Factors explaining lack of response to heel stick in preterm newborns

Developmental changes in the responses of preterm infants to a painful stressor

The purpose of this investigation was to examine longitudinally gestational age and developmental differences in preterm infants' self-regulatory abilities in response to a painful stressor, as well as associations between behavioral and cardiovascular responses. Participants included 49 healthy premature infants. Behavioral and cardiovascular responses to a heel stick blood draw were compared between infants of 28-31 and 32-34 weeks' gestation age at birth. Both gestational age groups displayed behavioral and cardiovascular indications of stress in response to the blood draw. However, both shortly after birth and several weeks later, infants born at younger gestational ages (28-31 weeks) were more physiologically reactive. Evidence that the behavioral stress responses of 28-31 weeks' gestation age group preterm infants do not reflect their physiological responses suggests that evaluation of preterm infants' experiences and risk require assessments of both physiology and behavior. The greater stress vulnerability of the 28-31 weeks' gestation group relative to the 32-34 weeks' gestation group and the implications of this for subsequent development are discussed.

Kangaroo Care (skin contact) reduces crying response to pain in preterm neonates: pilot results

Crying commonly occurs in response to heel stick and adversely affects the infant's physiologic stability. Minimal crying in response to pain is desired. "Kangaroo Care," skin contact between mother and infant, reduces pain and may reduce crying in response to pain. The purpose of this pilot study was to test Kangaroo Care's effect on the preterm infant's audible and inaudible crying response to heel stick. Inaudible crying has not been previously studied. A prospective randomized cross-over study with 10 preterm infants 2-9 days old (30-32 weeks' postmenstrual age) was conducted. Infants were randomly assigned to two sequences (sequence A: day 1 heel stick in Kangaroo Care [after 30 min of prone skin contact upright between maternal breasts] and day 2 heel stick in incubator [inclined, nested and prone]; or sequence B: opposite of sequence A) was conducted. Videotapes of baseline, heel warming, heel stick, and recovery phases were scored for audible and inaudible crying times. Audible and inaudible crying times for each subject in each phase were summed and analyzed by repeated-measures analysis of variance. Subject characteristics did not differ between those in the two sequences. Crying time differed between the study phases on both days (p <or= .001). When in Kangaroo Care compared with the incubator, crying time was less during the heel stick (p = .001) and recovery (p = .01) phases, regardless of sequence. Because Kangaroo Care reduced crying in response to heel stick in medically stable preterm infants, a definitive study is merited before making recommendations.

Clinical reliability and validity of the N-PASS: neonatal pain, agitation and sedation scale with prolonged pain

OBJECTIVE

To establish beginning evidence of clinical validity and reliability of the Neonatal Pain, Agitation and Sedation Scale (N-PASS) in neonates with prolonged pain postoperatively and during mechanical ventilation.

STUDY DESIGN

Prospective psychometric evaluation. Two nurses administered the N-PASS simultaneously and independently before and after pharmacologic interventions for pain or sedation. One nurse also administered the premature infant pain profile (PIPP) concurrently with the N-PASS. The setting consisted of 50-bed level III neonatal intensive care unit. Convenience sample of 72 observations of 46 ventilated and/or postoperative infants, 0 to 100 days of age, gestational age 23 to 40 weeks was used. Outcome measures comprised convergent and construct validity, interrater reliability and internal consistency.

RESULT

Interrater reliability measured by intraclass coefficients of 0.85 to 0.95 was high (P<0.001 to 0.0001). Convergent validity was demonstrated by correlation with the PIPP scores (Spearman's rank correlation coefficient of 0.83 at high pain scores, 0.61 at low pain scores). Internal consistency, measured by Cronbach's alpha, was evident with pain scores (0.82), and with sedation scores (0.87). Construct validity was established via the Wilcoxon signed-rank test, comparing the distribution of N-PASS scores before and after pharmacologic intervention showing pain scores of 4.86 (3.38) and 1.81 (1.53) (mean (s.d.), P<0.0001) and sedation scores of 0.85 (1.66) and -2.78 (2.81) (P<0.0001) for pre- and postintervention assessments, respectively.

CONCLUSIONS

This research provides beginning evidence that the N-PASS is a valid and reliable tool for assessing pain/agitation and sedation in ventilated and/or postoperative infants 0 to 100 days of age, and 23 weeks gestation and above.

Current controversies regarding pain assessment in neonates

Although over 40 methods of pain assessment in infants are available for use in clinical practice, unrecognized and under-treated pain remains one of the most commonly reported problems within the Neonatal Intensive Care Units. A number of factors have been found to account for differences in the robustness of the pain response in neonates of varying gestational ages. Discrepancies between behavioral and physiological pain indicators have also been reported. With newer technologies, there is an opportunity not only to verify infant pain perception, but these tools may allow an identification of which of the observed indicators are most sensitive in particular clinical situations. The current controversies regarding pain assessment in preterm and term infants are reviewed to define the most important issues and to develop a dialogue for future directions.

Effect of suckling on the peripheral sensitivity of full-term newborn infants

BACKGROUND

Sucking may reduce the manifestations of pain in newborn infants.

OBJECTIVE

To examine the effect of suckling on the threshold for peripheral somatosensory responses.

