infant relaxation’
The dependent variable analysed the placement of the preterm infant, taking into account behavioural, physiological, and pain responses. The pain response was measured by the Neonatal Infant Pain Scale (NIPS) and the behavioural response was checked by the Neonatal Beahviour Assessment Scale (NBAS) (Brazelton, 2011).
The NIPS scale is a multidimensional instrument used routinely in the NICU to assess acute pain. The scale evaluates behavioural and physiological responses by scoring on six different parameters. The infant is considered to be in pain when the score is greater than or equal to 4 (Ministério da Saúde, 2011b).
The NBAS (Brazelton, 2011) (Ministério da Saúde, 2011b) evaluates six behavioural states: deep sleep, light sleep, sleepy, awake, awake with activity, and cry (Vignochi et al, 2010; Ministério da Saúde, 2011b). This scale evaluates behaviour using direct observation of the preterm infant, resulting in a behavioural classification, scored from 1 to 6. Scores of 5 or 6 indicate that the preterm infant presented some discomfort (Bueno et al, 2014).
To record physiological responses, heart rate and peripheral oxygen saturation were verified by the Omnimed Omni 612 multiparameter monitor, while the researcher observed and counted the respiratory rate for 1 minute, once per hour during the intervention period. The researcher was a physiotherapist qualified to perform all the cited evaluations, and the preterm infants were continuously monitored, following a pre-established routine. All variables were evaluated 30 minutes before the beginning of the procedure, during the 3-hour study period, and 30 minutes after the intervention. The average of the data collected during the 3-hour interval of the standard operating procedure was made based on the three-data measurement for each variable: physiological (heart rate, respiratory rate, peripheral oxygen saturation), behavioural (BSM), and pain (NIPS). Each variable was measured five times: once before the intervention, three times during the intervention, and once after the intervention. As there were three measurements collected during the intervention, an average was calculated to compare with the data before and after.
All variables mentioned above were recorded in a research form designed specifically for the survey, which was pre-tested in its content and layout.
Data analysis on the chosen physiological variables—respiratory rate, heart rate and peripheral oxygen saturation—were based on a study by Peixe et al (2011). In Peixe et al's study, the average heart rate for a preterm infant was considered to be 125 beats per minute, ranging from 70–190 beats per minute, and the average respiratory rate was considered to be 30–50 breaths per minute.
Evidence (Watt and Strongman, 1985) has shown that preterm infants have a short sleep-wake cycle and that many aspects of neonatal intensive care environments, such as routine handling, invasive procedures, bright lighting and noise, can create stress, disrupt behaviour, and interfere with sleep in premature infants. In this study, all participants were exposed to the same effects of the NICU environment. To control any effects during the 4 hours of observation, all handling was registered, in order to identify any alterations in vital signs, NBAS score or NIPS assessment.
Intervention
The procedure was not started until the preterm infant was 72 hours old, due to the high risk of developing intracranial hypertension through excessive handling in this period. The intervention occurred during 5 consecutive days and the positioning was done by the responsible researcher.
The researcher started the collection of vital signs, NIPS assessment and NBAS score 30 minutes before the the preterm infant's second positioning change of the morning (Figure 1). After this, the preterm infants were positioned according to standard operating procedure (Toso et al, 2015) and evaluations were repeated 30 minutes after every hour and 30 minutes after the end of the procedure, when the preterm infant received the NICU's routine positioning. The preterm infant was always positioned according to the drawn group, and the researcher took care not to disturb equipment such as catheters. The researcher evaluated the integrity of the skin throughout the intervention. The comfort of the baby was emphasised in all positions, even in cases where mechanical ventilation was used. Mechanical ventilation did not interfere with the positioning.
The positioning according to the standard operating procedure Toso et al (2015) can be seen in Figure 2. In order to ensure the proper body positioning, nests, rolls or other forms of support were applied. The standard operating procedure consisted of:
Data analysis
Descriptive statistics (mean, standard deviation, median, minimum and maximum) were used to analyse the sample. Inferential analysis from the one-way Anova and Friedman tests with a significance level of 5%, using the BioStat 5.0 program, were used.
