Pain and analgesia in the newborn

Intranasal Analgesia in Preterm and Term Neonates

The prevention, recognition, and treatment of pain is crucial in the management of neonates. Infants do not tolerate pain better than adults; indeed, the immaturity of the endogenous antalgic system means they exhibit an increased stress response. Pain has been associated with worse cognitive and motor scores, reduced growth trend, reduced brain maturation, and altered corticospinal tract structure. The use of the intranasal route for drug delivery is currently expanding because it has many advantages. In certain contexts, it is preferable over the oral route because of the faster entry of drugs into the circulation, the absence of structural changes by the gastrointestinal environment, and the absence of the hepatic first-pass effect. The pharmacokinetics and pharmacodynamics of drugs commonly used for pain management have peculiar characteristics in infants, especially premature infants. In this article, we summarise the evidence regarding pain management in infants using intranasally administered drugs. We then provide a practical guide to the use of intranasal drugs currently being studied in the neonatal population, focusing on appropriate dosages and indications. Intranasal fentanest appears to be an attractive therapeutic alternative for procedural and palliative neonatal pain management when intravenous access is unavailable in preterm infants. Intranasal midazolam is a valid alternative to consider in term or near-term neonates, especially when the aim is to obtain sedation (and not analgesia, i.e. during magnetic resonance imaging), ketamine has favourable cardiovascular effects and should be considered in specific patients and situations. Intranasal dexmedetomidine is well tolerated in premature neonates. Additionally, endonasal dexmedetomidine can be used in combination with other anaesthetic, sedative, hypnotic, and opioid drugs to allow for dose reduction in sedated neonates.

Going Deeper than Tracking: A Survey of Computer-Vision Based Recognition of Animal Pain and Emotions

Advances in animal motion tracking and pose recognition have been a game changer in the study of animal behavior. Recently, an increasing number of works go ‘deeper’ than tracking, and address automated recognition of animals’ internal states such as emotions and pain with the aim of improving animal welfare, making this a timely moment for a systematization of the field. This paper provides a comprehensive survey of computer vision-based research on recognition of pain and emotional states in animals, addressing both facial and bodily behavior analysis. We summarize the efforts that have been presented so far within this topic—classifying them across different dimensions, highlight challenges and research gaps, and provide best practice recommendations for advancing the field, and some future directions for research.

Practices of Procedural Pain Management in Neonates through Continuous Quality Improvement Measures

Objective

Although the benefits of pain control measures in neonates are well known, the actual usage was not optimal in our unit. Therefore, we implemented a quality improvement project to improve pain management practices through multiple Plan-Do-Study-Act (PDSA) cycles.

Method

Our project included hemodynamically stable newborns weighing ≥1300 g. We identified four common procedures: intravenous cannulation, venous sampling, heel prick, and nasogastric tube insertion. The selected pain control measures were skin-to-skin contact, breastfeeding, expressed breast milk orally, and oral sucrose. Between April 2019 and September 2019, we intervened multiple times and reassessed shortcomings. We encouraged evidence-based practices and gave solutions for shortcomings. Data were interpreted weekly to assess the compliance to pain control interventions.

Results

Minimal pain control measures (3-4%) were utilized for identified procedures before the project began. We could improve the use of pain control measures steadily and achieve the target of 80% of procedures after seven different interventions over five months. There was a retention of the effect on reassessing twice at second and fourth months of stopping further intervention once the target got achieved.

Conclusion

Quality Improvement science can identify the shortcomings and help to improve the compliance for pain control practices in neonates, as demonstrated in this neonatal unit.

Effectiveness of various nonpharmacological analgesic methods in newborns

BACKGROUND

Pain during the developmental period may adversely affect developing neuronal pathways and result in adverse neurodevelopmental, cognitive, and behavioral effects in later life. Immunizations, e.g., hepatitis B vaccine (HBV), administered at birth are painful experiences to which neonates are universally subjected.

PURPOSE

Here we aimed to study and compare the effectiveness of various nonpharmacological pain management methods in newborns to enable the development of safe and effective analgesic methods for newborns.

METHODS

This prospective study was conducted at a tertiary care hospital in the Himalayan region. Three hundred term healthy neonates were divided into 6 groups of 50 each. Groups 1-5 were intervention groups, patients of which received a nonpharmacological intervention (breastfeeding, nonnutritive sucking, rocking, 25% sucrose, or distilled water) before the intramuscular HBV, while patients in group 6 received no intervention. The pain response in each group after the HBV injection was assessed and compared using cry duration and Douleur Aigue Nveau-ne (DAN) score, a behavioral acute pain rating scale for newborns.

RESULTS

Cry duration was decreased in all intervention groups, significantly so in the sucrose (19.90 seconds), breastfeeding (31.57 seconds), and nonnutritive sucking (36.93 seconds) groups compared with controls (52.86 seconds). DAN scores decreased significantly (P<0.05) at one or more points i.e. 30, 60, or 120 seconds in the breastfeeding and 25% sucrose intervention groups compared with controls.

CONCLUSION

Oral sucrose and nonnutritive sucking are simple yet underutilized nonpharmacological interventions that effectively reduce pain in newborns.

Invasive and non-invasive acupuncture techniques for pain management in neonates: a systematic review

BACKGROUND

Neonatal pain is an extensive research field and there are many possibilities to treat pain in neonates. Acupuncture is one new and non-pharmacological option and a promising tool to reduce pain in neonates undergoing minor painful interventions during routine medical care.

OBJECTIVES

This review summarises trials of acupuncture for pain reduction in neonates undergoing painful interventions during routine medical care.

DATA SOURCE

MEDLINE, Embase, CINAHL, electronic clinical trials registry platforms and reference lists were systematically screened for trials from their dates of inception to February 2017 (English language database search).

