Effectiveness of Prone versus Supine Position on Oxygen Saturation

Effectiveness of Prone versus Supine Position on Oxygen Saturation, Respiratory and Heart rate among Preterm Infants Suffering from Respiratory Distress
Amina Mohamed Thabet* & Nora Abd-El Hamid Zaki**
*Assistant professor of Pediatric Nursing, Faculty of Nursing, Assiut University
** Assistant professor of Pediatric Nursing, Faculty of Nursing, Assiut University
Abstract: Optimal oxygenation and heart rate in preterm neonates is very important. One of these measures is the position of these neonates. This study aimed to determine the effectiveness of prone versus supine position on oxygen saturation, respiratory and heart rate among preterm infants suffering from respiratory distress. Design: quasi-experimental research design was carried out. The subjects included 30 preterm neonates in Neonatal Intensive Care Unit (NICU) at Assuit University Children Hospital. A structured questionnaire sheet included two parts: Part one: Bio-demographic data, part two: Monitoring respiratory rate, heart rate and oxygen saturation. Results: The main results were the mean of respiratory rate was 53.63±11.38, and 59.42±11.3554 (c/min) in prone and supine position respectively. The mean of heart rate was 137.4±6.29 and 141.65±10.06 (beat/min) respectively. The mean of oxygen saturation was 93.38±2.4 and 91.46±2.26 (%) respectively and these differences was highly statistically significant (P=0.001, 0.001 and 0.003 respectively). Conclusion: Prone position can be made more desirable respiratory rate, heart rate, and effective in improving oxygen saturation in preterm neonates with respiratory distress. Recommendations: The nurses could be advised to put the preterm with respiratory distress in prone position. if there is no obstacle to changing the infant’s position.
Keywords: Prone position, Supine Position, Preterm infants, Oxygen saturation, Heart rate, Respiratory rate and Respiratory distress.

Introduction:
Preterm birth is defined as delivery before 37 completed weeks. The issue of preterm birth is still a major health problem in the world; 75% of neonatal mortalities are due to prematurity (Kliegman et al., 2007 ; Cunningham et al., 2010 ; Gibbs et al., 2008). A variety of morbidities are significantly increased in preterm neonates who survive. Morbidity in multiple organs such as respiratory tract, cardiovascular, gastrointestinal, metabolic, neurological and urinary system is much more common in premature neonates compared with those delivered at term (Martin et al., 2009).

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Soon after a premature infant is born, it’s a big challenge to maintain previous functional patterns against different stimuli. Today, prematurity is the most important cause of admission in Neonatal Intensive Care Units (NICUs). Prematurity of lung tissue and respiratory distress syndrome are the common problems in premature infants which illustrate the need for special attention for the respiratory cares (Abdeyazdan et al., 2010).

The main cause of morbidity and mortality in the early neonatal period is respiratory distress syndrome (RDS). According to the degree of prematurity, it occurs in 7%- 50% of neonates, it is responsible for 30%- 40% of newborns’ hospital admission (Morris and Adappa, 2012). Deficiency of alveolar surfactants caused by the immaturity of Type II pneumocyte, resulting low compliance of lungs, alveolar surface tension, decreased gas exchange and a demand for high ventilatory pressures is the significant cause of RDS (Edwards et al., 2013 ; Khattab, 2015).

Signs and symptoms of respiratory distress syndrome includes apnea, cyanosis, grunting, inspiratory stridor, nasal flaring, poor feeding, tachypnea, retractions in the intercostal, subcostal, or suprasternal spaces. These signs and symptoms are occurring at birth and then getting worse over the first 48- 72 hours of infant’s life (Zhang et al., 2015 & Varvarigou et al., 2015).
Cardio-respiratory interaction has been considered an important indicator of development in infants and as reported, heart rate fluctuations may present at the respiratory frequencies even in the absence of respiration. Positioning of preterm infants is a basic neonatal nursing care that includes, prone, supine, side-lying and head up tilted position, a variety of outcomes affected by different body positioning of preterm infants (Picheansathian et al., 2013). Therapeutic positioning of preterm infants is considered as an important intervention that a nurse can carry out with immediate effect and it can be integrated effectively into family-centered care to positively impact the future development of the preterm infant (Zarem et al., 2013).
The behavior of oxygen saturation depends on the body’s position. Scientific records have shown that positioning intervene positively in preterm newborns, contributing to improvement in oxygenation, reducing gastro-esophageal reflux episodes, and reducing thoracoabdominal asynchrony (Ammari et al., 2009). Positioning requires more assiduous care by the ICU nurse. A specific set of skills is needed to take care of preterm infants (Chadwick, 2010).

