Skin conductance as a measure of pain and stress in hospitalised infants

BACKGROUND: Reliable and valid methods of measuring pain responses in infants continue to be sought as a means of evaluating the effectiveness of pain reduction strategies. Skin conductance has recently been shown to be a promising physiological indicator of pain and stress in premature and term infants. AIM: To evaluate changes in skin conductance in hospitalised infants under different environmental conditions and during both painful and non-painful procedures. METHODS: Measurements of skin conductance activity were made in infants under three different environmental temperature conditions (open cot, incubator and overhead radiant heater), during the routine non-painful nursing procedure of either nappy change or oral feeding, and whilst undergoing the painful procedure of heel lancing for blood sampling. RESULTS: Skin conductance activity in 21 infants was studied on 43 separate occasions. Skin conductance activity was highly variable between infants but did not differ significantly under the three environmental conditions. Routine nursing care did not result in a significant increase in skin conductance activity above baseline; however, on cessation of care there was a significant reduction to levels below baseline (p < 0.05). Conversely, during the heel lance procedure, skin conductance activity significantly increased upon lance (p < 0.05) and remained elevated following completion of the procedure. There were no statistically significant differences between skin conductance activity changes from baseline as a result of routine nursing care compared to that of the heel lance procedure. CONCLUSION: Due to large variability in skin conductance activity further studies are needed before this technology can be recommended as a clinically useful indicator of pain and stress in neonates.     

Skin conductance compared to a combined behavioural and physiological pain measure in newborn infants

AIM: To assess the ability of galvanic skin response (GSR) to differentiate between tactile and painful stimulation in newborn infants, and to compare this with the ability of the premature infant pain profile (PIPP). METHODS: Thirty-two healthy full-term infants undergoing routine blood sampling were recruited. In a randomized order they were subjected to tactile and painful stimulation. The three GSR variables conductance baseline level, number of waves per second and mean amplitude of the waves were recorded together with the behavioural and physiological variables of PIPP. RESULTS: The GSR variables number of waves and amplitude of the waves increased more during painful stimulation than during tactile stimulation, as did also the PIPP score. Receiver operating characteristic curves analysis revealed no significant differences between the studied methods. CONCLUSION: GSR can differentiate painful from tactile stimulation, but more research is needed to achieve a clinically useful application.     

Skin conductance and behaviour during sensory stimulation of preterm and term infants

Aim: To investigate the responses to painful and tactile stimulation in preterm and term infants in terms of changes in the plantar skin conductance activity (SCA) and behavioural state. Plantar SCA reflects activity in the sympathetic nervous system. Design: The plantar SCA and behavioural state in response to nociceptive (the heel prick for blood samples, or immunization) and tactile (routine nursery handling) simulation was recorded in four different groups of infants (n=71): Preterm and term neonatal infants (defined here as up to 1 week old), and preterm and term infants in the postneonatal period. Results: The preterm infants had significant increases in all skin conductance variables during both tactile and nociceptive stimulation (p<0.02), except for wave amplitude when newborns were heel pricked. The term infants displayed a more varied picture, but both the number and amplitude of the waves increased significantly during both procedures in the newborn groups, while the postneonatal groups only showed significant increases in wave amplitude during nociceptive stimulation (p<0.05). Tactile stimulation of the preterm newborn infants produced significantly higher increases in SCA than nociceptive stimulation (p<0.01), while the behavioural state was highest during nociceptive stimulation (p<0.05). A gradual change in this relation was seen with advancing total age. Conclusion: Non-painful sensory stimulation of infants, especially the newborn and preterm ones, can produce equal or higher levels of physiological stress activation than painful stimulation. Repeated nociceptive stimulation probably sensitises the infants to pain.     