STUDY SELECTION

Inclusion criteria were (1) preterm or term neonates, (2) acupuncture for painful medical interventions and (3) formal pain assessment as a primary or secondary study outcome. We included only randomised controlled trials.

DATA EXTRACTION

Data were extracted using a standardised protocol and individual risk of bias was assessed.

RESULTS

The literature search revealed a total of 12 196 records. After application of inclusion criteria, five studies were included in this review. Two studies demonstrated significant pain reduction, one found equal outcomes in comparison to standard care, and two showed significantly higher pain scores with acupuncture alone.

LIMITATIONS

The main limitation of the results is the heterogeneity across trials in acupuncture modality, acupuncture point selection, control groups and pain assessment (heterogeneity: I²=87%).

CONCLUSION

The results of this review suggest that acupuncture may have a positive pain-relieving effect in neonates. However, due to the low number of available high-quality trials and heterogeneity across the studies it is not possible to state clear recommendations.

Does noninvasive electrical stimulation of acupuncture points reduce heelstick pain in neonates?

AIM

Noninvasive electrical stimulation at acupuncture points (NESAP) for analgesia is used in children, but has not been widely studied in neonates. The purpose of this study was to determine whether NESAP alone or in combination with sucrose relieved heelstick pain in neonates.

METHODS

Term neonates (n = 162) receiving routine heelsticks for newborn screening were enrolled following parental consent. All infants received facilitated tucking and non-nutritive sucking. Neonates were randomised to standard care, sucrose, NESAP or sucrose plus NESAP. NESAP (3.5 mA, 10 Hz) or sham was administered over four acupuncture points. The Premature Infant Pain Profile (PIPP), heart rate variability (HRV) and salivary cortisol were used to measure heelstick pain.

RESULTS

PIPP scores among all four treatment groups increased during heelstick, F (9,119) = 1.95, p = 0.05 and NESAP therapy had no significant effect on PIPP scores. However, PIPP scores from baseline to heelstick increased the most in the two groups not receiving sucrose (p < 0.01). Mean PIPP scores remained below five during the heelstick in all four groups, indicating minimal or no pain. Differences in HRV and salivary cortisol among groups were insignificant.

CONCLUSION

NESAP at 3.5 mA, 10 Hz is not effective in relieving pain during heelsticks in neonates.

Elimination communication as colic therapy

Colic is generally defined as excessive crying in early infancy and can have negative consequences on the infant as well as on the infant's family life. Excessive crying can result in escalating parental stress levels, abusive caregiver response, increased risk of shaken baby syndrome and parental postpartum depression. In addition to excessive crying, symptoms and descriptors of infant colic include inconsolable crying, screaming, legs drawn up against the abdomen, furrowing of eyebrows, distended abdomen, arched back, passing gas, post-feeding crying and difficulty defecating. There are few well-designed, reproducible, randomized, large-scale studies which demonstrate efficacy of any therapeutic method for colic. An unexplored etiology is that colic is functionally related to a decrease in stooling frequency. Gut distention may periodically result in intensifying discomfort for the infant and in concomitant inconsolable crying. Elimination communication (EC; also known as Natural Infant Hygiene and sometimes referred to as infant potty training, baby-led potty training or assisted infant toilet training) involves the use of cues by which the infant signals to the caregiver that the infant needs to micturate or defecate. Such cues can include types of crying, squirming, straining, wriggling, grimacing, fussing, vocalizing, intent look at caregiver, red face, passing gas and grunting, many of which are the same initial symptoms related to the onset of colicky infant states. A caregiver's attentive and nurturant response to an infant's cues involve uncovering the infant's intergluteal cleft and cradling the infant gently and non-coercively in a supported, secure squatting position. This position will increase the infant's anorectal angle thus facilitating complete defecation. It is hypothesized that effective and timely elimination will cause increased physical comfort for the infant; colic symptoms will concomitantly decrease.

Venepuncture versus heel lance for blood sampling in term neonates

BACKGROUND

Heel lance has been the conventional method of blood sampling in neonates for screening tests. Neonates undergoing heel lance experience pain which cannot be completely alleviated.

OBJECTIVES

To determine whether venepuncture or heel lance is less painful and more effective for blood sampling in term neonates.

SEARCH STRATEGY

Randomized or quasi-randomised controlled trials comparing pain response to venepuncture versus heel lance were identified by searching the Cochrane Central Regsiter of Controlled Trials (CENTRAL, The Cochrane Library), MEDLINE, EMBASE, CINAHL, and clinical trials registries in May 2011.

SELECTION CRITERIA

Trials comparing pain response to venepuncture versus heel lance with or with out the use of a sweet tasting solution as a co-intervention in term neonates.

DATA COLLECTION AND ANALYSIS

Outcomes included pain response to venepuncture versus heel lance with or without the use of a sweet tasting solution using validated pain measures, the need of repeat sampling and cry characteristics. Analyses included typical relative risk (RR), risk difference (RD), number needed to treat (NNT), weighted mean difference (WMD) and standardized mean difference (SMD) with their 95% confidence intervals (CI). Between study heterogeneity was reported including the I squared (I(2)) test.

MAIN RESULTS

Six studies (n = 478) of variable quality were included. A composite outcome of Infant Pain Scale (NIPS), Neonatal Facial Action Coding System (NFCS) and/or Premature Infant Pain Profile (PIPP) score was reported in 288 infants, who did not receive a sweet tasting solution. Meta-analysis showed a significant reduction in the venepuncture versus the heel lance group (SMD -0.76, 95% CI -1.00 to -0.52; I(2) = 0%). When a sweet tasting solution was provided the SMD remained significant favouring the venepuncture group (SMD - 0.38, 95% CI -0.69 to -0.07). The typical RD for requiring more than one skin puncture for venepuncture versus heel lance (reported in 4 studies; n = 254) was -0.34 (95% CI -0.43 to -0.25; I(2) = 97%). The NNT to avoid one repeat skin puncture was 3 (95% CI 2 to 4). Cry characteristics favoured the venepuncture group but the differences were reduced by the provision of sweet tasting solutions prior to either procedure.

