Original Article

From the *School of Nursing and

Midwifery, Tehran University of

Medical Sciences;†School of Nursing

and Midwifery, Nursing and

Midwifery Care Research Center,

Tehran University of Medical

Sciences, Tehran, Iran.

Address correspondence to Zeinab

Movahedi, School of Nursing and

Midwifery, Tehran University of

Medical Sciences, Nosrat St., Tohid Sq.,

Post Code 1419733171, Tehran, Iran.

E-mail: movahedi@gmx.us

Received December 7, 2010;

Revised October 6, 2011;

Accepted October 17, 2011.

Supported by the Deputy for

Research, Tehran University of

Medical Sciences, Tehran, Iran.

1524-9042/$36.00

� 2013 by the American Society for

Pain Management Nursing

doi:10.1016/j.pmn.2011.10.003

The Effect of a FamiliarScent on the Behavioraland Physiological PainResponses in Neonates

--- Akram Sadat Sadathosseini, MSc,*

Reza Negarandeh, PhD,† and Zeinab Movahedi, MSc*

- ABSTRACT:There are adverse physiologic effects of pain in neonates, and effective

pain management must be an essential aspect of neonatal care. In this

study we assessed the effect of a nonmaternal familiar scent on the

neonatal pain responses. This study included 135 neonates randomly

assigned to one of three groups. During arterial puncture, one group

was exposed to a vanillin scent on a gauze pad held next to their nose.

They were familiarized with it the night before blood sampling by

a scented gauze pad placed in the incubator next to their head for an

average duration of 8.65 hours. The second groupwas not familiarized

with the scent but was exposed to it during the procedure. The third

group was neither familiarized nor exposed to the scent. The duration

of crying in the familiar scent groupwas significantly lower than in the

two other groups. Comparison of the physiologic parameters showed

less variation in oxygen saturation level during arterial puncture in the

familiar scent group. In this study, a familiar scent could reduce crying

and oxygen consumption during arterial puncture.

� 2013 by the American Society for Pain Management Nursing

The days of assuming that neonates cannot experience pain are past (Golianu,

Krane, Seybold, Almgren, & Anand, 2007; Urso, 2007). It is now documented

that neonates not only feel pain, but also are more vulnerable to its

consequences (Parry, 2008) owing to immaturity of descending pathways that in-

hibit incoming pain impulses (Freire, Garcia, & Lamy, 2008; Ranger, Johnston, &

Annand, 2007). Studies have shown that untreated pain has immediate and long-

term consequences (Urso, 2007). Therefore, management of pain in neonates is

crucial and should be a priority (Kostandy, Ludington-Hoe, Cong, Abouelfettoh,Bronson, Stankus, & Jarrell, 2008). On the other hand, regarding the potential

side effects of general and local application of anesthetics, it is wise to consider

nonpharmacological approaches for repeated short stressful and painful proce-

dures (Axelin, Salantera, & Lehtonen, 2006; Cignacco, Hamers, Stoffel, Lingen,

Gessler, McDougall, & Nelle, 2007). Several studies have documented the

effectiveness of nonpharmacologic approaches such as swaddling (Fearon,

Kisilevsky, Hains, Muir, & Tranmer, 1997), nonnutritive sucking (Corbo, Mansi,

Stagni, Romano, van den Heuvel, Capasso, . & Paludetto, 2000), breastfeeding

Pain Management Nursing, Vol 14, No 4 (December), 2013: pp e196-e203

e197Effect of a Familiar Scent for Neonates

(Carbajal, Veerapen, Couderc, Jugie, & Ville, 2003; Effe

& Ozer, 2007; Gray, Miller, & Blass, 2002), skin-to-skin

contact (Castral, Warnock, Leite, Haas, & Scochi,

2008; Kostandy et al., 2008), auditory stimulation

(Butt & Kisilevsky, 2000), and multisensory stimulation

(Bellieni, Bagnoli, Perrone, Nenci, Cordelli, Fusi, &

Buonocore, 2002).In recent years, the soothing effect of scents as

a means to reduce distress responses in neonates has

been studied. The results of those studies have shown

that maternal and fetal scents can reduce distress

responses such as crying and motor activity of the neo-

nates who receive painful procedures or are separated

from their mother (Rattaz, Goubet, & Bullinger, 2005;

Nishitani, Miyamura, Tagawa, Sumi, Takase, Doi, . &Shinohara, 2009; Varendi, Christensson, Porter, &

Winberg, 1998). Also, Rattaz, Goubet, & Bullinger.

