Environmental contaminants and children's health: Cause for concern, time for action.

The present paper provides an outline of the developmental and behavioural characteristics that make children, especially the fetus and young child, more vulnerable to contaminants than adults. The major categories of contaminants are briefly described. The evidence for their possible effects on neurobehavioural development; immune, endocrine and respiratory systems; childhood cancer based on research studies with animals; children exposed to catastrophic 'accidents' involving overdose exposures; and pregnant women and children from communities with high 'background' levels of contamination who participated in studies is reviewed. While the data are worrisome, especially for children living in northern and certain urban communities, much remains to be learned about possible subtle effects and the potential for long term effects of the current background contamination experienced by the majority of Canadian children before its significance to their health can be fully evaluated. The present regulatory processes, which are based on risk assessment, are so cumbersome and costly that the great majority of chemicals in use have not been fully evaluated, and the ingenuity of new chemical production continually exceeds the capacity to test the new chemicals. Moreover, despite past insistence on scientific proof of adverse effects and safety, unanticipated effects have occurred that will threaten the sustainability of human life unless more effective control measures are taken to limit the release of toxic substances and persistent chemicals into the environment. Therefore, the shortcomings of risk assessment are discussed, and the precautionary principle, which is used in some countries and is proposed for use internationally as an alternative measure that may offer improved control for the future, is outlined. Finally, opportunities for physician action are suggested.

Children are different: environmental contaminants and children's health.

Although the impact of environmental contaminants on human health has been widely studied, few reports in the Canadian literature have focussed on the specific vulnerability of children. Because of their rapid growth, physiologic and metabolic immaturity, the fetus and child are often at increased risk from toxic substances in their environments. Furthermore, greater air, food and fluid intakes relative to body weight compared with the adult, increase the child's potential for excessive exposures. The crawling stage of infancy, the play patterns and short stature of toddlers also serve to increase their exposure to dust and heavy and volatile substances which accumulate near the floor. This article provides an overview of some of the developmental physiologic, anatomic and behavioural features of the fetus, infant and child which increase their vulnerability to environmental contaminants in comparison with adults. Specific examples are given.

A national survey of use of obstetric procedures and technologies in Canadian hospitals: routine or based on existing evidence?

BACKGROUND: The objective of this national survey was to describe the routine use of procedures and technologies in Canadian hospitals providing maternity care, and to determine the extent to which current use was consistent with the existing evidence and recommended guidelines for maternal and newborn care. METHODS: Representatives of 572 hospitals providing maternity care across Canada were sent questionnaires in the spring and summer of 1993; 523 (91.4%) responded. The primary outcome measures consisted of the self-reported use of obstetric procedures and technologies (perineal shaves, enemas/suppositories, intravenous infusions, initial and continuous electronic fetal heart monitoring, episiotomy rates). Hospitals were grouped according to location, size (number of live births per year), and university affiliation status. RESULTS: The hospitals in the Prairie provinces, in Quebec, and in the Atlantic provinces were significantly less likely than those in Ontario to restrict their use of perineal shaves and enemas to women on admission in labor. Small hospitals were significantly more likely than large hospitals (> 1000 live births) to restrict their use of intravenous infusions, and initial and continuous electronic fetal monitoring. The university-affiliated and nonteaching hospitals were significantly less likely than the university teaching hospitals to have episiotomy rates of less than 40 percent for primiparous women. Small hospitals were more likely than large hospitals to report episiotomy rates of less than 20 percent for multiparous women. CONCLUSIONS: Considerable variations occur in the routine use of obstetric procedures and technologies in Canadian hospitals providing maternity care, according to hospital location, size, and university affiliation status. Despite the existing evidence suggesting that the routine use of these practices and procedures is both unnecessary and potentially harmful, a significant number of Canadian hospitals continued to use them routinely in 1993.

Neonatal personnel in Canada.

