Five-year follow-up of effects of neonatal intensive care and morphine infusion during mechanical ventilation on diurnal cortisol rhythm

The influence of intensive care treatment in infancy on cortisol levels in childhood and adolescence

BACKGROUND

Infants admitted to the intensive care unit experience numerous early-life stressors, which may have long-term effects on hypothalamic-pituitary-adrenal axis functioning.

AIMS

To determine the effects of intensive care treatment and related exposure to stress, pain, and opioids in infancy on cortisol levels in childhood and adolescence.

STUDY DESIGN

Cross-sectional study.

SUBJECTS

Children and adolescents aged 8 to 18 years with a history of intensive care treatment in infancy and healthy controls. The intensive care treatment cohort consisted of four subgroups with varying levels of exposure to stress, pain, and opioids in infancy. They received either mechanical ventilation, extracorporeal membrane oxygenation, major surgery, or excochleation of a giant congenital melanocytic nevus.

OUTCOME MEASURES

Between-group differences in stress reactivity to a study visit consisting of pain threshold testing and an MRI examination and diurnal cortisol levels, as measured in saliva.

RESULTS

After adjustment for age, sex, and gestational age, the diurnal cortisol output (AUCg) in the overall intensive care group (N = 76) was 18 % (approximately 1000 nmol/L) (95 % CI [-31 %, -3 %], P = 0.022) lower than that in the control group (N = 67). Cortisol awakening response, diurnal decline, and stress reactivity neither differed significantly between the overall intensive care group and control group, nor between the intensive care subgroups and control group.

CONCLUSION

Children and adolescents with a history of intensive care treatment in infancy have similar cortisol profiles to those of healthy controls, except for an 18 % lower diurnal cortisol output. The clinical relevance of this reduction is yet to be determined.

Cortisol reactivity and negative affect among preterm infants at 12 months during a mother-infant interaction task

The purpose of this study was to investigate correlates of preterm (PT) infant's cortisol reactivity and the association to infant negative affect, during a mother-infant interaction procedure. Participants included 48 infants born prematurely (gestational age < 37 weeks) and their mothers, assessed when infants were 12 months old corrected for prematurity. The examined variables comprised both neonatal and environmental dimensions including maternal interactive behavior. Infant negative affect and maternal interactive behavior were assessed with a standardized mother-infant interaction task. A baseline infant saliva sample was collected before the interaction began, and a second sample after the interaction episodes ended. Results revealed that decrease of infant's cortisol concentration was significantly associated with the exposure to more sensitive, and less intrusive maternal behaviors. However, once controlled for neonatal risk, family SES and maternal psychological distress, the associations were rendered non-significant. Although the association between cortisol reactivity and negative affect trended toward significance, maternal intrusiveness was the only significant predictor of observed infant negative affect. Findings suggest the importance of primary relational experiences on PT infants' early regulatory competencies.

Consequences of Prematurity on Cortisol Regulation and Adjustment Difficulties: A 9-Year Longitudinal Study

A preterm birth represents a stressful event having potentially negative long-term consequences. Thirty-three children born preterm (<33 weeks gestational age) and eleven full-term children participated in a nine-year longitudinal study. Perinatal Risk Inventory (PERI) was used at birth to assess the perinatal stress. Salivary cortisol, collected four times a day over two consecutive days, was measured with radioimmunoassay technique at six months and nine years to assess the hypothalamic-pituitary-adrenal (HPA) axis. Mothers reported post-traumatic symptoms on a self-report questionnaire 12 months after their child's birth and children's adjustment problems at 9 years of child age on the Child Behavior Checklist. Results showed a significant difference in cortisol regulation at nine years between preterm and full-term children but no differences in adjustment problems. Whereas biological factors (i.e., PERI, cortisol regulation at six months) explained cortisol at nine years, maternal post-traumatic symptoms were predictive of adjustment problems in their child. In conclusion, very preterm birth has some long-term consequences on the HPA-axis regulation at nine years. Although cortisol regulation is mostly influenced by biological factors, the presence of maternal post-traumatic symptoms predicts the manifestation of adjustment problems in both groups. This shows the importance of maternal psychological well-being for child development. Further research is needed to understand the exact consequences of premature birth on cortisol regulation and the implication for the child's development and health.

