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 Table of Contents  
ORIGINAL ARTICLE
Year : 2018  |  Volume : 15  |  Issue : 3  |  Page : 324-330

Effect of earplugs on the physiological response of preterm infants during a nebulizer session


Department of Pediatric Nursing, Faculty of Nursing, Cairo University, Cairo, Egypt

Date of Submission26-Sep-2018
Date of Acceptance29-Oct-2018
Date of Web Publication28-Dec-2018

Correspondence Address:
Eman A Moselhi Mater
Department of Pediatric Nursing, Faculty of Nursing, Cairo University, Cairo, 12651
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/ENJ.ENJ_23_18

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  Abstract 


Background High noise levels may be harmful to preterm infants and have negative short-term effects on cardiovascular and respiratory systems. A nebulizer session before suction is the most common stressful procedure for preterm infants. Earplugs protect preterm infants from noise and improve their physiological state.
Aim This study aimed to evaluate the effect of earplugs on the physiological response of preterm infants during a nebulizer session.
Patients and methods The study, a one group time series quasi-experimental research design, was done on a purposive sample of 30 preterm infants attending the Neonatal Intensive Care Unit (NICU) of El Manial University Hospital (Kasr Al Ainy). A total of 30 preterm infants was involved first as a control group and then as the earplug group. Neonatal assessment, noise, and physiological response tools were utilized for data collection. A sound level meter was used to measure the level of noise before the nebulizer session.
Results Results of the study have shown that there was a statistically significant difference in preterm infants before and after using earplugs regarding the mean change of heart rate, oxygen saturation, and systolic and diastolic blood pressure during and after a nebulizer session (P<0.00). The mean change of respiratory rate was significant only during the nebulizer session but it was not significant after the procedure.
Conclusion The findings of the study concluded that the use of earplugs is effective to decrease the effect of noise on the physiological response of preterm infants during a nebulizer session.
Recommendations The educational program is needed to raise awareness among neonatal nurses and other health-care providers about the effect of noise reduction methods such as an earplug on the physiological state of preterm infants.

Keywords: ear plug, NICU, physiological response, preterm infants


How to cite this article:
Moselhi Mater EA. Effect of earplugs on the physiological response of preterm infants during a nebulizer session. Egypt Nurs J 2018;15:324-30

How to cite this URL:
Moselhi Mater EA. Effect of earplugs on the physiological response of preterm infants during a nebulizer session. Egypt Nurs J [serial online] 2018 [cited 2019 Aug 17];15:324-30. Available from: http://www.enj.eg.net/text.asp?2018/15/3/324/248966




  Introduction Top


An earplug is one of the noise reduction devices used for neonates in the NICU (Abdeyazdan et al., 2014), by lowering the sound levels that reach the neonates (Abdulraoof and Arne, 2015). Noise levels above the recommended amount of 45 decibels (dB) is routinely present in the NICU. Noise is considered sound pollution and places additional stress on the preterm infant that is already at a disadvantage for proper growth and development (Liu, 2011; Manske, 2017). Preterm infants are in contact with disturbing noises of short duration and at irregular intervals (Almadhoob and Ohlsson, 2015). Noise is produced by the operation of multiple devices and the unexpected noise from procedures (Santos et al., 2017).

The Environmental Protection Agency recommends that hospital noise levels do not exceed an average of 45 dB during the day and 35 dB at night. To achieve these goals, nurses need to be as quiet as a whisper, 24 h a day. Noise from equipment, alarms, and conversations in the NICU increase the sound levels. In some cases, the NICU can be as noisy as the community. For example, the noise from a nebulizer is equivalent to the sound of traffic, around 60 dB (Stafford et al., 2014). Noise pollution in the NICU can impact cardiovascular, respiratory, auditory, and nervous systems of the neonate. This can have both an immediate effect that causes distress to the infant and lasting effects on overall development. There is evidence of deleterious effects of high levels of sound pressure occurring in newborns, for example, higher oxygen consumption and increased heart rate (Cardoso et al., 2015).

Since nurses are a key participant in monitoring and maintaining the stability of the infant’s physiologic development in the NICU, it is imperative that evidence-based practice supports methods to safeguard the neonate from environmental stressors, such as noise (Zamberlan et al., 2012; Manske, 2017). Interventions to protect patients from noise in the NICU, such as earplugs, may be beneficial in optimizing the outcomes (Stafford et al., 2014). It is a more cost-effective way when used correctly. It can reduce noise by 15–30 dB (Szymczak and Shellhaas, 2013). Earplugs in the NICU improve the vital signs, increase growth, improve physiological and motor development, and improve sleep efficiency. Moreover, the staff, especially nurses, can decrease the sound levels by implementing noise reduction methods (Basner et al., 2014; Carvalhais et al., 2015; Watson et al., 2015; Babu, 2017). In Egypt, there are scarce researches conducted to evaluate noise reduction methods among preterm infants in the NICU, so the current study was conducted to evaluate the effect of earplugs on the physiological response of preterm infants during a nebulizer session. Hopefully the findings of the current study would help preterm infants to overcome the physiological effect of noise and to provide evidence-based data that can develop the neonatal nursing practice and research.