SUBJECTS AND METHODS

Graded Von Frey filaments were applied to the heel to initiate peripheral somatosensory responses (withdrawal reflex and gross body movements) in term infants.

RESULTS

Dummy sucking increases the somatosensory threshold, but breast feeding had a more marked effect, increasing the threshold of the flexion withdrawal reflex (p<or=0.002) and the threshold for gross body movements (p</=0.002).

CONCLUSION

Peripheral sensitivity of newborn infants is considerably reduced during sucking, particularly at the breast.

Psychometric testing of a Norwegian version of the Premature Infant Pain Profile: an acute pain assessment tool. A clinical validation study

As neonates are submitted to pain, assessing the pain is crucial in effective pain control. The Premature Infant Pain Profile, an acute measurement tool combining physiological, behavioural and contextual indicators, was translated into Norwegian and tested clinically. The purpose was to establish construct validity, interrater reliability and internal consistency. In addition, the effect of sucrose as pain analgesia was tested in neonates >or= 36 weeks of gestational age. In a known-groups comparisons design with repeated measures, 111 consecutive neonates, preterm and term, were all observed at baseline, non-pain and pain event. Neonates in the neonatal unit received sucrose at pain event. A significant interaction effect of gestational age and events was found in the sucrose neonates. A significant interaction effect was detected from sucrose and event type for neonates from 36 weeks. The internal consistency of the six-item score was acceptable. A correlation coefficient of 0.89-0.97 was obtained for interrater reliability. The Norwegian version of the Premature Infant Pain Profile seems to be a reliable and valid instrument for pain assessment in neonates.

Behavioral responses to pain are heightened after clustered care in preterm infants born between 30 and 32 weeks gestational age

OBJECTIVE

To compare biobehavioral pain responses of preterm infants born at differing gestational ages (GAs) when pain was preceded by a rest period or by a series of routine nursing interventions.

METHODS

In a randomized, within subjects, cross-over design, facial (Neonatal Facial Coding System), sleep/wake state and heart rate (HR) responses of 43 preterm infants [mean birth weight: 1303 g (range 590 g to 2345 g); mean GA at birth: 30 weeks (range 25 to 32)] were examined across 3 phases of blood collection (Baseline, Lance, and Recovery) under 2 conditions: pain after a 30-minute rest period versus pain after a series of routine nursing interventions (clustered care). Infant behavioral responses were coded from continuous bedside videotapes. HR was analyzed using custom physiologic signal processing software.

RESULTS

Infants born at earlier GA (<30 wk) had equally intense facial responses during the Lance phase regardless of condition. However, later born infants (> or =30 wk GA) showed heightened facial responses indicative of sensitized responses during blood collection when it was preceded by clustered care (P=0.05). Moreover, later born infants had significantly lower facial (P=0.05) and HR (P=0.04) reactivity during Recovery when blood collection followed clustered care.

DISCUSSION

Earlier born preterm infants showed heightened states of arousal and poor ability to modulate HR during Recovery when an invasive procedure was preceded by routine tactile nursing procedures. Alternatively, later born infants exhibited sensitized responses when clustered care preceded blood collection. Our findings support the importance of cue based individualized approaches to care.

'Facilitated tucking by parents' in pain management of preterm infants-a randomized crossover trial

BACKGROUND

There is a need for a safe and effective non-pharmacological pain management method for preterm infants. The parents could be given an active role in the pain management which may help the parents to cope with the stress related to painful situations of the infant.

AIMS

To examine the effectiveness of a method called 'facilitated tucking by parents' (a parent holds the infant in a flexed position) in pain management during endotracheal/pharyngeal suctioning of preterm infants. In addition, the parental perception of the method was studied.

STUDY DESIGN

A randomized crossover trial.

SUBJECTS

Twenty preterm infants with one of their parents participated in the study. Infants' gestational age ranged from 24 to 33 (median 28) weeks and postnatal age from 6 to 37 days (median 15 days).

OUTCOME MEASURES

The primary outcome was the Neonatal Infant Pain Scale (NIPS) score. Heart rate and oxygen saturation were recorded. Parents completed a questionnaire about their perception of the procedure.

RESULTS

The highest NIPS score was median 3 (range from 2 to 6) using 'facilitated tucking by parents' and median 5 (range from 2 to 7) without tucking during suctioning (p < 0.001). The infants calmed down more quickly after 'facilitated tucking by parents' (5 s vs. 17 s, p = 0.024). Nineteen out of twenty parents preferred facilitated tucking during suctioning compared to control care.

CONCLUSIONS

Facilitated tucking by parents is an effective and safe pain management method during suctioning of preterm infants. This study shows that parents can be given an active role in the pain care of their preterm infants.

The effects of early pain experience in neonates on pain responses in infancy and childhood

Iatrogenic pain is commonplace in newborn infants yet we know very little about its long-term effects. This article reviews the evidence for and against the suggestion that painful procedures experienced in the perinatal period influence subsequent pain responses in infancy or in childhood. The evidence suggests that early experiences with pain are associated with altered pain responses later in infancy. The direction of the altered response depends, in part, on the infant's developmental stage (full-term vs preterm), and his or her cumulative experience with pain. Preterm infants that are hospitalized as neonates and subjected to painful procedures appear to have a dampened response to painful procedures later in infancy. Full-term neonates exposed to extreme stress during delivery, or to a surgical procedure, react to later noxious procedures with heightened behavioral responsiveness. Studies in which analgesic agents (local anesthetics or opioids) have been administered prior to noxious procedures demonstrate less procedural pain and a reduction in the magnitude of long-term changes in pain behaviors. The precise determinants of these changes, their extent, and their permanence are not known but they appear to involve noxious stimulus-induced peripheral and central sensitization, as well as classical conditioning.