AUTHORS' CONCLUSIONS

Venepuncture, when performed by a skilled phlebotomist, appears to be the method of choice for blood sampling in term neonates. The use of a sweet tasting solution further reduces the pain.Further well designed randomised controlled trials should be conducted in settings where several individuals perform the procedures.

A survey of the use of analgesia in newborn intensive care

The use of analgesia and sedation in 70 United Kingdom units which practise newborn intensive care was examined by questionnaire. Sixty-one units (87 per cent) responded. Fifty-nine per cent of units used drugs for this purpose very commonly (more than once a week) and 26 per cent used them commonly (more than once a month). The commonest indication was to provide analgesia and/or sedation during mechanical ventilation, but drugs were frequently used in post-operative pain relief, in necrotising enterocolitis, for fractures and in meningitis, as well as for several less common indications. Opiates were widely used, particularly morphine (77 per cent of units), diamorphine (31 per cent), fentanyl (16 per cent) and pethidine (16 per cent). They were administered by bolus injection or continuous infusion, usually intravenously. The range of doses used, especially for morphine and diamorphine, was wide and adverse effects (cardiovascular, respiratory, bowel and bladder) were commonly reported (48 per cent). Non-opiate drugs, especially chloral hydrate and paracetamol, were commonly used, too; adverse effects were rarely reported. There is a need to examine the most effective and safest ways of adminstering analgesia and sedation, particularly opiates, to the newborn.

Comparison of distress and pain in infants randomized to groups receiving standard versus multiple immunizations

This randomized controlled trial compared distress and pain in healthy 4-month-old infants receiving three different immunizations either sequentially (control, n=50) or simultaneously, two at the same time, followed by the third (experimental, n=51). Although both groups demonstrated a significant increase in cortisol from baseline levels, the lack of significant difference on salivary cortisol between groups post-immunization suggests the study was underpowered. On NIPS scores, the experimental group demonstrated significantly less pain (Mann-Whitney U=1648.0, p=0.003). Simultaneous injections appeared to be effective in reducing pain behavior responses in infants receiving their 4-month immunizations. Longitudinal studies could determine whether reduced exposure to pain in infancy, through simultaneous immunization injections, could contribute to a reduction in sensitivity to pain and physiologic stress responses.

Endothelin-1 exposure on postnatal day 7 alters expression of the endothelin B receptor and behavioral sensitivity to endothelin-1 on postnatal day 11

Endothelin (ET)-1 is a chemical mediator released by the body at sites of injury and disease and is involved in various painful states. This study examined whether ET-1 exposure in the neonatal period alters subsequent ET-1 induced nociception and expression of the ET(B) receptor. ET-1 or saline was administered to postnatal day 7 rats. On postnatal day 11, ET-1 or saline was administered; a first exposure to ET-1 for one group, and a second exposure to ET-1 for another group. A statistically significant increase in ET-1 induced paw flinching was observed in postnatal day 11 male rats exposed to ET-1 for the second time as compared to male rats exposed to ET-1 for the first time. In contrast, a statistically significant decrease in ET-1 induced paw flinching was observed in postnatal day 11 female rats exposed to ET-1 for the second time as compared to female rats exposed to ET-1 for the first time. Furthermore, in males a positive correlation was found between ET-1 induced paw flinching on postnatal day 7 versus 11. In contrast, in females a negative correlation was found between ET-1 induced paw flinching on postnatal day 7 versus 11. Changes in behavioral sensitivity to ET-1 were accompanied by sex-specific ET-1 induced changes in expression of the ET(B) receptor on postnatal day 11 in the plantar hind paw with a statistically significant decrease and increase in ET(B) receptor expression in males and females, respectively. These findings suggest that ET-1 exposure in the neonatal period sex-specifically alters expression of the ET(B) receptor and behavioral sensitivity to ET-1 whereby males show sensitization and females show de-sensitization.

Breastfeeding or oral sucrose solution in term neonates receiving heel lance: a randomized, controlled trial

OBJECTIVE

The purpose of this work was to compare the efficacy of breastfeeding versus orally administered sucrose solution in reducing pain response during blood sampling through heel lance. METHODS; We conducted an open-label, randomized, controlled trial at a neonatal unit of a public hospital in northern Italy on 101 term neonates undergoing heel lance with an automated piercing device for routine neonatal screening for congenital disorders. Newborn infants were randomly assigned to breastfeeding during blood sampling or to the oral administration of 1 mL of 25% sucrose solution. We validated the multidimensional acute pain rating scale of the Premature Infant Pain Profile, heart rate increase, oxygen saturation decrease, crying behavior (duration of first cry, cry percentage in 2 minutes, and during blood sampling), duration of sampling, and the number of performed heel lances.

RESULTS

Median Premature Infant Pain Profile scores were lower in the breastfeeding group (3.0) than in the sucrose-solution group (8.5), and the median group difference was -5.0. The median heart rate increase, oxygen saturation decrease, and duration of first cry for the breastfeeding group were, respectively, 13.0, -1, and 3 and for sucrose group were 22, -3, and 21. Medians were significantly different between the groups. There were no significant differences in the sampling duration and numbers of heel lances.

CONCLUSIONS

This study suggests that breastfeeding provides superior analgesia for heel lance compared with oral sucrose in term neonates.

Prematurity and neonatal noxious events exert lasting effects on infant pain behaviour

BACKGROUND

There is concern that exposure of preterm infants to noxious insults over a prolonged period may have long term effects on their developing nervous system.

AIMS

To investigate medium and long term effects of heel pricks in infants over the first year of life.