Although the need for trained personnel to care for neonates with complex needs is recognized, there has been no systematic analysis of present or future personnel requirements. The Canadian Paediatric Society's Neonatal-Perinatal Medicine Section sponsored a symposium on neonatal personnel, inviting four Canadian experts to address issues related to future needs. Areas addressed included neonatal nurse practitioners providing increased patient care in some parts of the country as resident involvement in neonatal intensive care decreases, the extended roles of other health care personnel and increased direct patient care by neonatologists. There is no approved method to determine personnel needs, but paediatric department heads have indicated that the number of neonatologists needed is substantially greater than available funding allows. Considering economic factors and the need to educate perinatal care providers, it is important to assess present and future needs to ensure that quality care can be provided.

Breast-feeding policies and practices in Canadian hospitals providing maternity care.

OBJECTIVE: To determine the extent to which policies and practices of Canadian hospitals providing maternity care are consistent with the World Health Organization (WHO)/UNICEF 10 Steps to Successful Breastfeeding, the WHO International Code of Marketing of Breast-Milk Substitutes and the WHO/UNICEF Baby Friendly Hospital Initiative. DESIGN: Cross-sectional mailed survey. SETTING: Canada. PARTICIPANTS: Representatives of 572 hospitals providing maternity care across Canada were sent a questionnaire in the spring and summer of 1993, 523 (91.4%) responded. OUTCOME MEASURES: Self-reported implementation of policies and practices concerning infant feeding; hospitals were grouped according to location, size (number of live births per year) and university affiliation status. MAIN RESULTS: Although 58.4% (296/507) of the respondents reported that their hospital had a written policy on breast-feeding, only 4.6% (21/454) reported having one that complied with all of the WHO/UNICEF steps surveyed. This figure dropped to 1.3% (6/453) when compliance with the WHO code (distribution of free samples of formula to formula-feeding and breast-feeding mothers) was added. Hospitals in Quebec and the Prairie provinces were significantly more likely than those in Ontario to give free samples of formula to both breast-feeding (OR 2.39 [95% confidence interval (Cl) 1.39 to 4.09] and 20.22 [95% Cl 9.27 to 44.33] respectively) and formula-feeding mothers (OR 1.82 [95% Cl 1.07 to 3.11] and 8.03 [95% Cl 3.29 to 19.6] respectively), after adjustment for hospital size and university affiliation status. CONCLUSION: There are considerable variations in the implementation of individual WHO steps and provisions of the WHO code according to hospital location, size and university affiliation status. Very few Canadian hospitals meet all of the criteria that would enable them to be considered "baby friendly" according to the WHO/UNICEF definition.

Do parents and professionals agree on the developmental status of high-risk infants?

OBJECTIVES: To examine the degree of agreement between parental reporting of the development of high-risk infants and professional assessment by a multidisciplinary team. METHODS: The developmental status of 196 infants discharged from neonatal intensive care units (NICUs) was assessed by their parents using the Infant Monitoring Questionnaire (IMQ) at 4, 8, or 12 months' corrected age. On the same day, a clinical assessment was done by a multidisciplinary team consisting of a developmental pediatrician, physical therapist, and psychologist. The kappa statistic was used to measure agreement between the assessments. Logistic regression was used to investigate factors that might influence agreement. RESULTS: Both the IMQ and the multidisciplinary team classified infants as developing normally ("normal"), being at risk for abnormal development ("suspect"), or developing abnormally ("abnormal"). Although the same proportion of children fell into the three categories by both assessments, parents and the multidisciplinary team showed poor agreement with respect to the classification of individual infants (kappa = 0.276). No infant or family characteristic was found to have an influence on agreement. CONCLUSIONS: For a group of high-risk infants discharged from NICUs, the agreement between parental assessment of developmental status using the IMQ and the professional assessment by a multidisciplinary team is poor in the first year of life. We do not recommend the use of this questionnaire as a substitute for clinical assessment of biologically at-risk infants discharged from NICUs. However, it may be useful for those groups of infants for whom no other information is available or as an adjunct to clinical assessment when infants are not behaving typically because of an unfamiliar setting or concurrent illness.

Are Canadian hospitals providing family-centered maternity and newborn care?