Neurophysiological assessment of acute pain in infants: a scoping review of research methods

A systematic scoping search to describe the neurophysiological methods used in infant acute pain assessment research was conducted. Of the 2411 abstracts screened, 19 articles were retained. Nine studies utilised near‐infrared spectroscopy (NIRS), two utilised functional magnetic resonance imaging (fMRI), and eight utilised electroencephalography (EEG). There was methodological variability in studies utilising NIRS, whereas EEG and fMRI studies reported consistent methods. Of the eight EEG studies, six identified a nociceptive‐specific event‐related potential. Conclusion: While more methodologically rigorous studies are needed, ERPs appear to hold some promise as indicators of infant nociception during clinical procedures to supplement existing measures.     

Skin conductance measurements as pain assessment in newborn infants born at 22-27 weeks gestational age at different postnatal age

Background

To assess pain or stress in newborn infants submitted to intensive care is important but difficult, as different observational pain scales are not always reliable in premature infants. As an indicator of pain, skin conductance (SC) measurements have detected increased sweating in newborn infants > 28 gestational age (GA) submitted to heel lancing.

Objective

To measure SC during heel lancing and routine care in newborn infants, born at 22 to 27 GA, with special relation to postnatal age (PNA).

Methods

In six infants < 28 + 0 GA and 4 infants ≥ 28 + 0 GA spontaneous SC activity and behavioural state (Neonatal Pain Agitation and Sedation Scale (N-PASS)) was measured before, during and after each intervention. Measurements were repeated in each patient at different PNA.

Results

Baseline SC prior to intervention took longer time to stabilise and was higher in < 28 than in ≥ 28 + 0 PNA. The combination of heel lancing and squeezing gave an increased SC in < 28 PNA, whereas heel lancing alone gave the same SC response in ≥ 28 + 0 PNA. A possibly continued immature response in SC measurements was not observed. Oral glucose admission prior to heel lancing increased SC. Routine care did not give any changes in SC. Except during orogastric tube placement no signs of discomfort or pain could be detected by the neonatal pain, agitation and sedation scale (N-PASS) in < 28 PNA.

Conclusion

Changes in SC could be detected in infants at < 28 + 0 PNA and related to the combination of heel lancing and squeezing. A maturational development of the SC was observed in infants born < 28 GA. SC seems to be able to differentiate between pain and discomfort.     

Assessment of pain in newborn infants

Hospitalized newborn infants experience pain that can have negative short- and long-term consequences and thus should be prevented and treated. National and international guidelines state that adequate pain management requires valid pain assessment. Nociceptive signals cause a cascade of physical and behavioral reactions that alone or in combination can be observed and used to assess the presence and intensity of pain.Units that are caring for newborn infants must adopt sufficient pain assessment tools to cover the gestational ages and pain types that occurs in their setting. Pain assessment should be performed on a regular basis and any detection of pain should be acted on. Future research should focus on developing and validating pain assessment tools for specific situations.     

婴幼儿术后疼痛管理的研究进展

大部分手术婴幼儿经历着中度或重度的术后疼痛,如何有效地对婴幼儿术后疼痛进行评估,并在准确评估的基础上进行药物和非药物方法干预,是未来疼痛管理关注和研究的热点.而疼痛管理指南的建立和医护人员以及家长对婴幼儿疼痛的认知是影响婴幼儿术后疼痛管理的关键因素.     

Body temperature measurement in VLBW infants by continuous skin measurement is a good or even better alternative than continuous rectal measurement

Background: An inadequate body temperature in preterm infants influences morbidity and mortality. Continuous rectal measurement is a reliable method to measure body temperature but might have adverse effects and is even contra-indicated in case of low platelets or necrotising enterocolitis. A save and non-invasive method to measure body temperature is the transcutaneous 'zero heat flow' method.
Aim: We hypothesised that for monitoring body temperature in very low birth weight (VLBW) infants, central measurement of temperature by way of the zero heat flow principle is just as reliable as rectal temperature.
Methods: Twenty-six infants, birth weight between 520 g and 1250 g, gestational age 25.28–32.28 weeks were provided with an insulated continuous skin probe with 'zero heat flow' and a continuous rectal probe. Both measurements were registered every hour over a period of 48 h. The sample size was calculated to detect a difference of less than or equal to 0.20°C.
Results: 1205 of the 1248 temperature measurements were analysed. At any moment, skin temperature was higher or equal when compared to rectal temperature. Mean skin temperature was 0.13°C (SD 0.33) higher than mean rectal temperature ( t -test, p < 0.001). Correlation between rectal and skin temperature was 0.82 (p ≤ 0.05).
Conclusion: In VLBW infants, temperature measurement by 'zero heat flow' method is just as reliable as by rectal method.     