(2005) observed 44 full-term neonates during a heel-

stick. The samples were presented with their own

mother’s milk scent, a vanillin scent that they had

been familiarized with before testing, or an unfamiliar

vanillin scent. They showed that smelling a familiar

scent during a heel stick, either their own mother’smilk or a familiar vanillin scent, led to a decrease in

pain responses after the heel-stick and quicker recov-

ery; an unfamiliar vanillin scent was not soothing. In

a related study, Goubet, Strasbaugh, and Chesney

(2007) reported that neonates who had been exposed

to a vanillin scent either on a scarf in their crib or on

their mother’s skin, showed lower behavioral pain re-

sponses when they smelled the vanillin scent again dur-ing a heel-stick than neonates who smelled an

unfamiliar vanillin scent. In another study involving

48 healthy neonates who were exposed to either their

own mother’s breast milk scent or another mother’s

breast milk scent or formula milk scent during a heel-

stick, another mother’s milk and unfamiliar formula

milk scents did not decrease pain responses in neonates

(Nishitani et al., 2009). It therefore appears that thesoothing potency of scents is based on familiarity and

that a scent could be soothing only when it is experi-

enced by the neonate before the procedure (Goubet,

Rattaz, Pierrat, Bullinger, & Lequien, 2003). However,

in a study conducted on 5-day-old neonates who were

presented with the unfamiliar artificial scent of laven-

der or milk during the heel stick, investigators found

that the presence of either lavender or artificial milkscent attenuates the increase in cortisol levels as a bio-

chemical index of the pain (Kawakami, Kawakami,

Okazaki, Kurihara, Shimizu, & Yanaihar, 1997).

The majority of the earlier studies focused only on

the effects of scents on modulating behavioral and

biochemical responses to pain in neonates; few consid-

ered physiologic indices in assessing the effects of

scents on pain responses. In the present study, we eval-

uated pain responses differently from the previous

researches. We hypothesized that a nonmaternal famil-

iar scent would attenuate the duration of crying and

the physiologic responses associated with the pain dur-

ing arterial puncture. Also in this study, we investigated

the effect of an unfamiliar scent as an olfactory dis-tracter on the neonate’s behavioral and physiologic

pain responses.

METHODS

DesignFollowing the approval of the Ethics Committee of Teh-

ran University of Medical Sciences (No. 87-02-28-7170)

and obtaining written informed consents from parentsaccording to a protocol approved by the Deputy for

Research, this experimental clinical trial with three

groups of patients was carried out on 135 neonates

hospitalized in the neonatology ward of the Bahrami

Children Hospital affiliated with Tehran University of

Medical Sciences, Iran in 2009.

SampleBased on the mean and standard deviation of the neo-nates’ duration of crying obtained from an earlier study

(Goubet et al., 2007) and a ¼ 0.05, b ¼ 0.2, certainty

coefficient of 95% and power of 80%, we estimated

a sample size of 40 individuals per group.

The inclusion criteria were the following: 1-7 days

of age, 37-42 weeks gestational age at birth, and

absence of neurologic, cardiac, and respiratory impair-

ments and congenital anomalies. Also, neonates wereexcluded if they were not calm before data collection,

were on sedatives or analgesics in the 24 hours before

the procedure, or if the first attempt for blood sam-

pling was not successful.

Because it was probable for the control group to

be exposed to the vanillin scent spread from experi-

ment groups (diffusion effect), sampling was done

only for one group during each week, with groupsbeing randomly selected; in other words, on the first

day, the name of each group was written on a separate

piece of paper, which was enclosed in a envelope, and

an independent nurse who worked in the clinical con-

text and was unaware of purpose of the study picked

up one envelope randomly as the first group. Then,

selection was performed in the same way for the sec-

ond group, and the remaining envelope was consid-ered to be the third group. During each week,

eligible cases were recognized and selected by conve-

nience sampling only for one group, and groups

were replaced respectively (e.g., first week, unfamiliar

scent group; second week, familiar scent group; third

e198 Sadathosseini, Negarandeh, and Movahedi

week, control group; fourth week, unfamiliar scent

group; fifth week, familiar scent group; sixth week,

control group; and so on). Therefore, it took 6, 6,

and 8 weeks to put together a sample size for the famil-

iar scent group, unfamiliar scent group, and control

group, respectively.