Capturing postoperative pain responses in critically ill infants aged 0 to 9 months

OBJECTIVES

The purpose of this study was to describe physiologic and behavioral pain behaviors in postoperative critically ill infants. A secondary aim was to identify how these pain responses vary over time.

DESIGN

This observational study was conducted in the pediatric intensive care unit at two tertiary referral hospitals. Using ethological methods of observation, video recordings of postoperative infants were viewed to depict different situations of pain and no pain and were then coded using a reliable checklist.

PATIENTS

A total of 803 recorded segments were generated from recordings of five critically ill infants aged between 0 and 9 months who had undergone major surgery.

MEASUREMENTS AND MAIN RESULTS

There was an 82% agreement between the two coders. Multivariate analyses showed that physiologic responses differed only when adjusted for time. Significant decreases in systolic and diastolic arterial pressure (p < .001 and p = .036, respectively) were associated with postoperative pain exacerbated by painful procedures on day 2. On day 3, however, heart rate, arterial pressure (systolic, diastolic, and mean), and central venous pressure significantly increased (p < .05) in response to postoperative pain. Indicators included vertical stretch of the mouth, hand twitching, and jerky leg movements for postoperative pain and increase in respiratory distress, frown, eyes tightly closed, angular stretch of the mouth, silent or weak cry, jerky head movements, fist, pulling knees up, and spreading feet for postoperative pain exacerbated by painful stimuli.

CONCLUSIONS

Findings support the ability to capture different intensities of postoperative pain in critically ill infants beyond neonatal age. These pain indicators can be used for the development of a pain assessment tool for this group of infants.

Skin-to-Skin Contact (Kangaroo Care) Analgesia for Preterm Infant Heel Stick

The purpose of the study was to compare a heel stick conducted during Kangaroo Care (skin-to-skin contact) with the mother to a heel stick in a warmer in reducing premature infant physiologic and behavioral pain responses. Twenty-four premature infants in a university-based neonatal intensive care unit were recruited and randomized to 2 sequences: sequence A group received 3 hours of Kangaroo Care (with a heel stick in Kangaroo Care) followed by 3 hours in a warmer (with a heel stick in the warmer). Sequence B group had warmer care and a heel stick (in the warmer) before Kangaroo Care and a heel stick (in Kangaroo Care). Heart rate, respiratory rate, oxygen saturation, crying time, and behavioral state were measured before, during, and after heel stick. Repeated measures ANOVA and Mann Whitney U statistics were performed. Heart rate and length of crying in response to pain were significantly reduced during Kangaroo Care and the Kangaroo Care heel stick as compared to when infants were in the warmer and had a heel stick in the warmer. Three infants did not cry at all during the Kangaroo Care heel stick; infants slept more during Kangaroo Care than in the warmer. Kangaroo Care positioning before and during heel stick is a simple and inexpensive analgesic intervention to ameliorate pain in stable premature infants.

Prior pain induces heightened motor responses during clustered care in preterm infants in the NICU

BACKGROUND

Acute pain is a significant stressor for preterm infants in neonatal intensive care units (NICU); however, little is known about the effects of acute pain on subsequent motor responses during clusters of tactile handling.

AIMS

(1) To compare facial, body and heart rate reactivity in preterm infants at 32 weeks gestational age (GA) during routine care-giving tasks following a rest period (RCC: diapering, measuring abdominal girth and axillary temperature, mouth care) with their responses to Clustered Care following blood collection (PCC). (2) To examine how GA at birth affects patterns of stress and self-regulatory behaviors during RCC and PCC.

STUDY DESIGN

Within-group crossover design (random order).

SUBJECTS

Preterm infants, N=54 (mean GA at birth 29.3 +/- 2.2 weeks; mean birth weight 1257 +/- 423 g) were assessed at 32 weeks GA in the NICU.

OUTCOME MEASURES

The Newborn Developmental Care and Assessment Program (NIDCAP) and Neonatal Facial Coding System (NFCS) were coded from continuous bedside video recordings. Changes in mean heart rate (HR) were computed using custom physiologic software.

RESULTS

All infants had heightened facial, body and HR responses when CC followed a painful procedure compared to when they had not been handled prior to CC. Infants born at earlier GA (<30 weeks) had equal numbers of stress cues during RCC and PCC, but dampened self-regulatory behaviors during PCC.

CONCLUSION

Prior pain induces heightened biobehavioral reactivity in preterm infants during subsequent tactile procedures. In addition, clustering care is particularly stressful for infants born at earlier GA.

