The effects of skin‐to‐skin contact during acute pain in preterm newborns

Background and purpose: Several promising non‐pharmacological interventions have been developed to reduce acute pain in preterm infants including skin‐to‐skin contact between a mother and her infant. However, variability in physiological outcomes of existing studies on skin‐to‐skin makes it difficult to determine treatment effects of this naturalistic approach for the preterm infant. The aim of this study was to test the efficacy of mother and infant skin‐to‐skin contact during heel prick in premature infants. Method: Fifty nine stable preterm infants (born at least 30 weeks gestational age) who were undergoing routine heel lance were randomly assigned to either 15min of skin‐to‐skin contact before, during and following heel prick (n=31, treatment group), or to regular care (n=28, control group). Throughout the heel lance procedure, all infants were assessed for change in facial action (NFCS), behavioral state, crying, and heart rate. Results: Statistically significant differences were noted between the treatment and control groups during the puncture, heel squeeze and the post phases of heel prick. Infants who received skin‐to‐skin contact were more likely to show lower NFCS scores throughout the procedure. Both groups of infants cried and showed increased heart rate during puncture and heel squeeze although changes in these measures were less for the treated infants. Conclusions: Skin‐to‐skin contact promoted reduction in behavioral measures and less physiological increase during procedure. It is recommended that skin‐to‐skin contact be used as a non‐pharmacologic intervention to relieve acute pain in stable premature infants born 30 weeks gestational age or older.     

Objective and continuous measurement of peripheral motor indicators of pain in hospitalized infants: A feasibility study

Measurement of pain in pre-verbal infants is complex. Until now, pain behavior has mainly been assessed intermittently using observational tools. Therefore, we determined the feasibility of long-term, objective and continuous measurement of peripheral motor parameters through body-fixed sensors to discriminate between pain and no pain in hospitalized pre-verbal infants. Two pain modes were studied: for procedural pain 10 measurements were performed before, during and after routine heel lances in 9 infants (age range infants: 5–175 days), and for post-operative pain 14 infants (age range 45–400 days) were measured for prolonged periods (mean 7 h) using the validated COMFORT-behavior scale as reference method. Several peripheral motor parameters were studied: three body part activity parameters derived from acceleration sensors attached to one arm and both legs, and two muscle activity parameters derived from electromyographic (EMG) sensors attached to wrist flexor and extensor muscles. Results showed that the accelerometry-based parameters legs activity and overall extremity activity (i.e. mean of arm and legs) were significantly higher during heel lance than before or after lance (p ? 0.001), whereas arm activity accelerometry data and wrist muscle activity EMG data showed no significant change. For the post-operative pain measurements, relationships were found between accelerometry-based overall extremity activity and COMFORT-behavior (r = 0.76, p < 0.001), and between EMG-based wrist flexor activity and COMFORT-behavior (r = 0.55, p < 0.001, for a subgroup of 7 infants). We conclude that long-term, objective and continuous measurement of peripheral motor parameters is feasible, has high potential, and is promising to assess pain in pre-verbal hospitalized infants.     

Music modulates behaviour of premature infants following heel lance.

The physiological and behavioural effects of music during recovery from heel lance were examined in 14 preterm infants at 29 to 36 weeks post-conceptual age (PCA). Infants were tested on 2 occasions: during a music condition and during a no-music control condition. Each condition was videotaped during 3 periods: baseline, heel lance, and recovery. Infants were divided into 2 age groups for data analyses: less than and greater than 31 weeks PCA. Mixed model ANOVAs showed that heel lance elicited a stress response (i.e., increased heart rate, decreased oxygen saturation, increased state-of-arousal, and increased facial actions indicative of pain) in both age groups. The stress response was greater in the older group. During recovery, the older group had a more rapid return of heart rate, behavioural state, and facial expressions of pain to baseline levels in the presence of compared to the absence of music. It was concluded that music is an effective NICU intervention following a stress-provoking stimulus in infants older than 31 weeks PCA.     