Cortisol and Cortisone in Early Childhood in Very-Low-Birthweight Infants and Term-Born Infants

INTRODUCTION

Besides programming of the hypothalamic-pituitary-adrenal (HPA) axis, changes in the activity of 11β-hydroxysteroid dehydrogenase type 2 (11β-HSD2) could contribute to the later metabolic and cardiovascular consequences of preterm birth.

OBJECTIVE

We compared serum cortisol, cortisone, and cortisol/cortisone ratio in early childhood in very-low-birthweight (VLBW) infants and term appropriate for gestational age (AGA) born infants.

METHODS

We included 41 VLBW infants, participating in the randomized controlled Neonatal Insulin Replacement Therapy in Europe trial, and 64 term AGA-born infants. Cortisol and cortisone were measured in blood samples taken at 6 months and 2 years corrected age (VLBW children) and at 3 months and 1 and 2 years (term children). At 2 years of (corrected) age (HDL) cholesterol, triglycerides, glucose, and insulin were also measured.

RESULTS

During the first 2 years of life, cortisol/cortisone ratio is higher in VLBW children compared to term children. In the total group of children, cortisol/cortisone ratio is positively related to triglycerides at 2 years of (corrected) age. In VLBW children, over the first 2 years of life both cortisol and cortisone are higher in the early-insulin group compared to the standard care group.

CONCLUSIONS

In VLBW infants, lower 11β-HSD2 activity probably contributes to the long-term metabolic and cardiovascular risks. In VLBW infants, early insulin treatment could affect programming of the HPA axis, resulting in higher cortisol and cortisone levels during early childhood.

Safety and effectiveness of parent- or nurse-controlled analgesia in neonates: a systematic review

OBJECTIVE

The aim of this systematic review was to determine the safety and effectiveness of parent- or nurse-controlled analgesia on neonatal patient outcomes. More specifically, the objective was to determine the effect of parent- or nurse-controlled analgesia on neonatal pain scores, analgesic use, and incidence of iatrogenic withdrawal syndrome, as well as any opioid-associated adverse events.

INTRODUCTION

Despite recent innovations in neonatology leading to significant improvements in short- and long-term outcomes for newborns requiring intensive care, optimal management of pain and distress remains a challenge for the treating multidisciplinary team. The inability of neonates to communicate pain easily, inconsistent practice among health professionals, insufficient analgesic prescriptions, and delays in medical reviews all impact effective pain management. Exploring the effect of parent- or nurse-controlled analgesia may identify a modality that negates these concerns and improves the pharmacological management of pain in newborns.

INCLUSION CRITERIA

This review considered experimental and observational studies evaluating the safety and effectiveness of parent- or nurse-controlled analgesia that included babies born at 23 weeks' gestation to four weeks post-term. The interventions considered for inclusion were any type of analgesia delivered by an infusion pump that allowed bolus dosing or a continuous analgesic infusion with bolus dosing as required. Studies using algorithms and protocols to guide timing and dosage were eligible for inclusion. Comparators included the standard management of pain for neonates in the newborn intensive care unit. A modification to the a priori protocol was made to include all neonates nursed outside of a neonatal intensive care unit to ensure all studies that examined the use of parent- or nurse-controlled analgesia in the neonatal population were included in the review.

METHODS

An extensive search of six major databases was conducted (CINAHL, Cochrane Library, Embase, PubMed, PsycINFO, and Web of Science). Studies published from 1997 to 2020 in English were considered for inclusion in this review. Databases searched for unpublished studies included MedNar and ProQuest Dissertations and Theses.

RESULTS

Fourteen studies were included in this review: two randomized controlled trials, six quasi-experimental studies, one case-control study, and five case series. There was considerable heterogeneity in the interventions and study outcome measures within the studies, resulting in an inability to statistically pool results. The small sample sizes and inability to distinguish data specific to neonates in six of the studies resulted in low quality of evidence for the safety and effectiveness of parent- or nurse-controlled analgesia in neonates. However, studies reporting neonatal data demonstrated low pain scores and a trend in reduced opioid consumption when parent- or nurse-controlled analgesia was used.

CONCLUSIONS

The use of parent- or nurse-controlled analgesia in the neonatal population has shown some effect in reducing the amount of opioid analgesia required without compromising pain relief or increasing the risk of adverse events. Due to the paucity of evidence available, certainty of the results is compromised; therefore, larger trials exploring the use of parent- or nurse-controlled analgesia in neonates and the development of nurse-led models for analgesia delivery are needed.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42018114382.