The aim of the study:
The aim of this study was:
To determine the effectiveness of prone versus supine position on oxygen saturation, respiratory and heart rate among preterm infants suffering from respiratory distress.

Hypothesis:
There will be a difference in on oxygen saturation respiratory and heart rate among preterm when put in prone or supine position.

Preterm who put in prone or supine position will have good oxygen saturation, respiratory and heart rate than those who in other position.

The prone position will have good effect on cardio-respiratory status compare to supine position among preterm.
Materials and Method
Research design:
Quasi-experimental research design was utilized to meet the aim of this study.
Setting:
The study was conducted in Neonatal Intensive Care Unit (NICU) at Assiut University Children Hospital.
Subjects:
A convenient sample of thirty preterm infants with respiratory distress who had the following criteria:
Preterm who born at 28 -37 weeks of gestation.

Oxygen dependent preterm with respiratory distress (tachypnea, retractions or chest in drawing (subcostal, intercostal, sternal, suprasternal) and grunting).

Exclusion criteria: Parents who do not accept to participate in this study, preterm infants with invasive ventilator, who were not able to tolerate the position either due to secretions, presence of nasogastric tube, cephalhematoma, sudden drop in saturation when change the position, preterm with congenital abnormalities or clinical/surgical reasons which made positioning contraindicated, and whose treated with sedative or paralyzing drugs were excluded.

Tool for Data Collection:
One tool was used for collecting data in this study.

A structured questionnaire sheet to collect data and it included two parts:
Part one: Preterm neonate’s bio-demographic data such as (preterm’ postnatal age, gestational age, gender, birth weight, type of delivery) (recorded data).
Part two: An assessment sheet for monitoring respiratory rate, heart rate, and oxygen saturation level during each position and change of positioning.

A pilot study was done on 3 neonates to test the applicability of the tool; these 3neonates were excluded from the sample
Method:
An official approval for conducting the study was obtained from the responsible administrative personnel (the directors of Assiut University Children Hospital and the head of Neonatal Intensive Care Unit to carry out the study after explaining the purpose of the study. Explanation the aim and methodology of the study were done to them by the investigators.

Research was approved from ethical committee in the faculty of nursing
Written informed consent from parents of the studied preterm neonates’ was obtained
Confidential ability of the researchers was ascertained
The tool was developed by the researchers after the thorough review of literature.

Respiratory rate, heart rate, and oxygen saturation were measured 15 minutes after changing the position (time of watch out).
Respiratory rate, heart rate, and oxygen saturation were measured while the infant was receiving the nursing care; the observer didn’t interfere with the routine care of the infants.
Respiratory rate, heart rate, and oxygen saturation were (measured) for an hour (at15 minutes, 30 minutes and 45 minutes and 60 minutes).
Several normal physiological parameters were used to determine the relation to changing position, these were:
Desaturation: the oxygen saturation was is less than 88%;
High oxygen saturation: the oxygen saturation was is 95% or more;
Bradycardia: the heart rate was is less than 100 b/m;
Tachycardia: the heart rate was is more than 160 b/m.

Bradypnea: respiratory rate is less than 30 breath/minute
Tachypnea: respiratory rate is more than 50 breath/minute
Oxygen saturation and the heart rate were measured by the pulse oximeter. A tiny, lighted probe placed on the infant’s hand or foot projects a beam of light through the capillary beds in the tissue. The light beam is converted into an electric signal by a photodetector in the probe that is processed within the module and displayed as both a waveform and a digital value for both the oxygen saturation and the heart rate.