Results
Most of the preterm infants in the study were male, aged 28–32 weeks, and weighed 1000–1499 grams. Most (n=21) were given some kind of oxygen therapy during the hospital stay. Of the 24 infants, 14 were not given sedatives (Table 1).
| Variable | Absolute frequency | Relative frequency |
|---|---|---|
| Sex | ||
| Female | 8 | 33.3% |
| Male | 16 | 66.6% |
| Gestational age | ||
| <28 weeks | 4 | 16.6% |
| 28 to 32 weeks | 20 | 83.3% |
| Birth weight (grams) | ||
| <1000 | 5 | 20.8% |
| 1000–1499 | 16 | 66.6% |
| 1500–2000 | 3 | 12.5% |
| Oxygen therapy | ||
| Yes* | 21 | 87.5% |
| No | 3 | 12.5% |
| Sedation | ||
| Yes ** | 10 | 41.6% |
| No | 14 | 58.3% |
The relationships between physiological variables and infant positioning are presented in Table 2. Analysis showed that the heart rate was reduced in the right side, supine and prone position groups during the intervention, compared to before the intervention. While respiratory rate was reduced in all positions, the peripheral oxygen saturation remained stable in most positions, slightly increasing in the right side position group. The maintenance of the peripheral oxygen and the reduction of the heart rate and respiratory rate during the procedure demonstrate that the preterm infant achieved greater self regulatory competence when positioned according to standard operating procedure (Toso et al, 2015).
| Variable | Right side position Mean ± | Left side position Mean ± | Supine position Mean ± | Prone position Mean ± | P-value |
|---|---|---|---|---|---|
| Heart rate | |||||
| Before intervention | 161 ± 14 | 159 ± 13 | 156 ± 16 | 166 ± 17 | 0.51 |
| During intervention | 160 ± 12 | 159 ± 15 | 151 ± 12 | 163 ± 16 | 0.23 |
| After intervention | 160 ± 13 | 158 ± 14 | 152 ± 16 | 162 ± 15 | 0.53 |
| Respiratory rate | |||||
| Before intervention | 49 ± 11 | 44 ± 10 | 47 ± 13 | 51 ± 11 | 0.54 |
| During intervention | 48 ± 9 | 42 ± 10 | 43 ± 10 | 47 ± 12 | 0.57 |
| After intervention | 51 ± 11 | 44 ± 10 | 43 ± 9 | 49 ± 9 | 0.57 |
| Peripheral oxygen saturation | |||||
| Before intervention | 95 ± 2 | 95 ± 3 | 95 ± 2 | 95 ± 2 | 0.93 |
| During intervention | 96 ± 2 | 95 ± 2 | 95 ± 2 | 95 ± 2 | 0.65 |
| After intervention | 95 ± 2 | 95 ± 2 | 96 ± 1 | 95 ± 2 | 0.58 |
Table 3 shows analysis of behavioural variables and pain by infant position. In behavioural analysis, it was observed that all preterm infants started the procedure with a median NBAS score of 2. The prone position presented the maximum NBAS score at the beginning of the procedure. During the procedure, the median was reduced to 1 in the left side, supine and prone position groups, although the maximum NBAS score in the supine and prone position groups increased.
| Variable | Right side position Median (min–max) | Left side position Median (min–max) | Supine position Median (min–max) | Prone position Median (min–max) | P-value* |
|---|---|---|---|---|---|
| Neonatal Behaviour Assessment Scale | |||||
| Before intervention | 2 (1–4) | 2 (1–4) | 2 (1–3) | 2 (1–5) | 0.83 |
| During intervention | 2 (1–4) | 1 (1–4) | 1 (1–4) | 1 (1–6) | 0.73 |
| After intervention | 2 (1–4) | 1 (1–5) | 1 (1–4) | 2 (1–4) | 0.63 |
| P-value** | 0.13 | 0.95 | 0.07 | 0.27 | |
| Neonatal Infant Pain Scale | |||||
| Before intervention | 1 (0–3)** | 1 (0–4) | 1 (0–4)** | 1 (0–4) | 0.91 |
| During intervention | 0 (0–3) | 0 (0–4) | 0 (0–4)** | 0 (0–4) | 0.78 |
| After intervention | 0.5 (0–3)** | 0 (0–4) | 0 (0–4) | 0 (0–3) | 0.88 |
| P -value** | 0.03** | 0.35 | 0.01* | 0.07 | |
In all positions the median NIPS score before the intervention was 1, which indicates no pain. However, in the left side position, supine position and prone position groups, there was at least one preterm infant with pain, since they scored 4 on the NIPS scale. During the procedure, the median pain score for all positons was 0, but the left side position, supine position and prone position groups continued to present cases of pain, with a score of 4 in at least one preterm infant (Table 3). There was a significant reduction between the beginning and the end of the intervention in the right side position group (P=0.03), between the beginning and during the procedure in the supine position group (P=0.01). Although the prone position did not present a significant reduction, it was likely to present a reduction between the beginning and during the intervention (P=0.07).