Gabapentin in traumatic nerve injury pain: a randomized, double-blind, placebo-controlled, cross-over, multi-center study

A double-blind, randomized, placebo-controlled cross-over multi-center study was conducted to evaluate the efficacy and safety of gabapentin in the treatment of neuropathic pain caused by traumatic or postsurgical peripheral nerve injury, using doses up to 2400 mg/day. The study comprised a run-in period of two weeks, two treatment periods of five weeks separated by a three weeks’ washout period. The primary efficacy variable was the change in the mean pain intensity score from baseline to the last week of treatment. Other variables included pain relief, health related quality of life (SF-36), interference of sleep by pain, Clinician and Patient Global Impression of Change, and adverse effects. Nine centers randomized a total of 120 patients, 22 of whom withdrew. There was no statistically significant difference between the treatments for the primary outcome efficacy variable. However, gabapentin provided significantly better pain relief (p = 0.015) compared with placebo. More patients had at least a 30% pain reduction with gabapentin compared with placebo (p = 0.040) and pain interfered significantly less with sleep during gabapentin treatment compared with placebo (p = 0.0016). Both the Patient (p = 0.023) and Clinician (p = 0.037) Global Impression of Change indicated a better response with gabapentin compared with placebo. Gabapentin was well tolerated. The most common adverse effects were dizziness and tiredness.     

The effects of auditory interventions on pain and comfort in premature newborns in the neonatal intensive care unit; a randomised controlled trial

ObjectiveThis study investigated the effects of three auditory interventions; white noise, recorded mother's voice, and MiniMuffs, applied during a heel lance on pain and comfort in premature infants in the neonatal intensive care units.Design and methodsThis experimental, parallel, randomised controlled research was conducted in a state hospital tertiary-level neonatal intensive care unit. The sample comprised sixty-four premature infants with gestational ages of 31–36 weeks. The infants were randomly assigned to four groups: i) white noise, ii) recorded mother’s voice, iii) MiniMuffs, and iv) control. Pain and comfort of newborns were evaluated according to the Neonatal Infant Pain Scale (NIPS) and the COMFORTneo scale. Oxygen saturation, heart rate, and crying time were also measured.ResultsThe mean of oxygen saturation levels in the white noise, recorded mother's voice, and MiniMuffs group were higher than the control group. The heart rate, crying time, mean NIPS score, COMFORTneo score of the premature neonates in the white noise, recorded mother’s voice, and MiniMuffs groups were significantly lower than the control group (p < .001).ConclusionAuditory interventions used during heel lance reduce the pain and increase the comfort of the premature infants. White noise is extremely effective in preventing infants’s pain.     

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.     

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 ≤ .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.     

Determining behavioural and physiological responses to pain in infants at risk for neurological impairment

Multiple researchers have validated indicators and measures of infant pain. However, infants at risk for neurologic impairment (NI) have been under studied. Therefore, whether their pain responses are similar to those of other infants is unknown. Pain responses to heel lance from 149 neonates (GA>25-40 weeks) from 3 Canadian Neonatal Intensive Care units at high (Cohort A, n=54), moderate (Cohort B, n=45) and low (Cohort C, n=50) risk for NI were compared in a prospective observational cohort study. A significant Cohort by Phase interaction for total facial action (F(6,409)=3.50, p=0.0022) and 4 individual facial actions existed; with Cohort C demonstrating the most facial action. A significant Phase effect existed for increased maximum Heart Rate (F(3,431)=58.1, p=0.001), minimum Heart Rate (F(3,431)=78.7, p=0.001), maximum Oxygen saturation (F(3,425)=47.6, p=0.001), and minimum oxygen saturation (F(3,425)=12.2, p=0.001) with no Cohort differences. Cohort B had significantly higher minimum (F(2,79)=3.71, p=0.029), and mean (F(2,79)=4.04, p=0.021) fundamental cry frequencies. A significant Phase effect for low/high frequency Heart Rate Variability (HRV) ratio (F(2,216)=4.97, p=0.008) was found with the greatest decrease in Cohort A. Significant Cohort by Phase interactions existed for low and high frequency HRV. All infants responded to the most painful phase of the heel lance; however, infants at moderate and highest risk for NI exhibited decreased responses in some indicators.     

