The efficacy of developmentally sensitive interventions and sucrose for relieving procedural pain in very low birth weight neonates

The premature infant and painful procedures

Pain management for premature infants raises challenging questions for nurses. This group of infants is often physiologically fragile and they may undergo frequent painful procedures on a daily basis. Contrary to ideas from the past, premature infants are able to feel pain, and nervous system elements required for the transmission of painful stimuli are functional by 24 weeks gestation. Painful procedures are harmful to the infant's physiological stability and the ability to self-regulate, which includes maintenance of motor control and stable sleep/wake cycles. Assessment of pain in the premature infant is complex. Major indicators of pain include facial grimaces and physiological parameters such as heart rate and oxygen saturation. The Premature Infant Pain Profile (PIPP) is one tool designed specifically for preterm infants. Nonpharmacological nursing measures such as swaddling or nesting and offering a pacifier are useful strategies to help infants cope with painful procedures. The nurse may also maintain a therapeutic environment to assist the infant in self-regulation. Pharmacological agents such as morphine, fentanyl, and acetaminophen are effective in relieving procedural pain. The use of oral sucrose before and during painful procedures offers new possibilities for pain relief. Recent research shows that oral sucrose is a safe and effective analgesic for short-term procedures. Research studies to determine the most effective doses and modes of oral sucrose administration are ongoing. It is thought that the relief of pain is owing to the sweet taste of the sucrose that activates endogenous pain-modulating systems.

Pain assessment in infants and children

The science of pain assessment for infants and children has grown substantially in the past several decades to the point that valid and reliable methods for pain assessment are available for use in clinical settings. Accurate pain assessment requires consideration of children's developmental level, type of pain experienced, history and context of pain, family influences, and interaction with the health care team. Research is needed to improve the sensitivity, specificity, and generalizability of pain-assessment tools and to more fully incorporate contextual factors into the objective assessment process. Finally, the improvement of pain assessment in the clinical setting can be viewed as a patient care quality issue, and continuous quality improvement methods can be used effectively to incorporate pain assessment as an integral component of every infant's and child's health care.

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.

Sucrose for analgesia in newborn infants undergoing painful procedures

BACKGROUND

Management of pain for neonates is less than optimal. The administration of sucrose with and without non-nutritive sucking (pacifiers) has been the most frequently studied non-pharmacological intervention for relief of procedural pain in neonates.

OBJECTIVES

To determine the efficacy, effect of dose, and safety of sucrose for relieving procedural pain as assessed by physiologic and/or behavioural indicators.

SEARCH STRATEGY

Standard methods as per the Neonatal Collaborative Review Group. A MEDLINE search was carried out for relevant randomized controlled trials (RCTs) published from January 1966 - November 1, 1997; EMBASE from 1993-1997; Reference Update search on November 11, 1997 and search of the Cochrane Library Issue 4 on November 11, 1997. Key words and (MeSH) terms included, infant/newborn, pain, analgesia and sucrose. Personal files, bibliographies, the most recent relevant neonatal and pain journals and conference proceedings were searched manually. Unpublished studies were not included. Language restrictions were not imposed.

SELECTION CRITERIA

RCTs in which term and/or preterm neonates undergoing heel lance, venepuncture or intramuscular injection (immunization) received sucrose or water/placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Trial quality was assessed according to the methods of the Neonatal Collaborative Review Group. Quality measures included; blinding of randomization, blinding of intervention, completeness of follow up and blinding of outcome measurement. Data were abstracted and independently checked for accuracy by the two investigators. The inconsistency in outcome measures and differences in the statistical reporting of results made meta-analysis impossible. We were not able to identify two studies in which the same physiologic and/or behavioral outcomes following a noxious stimulus (heel-lance, venepuncture, intramuscular injection) were measured and reported in an identical fashion using means and standard deviations (or standard errors). The results are therefore reported for each accepted study separately.

MAIN RESULTS

Fifteen studies were identified for possible inclusion in this systematic review. Five studies were excluded; three RCTs were excluded as in these trials the number of infants randomized to treatment vs. placebo groups were not reported; one study was not an RCT, and in one RCT the neonates did not undergo a painful procedure. Ten RCTs were included in this review. Sucrose in a wide range of dosages was generally found to decrease univariate physiologic (heart rate) and behavioural (the mean percent time crying, total cry duration, duration of first cry, and facial action) pain indicators and multivariate [Premature Infant Pain Profile (PIPP)] pain outcomes in neonates undergoing heelstick or venepuncture. An optimal dose of sucrose to reduce pain associated with procedures in preterm and term neonates could not be identified through this systematic review.