Recruitment for the study took place at the neona-tology ward of the Bahrami Children Hospital. The new

neonates submitted to blood sampling were reviewed

every day. Two research assistants who were blind to

the study group assignments undertook the approach

to participants. They first identified eligible partici-

pants and then contacted parents for potential interest

in the study. Of the 253 participants approached, 73

neonates did not meet the inclusion criteria. Of 180 ne-onates who met the inclusion criteria, 15 parents did

not agree to their babies participating in the study

and three parents did not attend to sign the written

consent document. Also, 13 neonates were eliminated

from the sample because the arterial puncture was not

successful in the first attempt, and six neonates were

excluded due to crying during the baseline. Moreover,

eight neonates were submitted to venous puncture forblood sampling and could not be included in the study.

One hundred and thirty five neonates were assigned to

three groups and the final analysis included 135 cases,

45 individuals in each group.

Scent StimulusScent stimulus for the present study was 0.64 g vanillin

(HRCL 99%; Merck, Germany) diluted in 100 mL 85%

glycerol used to familiarize and stimulate neonates.This scent was chosen because the trigeminal activity

evoked by diluted vanillin is weak (Goubet et al.,

2003) and earlier studies reported reliable physiologic

and behavioral reactions (Goubet et al., 2007; Marlier,

Gaugler, & Messer, 2005; Rattaz et al., 2005). Moreover,

it is a pleasant scent for neonates hedonically and is not

known to cause undesirable side effects in long-

duration application (Marlier et al., 2005).

ProcedureThe familiarization protocol used in this study was

according to the previous studies (Goubet et al., 2003;

Goubet et al., 2007; Rattaz et al., 2005). For the familiar

scent group, familiarization was performed the night

before blood sampling and neonates were exposed to

the vanillin scent during the painful procedure. In this

group, a sterile gauze pad (10 � 10 cm) moistenedwith ten drops of vanillin solution was placed in the

incubator �10 cm from the neonate’s head. The next

morning, the scented gauze was removed for an

average familiarization duration of 8.65 hours (SD 1.93).

Blood sampling was done on average 42.29 minutes

(SD 20.15) after removing the gauze from the

incubator. For neonates in the unfamiliar scent group,

the familiarization was not carried out, but blood

sampling was done in the presence of the vanillin scent.

Data CollectionOn the morning of the study, each neonate was first

weighed with the use of a digital scale and was then

taken to a quiet room apart from other neonates andwas placed supine on an examination table under

a heater. The blood sampling was prescribed by the at-

tending physician for plasma bilirubin level testing and

was not implemented for the purpose of this study. Ve-

nous puncture is the primary method of obtaining

blood samples in neonates and it is preferred to arterial

puncture in our hospital. If venous access is not easily

obtained, alternative routes, including arterial punc-ture are implemented. But we recruited only neonates

who were submitted to arterial puncture, because

earlier works focused only on the effects of scents on

responses to neonatal pain during either heel-stick or

venous puncture. In all cases, the blood sampling

was performed by the same expert nurse to reduce

variability. All neonates were awake at the start of

data collection. Their diapers were dry and none ofthem were fed or received sucrose or any combination

of sucrose for #30 minutes before the painful proce-

dure. A pulse oximeter probe (Novametrix, Walling-

ford, CT) was attached to the great toe of the

neonate’s foot without pressure, and 2 minutes before

sampling, the heart rate and oxygen saturation levels

were recorded by a trained observer to obtain baseline

values (for only the first 60 seconds). The same trainedobserver was present for all research subjects, and she

was unaware of purpose of the study. After 2 minutes,

in the familiar scent and unfamiliar scent groups a ster-

ile gauze pad perfumed with ten drops of the vanillin

solution was held �1 cm from the neonate’s nose

without contact.