  Materials and methods Top


Research design

One group time series quasi-experimental design was utilized to accomplish the purpose of the study. A total of 30 preterm infants were involved first as a control group and then as the earplug group.

Operational definitions

For the purpose of the current study, the physiological responses of preterm infants are the changes of heart rate, respiratory rate, oxygen saturation, and blood pressure.

Hypothesis

Preterm babies who wear earplugs before a nebulizer session will have less physiological changes of heart rate, respiratory rate, oxygen saturation, and blood pressure than before.

Sample and sample size

A purposive sample of 30 preterm infants was selected according to the following inclusion criteria: gestational age from 28 to less than 37 weeks had respiratory distress, conscious, both sexes, newly admitted (chronological age was within the first week), and undergoing routine suction with a needed nebulizer session. The exclusion criteria included newborn infants with severe neonatal sepsis and congenital anomalies (central nervous system and cardiovascular system).

To determine a sample size, a power analysis was conducted using 0.05 as the level of significance, 0.95 as the power and effect size of 0.25. The minimum required sample size obtained was 30 preterm infants.

Ethical consideration

Prior to data collection, permission was obtained from the Research Scientific Board of the Hospital, the head of NICUs and Faculty of Nursing, Cairo University. The parents of newborn infants gave informed verbal consent prior to their newborn infants’ participation in the study. The participation was voluntary.

Setting

The study was conducted at the Neonatal Intensive Care Unit at El Manial University Hospital (Kasr Al Ainy).

Instruments

  1. The neonatal assessment tool was developed by the researcher to collect data about the preterm infant’s characteristics such as birth weight, gestational age, Apagr score, etc.
  2. Noise recording sheet was developed by the researcher to record minimum and maximum levels of environmental sound.
  3. Sound level meter was used to measure the level of noise in the NICU environment. It is professional tool solutions since 1991, model MT-4618, resolution 0.1 dB, measuring range is from 30 to 130 dB, can record minimum and maximum value with auto range and good anti-interference performance, ISO 9001, PROKIT’s Industries Co., and certified.
  4. The physiological response tool was developed by the researcher to record the physiological parameter (respiration, pulse, blood pressure, and oxygen saturation) during and after 10 min of nebulizer session.
  5. An earplug is a device that is meant to be inserted into the ear canal to protect the preterm infants’ ears from loud noises, is made of moldable silicone which is fitted to the ear canal.


Pilot study

A pilot study was carried out on 10% of sample size (three preterm infants) to ensure the clarity, applicability of the tools, test feasibility of the study, and to estimate the sample size and the time needed for data collection. The result of the pilot study confirmed that the study was feasible. The sample of the pilot study was excluded from the total sampling.

Validity and reliability

The tool was submitted to a panel of five experts in the field of high-risk neonates to examine content validity (covering, clarity, wording, length, format, and overall appearance). A minor modification was performed. Sound level meter was valid and reliable professional tool solutions since 1991, ISO 9001, and certified.

Procedure

Upon receiving the formal approval from the Research Scientific Board of the Hospital, the Head of NICUs and Faculty of Nursing, Cairo University and the parents verbal consent, data were collected through a period of 6 months from December 2017 to May 2018. Preterm infant’s characteristics were recorded from the medical sheet.

The environmental sound level was measured near the baby’s ear for 30 s by the sound level meter before a nebulizer session. The average of the maximum and minimum displayed voices in dB was considered as the environmental sound. Preterm infants were connected with a vital sign monitor to measure physiological response (pulse, respiration, oxygen saturation, and blood pressure) before, during, and 10 min after a nebulizer session for control and earplug groups, while silicon earplugs were inserted into the ear canal of preterm infants to protect them from loud noises before a nebulizer session only for the earplug group. Each preterm infant had specific earplugs which is disposable and not shared with other preterm infants.

Data analysis

The Statistical Package for the Social Sciences (SPSS) version 20 (IBM, Armonk, New York, USA) was utilized for statistical analysis. Descriptive statistics were computed to summarize the newborn infant’s characteristics, noise level, and physiological parameter. t-Test and one-way analysis of variance was used to compare means.