STUDY DESIGN

Study 1-a longitudinal study, 2 days and 4 weeks after heel prick. Study 2-a cross sectional study over the first year of life.

SUBJECTS

Study 1-13 healthy preterm (PT) infants. Study 2-63 full term (FT) and 62 PT infants, divided into 3 timed groups (0-20, 21-37 and 38-52 weeks postterm and corrected for prematurity).

OUTCOME MEASURES

Threshold responses (flexion withdrawal (FWR) , gross body movements (GBM) and grimace (G)) to increasing mechanical force applied with Von Frey filaments.

RESULTS

Study 1-Thresholds were all significantly lower (more sensitive) from the pricked heel compared to the contralateral side at 2 days and 4 weeks. Study 2-There were significant differences in threshold between PT and FT infants at all time points for both FWR (P=0.001, <0.001, <0.001) and GBM (P=<0.001, <0.001, 0.009 respectively), the preterm infants always being lower. The threshold for the FWR in FT infants steadily increased, but the threshold for the PT infants remained the same. GBM thresholds increased during the year in both FT and PT infants, but were always significantly lower in the ex-preterm group (P<0.012).

CONCLUSIONS

Either PT birth or repetitive procedures associated with such birth alters the sensitivity threshold of PT infants compared with FT infants for at least the first year of life.

Venepuncture versus heel lance for blood sampling in term neonates

BACKGROUND

Heel lance has been the conventional method of blood sampling in neonates for screening tests. Neonates undergoing this procedure experience pain. Despite various studies evaluating the role of pharmacological and non-pharmacological interventions to date, there are no effective and practical methods to alleviate pain from heel lance.

OBJECTIVES

To determine whether venepuncture or heel lance is less painful and more effective for blood sampling in term neonates.

SEARCH STRATEGY

Systematic search was performed in accordance with the Cochrane Neonatal Collaborative Review Group. Randomized controlled trials which compared pain response to venepuncture vs. heel lance were identified using MEDLINE (1966 - June 2007), EMBASE (1980 - June 2007), CINAHL (1982 - June 2007), Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2007), reference lists of identified trials and personal files. No language restrictions were applied.

SELECTION CRITERIA

Randomized controlled trials which compared pain response to venepuncture vs. heel lance were selected for this review.

DATA COLLECTION AND ANALYSIS

Data regarding the primary outcome of pain response to venepuncture vs. heel lance as assessed by validated pain measures were abstracted. Secondary outcomes included the need of repeat blood sampling, bruising/hematoma at local site, and parental perception of their own anxiety and infant's pain. All data were analysed using RevMan 4.2.10. When possible, meta-analyses were performed using relative risk (RR) and risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, number needed to treat (NNT) was calculated. Weighted mean difference (WMD) was used for continuous data. When present, statistically significant between study heterogeneity was reported including the I squared (I(2) ) test.

MAIN RESULTS

Five trials were eligible for inclusion in the review (including one additional trial identified in this update). Pain assessments were made using validated pain measures including Neonatal Infant Pain Scale (NIPS), Neonatal Facial Action Coding System (NFCS), Premature Infant Pain Profile (PIPP) score and cry characteristics. Two trials did not report on outcomes for all enrolled infants (not intention to treat analyses). Despite the many different pain measures used, all studies showed statistically significantly lower pain scores for venepuncture as compared to heel lance. A meta-analysis of the NIPS scores during the first minute of the procedure (reported in two studies) was statistically significantly lower in the venepuncture group compared to the heel lance group [typical WMD -1.84 (95% CI -2.61, -1.06)]. There was no statistically significant heterogeneity for this outcome (p = 0.22; I(2) 33.3%). The typical RR for requiring more than one skin puncture for venepuncture vs. heel lance (reported in 4 studies) was 0.30 (95% CI 0.18, 0.49). The RD was -0.31 (95% CI -0.41, -0.22). For this outcome there was statistically significant between study heterogeneity (for RR, p = 0.02, I(2 )74.3%; for RD, p < 0.00001, I(2) 96.6%). The number needed to treat (NNT) to avoid one repeat skin puncture was 3 (95% CI 2, 5). In one study, maternal anxiety was noted to be higher in the venepuncture group as compared to heel lance group prior to the procedure; however, after observing the procedure, mothers rated their infant's pain to be lower in the venepuncture group.

AUTHORS' CONCLUSIONS

Venepuncture, when performed by a skilled phlebotomist, appears to be the method of choice for blood sampling in term neonates. For each three venepunctures instead of heel lance, the need for one additional skin puncture can be avoided.Further well designed randomized controlled trials need to be conducted. The interventions should be compared in settings where several individuals perform the venepuncture and/or the heel lance.

Age- and Sex-Specific Nociceptive Response to Endothelin-1

Endothelin-1 (ET-1) is a chemical mediator released by the body at sites of injury and disease. This study tests the hypothesis that ET-1-induced nociception changes with age and sex. Intraplantar ET-1 (1.1 and 3.3 nmol) produced age-specific paw flinching and licking (postnatal day 7 > 21 > 60). The onset and duration of the nociceptive responses was dependent on age. Postnatal day (P) 21 and 60 rats displayed an immediate onset of behavior that subsided with time, whereas the P7 rats had a delayed behavioral response that onset at 20 minutes after ET-1 administration and continued beyond the 75 minute observation period. P7 males showed greater paw flinching compared with females. In addition to spontaneous nociceptive behaviors, ET-1 produced mechanical allodynia in all ages. As with spontaneous nociception, ET-1-induced mechanical allodynia was of a longer duration in the younger aged rats compared with adult rats. These findings show that ET-1 produces both spontaneous nociceptive behaviors and evoked mechanical allodynia in both young and adult rats but that the temporal profile and the size of the responses are age- and sex-dependent. These findings are the first description of age- and sex-specific ET-1-induced nociception.