Differential analgesic effects of morphine and gabapentin on behavioural measures of pain and disability in a model of osteoarthritis pain in rats

Osteoarthritis (OA) is associated with chronic debilitating joint pain. Pain is the result of an emotional and sensory experience and preclinical models of OA can thus be useful to better understand the underlying mechanisms of the disease and test new therapeutic options.We induced unilateral knee OA in Sprague-Dawley rats using monosodium iodoacetate (MIA), a glycolysis inhibitor and assessed the effects of acute and chronic morphine and gabapentin using a battery of quantitative behavioural outcome measures of pain and disability.Animals received a single intra-articular injection of 2 mg MIA in 25 μl saline, causing inflammation and progressive cartilage degradation. Mechanical and thermal sensitivity as well as ambulatory-evoked pain were then monitored using von Frey hairs, acetone and a rotarod. Once maximum nociceptive responses were reached, chronic bi-daily morphine (3 mg/kg s.c.) or gabapentin (30 mg/kg s.c.) were administered for 5 days.We observed a marked biphasic mechanical hypersensitivity that increased and reached a plateau from day 14 (317.6% of control response, p < 0.01, with von Frey 6 g). Moreover we found a marked cooling hypersensitivity, and validated a novel ambulatory-evoked pain score. These measures were significantly reduced after both acute (13.3% of sham response, p < 0.01, von Frey 6 g) and chronic (38.3%, p < 0.05) morphine whilst only chronic gabapentin (37.0%, p < 0.05) had an effect.We show the reliability of the model in terms of mechanical hypersensitivity and demonstrate cooling hypersensitivity and ambulatory-evoked pain. In terms of translational research, the effects of morphine and gabapentin validate the model and suggest trials of these therapeutic approaches in OA patients.     

Efficacy and safety of sucrose for procedural pain relief in preterm and term neonates

BACKGROUND: Preterm and acutely ill term neonates who are hospitalized in a neonatal intensive care unit are subjected to multiple frequent invasive and painful procedures aimed at improving their outcome. Although several trials to determine the efficacy of sucrose for managing procedural pain in preterm and acutely ill term neonates have been developed, these have generally lacked methodological rigor and have not provided clinicians with clear practice guidelines. OBJECTIVES: To compare the efficacy and safety of three interventions for relieving procedural pain associated with heel lances in preterm and term neonates, and to explore the influence of contextual factors including sex, severity of illness, and prior painful procedures on pain responses. METHODS: In a randomized controlled trial, 190 neonates were stratified by gestational age and then randomized to receive (a) sucrose and nonnutritive sucking (n = 64), (b) sucrose alone (n = 62), or (c) sterile water and nonnutritive sucking (control) (n = 64) to evaluate the efficacy (pain response as measured using the Premature Infant Pain Profile) (Stevens, Johnson, Petryshen, & Taddio, 1996) and safety (adverse events) following a scheduled heel lance during the first week of life. Stratification was used to control for the effects of age on pain response. RESULTS: Significant differences in pain response existed among treatment groups (F = 22.49, p <.001), with the lowest mean Premature Infant Pain Profile scores in the sucrose and nonnutritive sucking group. Efficacy of sucrose following a heel lance was not affected by severity of illness, postnatal age, or number of painful procedures. Intervention group and sex explained 12% of the variance in Premature Infant Pain Profile scores. Few adverse events occurred (n = 6), and none of them required medical or nursing interventions. CONCLUSIONS: The combination of sucrose and nonnutritive sucking is the most efficacious intervention for single heel lances. Research on the effects of gestational age on the efficacy and safety of repeated doses of sucrose is required.     