Discussion
The data showed that there was no change in heart rate within the different position groups, except during the intervention, in which the heart rate showed a greater reduction in the supine position. No statistically significant difference was identified. This observation is similar to evidence from the Joanna Briggs Institute (2010), where the heart rate also showed no changes between different positioning groups, or in incidences of bradycardia and apnoea.
A reduction in respiratory rate was identified in all positions, but no significant statistical difference was shown. A survey by Cândia et al (2014) found a reduction in respiratory rate when the preterm infant was placed in prone position, compared to the infant's initial position (or dorsal side) during hospitalisation in NICU. The standardised and appropriate positioning used by Cândia et al (2014) was able to improve respiratory capacity of the newborns, and the authors concluded that prone positioning reduced preterm infant stress based on the reduction of the respiratory rate, the salivary cortisol level and Brazelton sleep score. In addition, the physiological stability that enables an improvement in respiratory pattern also enables a reduction in respiratory rate (Empresa Brasileira de Serviços Hospitalares and Ministério da Educação, 2015). Moreover, Gouna et al (2013) noted in the comparison between positions of preterm infants that the left side and prone positions provided better results in pulmonary function and respiratory strategy in this population.
In the evaluation of the peripheral oxygen saturation, all groups started with the same mean and no statistical significance was oberved. The highest mean was shown in the right side position group, which confirms the findings of Hough et al (2013), who assessed ventilation distribution in three different positions (lateral, supine and prone) and found no statistical significance.
No significant difference was found between or within groups in relation to NBAS score. The same was observed during the NIPS pain evaluation, where every position group began with similar scores of 1, and maintained this value throughout the intervention. After, all groups scored 0, with the exception of the left side position group, which presented the lowest variation of all the positions, and no statistically significant differences. In a study conducted by the Joanna Briggs Institute (2010), there were also no significant differences related to the pain response in invasive procedures between preterm infants positioned in a supine position or prone position. However, the preterm infant positioned by a standardised procedure in a lateral position showed a significant reduction in pain scores compared to the preterm infant not positioned according to this protocol.
The reduction in NBAS scores in different positions demonstrated greater comfort and relaxation and reduced energy expenditure. Both of these results therefore contributed to the infant's development and clinical outcomes while in hospital.
Ammari et al (2009) evidenced in their study that the preterm infant spent less energy to maintain the thermal control when in a prone position. In addition, proper positioning has been shown to contribute to the maintenance of neuromuscular and osteo-articular function, as well as the development of spontaneous motor activity (Xavier et al, 2012). In their study, Xavier et al concluded that the preterm infant had a higher risk of cranial deformities due to the fact they remained with their head in the same position for long periods of time. The authors emphasised that the deformities went beyond the aesthetic changes, leading to delays in neuropsychomotor development, visual changes and episodes of otitis media. A regular change of position may therefore contribute to a reduction in the risks of deformities and other developmental changes, although this is beyond the scope of this article.
Based on the results of this study, which highlighted the importance of following the standard operating procedure for positioning (Toso et al, 2015), health professionals should therefore prioritise the standardised positioning of the preterm infant in NICU. Standardised positioning (Toso et al, 2015) consists of body alignment; the maintenance of the correct head position to avoid inappropriate lateralisation; stimulation of the midline; flexion of upper limbs; and lower limb support. Standardised positioning can be facilitated by accessories such as padded rolls and rings. Following these guidelines will help to provide greater comfort to the preterm infant during the hospital stay and reduce the risk of changes in the motor development in the NICU and after hospital discharge.
Conclusion
Positioning according to a standard operating procedure can assist physiological responses and behavioural adaptation of preterm infants. Despite no significant statistical difference between the different positions, there was a reduction in NIPS and NBAS scores, indicating greater relaxation of the preterm infant during the standard operating procedure positioning. Pain was likely to be reduced when positioned in prone position, and a significant reduction in pain scores? was noticed while in the right side and supine positions. In short, this study shows the effects of preterm infant positioning by following standard operating procedure guidelines.