Methadone effectively attenuates acute and long-term consequences of neonatal repetitive procedural pain in a rat model

BACKGROUND

Painful procedures in early life cause acute pain and can alter pain processing at a spinal level lasting into adulthood. Current methods of analgesia seem unable to prevent both acute and long-term hypersensitivity associated with neonatal pain. The current study aims to prevent acute and long-term hypersensitivity associated with neonatal procedural pain using methadone analgesia in rat pups.

METHODS

Sprague-Dawley rat pups received either methadone (1 mg/kg) or saline prior to repetitive needle pricks into the left hind paw from the day of birth (postnatal day (P)0) to P7. Control littermates received a tactile stimulus. Mechanical sensitivity was assessed during the neonatal period (P0-P7), from weaning to adulthood (3-7 weeks) and following surgical re-injury of the same dermatome in adulthood.

RESULTS

Methadone administration completely reversed acute hypersensitivity from P0 to P7. In addition, neonatal methadone analgesia prevented prolonged hypersensitivity after re-injury in adulthood, without affecting sensitivity from weaning to adulthood.

CONCLUSIONS

The current study shows that neonatal methadone analgesia can attenuate acute as well as long-term hypersensitivity associated with neonatal procedural pain in a rat model.

IMPACT

Methadone treatment attenuates acute and long-term hypersensitivity associated with neonatal pain in a rat model. Clinical effectiveness studies are urgently warranted to assess acute and long-term analgesic effectivity of methadone.

Opioids for newborn infants receiving mechanical ventilation

BACKGROUND

Mechanical ventilation is a potentially painful and discomforting intervention that is widely used in neonatal intensive care. Newborn infants demonstrate increased sensitivity to pain, which may affect clinical and neurodevelopmental outcomes. The use of drugs that reduce pain might be important in improving survival and neurodevelopmental outcomes.

OBJECTIVES

To determine the benefits and harms of opioid analgesics for neonates (term or preterm) receiving mechanical ventilation compared to placebo or no drug, other opioids, or other analgesics or sedatives.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 9), in the Cochrane Library; MEDLINE via PubMed (1966 to 29 September 2020); Embase (1980 to 29 September 2020); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 29 September 2020). We searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials comparing opioids to placebo or no drug, to other opioids, or to other analgesics or sedatives in newborn infants on mechanical ventilation. We excluded cross-over trials. We included term (≥ 37 weeks' gestational age) and preterm (< 37 weeks' gestational age) newborn infants on mechanical ventilation. We included any duration of drug treatment and any dosage given continuously or as bolus; we excluded studies that gave opioids to ventilated infants for procedures.

DATA COLLECTION AND ANALYSIS

For each of the included trials, we independently extracted data (e.g. number of participants, birth weight, gestational age, types of opioids) using Cochrane Effective Practice and Organisation of Care Group (EPOC) criteria and assessed the risk of bias (e.g. adequacy of randomisation, blinding, completeness of follow-up). We evaluated treatment effects using a fixed-effect model with risk ratio (RR) for categorical data and mean difference (MD) for continuous data. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included 23 studies (enrolling 2023 infants) published between 1992 and 2019. Fifteen studies (1632 infants) compared the use of morphine or fentanyl versus placebo or no intervention. Four studies included both term and preterm infants, and one study only term infants; all other studies included only preterm infants, with five studies including only very preterm infants. We are uncertain whether opioids have an effect on the Premature Infant Pain Profile (PIPP) Scale in the first 12 hours after infusion (MD -5.74, 95% confidence interval (CI) -6.88 to -4.59; 50 participants, 2 studies) and between 12 and 48 hours after infusion (MD -0.98, 95% CI -1.35 to -0.61; 963 participants, 3 studies) because of limitations in study design, high heterogeneity (inconsistency), and imprecision of estimates (very low-certainty evidence - GRADE). The use of morphine or fentanyl probably has little or no effect in reducing duration of mechanical ventilation (MD 0.23 days, 95% CI -0.38 to 0.83; 1259 participants, 7 studies; moderate-certainty evidence because of unclear risk of bias in most studies) and neonatal mortality (RR 1.12, 95% CI 0.80 to 1.55; 1189 participants, 5 studies; moderate-certainty evidence because of imprecision of estimates). We are uncertain whether opioids have an effect on neurodevelopmental outcomes at 18 to 24 months (RR 2.00, 95% CI 0.39 to 10.29; 78 participants, 1 study; very low-certainty evidence because of serious imprecision of the estimates and indirectness). Limited data were available for the other comparisons (i.e. two studies (54 infants) on morphine versus midazolam, three (222 infants) on morphine versus fentanyl, and one each on morphine versus diamorphine (88 infants), morphine versus remifentanil (20 infants), fentanyl versus sufentanil (20 infants), and fentanyl versus remifentanil (24 infants)). For these comparisons, no meta-analysis was conducted because outcomes were reported by one study.