Analgesic effects of oral sucrose and pacifier during eye examinations for retinopathy of prematurity

Oral sucrose reduces pain during heel sticks and venipunctures in preterm infants, but no studies have been done to determine the effectiveness of sucrose during eye examinations for retinopathy of prematurity. Therefore, the purpose of this study was to determine the effectiveness of local anesthetic eye drops and a pacifier, plus repeated doses of 24% sucrose, to relieve pain associated with eye examinations for retinopathy of prematurity. In this double-blind randomized controlled trial, 30 preterm infants were randomly assigned to one of two treatments, in which they received either local anesthetic eye drops, a pacifier, plus three doses of sterile water or local anesthetic eye drops, a pacifier, plus three doses of 24% sucrose during the eye examination. Treatment effectiveness was determined using a validated infant pain measure, the Premature Infant Pain Profile (PIPP), which includes measures of facial expressions, heart rate, and oxygen saturation and takes behavioral state and gestational age into consideration. Data were collected before, during, and following an examination of the left eye. Statistically significant differences in mean PIPP scores were found between the sucrose and water groups during the left eye examination. The mean PIPP score was 8.8 for the sucrose group and 11.4 for the water group ( t = 2.87, p = .008 two-tailed). No significant differences were found in PIPP scores immediately following the procedure. Sucrose and a pacifier may be beneficial for minimizing pain during eye examinations in preterm infants and should be considered as a part of evidence-based guidelines for relieving pain during this procedure.

The efficacy of facilitated tucking for relieving procedural pain of endotracheal suctioning in very low birthweight infants

PURPOSE

This study compared the efficacy of a behavioral pain reducing intervention (facilitated tucking) with standard neonatal intensive care unit (NICU) care for decreasing procedural pain (endotracheal suctioning) in very low birthweight (VLBW) infants.

STUDY DESIGN AND METHODS

A prospective randomized crossover design with infants as their own controls were used. The sample consisted of 40 VLBW infants, 23-32 weeks gestation, and weighing 560-1498 g with tracheal intubation. The infants were observed twice during each endotracheal suctioning experience; one suctioning was done according to normal nursery routine; another was done using facilitated tucking (the caregiver "hand-swaddling" the infant by placing a hand on the infant's head and feet while providing flexion and containment). The Premature Infant Pain Profile (PIPP) measured the infant's pain response, and severity of illness of each infant was measured by the Score for Neonatal Acute Physiology (SNAP) and the NTISS (Neonatal Therapeutic Intervention Scoring System). Repeated measures analysis of variance (RMANOVA) determined the efficacy of facilitated tucking for reducing procedural pain (PIPP) and the effects of order of intervention vs. control. Regression analyses examined the relationship of gestational age, severity of illness, and number of painful procedures to the pain response.

RESULTS

There was a significant difference between the PIPP scores for tucking and nontucking positions (p = 0.001) and a nonsignificant interaction with order (p = 0.64) as well as a nonsignificant main effect for order (p = 0.46). In the regression analyses, all predictors taken together did not significantly predict PIPP scores in the tucked position (p = 0.11) or nontucked position (p = 0.57).

CLINICAL IMPLICATIONS

Facilitated tucking is a developmentally sensitive, nonpharmacological comfort measure that can relieve procedural pain in VLBW infants. Nurses need to be increasingly aware of infant pain during daily care taking, and to use validated pain assessment instruments. Further clinical research on individual pain assessment is needed for better understanding of the quality and significance of pain for each infant, and the factors that affect pain expression.

A systematic integrative review of infant pain assessment tools

PURPOSE

To examine the issue of pain assessment in infants by acquiring all available published pain assessment tools and evaluating their reported reliability, validity, clinical utility, and feasibility.

DESIGN AND METHODS

A systematic integrative review of the literature was conducted using the following databases: MEDLINE and CINAHL (through February 2004), and Health and Psychosocial Instruments, and Cochrane Systematic Reviews (through 2003). MeSH headings searched included "pain measurement," with limit of "newborn infant"; "infant newborn"; and "pain perception."

SUBJECTS

Thirty-five neonatal pain assessment tools were found and evaluated using predetermined criteria. The critique consisted of a structured comparison of the classification and dimensions measured. Further, the population tested and reports of reliability, validity, clinical utility, and feasibility were reviewed.

RESULTS

Of the 35 measures reviewed, 18 were unidimensional and 17 were multidimensional. Six of the multidimensional measures were published as abstracts only, were not published at all, or the original work could not be obtained. None of the existing instruments fulfilled all criteria for an ideal measure; many require further psychometric testing.

CONCLUSIONS

When choosing a pain assessment tool, one must also consider the infant population and setting, and the type of pain experienced. The decision should be made after carefully considering the existing published options. Confidence that the instrument will assess pain in a reproducible way is essential, and must be demonstrated with validity and reliability testing. Using an untested instrument is not recommended, and should only occur within a research protocol, with appropriate ethics and parental approval. Because pain is a multidimensional phenomenon, well-tested multidimensional instruments may be preferable.

The relationship between physiological and behavioral measures of stress in preterm infants

OBJECTIVE AND DESIGN

The purpose of this exploratory descriptive analysis was to explore relationships among physiological stress, behavioral stress, and motor activity cues in preterm infants when they were not being handled or disturbed, and to determine whether there were differences between younger and older preterm infants in these variables or relationships.