At this time, an experienced nurse located the

approximate position of the right or left radial arteryby rolling the index finger, then disinfected the skin

over the proposed site of puncture with alcohol swabs

and inserted a 23-gauge and 1.8-cm needle toward the

point of maximum pulsation to obtain a sufficient

blood sample. When the needle was inserted into the

skin, a digital voice recorder (Samsung YV-120X;

Korea) was switched on to record the neonate’s crying.

The definition of the duration of crying was based onthe first cry, which was the duration of audible crying

from the beginning until the cessation of crying for five

seconds (Effe & Ozer, 2007). In this study, for ethical

reasons infant cry was recorded from onset after nee-

dle insertion until a cessation for 5 seconds, up to

e199Effect of a Familiar Scent for Neonates

a maximum of 1 minute after removing the needle.

Also, after inserting the needle and after removing it,

the heart rate and oxygen saturation levels were again

recorded. The heart rate and oxygen saturation were

recorded during a 60-second baseline, the first 30 sec-

onds after inserting the needle (except when the dura-

tion of the arterial puncture took <30 seconds, inwhich case they were measured from needle insertion

until needle removal), and a 60-second period after re-

moving the needle. The average heart rate and oxygen

saturation in each phase were calculated. Furthermore,

the duration of the arterial puncture from needle inser-

tion until needle removal was measured with a digital

stopwatch. During the blood sampling, from needle in-

sertion to removal, in the familiar scent and unfamiliarscent groups the sterile gauze pad perfumed with van-

illin was held next to the neonate’s nose. After the pro-

cedure, the nurse applied direct pressure over the

puncture site and applied a band-aid. In the control

group, data collection and blood sampling were per-

formed in the same manner as described for the exper-

imental groups but no scent was given to them. For

ethical reasons, we also encouraged the nurse whoperformed blood sampling to touch and talk softly to

neonates in both intervention groups and the control

group during the painful procedure. Parents and other

health care professionals could be present in the room,

but they were asked not to speak with the neonates or

touch them during data collection.

Throughout the duration of the study, the re-

searcher who performed familiarization and olfactorystimulation was the only person who had knowledge

of group assignments. The duration of crying was mea-

sured in seconds with a stopwatch by two trained re-

search assistants who were blinded to the allocation

assignment and had no contact with participants. In-

terrater reliability was determined for 10% of the sam-

ples, and Pearson correlation was 86%.

TABLE 1.

Demographic and Background Characteristics (Mean

VariableFamiliar Scent

(n ¼ 45)

Age (d) 5.04 � 1.20Sex (n, male:female) 23:22Birth weight (g) 3,213.55 � 370.42Weight at testing (g) 3,102 � 352.68Previous blood sampling (n)‡ 3.49 � 0.66Duration of arterial puncture (s) 33.13 � 13.65

*Kruskal-Wallis test.†Chi-square test.‡Number of blood samplings during hospitalization before study.

Statistical AnalysisKruskal-Wallis, Chi-square, and Fisher exact tests were

used to compare background characteristics among

the three groups. Kolmogorov-Smirnov test was usedto determine whether or not data were consistent

with normal distribution, and because they were not

normally distributed (p< .05), we used nonparametric

tests instead of their parametric counterparts. Mann-

Whitney U and Kruskal-Wallis tests were applied to as-

sess group differences. The level of significance was

considered to bep< .05, and statistical analysiswas per-

formed with SPSS software, version 16 (SPSS, Chicago,Illinois, USA).

RESULTS

Demographic and Background CharacteristicsWe studied 135 neonates: 45 in the familiar scent

group, 45 in the unfamiliar scent group, and 45 in

the control group. Their average gestational age was38.4 weeks (SD 0.85); 45.07% were born via cesarean

section, and 77.03% were breastfed. All neonates

were hospitalized because of icterus with a mean

plasma total bilirubin level of 15.69 mg/dL (SD 2.87)

at the time of testing. Some of the demographic and

background characteristics are presented in Table 1.

Statistical analysis revealed that postnatal age, gender,

birth weight, weight at testing, kind of delivery, feed-ing, level of plasma total bilirubin (mg/dL), number

of previous blood samplings, and duration of the arte-

rial puncture did not differ significantly among the

three groups.