AUTHORS' CONCLUSIONS

We are uncertain whether opioids have an effect on pain and neurodevelopmental outcomes at 18 to 24 months; the use of morphine or fentanyl probably has little or no effect in reducing the duration of mechanical ventilation and neonatal mortality. Data on the other comparisons planned in this review (opioids versus analgesics; opioids versus other opioids) are extremely limited and do not allow any conclusions. In the absence of firm evidence to support a routine policy, opioids should be used selectively - based on clinical judgement and evaluation of pain indicators - although pain measurement in newborns has limitations.

Repetitive noxious stimuli during early development affect acute and long-term mechanical sensitivity in rats

BACKGROUND

Prematurely born infants are frequently exposed to painful procedures in the neonatal intensive care unit, causing changes to the development of the nervous system lasting into adulthood. The current study aims to study acute and long-term consequences of neonatal repetitive noxious stimulation.

METHODS

Rat pups received either 4 or 10 unilateral needle pricks per day, while control littermates received 4 or 10 tactile stimuli in the first postnatal week. Behavioural sensitivity was assessed in the neonatal phase, in adulthood, and after re-injury of the same dermatome in adulthood.

RESULTS

An increase in the number of repetitive painful stimuli, from 4 to 10 needle pricks per day, resulted in increased mechanical hypersensitivity during the neonatal period. In adulthood, repetitive painful stimuli resulted in hyposensitivity to mechanical stimuli, while thermal sensitivity was unaffected. After re-injury of the same dermatome in adulthood, the number of repetitive noxious stimuli did not affect mechanical hypersensitivity. Both needle prick groups showed an increased duration of postoperative hypersensitivity compared to control.

CONCLUSION

This study shows that repetitive noxious stimulation during the early postnatal period affects acute and long-term mechanical sensitivity. Therefore, the amount of nociceptive stimuli should be minimized or adequately treated in a clinical setting.

Birth weight and postnatal growth in preterm born children are associated with cortisol in early infancy, but not at age 8 years

BACKGROUND

Preterm birth has been associated with altered hypothalamic-pituitary-adrenal (HPA-) axis activity as well as cardiometabolic diseases and neurodevelopmental impairments later in life. We assessed cortisol from term age to age 8 y in children born preterm, to explore the development of HPA-axis activity in association with intrauterine and early-postnatal growth until 6 mo. corrected age.

METHODS

In 152 children born at a gestational age ≤32 wks. and/or with a birth weight ≤1,500g, random serum cortisol was assessed at term age (n=150), 3 mo. (n=145) and 6 mo. corrected age (n=144), and age 8 y (n=59). Salivary cortisol was assessed at age 8 y (n=75): prior to bedtime, at awakening, 15min after awakening, and before lunch. Cortisol was analyzed in association with birth weight-standard deviation score (SDS), being born small for gestational age (SGA), and combinations of intrauterine and postnatal growth: appropriate for gestational age (AGA) with or without growth restriction (AGA GR+ or AGA GR-) at 6 mo. corrected age, and SGA with or without catch-up growth (SGA CUG+ or SGA CUG-) at 6 mo. corrected age. Cross-sectional associations at all time points were analyzed using linear regression, and longitudinal associations were analyzed using generalized estimating equations.

RESULTS

Longitudinally, birth weight-SDS was associated with cortisol (β [95%CI]): lower cortisol over time was seen in infants with a birth weight ≤-2 SDS (-50.69 [-94.27; -7.11], p=0.02), infants born SGA (-29.70 [-60.58; 1.19], p=0.06), AGA GR+ infants (-55.10 [-106.02; -4.17], p=0.03) and SGA CUG- infants (-61.91 [-104.73; -19.10], p=0.01). In cross-sectional analyses at age 8 y, no associations were found between either serum or salivary cortisol and birth weight-SDS, SGA-status, or growth from birth to 6 mo. corrected age.