SETTING AND PARTICIPANTS

The convenience sample included 42 preterm infants who had been 27 to 33 weeks gestational age at birth and were from 6 to 19 days old at the time of data collection in the neonatal intensive-care unit.

MEASURES

In each 10-minute observation, heart rate (HR) and oxygen saturation (O2 sat) levels were recorded every 5 seconds, and observational measures of behavioral distress and motor activity were recorded twice a minute. The physiological data were coded to reflect the percentage of each 10-minute period during which HR levels were less than 100 bpm or more than 200 bpm or O2 sat levels were abnormally low (less than 90 mg%). Data were analyzed with correlational and general linear mixed models procedures.

RESULTS

Stress cues and motor activity were more often related to low levels of O2 sat than to low or high HR. Physiological status was more often related to motor activity than to stress cues. Few differences in the relationships were observed between younger and older preterm infants.

CONCLUSION

Although these results are preliminary, they suggest that neonatal nurses should monitor preterm infants' behavioral stress and motor activity cues in response to caregiving and minimize stimuli that evoke stress responses linked to physiological instability.

Does prone or supine position influence pain responses in preterm infants at 32 weeks gestational age?

OBJECTIVE

The purpose of this study was to examine the influence of prone and supine position in preterm infants during acute pain of blood collection.

SETTING

Level III Neonatal Intensive Care Unit (NICU).

STUDY DESIGN

Thirty-eight preterm infants (birthweight 1339 [590-2525] g, GA 29 [25- 32] wks) were in 2 groups depending on their position in the isolette prior to and during heel lance at 32 weeks post-conceptional age. The study design was a comparison between groups (Prone, Supine) during 2 events (Baseline, Heel lance).

OUTCOME MEASURE

Pain measures were multidimensional, including behavioral (sleep-wake state and facial activity) and physiological (heart rate) responses measured continuously prior to (Baseline) and during blood collection (Lance).

RESULTS

Both groups of infants displayed statistically significant shifts in sleep-wake state to greater arousal, and increased facial activity and heart rate, from Baseline to Lance. Prone position was associated with significantly more deep sleep during Baseline, compared with Supine position, but there were no differences in sleep-wake state during Lance. Minor increased facial activity was shown in some time segments of Baseline for infants in Supine compared with Prone, but did not differ overall between positions. Prone and Supine position did not affect heart rate significantly during Baseline or Lance events.

CONCLUSIONS

Prone position promotes deep sleep in preterm neonates at 32 weeks post-conceptional age when they are undisturbed. However, placement in prone position is not a sufficient environmental comfort intervention for painful invasive procedures such as heel lance for blood sampling in the NICU. Neonates require other environmental supports to promote coping with this stressful event.

Behavioral and Physiological Indicators of Procedural and Postoperative Pain in High‐Risk Infants

Nurses play a critical role in the assessment and management of infant pain. In this article, infant pain assessment tools that are valid, reliable, clinically sensitive, and developmentally appropriate are discussed. Their purpose, use in acute pain, and applicability for premature and newborn infant populations are described. Behavioral and physiological indicators of pain, sleep-wake states, and infant development are discussed as important considerations in pain assessment. Recommendations for improving pain assessment practices are offered in conclusion.

Comprehensive description of newborn distress behavior in response to acute pain (newborn male circumcision)

One of the most difficult challenges still facing researchers and clinicians is assessing pain in the newborn. Behaviors provide one of the most promising avenues for deepening our fundamental understanding of complex phenomenon like newborn pain, and are key to developing descriptive-level knowledge to further newborn pain assessment efforts. In this ethologically based research, we report on the duration and frequency of neonatal distress behavior to seven distinct noxious and non-noxious but distress-provoking events including baseline (diaper change, post-diaper change, application of arm and leg restraints, post-application of arm and leg restraints, circumcision, post-circumcision) associated with newborn surgical pain. Approximately 67 min of videotaped data, involving four neonates who had undergone newborn male circumcision, were coded at 1-s intervals (4010 s in total). A reliably established coding scheme was used to code behaviors as they were observed on videotape for the duration of the seven designated events. This led to the identification of (1) 40 distress behaviors as they occurred along the continuum of distress, (2) eight distress behaviors specific to surgery, (3) 11 classes of behaviors occurring within the five sub-phases of circumcision, and (4) a description of 25 distinct post-distress behaviors. Findings support the ability to distinguish distress behaviors specific to pain and the ability to detect prolonged distress as well as individual differences in distress-related pain expression. Findings also justify ongoing use of ethological approaches to further newborn pain assessment and to investigate poorly understood topics such as infant self-regulation within the context of pain (pain recovery).

Foundations of knowledge about neonatal pain

This review appraises trends in the neonatal pain research literature. We searched the literature produced from 1941 to 2001. Information about the model of pain, measures of pain, design, and sample characteristics is included for each citation. Gaps in knowledge are attributed to specific conceptual and methodological problems, including the lack of basic knowledge about pain behavior, over-reliance on an invasive short-term pain model, pain measurement issues, and lack of knowledge about confounders. Ethological research methods could be used to expand basic knowledge about newborn pain.