Crying DurationBased on the findings of this study, the duration of cry-

ing in the familiar scent group was significantly lower

than in the two other groups (p < .001; Table 2).Also, based on the Mann-Whitney U test, there was

± SD) of Neonates (n ¼ 135)

Unfamiliar Scent(n ¼ 45)

Control(n ¼ 45) p Value

5 � 1.11 5.09 � 1.24 .797*21:24 20:25 .812†

3,164.67 � 410.21 3,227.11 � 385.28 .728*3,050.22 � 394.20 3,111.55 � 380.06 .947*

3.51 � 0.59 3.42 � 0.54 .785*33.20 � 13.33 32.49 � 13.03 .963*

TABLE 2.

Pain Behavioral and Physiologic Responses (Mean ± SD) of Neonates During Arterial Puncture (n¼ 135)

VariableFamiliar Scent

(n ¼ 45)Unfamiliar Scent

(n ¼ 45)Control(n ¼ 45) c2* p Value

Crying duration (s) 41.75 � 24.51 64.71 � 25.04 66.97 � 23.87 25.409 <.001Oxygen saturation after inserting the needle (%) 95.89 � 1.63 95.62 � 1.96 95.24 � 2.02 21.146 .342Oxygen saturation after removing the needle (%) 94.77 � 1.90 93.84 � 2.84 93.73 � 2.45 15.690 .04

*Kruskal-Wallis test.

e200 Sadathosseini, Negarandeh, and Movahedi

no significant difference in the duration of crying be-

tween the unfamiliar scent group (mean 64.71 s, SD

25.04) and the control group (mean 66.97 s, SD

23.87; p ¼ .55).

Physiologic MeasuresComparison of heart rate (p ¼ .345) and blood oxygen

saturation levels (p ¼ .689) at baseline showed no sig-

nificant difference among the three groups. Based on

our findings, the mean heart rate after the needle

was inserted in the skin was 145.71 beats/min (SD

14.75) in the familiar scent group, 143.34 beats/min

(SD 14.51) in the unfamiliar scent group, and 145.37beats/min (SD 14.54) in the control group. During

a 60-second period after removing the needle, these

values changed to 148.62 (SD 15.36), 147.80 (SD

14.62), and 150.68 (SD 14.61), respectively. Statistical

analysis showed no significant difference in those

parameters after inserting the needle (p ¼ .627) and

after removing it (p ¼ .692) among the groups.

Although there was no statistically significant dif-ference in blood oxygen saturation levels after insert-

ing the needle among the groups, blood oxygen

saturation level was significantly higher in the familiar

scent group compared with the other groups over a 60-

second period after removing the needle (p ¼ .04;

Table 2).

DISCUSSION

In the present study, stimulating the neonates with

a familiar vanillin scent during the arterial puncture re-

duced the duration of crying compared with the other

groups. In other words, these neonates revealed pain

behavioral indicator for a shorter period of time and

faster. Also, the findings of the present study showed

that an unfamiliar vanillin scent did not reduce the du-ration of crying compared with the control group. Our

findings are consistent with the results of earlier stud-

ies (Goubet et al., 2003; Goubet et al., 2007; Rattaz

et al., 2005). Nishitani et al. (2009) also showed the

soothing effects of maternal milk scent as a familiar

stimulus and no soothing effects for another mother’s

milk scent as an unfamiliar stimulus during heel-stick.

Based on the findings of the present study, an unfamil-

iar scent as an attention distracter cannot relieve the

pain in neonates, and a scent can reduce the distressresponses only when the neonate is familiarized with

it before the stressful event.

Goubet et al. (2003) described the familiar scent

as an ‘‘experiential distracter (p. 177).’’ Varendi et al.