Respiratory rate was measured through observation of chest wall and abdomen movement for one minute.

The procedure was performed in the following manner:
Changing positioning:
The pediatric nurse picked up the preterm infant during a calm period one continuous motion.
First, the supine position was performed by supporting the preterm’s head, feet and the body in the midline by using soft rolls around them. A roll under the shoulders was placed to support the newborn’s (preterm’s) airway and allowed slightly forward flexion of the head.

Second, the prone position was performed by putting the newborn’s (preterm’s) body prone. The arms should be close to the body with the hands symmetrically close up to the mouth. Flexion of the legs can be encouraged with the knees brought up to the chest, raising the hips slightly. This position was maintained by using a rolled blanket to make a boundary; the small hip roll was used to assist in maintaining flexion. Use of a rolled cloth placed under the infant (from top of the head to umbilicus) to provide elevation of the body. Careful observation was made while the preterm neonates were in the prone position to avoid the sudden infant death syndrome.

The preterm neonates were studied when awake and about one hour after a feed. All the infants were on full enteral feeds.

The effectiveness of supine position or prone position on oxygen saturation, respiratory and heart rate among the preterm neonates were assessed.

The effectiveness of supine position and prone position on oxygen saturation, respiratory and heart rate among the preterm neonates were compared.

The obtained sequence position was donning on two days (the first day for supine position and the second day for the prone position).

Field of the study:
Data collection was done by the researchers during 3 months period from the beginning of from April 2017 to June 2017. It was done during the routine work of the hospital in the morning. The sheet required about 60 minutes for filling it; about one preterm was collected per day.

Statistical analysis
The data were tested for normality using the Anderson-Darling test and for homogeneity variances prior to further statistical analysis. Categorical variables were described by number and percent (N,%), where continuous variables described by mean and standard deviation (Mean, SD). where compare between continuous variables by Paired T-test. A two-tailed p;0.05 was considered statistically signi?cant. All analyses were performed with the IBM SPSS 20.0 software.

Results:
Table 1: Percentage distribution of the preterm neonates according to their biodemographic data.

 Biodemographic Characteristics No = 30 %
Age of newborn / days    
Range 1-3
Mean ±SD 2.1±0.75
Gender    
Male 18 60.0
Female 12 40.0
Gestational age/ weeks    
28- 10 33.3
30- 11 36.7
33-34 9 30.0
Birth weight / grams    
1000 13 43.3
1500-2020 17 56.7
Type of delivery    
Cesarean section 30 100.0
Table 2: Comparison between mean and standard deviations of prone and supine position on respiratory rate among preterm:
Respiratory rate  prone position supine position P. value
RR 15 minutes 60.83±15.72 65.8±15.15 0.001**
RR 30 minutes 55.67±12.09 60.27±11.88 0.003**
RR 45 minutes 50.5±11.07 56.37±11.05 0.000**
RR 60 minutes 44.17±13.03 53.4±18.83 0.021*
T-test * Statistical significant difference (p;0.05), ** Highly statistically significant difference (p;0.01).

Table 3: Comparison between mean and standard deviations of prone and supine position on heart rate among preterm
Heart rate prone position supine position P. value
HR 15 minutes 144.93±10.53 148.83±16.14 0.047*
HR 30 minutes 140.77±8.19 144.13±12.68 0.110
HR 45 minutes 135.7±6.27 141.37±9.74 0.001**
HR 60 minutes 129.97±7.42 131.57±24.2 0.697
T-test * Statistical significant difference (p;0.05), ** Highly statistically significant difference (p;0.01).

Table 4: Comparison between mean and standard deviations of prone and supine position on oxygen saturation among preterm
Oxygen saturation prone position supine position P. value
O2 15 minutes 94.63±4.13 92.7±3.89 0.022*
O2 30 minutes 93.1±2.41 91±3.1 0.002**
O2 45 minutes 92.47±2.16 91.03±2.27 0.024*
O2 60 minutes 94.5±2.39 92.1±2.58 0.000**
T-test * Statistical significant difference (p;0.05), ** Highly statistically significant difference (p;0.01).