PERSPECTIVE

Endothelin-1 is a vasoactive peptide released into the systemic circulation after stress and cold pain as well as locally in tissue after injury and disease. These findings suggest greater pain to stimuli that release endogenous endothelin in younger versus older organisms. This developmental approach to studying ET-1-induced pain further illustrates the need for understanding pain mechanisms as a function of the development of the organism so as to better treat pain across the life span.

Venepuncture is preferable to heel lance for blood sampling in term neonates

BACKGROUND

The analgesic effect of oral sucrose in newborn infants undergoing painful procedures is generally accepted. For blood sampling, some studies have shown that venepuncture (VP) is less painful than heel lance (HL).

OBJECTIVE

To determine the least painful and most effective method among blood sampling by VP or HL with or without sucrose.

DESIGN

Randomised, double blind, placebo controlled trial.

SUBJECTS

A total of 100 healthy, full term newborn infants being screened for inborn errors of metabolism were randomly allocated to one of four experimental groups (25 infants in each). Intervention and

OUTCOME MEASURE

Seven specially trained nurses took turns to carry out blood sampling two minutes after administration of oral sucrose or water. Neonatal pain was assessed by the neonatal facial coding system (NFCS), as well as by crying.

RESULTS

Without sucrose, the NFCS score was higher in the HL group than the VP group during blood sampling (median 58 v 23, p<0.001). Oral sucrose significantly reduced the score of the HL group (58 v 47, p<0.01) and also tended to reduce the score of the VP group (23 v 2, p<0.1). However, the HL with sucrose group still had a higher score than the VP without sucrose group (47 v 23, p<0.01). Crying and the total procedure time showed the same trends as the NFCS score.

CONCLUSIONS

VP is less painful and more effective than HL for blood sampling in newborn infants. Although oral sucrose may have an additive analgesic effect, it is not necessarily required if VP is used for blood sampling.

Venepuncture versus heel lance for blood sampling in term neonates

BACKGROUND

Heel lance has been the conventional method of blood sampling in neonates for screening tests. Neonates undergoing this procedure experience pain. Despite various studies evaluating the role of pharmacological and non-pharmacological interventions to date, there are no effective and practical methods to alleviate pain from heel lance.

OBJECTIVES

To determine whether venepuncture or heel lance is less painful and more effective for blood sampling in term neonates.

SEARCH STRATEGY

Systematic search in accordance with the Cochrane Neonatal Collaborative Review Group. All randomized controlled trials which compared pain response to venepuncture vs. heel lance were identified using MEDLINE (1966-June 2004), EMBASE (1980-June 2004), CINAHL (1982-June 2004, Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 2, 2004), reference lists of identified trials and personal files. No language restrictions were applied.

SELECTION CRITERIA

Randomized controlled trials which compared pain response to venepuncture vs. heel lance were selected for this review.

DATA COLLECTION AND ANALYSIS

Data regarding the primary outcome of pain response to venepuncture vs. heel lance as assessed by validated pain measures were abstracted. Secondary outcomes including the need of repeat blood sampling, bruising/hematoma at local site, and parental perception of their own anxiety and infant's pain were abstracted. All data were analysed using RevMan 4.2. When possible, meta-analysis was done using relative risk (RR) and risk difference (RD), along with their 95% confidence intervals (CI). If RD was significant, number needed to treat (NNT) was calculated. Weighted mean difference (WMD) was used for continuous data. When present, statistically significant between study heterogeneity was reported including the I(2) test.

MAIN RESULTS

Four trials were eligible for inclusion in the review. Pain assessments were made using validated pain measures including Neonatal Infant Pain Scale (NIPS), Neonatal Facial Action Coding System (NFCS), Premature Infant Pain Profile (PIPP) score and cry characteristics. Two trials did not report on outcomes for all enrolled infants (not intention to treat analyses). Despite the heterogeneity in the pain measures used, all studies showed statistically significantly lower pain scores for venepuncture as compared to heel lance. A meta-analysis of the NIPS scores during the first minute of the procedure (reported in two studies) was statistically significantly decreased in the VP group compared to the HL group [WMD -1.84 (95% CI -2.61, -1.06)]. There was no statistically significant heterogeneity for this outcome (p = 0.22; I(2) 33.3%). The RR for requiring more than one skin puncture for venepuncture vs. heel lance (reported in 3 studies) was 0.30 (95% CI 0.18, 0.49. The risk difference was -39% (95% CI -50%, -28%). For this outcome there was statistically significant between study heterogeneity (for RR, p=0.02, I(2 )74.3%; for RD, p=0.0001, I(2) 88.9%). The number needed to treat (NNT) to avoid one repeat skin puncture was 3 (95% CI 2, 4). In one study, maternal anxiety was noted to be higher in the venepuncture group as compared to heel lance group prior to the procedure; however, after observing the procedure, mothers rated their infant's pain to be lower in the venepuncture group.

REVIEWERS' CONCLUSIONS

Venepuncture, when performed by a skilled phlebotomist, appears to be the method of choice for blood sampling in term neonates. For each three venepunctures instead of heel lance, the need for one additional skin puncture can be avoided. Further well designed randomized controlled trials need to be conducted. The interventions should be compared in settings where several individuals perform the venepuncture and/or the heel lance.

Gastrointestinal motility and sensory abnormalities may contribute to food refusal in medically fragile toddlers

BACKGROUND

In chronically ill children who refuse to eat, surgery to correct anatomic problems and behavioral treatments to overcome oral aversion often succeed. A few patients fail with standard treatments. The aims of the study were to: 1) investigate motility and gastric sensory abnormalities and 2) describe treatment that was individualized based on pathophysiology in children who failed surgery and behavioral treatments.

