Skin conductance and the stress response from heel stick in preterm infants

AIM: To evaluate whether spontaneous skin conductance activity is an objective method for measuring the stress response to painful stimuli in premature infants. The number and amplitude of the waves and the baseline increase with the activity of the sympathetic nervous system. METHODS: In 20 preterm infants of gestational age >/= 29 weeks, behavioural state and spontaneous skin conductance activity variables were measured for three minutes before, during, and for three minutes after heel stick. RESULTS: The number of waves (p < 0.001), the amplitude of the waves (p = 0.001), and the level of the behavioural state (p < 0.001) increased during heel stick, and then decreased to levels found before the procedure. The baseline increased both during (p < 0.001) and after heel stick (p < 0.001), compared with levels before. CONCLUSION: Spontaneous skin conductance activity reflects the stress response to heel stick in premature infants from at least 29 weeks of gestational age.     

Neonatal screening and long-term follow-up of phenylketonuria: the French database

Skin conductance shows the emotional state, as reflected in changes in the sympathetic nervous system. Skin conductance changes (number and amplitude of the waves, as well as mean skin conductance level) were measured in connection with heel prick from 29 weeks gestational age. The purposes of this study were to examine the development of emotional sweating in preterm infants, and to correlate the changes in emotional sweating with the changes in behavioural state.Fifty infants' behavioural state and skin conductance changes were measured for 2 min before, 2 min during, and 2 min after heel prick. Half of the infants were between 29 and 31 weeks gestational age. They were divided into three sub-groups; 0-10, 11-20 and 21-30 days postnatal age. The other half of the infants were between 32 and 34 weeks gestational age and they were divided into three similar sub-groups. They changed their behavioural state 114 times.Infants from 29 weeks gestational age and more than 10 days old showed emotional sweating as measured by the number and amplitude of the waves that were lowest in sleep and highest during crying (p<0.05). The mean skin conductance level mirrored the behavioural state from 34 weeks gestational age (p<0.05).To conclude, skin conductance changes increased with the level of behavioural state from 29 weeks gestational age and more than 10 days postnatal age.     

Food intake and oral sucrose in preterms prior to heel prick

To investigate the soothing effect of feeding on infants in distress, the effects of 2 mL 15% and 1 mL 25% sucrose given orally 2 min before heel prick in fasting preterms to reduce the pain response were assessed. The effects of milk intake by nasogastric tube were also assessed once during the last hour before heel prick, and the effects of milk intake by nasogastric tube once during the last hour before heel prick together with 1 mL 25% sucrose given orally 2 min before heel prick. The pain response was measured as changes in crying time, behavioural state, skin conductance and heart rate. Each group included 12 healthy preterm infants with a median gestational age of 32 wk and a median postnatal age of 14 d. These infants were randomly studied twice; one in connection with the intervention and once after being given sterilized water. Differences in the measured variables before and during heel prick showed that only the crying time was reduced when the infants received milk or 25% sucrose prior to heel prick (p < 0.05). If the infants received milk and 25% sucrose before heel prick, the crying time and the level of behavioural state were reduced (p < 0.05). The increase from before to during heel prick in skin conductance (number and amplitude of the waves) and heart rate correlated with the crying time (p < 0.01).     

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.     

Relationship between maturation of the skin and electrical skin resistance

In 16 newborn infants (24 6-39 wk 6 days 830-3390 g) at ages between 0-70 days, the skin's electrical resistance was measured. Over 30 min we sequentially measured direct current resistance between two skin electrodes placed on the abdomen. The resistance was found to be low in very premature infants with gestation ages of 30 wk or less. It increased with both gestational age and postnatal age. In these infants, the resistance measured at 30 min during the first 4 days of life (3.4 +/- 0.3 K omega; mean +/- SD) was significantly less than that found at 20-70 days (8.8 +/- 1.2 k omega; p less than 0.001). The relationship between the infant's electrical skin resistance (y) and the gestational age (x) best fit the exponential formula: y = 7.42 X e0.24x X 10(-4) + 2.74. This formula shows that the electrical skin resistance increases exponentially during the last trimester. The measurement of electrical skin resistance is a quantitative method that can be utilized to evaluate the gestational age of infants.     