Suckling- and sucrose-induced analgesia in human newborns

This experiment had three goals: 1. To identify the basis of sucking-induced analgesia in healthy, term, newborn humans undergoing the painful, routine, procedure of heel lance and blood collection. 2. To evaluate how taste-induced and sucking-induced analgesias combine to combat pain. 3. To determine whether facial grimacing was an accurate index of diminished pain, or whether it was linked to tissue trauma. We report that: 1. Sucking an unflavored pacifier was analgesic when and only when suck rate exceeded 30 sucks/min. 2. The combination of sucrose and nonnutritive sucking was remarkably analgesic; we saw no behavioral indication in nine of the ten infants that the heel lance had even occurred. 3. Grimacing was reduced to almost naught by procedures that essentially eliminated crying and markedly reduced heart rate during the blood harvesting procedure.     

The effect of Yakson and Gentle Human Touch methods on pain and physiological parameters in preterm infants during heel lancing

BackgroundVarious non-pharmacologic methods are used to alleviate pain in preterm infants who spend their first days in neonatal intensive care units (NICU) because they are exposed to numerous painful interventions.ObjectiveTo determine the effects of Yakson and Gentle Human Touch (GHT) methods on pain and physiologic parameters during heel lancing procedures in preterm infants.Design and methodsThis was a randomised controlled trial. The study was conducted in a NICU between June 2018 and June 2019. A total of 90 preterm infants were divided into three groups: 30 infants in the Yakson group, 30 infants in the GHT group, and 30 infants in the control group. All preterm infants were randomly divided into groups. Pain responses were evaluated using the Neonatal Infant Pain Scale.ResultsIt was found that pain scores and heart rates were significantly lower during and after heel lancing in preterm infants in the Yakson and GHT groups than in the control group, the difference was statistically significant (p < .001).Practical implicationsYakson and GHT applied to preterm infants during heel lancing has positive effects on pain and physiologic parameters.     

非营养性吸吮缓解新生儿疼痛的临床研究

目的探讨非营养吸吮(NNS)缓解新生儿疼痛的临床有效性及可行性,为NNS在新生儿病房的推广提供依据。方法患儿分为NNS组40例,对照组40例。选用新生儿急性疼痛行为评分量表(DAN)对接受足跟取血的80例新生儿进行疼痛评分。结果对照组患儿疼痛总分为8.03±1.74分,NNS组患儿疼痛总分为4.68±1.54分,NNS组患儿在面部表情、肢体活动、声音表现各方面得分均有显著下降,各方面得分差异均具有显著意义(P<0.01),NNS组和对照组患儿疼痛得分与其性别、胎龄、日龄及体重等均无显著关系(P>0.05)。结论应重视新生儿疼痛的管理,NNS操作简单,镇痛效果良好,对在临床工作中缓解新生儿疼痛具有良好的实用性。     

Comparison of two infant lancet devices on ease of use and post lance bleeding times

BackgroundThere is a need to choose neonatal heel lance phlebotomy devices with the least potential for pain and post-phlebotomy complications. The purpose of this study was to evaluate two lancet devices (BD's Quikheel and Hawaii Medical's NeatNick) in terms of ease of use and frequency of infant bleeding longer than 5 min.Materials and methodsBetween April 5 and July 15, 2010, phlebotomy staff alternated between using each lancet device on 1243 full term infants at three tertiary care hospitals in Calgary, Alberta.ResultsMore NeatNick than Quikheel subjects bled longer than 5 min post phlebotomy (p < 0.0001). Of eight variables concerning ease of use of the device, seven favoured the Quikheel device and the eighth was not statistically different.ConclusionsThe Quikheel lancet was preferred over the NeatNick lancet for blood collection in terms of ease of use by phlebotomists and fewer excess bleeding times in newborns.     

Pain in infancy: neonatal reaction to a heel lance

A combined single subject and group design was used to investigate changes in heart rate and crying in response to a heel lance, non-invasive tactile stimulation and baseline periods in 10 male and 10 female infants, each in their second full day of life. Heart rate was measured with an electrocardiogram. Percentage of time crying was computed from observations of audiotapes. Results for individual subjects indicated that heart rate and percentage of crying were consistently increased by the heel lance but that there was often wide baseline variability in the two measures. Analysis of variance indicated that responses to heel lance were higher than responses to tactile stimulation which were in turn higher than responses to baseline for both heart rate and percentage of crying (P less than 0.01). No significant sex differences were found. It was suggested that the increases in heart rate and crying in the context of a tissue damaging stimulus indicated that the infants experienced pain and that pain in infants can be reliably measured in clinical settings.     