  Results Top


The characteristics of the preterm infants’ are summarized in [Table 1], [Figure 1] and [Figure 2]. The mean of gestational age was 30.8±7.21 weeks ranging from 30 to less than 37 weeks; the mean of birth weight was 1451±357 g; Apgar score at 10 min was 8.93±1.28; 83.3% of them stayed in the incubator; more than half of them (53.3%) were delivered by a caesarian section; 70% of preterm infants were women; and 46.7% of them were supported by a mechanical ventilator.
Table 1 Newborn infant’s characteristics (n=30)

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Figure 1 Percentage distribution of preterm infants according to their sex (n=30).

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Figure 2 Percentage distribution of preterm infants according to their type of ventilation (n=30).

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[Table 2] illustrates that there was no significant difference between the control and earplug groups regarding the mean of noise level (69.26±5.31 and 68.20±5.96 dB, respectively) and the maximum levels were 78 and 69 dB, respectively, while the minimum levels were 56 dB in both groups. The values were significantly above the AAP standard recommendation (P<0.02).
Table 2 Levels of noise between control and earplugs group (n=30)

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[Table 3] shows that there was a statistically significant difference between control and earplug groups regarding the mean changes of physiological response of preterm infants during the nebulizer session at P less than 0.00; it included the mean change of heart rate (160.96±12.69 and 150.53±14.35, respectively) that increased by 9 beats/min compared with 11 beats/min in the control group, respiration rate (58.13±7.61 and 53.13±6.48, respectively) that increased by 10 beats/min in the earplug group and 21 beats/min in the control group; oxygen saturation (94.20±5.32 and 97.96±1.62, respectively) that decreased by 2% in the earplug group compared with 5% in the control group; systolic blood pressure (83.86±6.25 and 80.53±5.73, respectively) that was increased by 7 mmHg in the earplugs group and 9 mmHg in the control group and diastolic blood pressure (53.33±12.66 and 48.16±5.72, respectively) that increased by 9 mmHg in the earplug group compared with 15 mmHg in the control group.
Table 3 Mean changes of the physiological parameter of preterm infants before, during, and after a nebulizer session among control and earplugs groups (n=30)

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Also, there was a statistically significant difference between preterm infants in control and earplug groups regarding the mean changes of the physiological parameters after 10 min of nebulizer session, the mean of heart rate decreased by 14 beats/min in the earplugs group compared with 10 beats/min in the control group (P<0.05). The mean of oxygen saturation increased by 2% in the earplug and control groups (P<0.05). The mean of systolic blood pressure group increased by 2 mmHg in the earplug group and 3 mmHg in the control group. Diastolic blood pressure decreased by 8 mmHg in the earplug and control groups (P<0.00), while there was no statistically significant difference between control and earplug groups regarding the mean change of respiratory rate after 10 min of nebulizer session, respiratory rate decreased by 14 beats/min in the earplug group compared with 10 beats/min in the control group.


  Discussion Top


The current study results showed that there was a significant difference between preterm infants in the control and earplug groups regarding the mean change of heart rate, oxygen saturation, and systolic and diastolic blood pressures during and after a nebulizer session except that the mean change of respiratory rate was significant during the procedure.

Concerning the mean change of heart rate, the study has shown that an increase in heart rate during the nebulizer session in the control group was higher than the earplugs group (160.96±12.69 and 150.53±14.35, respectively). These results were in agreement with Allinson et al. (2017) who studied the physiological stress responses in infants at 29–32 weeks’ postmenstrual age during clustered nursing cares and standardized neurobehavioral assessments. They found that the heart rate was higher during assessments (mean: 165.2±13.1). Shimizu and Matsuo (2016) reported that several studies have reported increased heart rate during clustered nursing care procedures. The exposure to noise can result in tachycardia and increasing the risks of hypoxic episodes and so impacting the recovery and survival of the vulnerable preterm.