REVIEWER'S CONCLUSIONS

Sucrose reduces physiologic and/or behavioral indicators of stress/pain in neonates following procedural pain stimuli (heel lance, venepuncture, immunization). There was inconsistency in the dose of sucrose that was effective and an optimal dose to be used in preterm and/or term infants could not be identified. Considerations for future research are to describe the painful procedure and intervention in detail, to use appropriate sample size to show a statistically significant reduction in pain, to use a multidimensional conceptualization of pain, to select outcome measures that are reliable and valid pain indicators and to account for the variation in the infant's response and context in which the pain is experienced. The use of repeated administrations of sucrose in neonates needs to be investigated. Use of sucrose in neonates that are very low birth weight, unstable and/or ventilated also needs to be addressed. (ABSTRACT TRUNCATED)

Validation of the premature infant pain profile in the clinical setting

OBJECTIVE

The Premature Infant Pain Profile (PIPP) is a 7-indicator composite measure developed to assess acute pain in preterm and term neonates. It has been validated in studies using synchronized videotaping of infants undergoing procedures. The purpose of this study was to establish (a) construct validity of the PIPP and (b) inter- and intrarater reliability of the PIPP prospectively in the clinical environment.

DESIGN

A randomized, crossover design was used.

SETTING

The study was conducted in a Level III outborn neonatal intensive care unit.

PARTICIPANTS

A convenience sample of 43 neonates, stratified by gestational age, was studied.

INTERVENTIONS

Each infant experienced three separate, randomly ordered events: baseline, a painful event, and a nonpain event. Infants were videotaped and scored at the bedside using the PIPP by the nurse caring for the infant and the clinical nurse specialist who bad expertise in infant pain. The videotapes were later reviewed by two additional experts; one in real time and one using a second-to-second stop frame technique.

RESULTS

Repeated-measures analysis of the main effects and interactions yielded a statistically significant main effect for event (pain, nonpain, baseline), thus differentiating pain from nonpain and baseline events (F = 48, p = 0.0001) and establishing construct validity. Interrater reliability analysis of individual event scores of the PIPP yielded reliability coefficients of 0.93-0.96. Intrarater reliability coefficients analysis for individual events were equally high at 0.94-0.98.

CONCLUSIONS

This study demonstrates that the PIPP is a pain measure with good construct validity and excellent inter- and intrarater reliability for the assessment of procedural pain of preterm and term infants in clinical settings.

Factors explaining lack of response to heel stick in preterm newborns

OBJECTIVE

To determine factors explaining lack of response by preterm newborns to heel stick for blood sampling.

DESIGN

A cross-sectional design based on secondary analysis of the control session of a randomized crossover design.

SETTING

Four Level III neonatal intensive-care units of university teaching hospitals.

PARTICIPANTS

120 preterm newborns with an average age of 28 weeks postconceptional age.

INTERVENTION

24 newborns who showed a "no change" response according the Premature Infant Pain Profile were compared to the remaining 96 newborns who had shown a pain response.

MAIN OUTCOME MEASURES

Age (postconceptional age at birth, postnatal age at study), Apgar score at 5 minutes, severity of illness, sex, race, wake/sleep state, previous study sessions, total number of painful procedures since birth, and time since last painful procedure.

RESULTS

After stepwise logistic regression analysis the variables remaining in the final model that explained the difference between the groups were postnatal age at time of study, postconceptional age at birth, time since last painful procedure, and wake/sleep state.

CONCLUSIONS

Newborns who were younger, asleep, and had undergone a painful event more recently were less likely to demonstrate behavioral and physiologic indicators of pain.

Do cry features reflect pain intensity in preterm neonates? A preliminary study

The purpose of this study was to investigate if cries from preterm neonates would reflect changes in pain intensity following interventions. The cries from 25 preterm neonates from an original sample of 122 were audiorecorded while the infant was undergoing heelstick during a randomized crossover design testing the efficacy of: pacifier with sucrose or water, or prone position as compared to standard care. Both pacifier conditions reduced procedural pain according to a validated composite pain measure (the Premature Infant Pain Profile). There were proportionately fewer cries in the two pacifier groups compared to the prone positioning and standard care groups, and cry duration was positively correlated with PIPP scores. However, neither cry duration nor fundamental frequency reflected group differences. Further research is needed to determine if cry is a sensitive and valid indicator of pain in preterm infants.