Non-nutritive sucking,oral breast milk,and facilitated tucking relieve preterm infant pain during heel-stick procedures: A prospective,randomized controlled trial

BackgroundPreterm infant pain can be relieved by combining non-nutritive sucking (sucking), oral sucrose, and facilitated tucking (tucking), but the pain-relief effects of oral expressed breast milk (breast milk) are ambiguous.AimsWe compared the effects of combined sucking+ breast milk, sucking + breast milk + tucking, and routine care on preterm infant pain during and after heel-stick procedures.DesignA prospective, randomized controlled trial.SettingsLevel III neonatal intensive care unit and a neonatal unit at a medical center in Taipei.Participants/subjectsPreterm infants (N = 109, gestational age 29–37 weeks, stable disease condition) needing procedural heel sticks were recruited by convenience sampling and randomly assigned to three treatment conditions: routine care, sucking+ breast milk, and sucking + breast milk + tucking.MethodsPain was measured by watching video recordings of infants undergoing heel-stick procedures and scoring pain at 1-min intervals with the Premature Infant Pain Profile. Data were collected over eight phases: baseline (phase 1, 10 min without stimuli before heel stick), during heel stick (phases 2 and 3), and a 10-min recovery (phases 4–8).ResultsFor infants receiving sucking+ breast milk, pain-score changes from baseline across phases 2–8 were 2.634, 4.303, 2.812, 2.271, 1.465, 0.704, and 1.452 units lower than corresponding pain-score changes of infants receiving routine care (all p-values < 0.05 except for phases 6 and 7). Similarly, for infants receiving sucking +breast milk+ tucking, pain-score changes from baseline were 2.652, 3.644, 1.686, 1.770, 1.409, 1.165, and 2.210 units lower than corresponding pain-score changes in infants receiving routine care across phases 2–8 (all p-values < 0.05 except for phase 4). After receiving sucking +breast milk +tucking and sucking +breast milk, infants’ risk of mild pain (pain score ≥6) significantly decreased 67.0% and 70.1%, respectively, compared to infants receiving routine care. After receiving sucking +breast milk +tucking and sucking +breast milk, infants’ risk of moderate-to-severe pain (pain score ≥12) decreased 87.4% and 95.7%, respectively, compared to infants receiving routine care.ConclusionThe combined use of sucking + breast milk +tucking and sucking + breast milk effectively reduced preterm infants’ mild pain and moderate-to-severe pain during heel-stick procedures. Adding facilitated tucking helped infants recover from pain across eight phases of heel-stick procedures. Our findings advance knowledge on the effects of combining expressed breast milk, sucking, and tucking on preterm infants’ procedural pain.     

The Use of Oral Sucrose for Procedural Pain Relief in Infants Up to Six Months of Age: A Randomized Controlled Trial

The aim of this study was to evaluate the effectiveness of oral sucrose in decreasing pain during minor procedures in infants of 1-6 months corrected age. A blinded randomized controlled trial with infants aged 4-26 weeks who underwent venipuncture, heel lance or intravenous cannulation were stratified by corrected age into >4-12 weeks and >12-26 weeks. They received 2 mL of either 25% sucrose or sterile water orally 2 minutes before the painful procedure. Nonnutritional sucking and parental comfort, provided in adherence to hospital guidelines, were recorded. Pain behavior was recorded using a validated 10 point scale at baseline, during and following the procedure. Data collectors were blinded to the intervention. A total of 21 and 20 infants received sucrose and water, respectively, in the >4–12-week age group, and 21 and 22, respectively, in the >12–26-week age group. No statistical differences were found in pain scores between treatment and control groups at any data collection points in either age group. Infants aged >4-12 weeks who did nonnutritional sucking showed statistically significantly lower median pain scores at 1, 2, and 3 minutes after the procedure than those who did not suck. Infants aged >4-26 weeks exhibited pain behavior scores that indicated moderate to large pain during painful procedures; however, there was insufficient evidence to show that 2 mL 25% sucrose had a statistically significant effect in decreasing pain. Infants should be offered nonnutritional sucking in compliance with the Baby Friendly Health Initiative during painful procedures.     