Bone turnover in preterm infants

Total parenteral nutrition is associated with osteopenia in preterm infants. Insufficient calcium and phosphate are likely causes: aluminum contamination is another possible contributing factor as this adversely affects bone formation and mineralization. The study was designed to evaluate changes in biochemical markers of bone turnover in 22 preterm infants receiving total parenteral nutrition in comparison with 19 term infants. We collected urine and serum samples from 22 preterm infants, mean gestational age 29 wk, within 48 h and again at 3 wk of life. We also collected urine samples from 19 term infants, mean gestational age 39 wk, during the first day of life. Bone resorption was assessed by the measurement of urinary pyridinium cross-links by HPLC and ELISA and the N-telopeptide of type I collagen by ELISA. Bone formation was assessed in premature infants by the measurement of serum osteocalcin. The N-telopeptide of type I collagen was higher in the preterm infants compared with term at baseline (p < 0.01). There was no difference between the pyridinium cross-links in the preterm and term infants. All the biochemical markers of bone turnover increased significantly in the preterm infants during the first 3 wk of life, e.g. N-telopeptide was a 153% change from baseline (p < 0.001). Aluminum in the total parenteral nutrition solutions did not cause a decrease in bone formation at the level administered (3-6 microg, 0.1-0.2 micromol x kg(-1) x d(-1)).     

Capillary blood cell velocity in full-term infants as determined in skin by videophotometric microscopy

In order to study the neonatal microcirculation, the capillary hemodynamics in skin was investigated in 43 full-term infants 2-7 days after birth. The nailfold capillaries of the thumb were visualized by means of television microscopy and the capillary blood cell velocity (CBV) was videophotometrically quantified in 107 microvessels. The skin temperature, mean arterial blood pressure, and heel puncture hematocrit were measured simultaneously to evaluate any relation with the CBV. The mean CBV in all infants was 0.38 +/- 0.21 mm/s, with a range of 0.04 to 1.2 mm/s in individual capillaries. There was no correlation between CBV and skin temperature (27-33 degrees C), mean arterial blood pressure (44-68 mm Hg), or postnatal age. However, a significant correlation was found between the log CBV and the skin prick hematocrit (r = -0.64, p less than 0.001). It is concluded that the mean CBV during the 1st wk of life is not significantly different from the capillary velocity reported in adults. Normal variations in skin temperature and mean arterial blood pressure, as well as age differences 2-7 days after birth, do not significantly influence the neonatal skin capillary blood flow. However, the hematocrit is of major importance for skin capillary perfusion in the newborn infant.     

Correlation of patent ductus arteriosus shunting with plasma atrial natriuretic factor concentration in preterm infants with respiratory distress syndrome

The concentration of plasma atrial natriuretic factor (ANF) and the mechanism for its secretion were investigated in 17 preterm infants with respiratory distress. Their mean gestational age was 29 wk and wt 1250 g. The infants were followed during the first week of life by sequential Doppler ultrasound studies. Ductal openness versus closure and amount of ductal flow were correlated with plasma ANF concentrations. In a subset of 10 infants, sequential Doppler color flow mapping was used to quantify the ductal flow. During the first 72 h, plasma ANF was high, 361 pg/mL; it decreased to 96 pg/mL by the end of the 1st wk. The ANF level was significantly higher when the ductus was open than closed (393 versus 123 pg/mL, p less than 0.05). In patients with open ductus and bidirectional foramen ovale shunting (n = 3) ANF was 567 pg/mL and in those with left-to-right shunt 355 pg/mL (n 15, NS). The left atrial size, i.e. the left atrial to aortic root ratio, correlated with the amount of ductal shunting (r = 0.63, p less than 0.01) and with ANF concentration (r = 0.46, p less than 0.02). The correlation of ANF values and the magnitude of left-to-right ductal shunting assessed by color flow mapping was highly significant (r = 0.66, p less than 0.001). In these patients, the elevation of ANF is reflective of ductal flow.     

Effects of dexamethasone treatment on bone and collagen turnover in preterm infants with chronic lung disease