The challenges of pain measurement in critically ill young children: A comprehensive review

This article addresses the issues in measuring pain in critically ill children, provides a comprehensive review of the pain measures for children aged between 0 and 3 years, and discusses their applicability to this group of children. When children are critically ill, pain can only exacerbate the stress response that already exists, to the extent that homeostasis cannot be maintained. Severity of illness is thus likely to affect physiologic and behavioural pain responses that would normally be demonstrated in healthy children. The problem of differentiating pain from other constructs adds to the complexity of assessing pain in non-verbal children. A pain measure to be useful clinically must be adapted to the developmental age of the target population. Search of electronic databases and other electronic sources was supplemented by hand review of relevant journals to identify published and unpublished pain measures for use in children aged between 0 and 3 years. Twenty eight pain measures were identified in the literature; 11 for neonates only, 11 for children aged between 0 and 3 years, and six for children more than 12 months. These measures vary in relation to their psychometric properties, clinical utility and the context in which the study was performed. These measures may not be suitable for the critically ill young child, because the items included were derived from observations of healthy or moderately sick children, and may not reflect pain behaviour in those who are critically ill. It is therefore recommended to develop new pain scales for this population of compromised children.

Myths and facts about pain in neonates

THE PURPOSE OF THIS COLUMN is to examine some of the common myths and misconceptions about neonatal pain and to present facts found in clinical and evidence-based nursing research. Research shows that pain and stress in the preterm infant have both immediate and long-range deleterious effects.Nociceptionis the term frequently used to describe the neonate’s nerve perception of painful stimuli.1

Oral sucrose for procedural pain in sick hospitalized infants: a randomized-controlled trial

OBJECTIVE

To determine the efficacy of 25% oral sucrose in the reduction of pain during a heel lance procedure in sick hospitalized infants.

METHODOLOGY

In a blinded randomized- controlled trial, hospitalized infants were given either 1 mL 25% sucrose or 1 mL water 2 min prior to a heel lance procedure. Pain assessment comprised a four-point facial expression score, incidence and duration of crying, heart rate and oxygen saturation changes.

RESULTS

A total of 128 infants were included. Facial scores immediately upon heel lance, and at 1 and 2 min in the recovery period were reduced in the treatment (sucrose) group compared to the placebo (water) group (P < 0.05). At other observation points, the differences in facial scores between the two groups of infants did not reach statistical significance. Neither incidence nor duration of crying whilst the blood collection was in progress was significantly reduced by sucrose. In the 3-min recovery period following completion of the blood collection, incidence and duration of crying were significantly less in the treatment group of infants (P < 0.05). Physiological responses of heart rate and oxygen saturation were not attenuated by sucrose at any time point during or following the blood collection.

CONCLUSION

Oral sucrose was effective in reducing behavioural responses to pain upon heel lance and in the period following completion of a heel lance procedure in this group of sick hospitalized infants. This simple strategy can be promoted in institutions caring for sick babies, as a method of reducing behavioural responses to procedural pain.

Oral sucrose and pain relief for preterm infants

The frequency of painful procedures performed on preterm infants in the neonatal intensive care unit (NICU) presents a challenge to nurses who are attempting to provide effective pain relief, and to the infants themselves who may suffer adverse consequences in response to repeated painful procedures. One new pain relief intervention under study is the administration of oral sucrose, which may activate endogenous opioid systems within the body. Studies with preterm infants that have examined the use of oral sucrose as an analgesic during heelsticks and venipunctures have shown that sucrose is effective in reducing pain. Sucrose may also be combined with nonnutritive sucking to provide significant pain relief. The use of oral sucrose is now recommended with a wide range of painful procedures in the NICU. Promising results have been observed in studies with both term and preterm infants, but less research has occurred with preterm infants. Additional research is warranted to determine the most effective approaches for the administration of sucrose, to examine the effectiveness of sucrose with additional types of painful procedures, and to examine the effects of long-term repeated use of sucrose.

Pain management in nursing procedures on premature babies

BACKGROUND

Pain can be caused to premature babies when nursing and other procedures are carried out. Procedural pain management for these babies raises challenging questions for health care professionals. Optimal pain management for premature babies can be reached by using and further developing existing pharmacological and non-pharmacological pain alleviation methods for procedural pain before, during, and after procedures.

AIMS

The aims of this study were to describe the environment of pain management in nursing procedures and examinations with premature babies; to describe preparation of the baby for the procedure; to describe non-pharmacological pain alleviation methods during and after the procedures; and to develop a process describing procedural pain management in premature babies.

METHOD

The material for this study consisted of journal articles on non-pharmacological procedural pain alleviation in infants published between 1994 and 2002. During this period knowledge of pain management in premature babies has improved considerably. The study was based on the method of content analysis.

FINDINGS

Procedural pain management in premature babies was described by researchers as a process comprising: (1) an environment that is favourable to effective pain management, (2) safe preparation of the baby for the procedure, (3) pain alleviation during the procedure, and (4) restoring the baby's sense of security after the procedure. Pain management is recommended to be used alone or together with pharmacological interventions. Additionally, systematic pain management requires documentation of the whole pain management process.

CONCLUSION

Pain management can be described as a process. It is important to test and assess this process and individual non-pharmacological pain management methods in practical nursing situations. The findings of this review can be used to improve pain management methods in premature babies.

Health care implications and space allocation of research published in nursing journals

PURPOSE

To examine how research is disseminated through nursing journals and to examine characteristics of published research.