(1998), in a group of 47 healthy full-term neonates,

could identify the soothing effect of the amniotic fluid

scent on the total crying time of the neonates 31-90

minutes after birth when their mothers were absent.They proposed that this scent reminded the neonates

of the calm intrauterine environment and therefore

soothed the neonates. What is noticed by most re-

searchers regarding the memory is ‘‘context,’’ which re-

fers to a sensorial stimulus that presents when

a memory is acquired, and its reappearance may be

a condition for retrieval of the memory and the desired

information, as a result affecting the individual’s behav-ioral responses. According to researchers, scents can

be effective context cues to retrieve encoded memo-

ries (Schroers, Prigot, & Fagen, 2007). So it can be as-

sumed that the familiar vanillin scent was able to

evoke the calmness of the incubator and to calm the

neonate (Goubet et al., 2003; Rattaz et al., 2005).

However, neither a familiar scent nor an unfamil-

iar scent could attenuate the increase in heart rateand the decrease in blood oxygen saturation level

that were associated with pain after inserting the nee-

dle in the skin. Effe and Ozer (2007) were unable to

demonstrate the effect of breastfeeding on the heart

rate and the blood oxygen saturation level during

immunization injection. In their study, injection was

performed right after 3 minutes of breastfeeding. How-

ever, in a study by Freire et al. (2008), the analgesic ef-fect of skin-to-skin contact for 10 minutes before the

painful stimulus was confirmed. It seems that pro-

longed duration of the comforting intervention in-

creases exposure to pain-relieving effects (Castral

et al., 2008) and provides sufficient opportunity to

e201Effect of a Familiar Scent for Neonates

produce a calmer organized physiologic state. On the

other hand, an increase in physiologic responses dur-

ing painless procedures is inevitable (Bauer, Ketteler,

Magdalena, Maren, & Versmold, 2004). Gaspardo,

Chimello, Cugler, Martinez, and Linhares (2008) dem-

onstrated that tactile stimuli during handling for anti-

sepsis increased the heart rate. In the present study,we handled neonates for antisepsis and prepared

them for blood sampling immediately after they were

exposed to the familiar scent and then inserted the

needle just a few seconds later. It seems that there

was no sufficient time for neonates to achieve physio-

logic system adaptation.

Also we observed a 7%-10% increase of heart rate

relative to baseline after removing the needle in thethree groups. We did not identify significant group dif-

ferences regarding the heart rate during this phase.

Goubet et al. (2003) and Rattaz et al. (2005) found

no reduction in pain responses during a painful proce-

dure, but neonates who were exposed to a familiar

scent were faster to return to basal levels in the recov-

ery phase. However, two important issues make it

difficult to pass judgment in this regard. First, theabove-mentioned studies focused on behavioral pain

responses. Second, in the present study for ethical

and practical reasons we did not measure physiologic

parameters in the recovery phase and limited it to

60 seconds after removing the needle. It seems that

appropriate time for neonates’ recovery and return to

basal physiologic values is �10 minutes (Gasprado

et al., 2008). Therefore, further studies are necessaryto examine the effect of scents on quickness of the

return to basal physiologic levels during recovery.

Finally, neonates in the familiar scent group

showed less variation in oxygen saturation level after

removing the needle relative to baseline. The most

frequently behavioral response of neonates to pain is

crying (Bellieni, Sisto, Cordelli, & Buonocore, 2004;

Kostandy et al., 2008; Schollin, 2005) which isaccompanied by an increased irregular respiratory

rate, reduced oxygen level, and hypoxemia (Baken,

1976; Ludington-Hoe, Cong, & Hashemi, 2002;

Schaal, Hummel, & Soussignan, 2004). In the present

study, neonates in the familiar scent group showed

a 36% reduction in the duration of crying compared

with the other groups. Also, variation in oxygen

saturation level was about 30% lower than in the twoother groups. Therefore, it can be assumed that less

crying was accompanied by less irregularities of

respiration and oxygen consumption in the familiar

scent group. On the other hand, it seems that if we

had measured the total sum of crying within the first

3 minutes after its beginning (Effe & Ozer, 2007) rather

than the first cry, and then recorded physiologic

parameters during the whole crying, we might have re-

corded more reduction in the oxygen saturation level

in the familiar scent group.

However, we cannot claim that scents do not in-

fluence physiologic pain responses of the neonates,

and there is uncertainty about this. We think that

more studies will provide further information in this re-gard. Also, it is worth mentioning that the lack of signif-

icant group differences in the physiologic parameters

may have been due to short observation periods.