Dexamethasone is used commonly in the treatment of chronic lung disease of prematurity, but there are concerns about possible deleterious effects on growth and bone. Our aim in this study was to examine the effects of dexamethasone treatment on bone and collagen turnover in preterm infants. Bone-specific alkaline phosphatase, the C-terminal propeptide of type I collagen (PICP, reflecting whole-body type I collagen synthesis), and the N-terminal propeptide of type III procollagen (P3NP, reflecting soft tissue collagen turnover), together with the C-terminal telopeptide of type I collagen (ICTP), urinary pyridinoline (Pyd), and deoxypyridinoline (all markers of collagen breakdown) were measured at weekly intervals over the first 12 wk of life in 14 preterm infants with chronic lung disease treated with dexamethasone. Results were expressed as SD scores relative to preterm control infants not treated with dexamethasone. PICP, P3NP, ICTP, and Pyd all showed marked decreases (-2.1 to -3.7 SD scores) during the first week of treatment (p < 0.001), returning to pretreatment levels after stopping dexamethasone. In the group as a whole, these collagen markers were negatively correlated with dexamethasone dose (p < 0.0001); negative correlations were also seen in most individual babies, although the slopes of individual regression lines varied by a factor of 2. Weight gain at 12 wk was correlated with PICP, expressed as the mean SD score over 12 wk for each baby, (r = 0.69, p < 0.01) but not with other markers or cumulative dose of dexamethasone. We conclude that dexamethasone markedly suppressed collagen turnover in preterm infants in a dose-dependent fashion, although some babies were more affected than others. The degree of suppression of type I collagen synthesis was a strong independent predictor of overall weight gain over the first 12 wk of life.     

The relationship of insulin-like growth factor-I to total thyroxine in normal and low birth weight infants

IGF-I concentrations were determined by RIA in eluates of dried blood collected on filter paper from infants who ranged in age from 3 to 21 d. The infants were separated into normal (greater than 2.5 kg) and low (less than 2.5 kg) birth wt groups and further subdivided on the basis of normal (greater than 83.7 nmol/liter) or low (less than 64.4 nmol/liter) levels of thyroxine. Both the normal and low birth wt groups whose blood thyroxine was in the normal range had similar mean IGF-I values during the 1st wk of life that were significantly higher (p less than 0.05) than those of either the normal or low birth wt groups whose thyroxine concentrations were below normal. Infants older than 1 wk of age with normal birth wt and normal thyroxine levels had significantly greater (p less than 0.05) mean IGF-I values than those of any of the other groups. Infants in the low birth wt-normal thyroxine group exhibited modest increases in IGF-I levels after the 1st wk of life that were significantly greater (p less than 0.05) than those found in the low birth wt-low thyroxine infants. These studies have demonstrated that IGF-I concentration is correlated positively with total thyroxine and with birth wt and that the latter is confounded by the former.     

Comparison of sucking patterns at introduction of oral feeding and at term in Israeli and American preterm infants

BACKGROUND: It has been hypothesized that early initiation of oral feeding in premature infants may enhance the maturation of sucking patterns. AIM: To compare preterm infant sucking characteristics in urban level III neonatal care units in the USA and Israel. The two hospitals have different practices regarding the introduction of oral feeding. METHODS: Infants were assessed at 34-35 wk postconceptional age (PCA) and at term. Sucking parameters were assessed with the Kron's Nutritive Sucking Apparatus. RESULTS: 70 infants (38 Americans and 32 Israelis) participated in the study. Oral feedings were initiated earlier (32.6 +/- 4.3 vs 34.5 +/- 1.8 wk PCA, p < 0.01) and full oral feedings were reached earlier (35.4 +/- 2.8 vs 36.5 +/- 2.5 wk PCA, p < 0.05) in the USA infants. American preterm infants produced significantly more sucks (p < 0.001), had a higher suck rate (p < 0.001), more sucks per burst (p < 0.05), and a shorter interburst width (p < 0.01) at 34 wk PCA than Israeli infants. At term, American infants produced significant more sucks (p < 0.001), higher suck rate (p < 0.001), shorter intersuck width (p < 0.001), and a shorter interburst width (p < 0.05) than the Israeli infants of the same PCA. CONCLUSION: Different practices in the care of preterm infants, such as postconceptional age at introduction of oral feeding, may play a role in the development of feeding and feeding organization at term.     

Adrenocortical steroids in small-for-gestational-age term infants during the early neonatal period

We evaluated adrenocortical steroid concentrations at birth and during postnatal adaptation (2 h until 7 days) in 10 vaginally delivered term small-for-gestational-age (SGA) infants and 12 term appropriate-for-gestational age infants. Plasma aldosterone, 11-deoxycorticosterone, corticosterone, progesterone, 17-hydroxyprogesterone, 11-deoxycortisol, cortisol, and cortisone were longitudinally measured by specific RIA after Sephadex LH-20 chromatography. Mean aldosterone was significantly higher in SGA than in appropriate-for-gestational-age infants (2 h to 7 days; p less than 0.001). In SGA infants, cortisone and cortisol levels were significantly lower in umbilical artery (p less than 0.05), and all glucocorticoid levels were significantly lower 12 h after birth (p less than 0.05). Thereafter (24 h to 7 days), only 11-deoxycortisol levels remained significantly lower in SGA; corticosterone and cortisol levels were even higher (p less than 0.05) in SGA 24 h after birth. The data suggest that SGA infants maintain high aldosterone levels throughout the 1st wk of life. Low cortisol and cortisone levels in umbilical artery as well as low glucocorticoid levels at 2 h and/or 12 h compared to term appropriate-for-gestational-age infants may reflect either a less stressful postnatal adaptation or, more likely, a reduced adrenocortical synthesis in term SGA infants.     