METHODS

We studied 14 patients (age 1.5-6; mean 2.5; M/F: 7/7). All had a lifelong history of food aversion and retching or vomiting persisting after feeding therapy and fundoplication. All were fed through gastrostomy or gastro-jejunostomy tubes. We studied esophageal and antroduodenal manometry, and gastric volume threshold for retching. We identified when gastric antral contractions were associated with retching and pain. A multidisciplinary treatment program included a variable combination of continuous post-pyloric feedings, drugs to decrease visceral pain, drugs for motility disorders, and behavioral, cognitive, and family therapy. We interviewed parents 2-6 months following testing to evaluate symptoms, mode of feeding and emotional health.

RESULTS

We found a motility disorder alone in 2, decreased threshold for retching alone in 5 and both motility and sensory abnormalities in 7. After treatment, 6 of 14 (43%) began eating orally and 80% had improved emotional health. Retching decreased from 15 episodes per day to an average of 1.4 per day (p <0.01).

CONCLUSIONS

Upper gastrointestinal motor and/or sensory disorders contributed to reduced quality of life for a majority of children and families with persistent feeding problems. A multidisciplinary approach improved symptoms and problems in these children

Assessment and management of pain in infants

Infants, including newborn babies, experience pain similarly and probably more intensely than older children and adults. They are also at risk of adverse long term effects on behaviour and development, through inadequate attention towards pain relief in early life. However, the issue of analgesia in young babies has been largely neglected in most clinical settings, despite subjecting them to painful diagnostic and therapeutic procedures. Several therapeutic and preventive strategies, including systemic and local pharmacological and non-pharmacological interventions, are reported to be effective in relieving pain in infants. A judicious application of these interventions, backed by awareness and sensitivity to pain perception, on the part of the caregivers is likely to yield the best results. This article is a review of the mechanisms of pain perception, objective assessment, and management strategies of pain in infants.

Effects of rectally administered paracetamol on infants delivered by vacuum extraction

OBJECTIVE

To evaluate whether paracetamol (20 mg/kg rectally) relieves pain in infants delivered by vacuum extraction, and improves clinical condition.

METHODS

Prospective, randomised, double-blind, placebo-controlled study. Infants delivered by vacuum extraction were randomised either to the study group (n=61) and given paracetamol or to the control group (n=61) receiving placebo. Pain assessment was performed by a validated pain score and by scoring the clinical condition. Both scores and clinical symptoms in these groups were compared with symptoms in a reference group (n=66) with uncomplicated pregnancy and delivery in vertex position without vacuum extraction.

RESULTS

Pain score did not differ between groups; clinical condition in the study group improved only after the first dose. There was a significant difference (P<0.05) in objective clinical symptoms in the vacuum extraction groups, compared to the reference group.

CONCLUSION

One dose of paracetamol given to neonates delivered by vacuum extraction significantly improved their clinical condition, but did not result in a significant change in objective pain scores. Subsequent doses of paracetamol did not show any effect on the clinical symptoms or appearance of the neonates studied.

Postnatal development of central nociceptive mechanisms modulating jaw muscle activity in the rat

Postnatal changes in the electromyographic (EMG) activity of jaw muscles evoked by mustard oil (MO) application into the rat temporomandibular joint region and the recurrence of increased jaw muscle activities after intravenous injection of naloxone were compared among 4, 6 and 8-week-old rats. In all the groups, MO application increased EMG activity on the ipsilateral side, however, 4-week old rats showed only a small increase in EMG activity on the contralateral side. The EMG activity on the contralateral side increased in an age-dependent manner. The recurrence of increased jaw muscle activity was not induced in 4-week old rats. These results suggest that a neural circuit for generating contralateral responses and mechanisms for central excitation are not established until after 4 weeks postnatally.

Pediatric acute pain management

The past decade has brought about an explosion of knowledge about the physiology of nociception and many new techniques for pain relief, new analgesic drugs, and new applications of old analgesic drugs. These techniques include methods of opioid administration by transdermal and transmucosal absorption and the use of neuraxial analgesia for the management of pain in children. Interest in the use of regional anesthesia in children has been rekindled, and analgesic properties and pre-emptive analgesic properties of many agents not typically considered analgesics, such as clonidine and ketamine, have been recognized. Perhaps the greatest advance has been the paradigm shift in the recognition that pain not only exists in infants and children but also is a significant cause of morbidity and even mortality. Given the unprecedented interest in pain management in adults and children, physicians can now look forward to the development of new methods of drug delivery and of receptor-specific drugs that divorce analgesia from the untoward side effects of existing analgesics. Improvement in the quality of life of hospitalized children also will occur.

Evaluating the implementation of a pain management flow sheet

This study evaluated the outcome of implementing a pain flow sheet, using protocols derived from the Agency for Health Care Policy and Research (AHCPR) guidelines for pain management, for children recovering from surgery. Findings indicated the flow sheet was not used as designed; thus, implementing the flow sheet did not result in increased documentation of pain assessments, interventions, and outcomes, except in the increased documentation of nonpharmacological interventions for pain management. Rogers' Diffusion of Innovation Theory gives insight as to why this occurred and provides rationale for more intensive in-service education when new innovations are implemented.

Pain in neonate

Anatomical, functional and neurochemical maturation of pain pathways is well developed in fetus and neonates. Various physiological and behavioural responses to painful stimuli in neonates substantiate their ability to feel pain. Biological effects of pain are systematically studied in human fetus and neonates. Pain expressions in the newborn not only reflect tissue damage but are a function of ongoing behavioural state. The ultimate aim should be to keep neonates free from pain and other stressful stimuli as far as possible, by advocating minimal handling protocol, giving comforts after painful procedures, local anesthesia while carrying out painful procedures like cutdown and insertion of chest tubes, and if a baby is ventilated fentanyl and/or midazalam infusion must be carried out during initial periods of ventilation.

Pain in the very preterm baby: 'suffer little children?'