Skin conductance variability between and within hospitalised infants at rest

Background

Various methods of pain assessment in infants have been trialled in the search for objective, specific, physiologic measures of responses to pain. Skin conductance (SC) measured in the palm of the hand or on the plantar aspect of the foot may be one such measure. SC in these sites reflects the emotional sweating due to sympathetic nerve activity. The skin conductance response (SCR), which results from filling and reabsorption of sweat in the sweat glands, has previously been suggested to be the most sensitive SC parameter of sympathetic nerve activity in response to painful stimulation.

Aim

To study SCRs within and between medically stable hospitalised infants while at rest.

Methods

SCRs were measured in infants during at least six periods of monitoring in a maximum 48-h period. Behavioural state was recorded throughout the data collection periods.

Results

SC recordings (n = 91) from 15 infants during sleep showed that frequency of SCRs varied between 0 and 0.04 SCRs per second (SCRs/s), median 0.002 SCRs/s. 73% of the total variation was within-infant variation, with the remaining 27% of variation due to variation between the mean SCR values of different infants.

Conclusion

This pilot study contributes to establishing baseline phasic SC activity in hospitalised infants at rest by measuring SCRs. These data can be used as a reference for future studies to determine the validity and reliability of SC measurement in infants exposed to painful or stressful interventions within a neonatal unit.     

Long-term consequences of pain in human neonates

The low tactile threshold in preterm infants when they are in the neonatal intensive care unit (NICU), while their physiological systems are unstable and immature, potentially renders them more vulnerable to the effects of repeated invasive procedures. There is a small but growing literature on pain and tactile responsivity following procedural pain in the NICU, or early surgery. Long-term effects of repeated pain in the neonatal period on neurodevelopment await further research. However, there are multiple sources of stress in the NICU, which contribute to inducing high overall 'allostatic load', therefore determining specific effects of neonatal pain in human infants is challenging.     

Amplitude-integrated electroencephalographic activity is suppressed in preterm infants with high scores on illness severity

Background

The neonatal acute physiology score, SNAP-II, reflects the severity of illness in newborns. In term newborns, amplitude integrated EEG (aEEG), is depressed following asphyxia. In preterm infants aEEG is discontinuous, and therefore more difficult to assess compared to term infants.

Aims

Our first aim was to investigate whether assessing aEEG amplitudes by calculating amplitude centiles was consistent with assessment by pattern recognition. Our second aim was to investigate whether the aEEGs of preterm infants were influenced by SNAP-II.

Study Design and Subjects

We recorded aEEGs in 38 infants with a mean gestational age of 29.7 weeks (26.0-31.8 weeks) during the first five days of life. The mean recording time was 130 min. The aEEGs were assessed by pattern recognition, by calculating Burdjalov score, and by calculating the mean values of the 5th, 50th, and 95th centiles of the aEEG amplitudes. Illness severity was determined within the first 24 h.

Results

We assessed 151 recordings and found strong correlations between the 5th and 50th amplitude centiles and the Burdjalov scores (r = 0.71, p < 0.001 and r = 0.47, p < 0.001, respectively). The 5th and 50th amplitude centiles correlated with SNAP-II (r = − 0.34, p < 0.0001 and r = − 0.27, p = 0.001). These correlations were the strongest on the first day of life (r = − 0.55, p = 0.005 and r = − 0.47, p = 0.018, respectively). The 5th and the 50th amplitude centiles were best predicted by gestational age, SNAP-II, and low blood pressure.

Conclusions

Severe illness as measured by the SNAP-II, and low blood pressure had a negative influence on the aEEGs of preterm infants.     