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.     

Longitudinal development of specific and functional antibody in very low birth weight premature infants

We evaluated the formation of specific and functional antibody in preterm infants born weighing less than 1500 g (mean 1088 g) and less than 32 wk gestational age (mean 28.8 wk). Plasma IgG antibody against tetanus and diphtheria toxoids were measured by an enzyme-linked immunosorbent assay. Opsonic activity of heat-inactivated plasma was measured using radiolabeled bacteria, adult polymorphonuclear leukocytes and exogenous human complement. In the presence of complement, the strain of coagulase negative staphylococcus used was opsonized by IgG antibody, and the strain of Escherichia coli by IgM. Geometric mean plasma levels of tetanus and diphtheria IgG antibody fell from birth to 4 months chronological age, but rose significantly by 9 months (approximately 2 months after the third dose of diphtheria, tetanus, pertussis vaccine). However, at 9 months they remained lower than the respective geometric mean levels in 9-month-old term infants (tetanus: p less than 0.001; diphtheria: p = 0.02). The preterm infants' mean plasma IgG staphylococcal opsonic activity fell from birth to 2.5 months, but by 9 months was comparable to that of term infants of the same age. Mean IgM opsonic activity for E. coli was very low at birth in both preterm and term infants. It rose with chronological age, correlating with the rise in total IgM (r = 0.48, p less than 0.001) and by 9 months the mean preterm and term infants' levels of IgM opsonic activity for E. coli were comparable.(ABSTRACT TRUNCATED AT 250 WORDS)     

Skin microcirculation before and after local warming in infants delivered vaginally or by caesarean section

To elucidate early postnatal changes in skin microcirculation, term newborn infants were studied at 2,6 and 24 h after vaginal delivery (VD, n = 20) or elective caesarean section (CS, n = 10). Laser Doppler technique was used to measure perfusion, rhythmical perfusion changes, i.e. vasomotion, and reactive hyperaemia of the dorsal hand, before and after local warming of the skin to 37°C. The skin perfusion and the magnitude of reactive hyperaemia (mean 85%) remained essentially unchanged, while vasomotion increased from 0–5 to 2–8 cycles/min ( p < 0.001) during the first day of life. Local warming of the skin promoted microcirculation slightly at 2 h and more markedly at 24 h postnatal age. The CS group showed a higher degree of skin perfusion, vasomotion and reactive hyperaemia than did VD infants at 2 h postnatal age. Our findings most likely reflect skin microcirculatory effects of birth-related events, such as a drop in body temperature, sympathoadrenal activation and placental transfusion.     

The influence of NaCl supplementation on the postnatal development of urinary excretion of noradrenaline, dopamine, and serotonin in premature infants

The present study was designed to investigate the role of noradrenaline (NA), dopamine (DA), and serotonin (5-HT) in the adaptation of premature infants to alterations of sodium balance. Urinary excretion of NA, DA, and 5-HT was measured spectrofluorimetrically in a group of low birth weight premature infants with (group S) and without (group NS) NaCl supplementation. Group NS consisted of 10 infants with a birth weight of 1200-1750 g (mean, 1493 g) and gestational age of 28-31 wk (mean, 30.1 wk). Group S included 10 infants with mean birth weight of 1414 g (range, 1150-1600 g) and mean gestational age of 30.5 wk (range, 27-32 wk). Measurements were made on the 7th day and weekly thereafter until the 5th wk of life. NaCl supplementation was given in a dose of 3-5 and 1.5-2.5 mEq/kg/day for 8-21 and 22-35 days, respectively. In group NS, mean urinary excretion of NA and DA increased from 8.6 +/- 1.5 and 15.8 +/- 2.4 micrograms/day to maximum values of 21.4 +/- 5.5 (p less than 0.05) and 33.4 +/- 6.0 micrograms/day (p less than 0.01) in weeks 2-3, respectively. 5-HT excretion averaged about 60 micrograms/day and showed no consistent change during the course of the study. NaCl supplementation prevented the rise of NA and DA excretion above the initial baseline values. The postnatal course of 5-HT excretion, however, remained unaffected by NaCl supplementation. Urinary excretion of NA in weeks 2-3 (p less than 0.05) and DA in weeks 2-4 (p less than 0.05) were significantly lower in group NS.     