Increases in medical expertise and technological advances have enabled the survival of very preterm babies who form a new and growing population. Comparisons between the foetus, full-term baby and the very preterm baby indicate that by the time the foetus is of 23 weeks gestation, many of the abilities, for example, sensing touch, hearing, seeing, moving and even learning may be common to all three. Thus, the very preterm infant who has been described as a unique organism, is not passive, but is a sentient being who is unlikely to survive without the medical and technical support of the Neonatal Intensive Care Unit (NICU) where he/she is exposed to frequent and regular medical procedures. Many of these procedures would be, for any normal, fully developed human being at best uncomfortable and at worst painful. Reviews within the past 10 years have shown that the neurochemical, anatomic and functional systems of newborns are developed enough to perceive pain. More importantly, rat pup studies have indicated that not only may the very preterm baby experience pain but it may experience it more intensely than the more mature infant. Moreover, there may be serious consequences of repeated painful medical intervention. Alleviation of pain and/or distress in very preterm infants is, therefore, an important issue.

A simultaneous comparison of three neonatal pain scales during common NICU procedures

OBJECTIVE

This study evaluated neonatal pain scales during procedures commonly performed in a neonatal intensive care unit.

DESIGN

Evaluated were the Neonatal Infant Pain Scale (NIPS), the Comfort scale, and a new scale known as the Scale for Use in Newborns (SUN). Four procedures were scored: intubation, intravenous catheter insertion, endotracheal tube suctioning, and diaper changes. Scoring was done before, during, and after each procedure. Thirty-three patients were tested during 68 procedures with 1,428 scale scores.

RESULTS

All scales demonstrated significant changes. In before-versus-during for each procedure, the increase in pain scale score was significant for the NIPS, Comfort scale, and SUN. All three scales also demonstrated a return to baseline (before-vs.-after) for the four procedures, except for the Comfort scale, which remained elevated (p < .05) following diaper change. The NIPS had a significantly larger coefficient of variation (CV, 188% +/- 99%), whereas the Comfort scale and SUN had small CVs (27% +/- 5% and 33% +/- 8%, respectively). In evaluating potential confounding influences, it was found that infants > 2.5 kg on sedative or analgesic medications appeared to have procedure-related accentuation and sustained elevation in scale scores, whereas swaddling seemed to provide little added benefit.

CONCLUSIONS

The pain scale scores identify changes in an infant's behavior/physiologic state. It is unclear whether these changes are totally "pain specific." In comparing the three scales, the SUN overall was a preferable tool because of its ease of use, scale symmetry, and scoring consistency.

Neonatal pain response to heel stick vs venepuncture for routine blood sampling

Neonatal pain response and adverse effects and maternal anxiety were assessed in 27 infants who were randomly allocated to venepuncture or heel stick. Pain was assessed by nurses using the Neonatal Infant Pain Scale (NIPS) and a three point scale for the mothers. NIPS scores were higher in the heel stick group compared with the venepuncture group. Maternal anxiety was higher before the procedure while perception of an infant's pain was lower in the venepuncture group compared with the heel stick group. Venepuncture is less painful than heel stick in newborn infants undergoing routine blood sampling.

[Anatomical route of pain in premature newborn infants]

Recent research about nociceptive pathways in newborn infants have shown that, even very immature, preterm infants have all the anatomical and functional components required for the perception of painful stimuli. However, the perception of pain in preterm infants is thought to be slightly different from that of term infants: because of a lack of myelination of their sensitive fibers and a still immature cortical organization of the somatosensory system, painful stimuli are perceived more widespread and durable. In addition, the threshold of pain seems to be lower in premature infants, probably due to a lack of protection of their spinal and supraspinal inhibitory pathways. Finally, abnormal behavioural imprinting secondary to early painful stimuli is now suggested. Thus in contrast with the former misconception of "insensitivity towards pain", premature infants must be now considered as "hypersensitive" and vulnerable.

Special needs of preterm infants in the management of pain and discomfort

Most infants born preterm are admitted to hospital neonatal intensive care units, where they undergo repeated multiple diagnostic and therapeutic procedures that result in pain and discomfort. Although there is convincing evidence to support the preterm infant's neurologic capacity for pain, management of pain often is not optimal. Accurate and reliable assessment of the preterm infant's pain is an important prerequisite for effective pain management. Pain assessment is a challenge for health professionals because the preterm infant's responses are less vigorous, more variable, and less consistent than are the responses of term neonates and older infants. Few reliable and valid assessment measures exist for this age group. There also is uncertainty in implementing pain-relieving intervention because of inadequate information on their safety and effectiveness and preconceived attitudes and beliefs of health professionals. The special needs of preterm infants related to the assessment and management of pain are discussed.

The analgesic effect of sucrose in full term infants: a randomised controlled trial

OBJECTIVE

To evaluate the effects of different sucrose concentrations on measures of neonatal pain.

DESIGN

Randomised, double blind, placebo controlled trial of sterile water (control) or one of three solutions of sucrose--namely, 12.5%, 25%, and 50% wt/vol.

SETTING

Postnatal ward.

PATIENTS

60 healthy infants of gestational age 37-42 weeks and postnatal age 1-6 days randomised to receive 2 ml of one of the four solutions on to the tongue two minutes before heel prick sampling for serum bilirubin concentrations.

MAIN OUTCOME MEASURE

Duration of crying over the first three minutes after heel prick.

RESULTS

There was a significant reduction in overall crying time and heart rate after three minutes in the babies given 50% sucrose as compared with controls. This was maximal one minute after heel prick in the 50% sucrose group and became statistically significant in the 25% sucrose group at two minutes. There was a significant trend for a reduction in crying time with increasing concentrations of sucrose over the first three minutes.

CONCLUSION

Concentrated sucrose solution seems to reduce crying and the autonomic effects of a painful procedure in healthy normal babies. Sucrose may be a useful and safe analgesic for minor procedures in neonates.