Tactile discrimination, but not tactile stimulation alone, reduces chronic limb pain

Chronic pain is often associated with reduced tactile acuity. A relationship exists between pain intensity, tactile acuity and cortical reorganisation. When pain resolves, tactile function improves and cortical organisation normalises. Tactile acuity can be improved in healthy controls when tactile stimulation is associated with a behavioural objective. We hypothesised that, in patients with chronic limb pain and decreased tactile acuity, discriminating between tactile stimuli would decrease pain and increase tactile acuity, but tactile stimulation alone would not. Thirteen patients with complex regional pain syndrome (CRPS) of one limb underwent a waiting period and then 2 weeks of tactile stimulation under two conditions: stimulation alone or discrimination between stimuli according to their diameter and location. There was no change in pain (100 mm VAS) or two-point discrimination (TPD) during a no-treatment waiting period, nor during the stimulation phase (p > 0.32 for both). Pain and TPD were lower after the discrimination phase [mean (95% CI) effect size for pain VAS = 27 mm (14–40 mm) and for TPD = 5.7 mm (2.9–8.5 mm), p < 0.015 for both]. These gains were maintained at three-month follow-up. We conclude that tactile stimulation can decrease pain and increase tactile acuity when patients are required to discriminate between the type and location of tactile stimuli.     

Exploring relationships for visceral and somatic pain with autonomic control and personality

The autonomic nervous system (ANS) integrates afferent and motor activity for homeostatic processes including pain. The aim of the study was to compare hitherto poorly characterised relations between brainstem autonomic control and personality in response to visceral and somatic pain. Eighteen healthy subjects (16 females, mean age 34) had recordings during rest and pain of heart rate (HR), cardiac vagal tone (CVT), cardiac sensitivity to baroreflex (CSB), skin conductance level (SC), cardiac sympathetic index (CSI) and mean blood pressure (MBP). Visceral pain was induced by balloon distension in proximal (PB) and distal (DB) oesophagus and somatic pain by nail-bed pressure (NBP). Eight painful stimuli were delivered at each site and unpleasantness and intensity measured. Personality was profiled with the Big Five inventory. (1) Oesophageal intubation evoked “fight-flight” responses: HR and sympathetic (CSI, SC, MBP) elevation with parasympathetic (CVT) withdrawal (p < 0.05). (2) Pain at all sites evoked novel parasympathetic/sympathetic co-activation with elevated HR but vasodepression (all p < 0.05). (3) Personality traits correlated with slope of distal oesophageal pain-related CVT changes wherein more neurotic-introvert subjects had greater positive pain-related CVT slope change (neuroticism r 0.8, p < 0.05; extroversion r −0.5, p < 0.05). Pain-evoked heart rate increases were mediated by parasympathetic and sympathetic co-activation – a novel finding in humans but recently described in mammals too. Visceral pain-related parasympathetic change correlated with personality. ANS defence responses are nuanced and may relate to personality type for visceral pain. Clinical relevance of these findings warrants further exploration.     

Cutaneous hypersensitivity following peripheral tissue damage in newborn infants and its reversal with topical anaesthesia

The flexion reflex threshold has been used as a measure of sensation in a group of premature infants born at 27-32 weeks postmenstrual age. The threshold in an area of local tissue damage created by routine heel lances was half the threshold on the intact heel on the other side. This indicated a hypersensitivity to tissue damage analogous to tenderness or hyperalgesia reported in adults. In a double-blind study, treatment of the damaged area with the topical anaesthetic cream, EMLA, was found to reverse this hypersensitivity or in other words increase the flexion reflex threshold. Treatment with placebo had no effect. The results show that the newborn infant central nervous system is capable of mounting a chronic pain response to local injury which can be reduced by local anaesthetic.