Karlsson et al. (2012) documented that a higher sound level was linked to a higher heart rate (P=0.05). Another study by Abujarira et al. (2012) who studied the impact of earmuffs on vital signs in the NICU documented that the observed linear increase in heart rate was significantly reduced within the earmuffs group (139 vs. 146 beats per minute for the control group) with a P value of less than 0.001.As regards the mean change of respiratory rate, the study found that an increase in respiratory rate during the nebulizer session in the control group was higher than the earplugs group (58.13±7.61 and 53.13±6.48, respectively). Aly and Ahmed (2016) who conducted a study on the effect of noise on neonatal vital data and behavior in NICU in the Al Azhar University Hospital in Egypt reported that there was a significant increase in respiratory rate due to noise exposure (from 42.57±0.63 to 46.49±0.61). Noise exposure in the NICU has some negative drawbacks on the vital signs of neonates (Chen et al., 2009). In addition, Nasimi et al. (2015) who studied the effect of quiet time protocol on the physiological characteristics of preterm infants reported that the respiratory rate at the second hour of intervention was lower in the quiet time group than that in the control (P<0.007). The implementation of quiet time protocol can decrease heart rate and respiratory rate through a decrease in environmental stimuli and is recommended for reducing stress in preterm infants. Moreover, Abujarira et al. (2012) added that the average RR in the earmuffs group was significantly lower than the control group (0.001).Wearing earmuffs inside the NICU had a positive effect on the infants’ vital signs.

According to the mean change of oxygen saturation, the study illustrated that an increase in oxygen saturation during a nebulizer session in the control group was higher than the earplugs group(94.20±5.32 and 97.96±1.62, respectively). This result was consistent with Babu (2017) and Almadhoob and Ohlsson (2015) who reported that noise may cause alternation in oxygen saturation and increased oxygen consumption secondary to elevated heart and respiratory rates and may decrease the amount of calories available for growth. Moreover, Abdeyazdan et al. (2014), who emphasized that when infants wore earmuffs, they had significantly higher oxygen saturation. Earmuffs can protect premature infants against noise in the NICU and improve their physiological state. Another study by Cardoso et al. (2015) who performed several noise measurement levels in a neonatal unit found that oxygen saturation decreases with the noise, going from 95.58 to 94.96%.

Concerning the mean change of blood pressure, the study illustrated that an increase in systolic and diastolic blood pressures during a nebulizer session in the control group was higher than the earplug group (systolic blood pressure was 83.86±6.25 and 80.53±5.73, respectively) and the diastolic blood pressure was 53.33±12.66 and 48.16±5.72, respectively. Sweeney and Blackburn (2013) studied that the neonatal physiological and behavioral stress during neurological assessment observed that the preterm subjects had a higher increase in blood pressure during neurological assessment. This increase in blood pressure for preterm subjects may indicate that a concomitant decrease in peripheral blood flow was required to maintain adequate internal perfusion of vital organs for cardiovascular homeostasis during the stress of neurological assessment.

In contrast, Nasimi et al. (2015) who studied the effect of quiet time protocol on the physiological characteristics of preterm infants reported that there was no significant difference between the groups regarding systolic (P<0.44) and diastolic blood pressures (P<0.36). A literature review of eight studies examined preterm neonatal response to auditory overstimulation and automatic responses to measure the effectiveness of earplugs and earmuffs. Five of the studies found fewer fluctuations in heart rate, respiratory rate, and oxygen saturation in the earplugs or earmuffs group (Manske, 2017; Wachman and Lahav, 2011). From the researcher’s point of view, different gestational age affected the level of fluctuation of heart rate, blood pressure, respiratory rate, and oxygen saturation.

Limitation

Interpretation of the results should acknowledge some limitations such as lack of blinding in the studies and small sample size. Future studies should try to ensure that the research be performed in a facility that will offer an adequate sample size in order to validate the findings.


  Conclusion Top


The finding of the study concluded that the use of earplugs is effective to decrease the effect of noise on physiological responses (heart rate, respiratory rate, blood pressure, and oxygen saturation of preterm infants during a nebulizer session).

Recommendation

Based on the study results, the following recommendations are proposed:
  1. Earplugs should be applied before any noisy procedures as a routine care for preterm infants.
  2. The methods of noise reduction should be applied in the NICU as a routine care.
  3. An educational program is needed to raise awareness among nurses and other health-care providers about the effects of noise on the physiological parameter and noise reduction methods.
  4. Further studies that evaluate the long-term outcomes of using earplugs on the physiological and behavioral states of newborn infants.
[23]

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.



 
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Abdeyazdan Z, Ghassemi S, Marofi M (2014). The effects of ear muffs on the physiologic and motor responses of premature infants in the NICU. Iran J Nurs Midwifery Res 10:107–112.  Back to cited text no. 1
    
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Allinson LG, Denehy L, Doyle LW, Eeles AL, Dawson JA, Lee KJ, Spittle AJ (2017). Physiological stress responses in infants at 29–32 weeks’ postmenstrual age during clustered nursing cares and standardized neurobehavioural assessments. BMJ Paediatr Open 1:10–25.  Back to cited text no. 4
    
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    Figures

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    Tables

  [Table 1], [Table 2], [Table 3]



 

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