B-type natriuretic peptide to predict ductus intervention in infants <28 weeks

Patent ductus arteriosus (PDA) is frequent in neonates with gestational age of less than 28 wk. Clinical and echocardiographic signs define hemodynamic significance of PDA, but do not reveal the need for PDA intervention in the first days of life. B-type natriuretic peptide (BNP) has been proposed as a screening tool for PDA in preterm infants. To determine whether BNP can predict the need for PDA intervention, plasma BNP was measured by chemiluminescence immunoassay in 67 preterm infants <28 wk (median 26) on the second day of life in a prospective blinded study. PDA intervention was based on specified clinical and echocardiographic findings. Twenty-four patients (intervention group) received treatment for PDA and 43 patients (controls) remained without intervention. BNP concentrations were higher in the intervention (median 1069 pg/mL) than in the control group (247 pg/mL, p < 0.001). BNP correlated positively with ductal size (R = 0.46, p < 0.001) and atrial/aortic root ratio (R = 0.54, p < 0.001). In conclusion, plasma BNP proved to be a good predictor for ductus intervention (area under the curve: 0.86) with the best cutoff at 550 pg/mL on the second day of life in ventilated infants less than 28 wk gestation (sensitivity: 83%; specificity: 86%).     

The relationship between breast milk leptin and neonatal weight gain

Aim: To investigate whether change in leptin content of breast milk during lactation acts on neonatal body weight gain.
Methods: In total 15 lactating women and their 15 term infants were involved in the study. Breast milk and neonatal serum samples were obtained from the same women and their neonates on the 1st day and any day between the 21st and 30th days after birth. Breast milk and serum leptin concentrations were determined by radioimmunoassay. Anthropometric indexes of the infants were recorded.
Results: The study was completed with 15 multiparious mothers aged 19–37 years and their infants. The mean collection time of the first samples after birth was 6.07 ± 1.94 h. The leptin level in the mature milk was significantly higher than in the colostrum (p < 0.001). Neonatal weight and height were significantly increased on 21–30 lactation days compared to 1st day of lactation (p < 0.05 and p < 0.001, respectively). The leptin concentration in the mature milk was negatively correlated with delta BMI (r =−0.53; p < 0.05). The delta breast milk leptin concentration was also found to be inversely correlated with delta BMI (r =−0.529; p < 0.05).
Conclusion: The results of this study have suggested that change in the leptin content of breast milk during lactation might play a role in the regulation of weight gain in healthy neonates.     

Decreased interleukin-10 in tracheal aspirates from preterm infants developing chronic lung disease

The inability to balance pulmonary injury with healing may predispose preterm infants to chronic lung disease (CLD). It is postulated that the production of interleukin (IL)-10, an anti-inflammatory cytokine, is gestationally influenced and that CLD-prone infants may have a reduced ability to produce IL-10. METHODS: Tracheal fluid (TF) was collected at least twice weekly from 48 mechanically ventilated infants within the first 7 d of life while intubated. RESULTS: A total of 87 TF specimens were obtained. None of the 11 CLD infants (24-31 wk of gestation) had TF IL-10 levels above 4 pg/ml (0/20 TF specimens), while 14 (70%) of the 20 non-CLD preterm infants (27-36 wk of gestation) had IL-10 levels above 5 pg/ml in one or more of their TF specimens (18/48 TF specimens, p < 0.001). Only the 5 term infants who were ventilated for severe lung disease had raised IL-10 levels (17 infants, 5/19 TF specimens). IL-10 levels, if detected, (range 6-938 pg/ml) tended to be higher with increasing gestation (Spearman's rho coefficient = 0.43; p = 0.003). TF IL-10 detection was not associated with hyaline membrane disease, antenatal steroids or influenced by TF sample volume. Overall IL-8 levels were wide ranging but towards the end of week 1 the levels were significantly higher in CLD infants (CLD: median 34 184 ng/ml, preterm non-CLD: median 699 ng/ml, p < 0.001, term: 2961 ng/ml, p = 0.028). CONCLUSION: A gestationally influenced low IL-10 may predispose preterm infants to persistent pulmonary inflammation of CLD.