CONCLUSION

In children born preterm, poor intrauterine and postnatal growth were associated with lower cortisol in early infancy, but not at age 8 y. Even though HPA-axis activity no longer differed between groups at age 8 y, or differences could not be confirmed due to attrition, it is unknown whether the differences found in early infancy could attribute to increased health risks later in life.

Glucocorticoid Programming in Very Preterm Birth

Very preterm (i.e., <32 weeks of gestation) infants admitted to the neonatal intensive care unit are compromised in their abilities to respond adequately to common threats like hemodynamic changes and reduced energy supplies, which is partly attributable to adrenocortical insufficiency. Conversely, later in life, these infants show features of increased glucocorticoid bioactivity, such as abdominal fat distribution, raised blood pressure, insulin resistance and diabetes mellitus type 2. It has been suggested that the very preterm newborn responds to the adverse postnatal environment with a sustained elevation in hypothalamus-pituitary-adrenal axis activity that persists beyond infancy. This has implications for subsequent growth, body composition, metabolism, neurodevelopment and, ultimately, long-term disease risk. The mechanisms underpinning these associations are not fully elucidated yet. This review gives a brief summary of studies that investigated adrenocortical function in very preterm newborns and how the axis changes with age, as a possible explanation for the association between prematurity and long-term outcome.

Programming of the Hypothalamus-Pituitary-Adrenal Axis by Very Preterm Birth

BACKGROUND

Many very preterm (i.e., <32 weeks of gestation) newborns fail to mount an adequate adrenocortical response to stress or illness, termed relative adrenal insufficiency. Conversely, later in life these infants show features of increased glucocorticoid bioactivity, such as abdominal adiposity, insulin resistance, raised blood pressure, shorter stature and internalizing problem behavior.

SUMMARY

Studies suggested that very preterm newborns have impairments along multiple levels of the hypothalamus-pituitary-adrenal (HPA) axis. Among the impairment were defects in: (1) the pituitary responsiveness to exogenous corticotropin-releasing hormone, (2) 11β-hydroxylase activity, and (3) the interconversion between cortisol and inert cortisone. There is some evidence suggesting that later in life these infants have an increased basal secretion rate of cortisol and adrenal hyperandrogenism. However, the response to acute (psychosocial) stress was blunted rather than enhanced in them. The mechanisms explaining this switch in HPA axis activity are complex and not yet fully understood. Key Messages: Very preterm newborns have several impairments along the HPA axis that could impede an adequate adrenocortical response to stress or illness. Later in life, these infants are predisposed to increased HPA axis activity, which could partially explain their phenotype.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.

Diurnal Cortisol Patterns and Dexamethasone Suppression Test Responses in Healthy Young Adults Born Preterm at Very Low Birth Weight

Background

Early life stress, such as painful and stressful procedures during neonatal intensive care after preterm birth, can permanently affect physiological, hormonal and neurobiological systems. This may contribute to altered programming of the hypothalamic-pituitary-adrenal axis (HPAA) and provoke changes in HPAA function with long-term health impacts. Previous studies suggest a lower HPAA response to stress in young adults born preterm compared with controls born at term. We assessed whether these differences in HPAA stress responsiveness are reflected in everyday life HPAA functioning, i.e. in diurnal salivary cortisol patterns, and reactivity to a low-dose dexamethasone suppression test (DST), in unimpaired young adults born preterm at very low birth weight (VLBW; <1500 g).

Methods

The participants were recruited from the Helsinki Study of Very Low Birth Weight Adults cohort study. At mean age 23.3 years (2.1 SD), 49 VLBW and 36 controls born at term participated in the study. For cortisol analyzes, saliva samples were collected on two consecutive days at 0, 15, 30 and 60 min after wake-up, at 12:00 h, 17:00 h and 22:00 h. After the last salivary sample of the first study day the participants were instructed to take a 0.5 mg dexamethasone tablet.

Results

With mixed-effects model no difference was seen in overall diurnal salivary cortisol between VLBW and control groups [13.9% (95% CI: -11.6, 47.0), P = 0.31]. Salivary cortisol increased similarly after awakening in both VLBW and control participants [mean difference -2.9% (29.2, 33.0), P = 0.85]. Also reactivity to the low-dose DST (awakening cortisol ratio day2/day1) was similar between VLBW and control groups [-1.1% (-53.5, 103.8), P = 0.97)].

Conclusions

Diurnal cortisol patterns and reactivity to a low-dose DST in young adulthood were not associated with preterm birth.