DESIGN

A cross-sectional descriptive survey was conducted with manuscripts from 78 nursing journals that publish research.

METHOD

The final issue for 1999 was examined. Pairs of independent raters content-analyzed all research manuscripts.

DISCUSSION

Research studies comprised 241 (42.9%) of the manuscripts and 51.4% of the journal space. Many empirical studies omitted validity and reliability. Few manuscripts reported the date for completion of data collection, and fewer than one third contained the length of time from acceptance to publication.

CONCLUSIONS

Enhanced instrumentation reporting, shorter time from data collection to publication, and an increase in journal space devoted to research might enable nurses to make more cutting-edge clinical decisions.

Repeated neonatal pain influences maternal behavior, but not stress responsiveness in rat offspring

Early preterm neonates in the Neonatal Intensive Care Unit (NICU) are subjected to repeated painful procedures which could sensitize their responses to pain and potentiate neuroendocrine and behavioral responses to subsequent stressors in the long-term. In this study, we used the model of the neonatal rat to test the effects of repeated pain during the first 2 weeks of life on neuroendocrine responses (CRF, ACTH and corticosterone) to stressors varying in intensity and on maternal behavior in the postnatal period. To closely mimic the type of repeated painful stimulus experienced by preterm neonates (i.e., heelstick), neonatal rats aged day 2-14 were submitted daily to having their rear heels warmed to 34 degrees C and pricked (handled and pain, HP) or not (handled, H) with a needle. For the procedure, all pups were separated from their mothers for a total period of 15 min and reunited afterwards. Unhandled (UH) pups not subjected to daily maternal separation were used as controls. On days 6 and 12, litters from the HP and H groups were videotaped for 90 min upon return with the mother and maternal behavior was analyzed. Frequency of ultrasonic vocalizations (USV) were recorded during the procedure and upon return of pups with the mother. On day 15 and 20, rat pups from all groups were exposed to a 3-min ether vapor stressor or to an openfield for 10 min. Plasma ACTH and corticosterone concentrations were determined at 0, 5, 30, 60 and 120 min after stress onset. Our results show that repeated pain did not modify body weight of the pups, however, on day 6 of life, maternal pup grooming was increased significantly (P<0.05) in the HP group compared to the H group. Frequency of USV was not changed between H and HP rats either during the separation or after reunion with the mother. Plasma ACTH and corticosterone levels under basal or stimulated conditions were not different between UH, H and HP groups. However, the UH pups showed a tendency towards higher ACTH secretion after stress compared to H and HP groups. These results suggest that repeated pain during the first 2 weeks of life in the rat does not lead to significant changes in stress responsiveness in 2-week-old pups, but we suggest that changes in mother-pup interaction (increased grooming) might act as a buffer on the cumulative effect of pain on stress responsiveness.

Validation of the Pain Assessment in Neonates (PAIN) scale with the Neonatal Infant Pain Scale (NIPS)

PURPOSE

To establish the validity and clinical usefulness of a modified pain assessment scale, the Pain Assessment in Neonates (PAIN) scale.

DESIGN

Correlational design to compare scores obtained on the PAIN with scores obtained on the Neonatal Infant Pain Scale (NIPS).

SAMPLE

A convenience sample of 196 neonates from an NICU and a step-down unit with gestational ages of 26 to 47 weeks.

METHOD

Bedside nurses observed the neonates for two minutes and then scored their responses on both scales. The scales were scored sequentially and in a randomized order.

MAIN OUTCOME VARIABLE

Correlation of individual item scores and total scores on the PAIN and the NIPS.

RESULTS

The scores for individual items on the PAIN were significantly associated with scores obtained on the NIPS. Overall correlation between the scales was 0.93. These associations suggest that the PAIN is a valid scale for assessment of neonatal pain.

Animal models of long-term consequences of early exposure to repetitive pain

Although animal models will never match the complexity of human systems, a number of basic mechanisms can be accessed only by using animal models. Results from studies using animal models of pain can give insight into basic mechanisms underlying long-term consequences of pain and provide sufficient data to generate hypotheses to be tested in human infants. Interaction between clinicians and basic scientists, with an understanding of the domain in which each group is working, is critical to the meshing of efforts from these domains. With collaboration between these groups, more relevant research can be conducted that can lead to the decrease in pain and its consequences in neonates.

Early pain in preterm infants. A model of long-term effects

There are multiple lines of evidence suggesting that in vulnerable prematurely born infants, repeated and prolonged pain exposure may affect the subsequent development of pain systems, as well as potentially contribute to alterations in long-term development and behavior. Multiple factors cumulatively contribute to altered developmental trajectories in such infants. These include characteristics of the developing organism (low tactile threshold, sensitization, rapid brain development), characteristics intrinsic to the infant (gestation, illness severity), characteristics of the experience in the neonatal intensive care unit (pain exposure and cumulative stress), and characteristics of the caregivers within their family and social context. This article provides a model for examining long-term effects of pain in the newborn period embedded in a developmental context framework.

Are postoperative pain instruments useful for specific groups of vulnerable infants?