Basic and clinical aspects of visceral hyperalgesia

Although physiological stimuli in the healthy gastrointestinal tract are generally not associated with conscious perception, chronic abdominal discomfort and pain are the most common symptoms resulting in patient visits with gastroenterologists. Symptoms may be associated with inflammatory conditions of the gut or occur in the form of so-called functional disorders. The majority of patients with functional disorders appear to primarily have inappropriate perception of physiological events and altered reflex responses in different gut regions. Recent breakthroughs in the neurophysiology of somatic and visceral sensation are providing a series of plausible mechanisms to explain the development of chronic hyperalgesia within the human gastrointestinal tract. A central concept to all these mechanisms is the development of hyperexcitability of neurons in the dorsal horn, which can develop either in response to peripheral tissue irritation or in response to descending influences originating in the brainstem. Taking clinical characteristics and the concept of central hyperexcitability into account, a model is proposed by which abdominal pain from chronic inflammatory conditions of the gut and functional bowel disorders such as noncardiac chest pain, nonulcer dyspepsia, and irritable bowel syndrome could develop by multiple mechanisms either alone or in combination.

Reliability and validity of preverbal pain assessment tools

Pain assessments using three different observational pain assessment tools--the Post Operative Pain Score (POPS), the Nursing Assessment of Pain Intensity (NAPI), and the Pain Rating Scale (PRS)--were made on 98 preverbal children following surgery in an attempt to establish the reliability and validity of the three tools. Two observers (raters) scored pain intensity using each of the three instruments before and after administration of an analgesic. Interrater agreements were satisfactory on all three tools, with Interclass Correlations (ICC) ranging from .71 to .85. T tests supported the discriminant validity of all three tools at the p < .0001 level. The POPS and NAPI had internal consistency reliability alphas ranging from .79 to .88 for the POPS and .59 to .77 for the NAPI. Item analyses suggested specific revisions of the tools that might increase their reliability.

Multidimensional pain assessment in premature neonates: a pilot study

OBJECTIVE

To describe the physiologic and behavioral responses of premature neonates to a painful stimulus.

DESIGN

Descriptive.

SETTING

Secondary-level neonatal unit in a large metropolitan university teaching hospital.

PARTICIPANTS

Forty neonates between 32 and 34 weeks' postconceptual age and less than 5 days' postnatal age.

MAIN OUTCOME MEASURES

Physiologic (heart rate, oxygen saturation, and intracranial pressure) and behavioral (facial expression and cry) outcomes observed during a routine heel stick.

RESULTS

Physiologic responses were significant, but were not specific to pain. Behavioral responses were more promising and indicated that premature neonates were capable of responding in a manner similar to full-term neonates.

CONCLUSIONS

Premature neonates are capable of expressing their pain in a manner similar to healthy, full-term neonates. Factors that alter this response were not clearly delineated. Further research is needed to determine more precise patterns of response in this age group.

Pain in the preterm neonate: behavioural and physiological indices

The impact of invasive procedures on preterm neonates has received little systematic attention. We examined facial activity, body movements, and physiological measures in 56 preterm and full-term newborns in response to heel lancing, along with comparison preparatory and recovery intervals. The measures were recorded in special care and full-term nurseries during routine blood sampling. Data analyses indicated that in all measurement categories reactions of greatest magnitude were to the lancing procedure. Neonates with gestational ages as short as 25-27 weeks displayed physiological responsivity to the heel lance, but only in the heart rate measure did this vary with gestational age. Bodily activity was diminished in preterm neonates in general, relative to full-term newborns. Facial activity increased with the gestational age of the infant. Specificity of the response to the heel lance was greatest on the facial activity measure. Identification of pain requires attention to gestational age in the preterm neonate.

[Acute pain in children and its treatment]

Pain in paediatrics has long been underestimated. The numerous scientific studies carried out during the last decade show that its existence can no longer be doubted: in fact, pain already exists during the neonatal period, and probably throughout the last trimester of gestation as well. Pain pathways mature during the embryonic period and peripheral receptors develop between the 7th and 20th week. A-delta and C fibers, as well as spinal roots and nerves, are completely differentiated before the end of the second month. The development of specific neurotransmitters and thalamic and cortical dendritic branching occurs later on; it is well enough developed to allow perception of painful stimuli (slow or protopathic component) from the beginning of the foetal period onwards. The discriminative rapid component develops in parallel to myelinisation, and the psycho-affective component, which requires a long and complex learning process, will not be fully operative until the end of puberty. Assessing pain, already a difficult task in the adult, is all the more so in children because of lesser verbal communicative capabilities, difficulty in handling abstract concepts, lack of experience of painful stimuli to make comparisons, and ignorance of their body image. In the very young child, diagnosing pain relies on suggestive circumstances, and an altered behaviour, knowing that no one symptom in pathognomonic. As the child grows up, methods for self-assessment of pain become usable, such as coloured scales and simplified verbal scales. However, behavioural tests remain the mainstay until the prepubertal period. The treatment of acute pain requires a reasoned approach which takes into account the state of the child, that of the aetiological investigations, the likely course of the lesions, as well as the patient's analgesic requirements. Therapeutic means do not differ from those for adult patients; however, the differences of distribution of body water, the small possibilities of linking with plasma proteins, and limited conjugation with glucuronate must be taken into account, especially during the first months of life. Local and regional anaesthetic block techniques are of great interest in elective and emergency surgery, as well as in trauma: they can provide complete pain relief, mostly without having any effect on the patient's physiological state (haemodynamics and consciousness). Peripherally acting analgesic agents, which are well supported on the whole, as well as co-analgesics, have a great part to play, although there are less drugs available than for adults. The most useful ones are paracetamol, followed by the salicylates, propionic acid derivatives and non steroid anti-inflammatory drugs.(ABSTRACT TRUNCATED AT 400 WORDS)