Table 5: Comparison between mean and standard deviations of supine and prone position on oxygen saturation, respiratory and heart rate among preterm at one hour.

Items Prone Supine P. value
RR 53.63±11.38 59.42±11.35 ;0.001**
HR 137.4±6.29 141.65±10.06 ;0.001**
SaO2 93.38±2.4 91.46±2.26 0.003**
T-test * * Highly Statistically significant difference (p;0.05),

Fig., (1): Comparison of means and standard deviations of preterm infants’ respiratory rate, heart rate, and oxygen saturation in the two positions.

In this study (table 1), the mean ±SD of preterms’ age were 2.1±0.75, they were 18 (60.0%) males and 12 (40.0%) females. The minimum and maximum gestational ages are 28 and 33-34 weeks, respectively. With regard to birth weights of the newborns, 43.3% is 1000 g and 56.7% are 1500-2020 g. All of the newborns (100%) are Cesarean section delivery.

As regard to the respiratory rate (RR) the study showed that, the mean of RR was 60.83±15.72, 55.67±12.09, 50.5±11.07 and44.17±13.03 in the prone position on 15 minutes, 30 minutes, 45 minutes and 60 minutes respectively compared to 65.8±15.15, 60.27±11.88, 56.37±11.05, and 53.4±18.83 in supine positions respectively at the same times and the differences were statistically highly significant between the two positions (P=0.001, 0.003, 0.000 and 0.021 respectively) (table 2).

As regarding the heart rate the study revealed in table 3 that, the mean of HR was 144.93±10.53, 140.77±8.19, 135.7±6.27 and 129.97±7.42 in prone positions on 15 minutes, 30 minutes, 45 minutes and 60 minutes respectively compared to 148.83±16.14, 144.13±12.68, 141.37±9.74, and 131.57±24.2 in supine position at the same times and no statistical differences were found between the two positions on 30 minutes and 60 minutes (P=0.110, and 0.697respectively).

The mean of oxygen saturation in supine, and prone illustrated in table 4.The study revealed that, the mean of oxygen saturation in preterm neonates’ with respiratory distress was 94.63±4.13, 93.1±2.41, 92.47±2.16, and 94.5±2.39 in the prone position on 15 minutes, 30 minutes, 45 minutes and 60 minutes respectively compared to 92.7±3.89, 91±3.1, 91.03±2.27, and 92.1±2.58 in supine positions respectively at the same times and the differences were statistically significant between the two positions (P=0.022, 0.002, 0.024, 0.000 and 0.000 respectively).

Table 5 showed the mean of respiratory rate, mean of heart rate, and the mean of oxygen saturation at one hour, the mean of respiratory rate was 53.63±11.38, and 59.42±11.3554 (c/min) in prone and supine position respectively. The mean of heart rate was 137.4±6.29 and 141.65±10.06 (beat/min) in prone and supine position respectively. The mean of oxygen saturation was 93.38±2.4 and 91.46±2.26 (%) in prone and supine position respectively and these differences was highly statistically significant (P=0.001, 0.001 and 0.003 respectively).
Figure (1) shows the means and standard deviations of preterm infants’ respiratory rate, heart rate, and oxygen saturation in prone and supine position at one hour.

Discussion:
It was found that placing preterm infants in prone or supine position has effects on physiological factors such as cardiorespiratory function, thermoregulation, oxygen saturation (Sahni et al., 2010). Respiratory functions of preterm infants should be supported, since they often experience respiratory distress. The proper positioning of the infant is one of the nursing interventions, which are implemented for this purpose (Arslan et al., 2007). And therefore the aim of this study was to determine the effectiveness of prone versus supine position on oxygen saturation, respiratory and heart rate among preterm infants suffering from respiratory distress.