Based on the authors' review of the literature on pediatric postoperative pain assessment with special attention to groups of vulnerable infants, this article (1) reports on type of surgery and its relationship to postoperative pain intensity; (2) reviews the characteristics of existing postoperative pain instruments for neonates, infants, and toddlers; (3) discusses timing, duration, and who should assess postoperative pain; (4) reviews the specific literature on pain assessment in critically ill infants, including the extremely low birth weight and the cognitively and/or neurologically impaired infant, and (5) discusses the role of parents in postoperative pain assessment. Postoperative pain instruments are useful for specific groups of vulnerable infants, but it is important that in addition to the valuable scoring of pain, common sense is used and factors such as developmental stage, temperament and personality, number of previous painful experiences, anxiety, and environmental factors are taken into account.

Bedside assessment of heel lance pain in the hospitalized infant

OBJECTIVE

To evaluate a method of pain assessment to be used for hospitalized infants requiring blood test by a heel lance procedure.

DESIGN

Observational study evaluating pain measurement and interrater reliability of pain measurement in hospitalized infants.

SETTING

A Level III neonatal unit and a cardiac surgical unit at a major pediatric teaching hospital.

PARTICIPANTS

20 infants whose gestational age ranged from 28 weeks to full-term.

MAIN OUTCOME MEASURES

Observations included behavioral measurements (facial expressions, body movements, and crying characteristics) and the physiologic measure of heart rate. Interrater reliability and the feasibility of using the procedural pain assessment method at the bedside were considered.

RESULTS

The three behavioral measurements and heart rate were responsive to the heel lance. Interrater reliability was high for facial expressions and crying scores but was low for body movements.

CONCLUSIONS

Modifications have been made to the method of procedural pain assessment to be used in a subsequent study. The modified method is expected to be a reliable measure of procedural pain caused by a heel lance and can easily be used at the bedside during the course of further research.

Assessment and management of pain in neonates

Neonates are capable of experiencing pain from birth onwards. An impressive body of neuroanatomical, neurochemical and biobehavioural evidence, which has accumulated over the past 2 decades, supports this capability. This evidence mandates health professionals to attend to the prevention, elimination, or at the very least, control of pain for infants. This mandate is essential since pain is known to have both immediate and long term effects, especially if pain is untreated and is severe, prolonged or frequently experienced. Therefore, pain must be assessed frequently, not only to measure location, intensity and duration but also to determine the effectiveness of interventions implemented to control pain. An impressive array of measures for assessing acute pain in infants exists which incorporates valid pain indicators in this population. However, there is a need to develop new measures to assess chronic pain conditions and pain in infants in acute situations.

Relations between behavioral and cardiac autonomic reactivity to acute pain in preterm neonates

OBJECTIVE

The purpose of this study was to assess relations and concordance between behavioral and physiologic reactivity to pain in preterm neonates at 32 weeks postconceptional age as a function of gestational age at birth.

SETTING

Level III neonatal intensive care unit.

DESIGN/PATIENTS

The study group comprised 136 preterm neonates (mean [range] birthweight, 1,020 g [445-1,500 g]: gestational age at birth, 28 weeks [23-32 weeks]) separated into three groups according to gestational age at birth as follows: 23 to 26 weeks (n = 48), 27 to 29 weeks (n = 52), and 30 to 32 weeks (n = 36).

OUTCOME MEASURES

Reactivity to routine blood collection at 32 weeks postconceptional age was assessed using bedside-recorded behavioral and autonomic measures. Coders who were blinded to the study design scored behavioral responses (facial activity using the Neonatal Facial Coding System, sleep/waking state, and finger splay). Autonomic reactivity was assessed by change in heart rate and spectral analysis of heart rate variability (change in low-frequency and high-frequency power, and the ratio of low-frequency to high-frequency power during blood collection).

RESULTS

Facial activity and state correlated moderately with change in heart rate across gestational age groups (r = 0.41-0.62). Facial activity and state did not correlate significantly with change in low-frequency and high-frequency power, or the ratio of low-frequency to high-frequency power (r = 0.00-0.31). Finger splay did not correlate with any autonomic recording (r = 0.03-0.41). Concordance between established biobehavioral measures of pain revealed individual differences. Although some neonates showed high behavioral but low physiologic reactivity, other neonates displayed the opposite reaction; however, the majority displayed concordant reactions.

CONCLUSIONS

The study findings confirm the value of measuring domains independently, especially in neonates born at a very young gestational age.

Treatment of pain in the neonatal intensive care unit

Pain is a disruptive influence on infants in the NICU. The most obvious and effective strategy to decrease infant pain in the NICU is to stringently limit the frequency of painful procedures, especially those that are most commonly reported (i.e., heel lances and endotracheal suctioning), and have these performed on infants that are most unstable or critically ill by the most experienced person available. Organizational concerns over the cost of NICU care have forced a re-evaluation of the necessity of certain diagnostic and care procedures and a limiting of procedures to those that can be documented to positively affect clinical outcome. Pharmacologic and nonpharmacologic strategies are essential to the prevention and management of neonatal pain, and these should be considered for complementary use for every infant. Research has shown the safety and effectiveness of some of the strategies in reducing mild pain caused by brief invasive procedures; however, many of the studies had methodologic limitations. Therefore, more research is required to determine the comparative efficacy of the various strategies and to document additive or synergistic effects when combined.