Future studies may benefit from continuous recording

of the parameters from baseline to the end of the

recovery (Bauer et al., 2004) and/or spectral analysis

of heart rate fluctuations (Castral et al., 2008;

Oberlander & Saul, 2002). In addition, movements ofthe neonates during blood sampling could reduce the

sensitivity of pulse oximetry (Effe & Ozer, 2007). Fur-

ther studies can provide more insight into physiologic

responses with consideration these issues.

Strengths of the StudyIt is worth mentioning that although a number of valid

and reliable scales are available for measuring acute

pain associated with procedures in neonates, we mea-sured independently the behavioral and physiologic

indicators to assess the effects of intervention on the

range of varied responses to pain. A composite multidi-

mensional scale may hide important information re-

garding stress reactivity in neonates (Castral et al.,

2008; Holsti & Grunau, 2007).

In addition, this study had other strengths, includ-

ing measuring the number of previous blood sam-plings, using a standardized protocol and same

expert nurse for minimizing group differences in blood

sampling technique, measuring the duration of the

arterial puncture, and lack of significant group differ-

ences in duration. The duration of blood sampling is

an important factor that can affect the crying and phys-

iologic indices (Castral et al., 2008).

Limitations of the StudyOne limitation of this study was that the observer

could not be blinded to group assignment (control

group vs. experiment groups), owing to the nature of

the intervention and the vanillin scent of the environ-

ment. However, she was not informed about the pur-

pose of the study.

Future StudiesFor future studies, it would have been interesting to

examine the effects ofmultisensory stimulation versus fa-

miliar scent on pain responses and the soothing effect of

a familiar scent on the responses associated with other

typesofpainfulprocedures (e.g., suctioning) inneonates.

e202 Sadathosseini, Negarandeh, and Movahedi

CONCLUSION

Acute pain may be accompanied by responses alteringthe physiologic functions in neonates (Bauer et al.,

2004; Im, Kim, Park, & Sung, 2008). Crying elicited

by untreated pain induces restlessness and delayed

physiologic adaptation. Also, 3-4 minutes of crying

can lead to a 13.2% increase in heat loss (Goubet

et al., 2003; Schaal et al., 2004). One of the most

important goals of neonatal pain management is to

minimize behavioral and physiologic costs (Halimaa,2003; Im et al., 2008; Littleton & Engebretson, 2002).

Our findings support earlier evidence and show the

effectiveness of a familiar vanillin scent in reducing

neonates’ crying and maintaining the level of blood

oxygen saturation during a painful procedure.

Therefore, a familiar vanillin scent can be used

with neonates to decrease crying and deleterious

physiologic effects, including energy expenditure,oxygen consumption, and increased risk of

hypoxemia (Goubet et al., 2003; Goubet et al., 2007;

Ludington-Hoe et al., 2002; Schaal et al., 2004).

Clinical ImplicationsManagement of pain is one of the most important

goals of nursing care for neonates (Jonsdottir &

Kristjansdottir, 2005; Urso, 2007). Neonatal nurses

must minimize the physiologic costs of the pain and

assist the neonates in coping with painful procedures

when pain cannot be prevented (Halimaa, 2003). It is

worth noting that crying is one of the most widely ac-

cepted indicators of pain in neonates and that crying

duration increases with increasing perceived pain

(Kostandy et al., 2008; Schollin, 2005). The reductionin crying duration could mean that the familiar scent

allowed the neonate to self-regulate and to cope with

the painful procedure. According to the available evi-

dence, we suggest that use of a familiar vanillin scent

is a noninvasive technique, low cost and low risk,

that can be comforting enough to reduce signs of dis-

tress during the painful event and sustain physiologic

stability. What really needs to be done is more re-search. More and larger studies are needed to provide

more reliable evidence regarding efficacy and safety.

Acknowledgments

The authors of this paper express their gratitude to all of the

nurses and families for their kind cooperation in this study.

Also, special thanks to Dr. Alireza Foroumadi from the School

of Pharmacy of Tehran University of Medical Sciences

(TUMS) for his technical support and Abbas Mehran from

the Department of Biostatistics of the School of Nursing

and Midwifery, TUMS, for supporting the statistical data

analysis.

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