Infants sleeping outdoors in a northern winter climate: skin temperature and duration of sleep

Aim: The aim of the study is to describe the relationships among thermal environment, skin temperatures and infants’ daytime outdoor sleep duration in northern winter conditions. Methods: This study is a cross‐over observational study. Skin temperatures of three‐month‐old infants were recorded from seven skin sites continuously throughout outdoor (n = 34) and indoor sleep (n = 33) in the families’ homes. The duration of the sleep was observed, and temperature and the air velocity of the environment were recorded. Results: Skin temperatures increased towards the end of indoor sleeping, whereas they decreased during outdoor sleeping. The cooling rate of mean skin temperature (T_sk) increased in lower outdoor temperatures (r_s = 0.628, p < 0.001) in spite of increased clothing. On some occasions, cold extremities were observed, suggesting slight deviations from thermoneutrality. Sleep time was 92 min longer in outdoors than in indoors. However, outdoor sleep duration was shortened when the cooling rate of T_sk increased (r_s = 0.611, p < 0.001). Conclusion: The longest sleep was recorded outdoors when the cooling rate of T_sk was minimal. Restriction of movements by clothing probably increases the length of sleep, and a cold environment makes swaddling possible without overheating. A decrease in ambient temperature increased the cooling rate, suggesting that the cold protection of the clothing compensated only partly for the increased heat loss.     

Children's skin conductance reactivity as a mechanism of risk in the context of parental depressive symptoms

BACKGROUND: Children's physiological reactivity was examined as a moderator of relations between parental dysphoria and child adjustment problems, addressing gaps in the study of child characteristics as risk processes. METHOD: One hundred fifty-seven children (86 boys, 71 girls) were assessed twice over a two-year interval. Skin conductance level reactivity (SCLR) to inter-adult argument and problem-solving tasks was observed. RESULTS: SCLR moderated longitudinal predictions of children's internalizing, externalizing and social adjustment problems, especially for paternal rather than maternal dysphoria. Higher SCLR predicted greater vulnerability to parental depressive symptomatology. CONCLUSIONS: Findings highlight that individual differences in children's physiological reactivity may relate to risk for adjustment problems in the context of parental depressive symptoms.     

Regional skin temperature, heat flow and conductance in preterm neonates nursed in low and in neutral environmental temperature

The changes of regional dry heat loss and skin temperature in 15 healthy preterm babies, 8 with a gestational age (GA) of 33–36 weeks and 7 with a GA of 28–31 weeks, were studied under controlled conditions at environmental temperatures ranging from 29.5 to 34.0°C. In both groups of babies the skin temperature for all body regions followed the changes in operative temperatures. Regional dry heat losses also closely followed the external temperature gradient. In the 33–36 weeks GA neonates the regional changes in thermal conductance (index of cutaneous blood flow) indicated that only the foot responded to low environmental temperature with vasoconstriction while vasodilatation was indicated for the trunk. in the 28–31 weeks GA neonates similar but not significant changes of thermal conductance were calculated. The limited ability to reduce heat loss by reducing the skin conductance over a major part of the body surface area contributes to the vulnerability to low environmental temperature in preterm neonates.     

The management of acute abdominal pain in children

Objective : Acute abdominal pain is a common problem in childhood, and appendicitis is frequently diagnosed by general practitioners and doctors working in emergency departments. The objective of the present report was to determine the frequency of appendicitis in a group of children with acute abdominal pain presenting to the emergency department of a general hospital, as well as attempting to analyse the manner in which these patients were managed.
Methodology : The initial assessment in hospital (by resident hospital staff) of the study group of patients was analysed and their subsequent clinical progress documented.
Results : The present report shows that the vast majority of children with acute abdominal pain do not have appendicitis and that appendicitis is significantly over-diagnosed by junior hospital doctors.
Conclusions : Appendicitis is a clinical diagnosis, best made by an experienced member of the paediatric surgical team. Frequent review, with a minimum of investigations, provides the best means of making a rational decision regarding surgery.