In our study, thirty preterm neonates participated; the mean ±SD of preterm’s age was 2.1±0.75 days. More than half of the studied samples were males and more than half of them their weights were 1500-2020 g. All of the preterm were cesarean section delivery. These results were matched with the results of (Malagoli et al., 2012), who conduct study about influence of prone position on oxygenation, respiratory rate and muscle strength in preterm infants being weaned from mechanical ventilation and mentioned that forty-five preterm children, born with a mean gestational age of 30.4 weeks and a mean birth weight of 1522g were assessed. Of these, 23 (51%) were male and 25 (56%) were born through vaginal delivery. Also, Sadeh et al., (2011) said thirty-two preterm infants, the mean postmenstrual age 30.37±2.57, and mean birth weight 1250g±313.86, participated in this study.

This study revealed that both supine and prone position was effective in improving respiratory rate in the preterm infants with respiratory distress. However, the effect of prone position was significantly higher in improving respiratory rate in preterm compared with the supine position and this result was agreed with the result of Ghorbani et al., (2013) who conducted a study on comparison the effect of sleep positioning on cardio-respiratory rate in noninvasive ventilated premature infants and stated that, there was a significant difference respiratory rate of premature infants who were similar in gestational age and clinical condition and placed in two positions. Premature infants’ respiratory rate became lower at the prone position than supine in both groups. As agreed with Malagoli et al., (2012) reported that the mean RR in 45 neonates was 57 bpm in the supine position and 53.6 bpm in prone (p = 0.072).

The current study showed that the mean of heart rate was normal in the both positions but the mean heart rate in the prone position was less than the mean in supine position this finding was agreed with another study of Ghorbani et al., (2013) who stated that premature infants’ heart rate became less in the prone position than supine in both groups, and also agreed with Akbarian Rad et al., 2016 who stated that, heart rate was normal in all three positions but the HR variability in the prone position was slightly lower than other positions (P=0.596). However, Fifer et al., 2005 and Ammaria et al., 2009 found adverse results in their studies, they showed that infants’ cardio-respiratory rates are more likely in prone than in supine position. In our view these results may be due premature infants in the prone position spends less time in waking up and a quieter and sleep time, which facilitates and improves the cardio-respiratory status.

In our study the mean of oxygen saturation in the prone position was more than the supine position indicating that this position had improved oxygenation and there was a highly statistically significant difference between them (P=0.003), in my opinion this may be due to when the preterm infants placed in prone position showing less physical activity and energy expenditure that improves their oxygen saturation. This result was in accordance with the result of Akbarian Rad et al., 2016 who conduct study about the effect of position on oxygen saturation and heart rate in very low birth weight neonates and stated that the mean of SaO2 was 97.41±1.91%, 96.74±2.09% and 96.14±2.36% in prone, supine and left lateral positions, respectively and this difference was statistically significant (P=0.032). This finding was also agreed upon with the study of Balaguer et al, (2013) who conducted a study on the infant position in neonates who receive mechanical ventilation and found that the percentage of oxygen saturation was higher in the prone than supine position. Also, Lal et al., (2013) who conducted a study on the effects of position on oxygen saturation in acute respiratory distress at neonates agreed that prone position improved oxygenation in the majority of the patients with respiratory distress.

Eghbalian, (2014) also examined the effect of prone position on oxygen saturation among premature infant with RD, and concluded in his study that oxygen saturation was significantly higher in prone position than supine. Also, the results in the present study were similar to the study by Das et al., (2011) who concluded that prone position improves oxygen saturation and reduces respiratory distress compared to the supine position in neonates suffering from respiratory distress. In our opinion these results may be due premature infants in the prone position may exhibit better expansion of the dorsal lung regions, an increase in lung volume and reduction in atelectatic lung regions and, finally, an improvement in clearance of secretions with a consequent improvement in oxygenation.

Conclusion:
According to the findings, the current study deduces that the prone position as a simple and noninvasive method can be made more desirable respiratory rate, heart rate, and effective in improving oxygen saturation in preterm infants with respiratory distress compared to the supine position that may increase them. Thence our findings support the prone positioning for premature infants.

Recommendations:
With regard to the results of the current study, the study recommended the following:
Nurses in neonatal intensive care units should be advised to place preterm infants with respiratory distress in prone position if there is no impediment to changing the infant’s position.

Regarding the fact that prone position is a risk factor for sudden infant death syndrome, the prone position should be used only when the preterm is carefully supervised.

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