A philosophy of family-centered maternity and newborn care requires that there be open communication between a woman, her family and health professionals; that the woman be able to choose people to support her, and have those people present during labour and birth; and that the mother and infant remain in close contact whenever possible following birth. Using data from a 1993 survey, the authors conclude that Canadian hospitals still have a long way to go before putting these ideals into practice.

Strategies for school-based response to loss: proactive training and postvention consultation.

The suicide of a student or staff member is one of the most difficult crisis confronting a high school. This article describes the first year of a school-based postvention program to train and consult with crisis personnel in a structured response to this crisis. Responding to Loss (RTL) is one program offered by Community Action for Youth Survival, a project of the Ronald McDonald Children's Charities. Serving a contiguous three county urban area, this program integrates public health, epidemiological, psychiatric, and prevention paradigms to provide a comprehensive approach to the aftermath of adolescent suicide. RTL provides an interdisciplinary model for comprehensive, school-based postvention programs based on the guidelines developed by the Centers for Disease Control and national and local psychological autopsy data. It highlights the significance of responding to increased rates of suicide in minority youth, suicide witnessed by peers, and suicide victims who have dropped out of school. Organizational issues, such as systematic school entry, development of a computerized school database, proactive training, and collaboration with the offices of medical examiners and coroners, are described. Initial evaluation data from year 1 indicate significant gains in participants' knowledge and skills, as well as a high rate of consumer satisfaction.

Sound localization in newborn human infants.

Newborns' localization of sounds was examined in two experiments that utilized different psychophysical procedures and imposed different task demands. The results of both experiments were consistent in indicating that neonates not only differentiate the hemifield of a sound source but have some capacity to localize a sound within the hemifields. Adjustment of their initial head turn angle following a within-hemifield shift in location of an ongoing sound indicated that head orientation in neonates is elicited not only by sound onset but also by changes in location of an ongoing sound. Thus, multiple stimulus parameters impact on this neonatal response. Results are related to research on sound localization in older infants, and discussed in light of early development of the central auditory system.

Postnatal changes in serum retinol status in very low birth weight infants.

BACKGROUND: Retinol deficiency may contribute toward the development of chronic lung disease in very low birth weight (VLBW) infants. We examined the retinol status during early infancy in VLBW infants from birth to 6 weeks 'post-term'. METHODS: Concentrations of serum retinol (SR) and its carrier proteins, retinol-binding protein (RBP), and transthyretin (TTR), were determined at birth, then weekly for 8 weeks, and at 4-6 weeks 'post-term' in preterm infants of less than 34 weeks gestation. The SR values of umbilical cord blood at birth from the preterm infants were compared to the maternal SR levels as well as to cord SR levels of term infants. RESULTS: From 24 through 33 weeks gestation, umbilical cord SR at birth was significantly lower than, but did not correlate with, maternal SR (P < 0.01). The cord SR in term infants was also higher than that in preterm infants (262 +/- 68 vs. 183 +/- 67 micrograms/l, P < 0.01). Longitudinal profiles of SR in 18 VLBW infants showed that, despite regular retinol supplementation, there was a decline in SR after birth, reaching a nadir of 128 +/- 40 microgram/l at 5-7 weeks (P < 0.001), followed by an increase toward levels comparable to those seen in full term infants. At follow-up at the corrected age of 4-6 weeks 'post-term', SR levels in VLBW infant (222 +/- 74 micrograms/l) had returned to within the normal range for term cord SR values. The concentrations of RBP also showed a similar biphasic pattern. Transthyretin levels did not change for 8 weeks but increased significantly at 4-6 weeks 'post-term'. CONCLUSIONS: Current practices of retinol supplementation in VLBW infants fail to maintain adequate retinol status in those infants during the neonatal period. Further efforts to improve the retinol status in these infants should be explored.

Factors predictive of follow-up clinic attendance and developmental outcome in a regional cohort of very low birth weight infants.

This population-based, retrospective cohort study of very low birth weight infants was undertaken to: 1) identify factors associated with nonattendance for follow-up, 2) estimate the prevalence of cerebral palsy at age > or = 18 months, and 3) model the prognostic association between prenatal and perinatal risk markers and cerebral palsy. The sample included 496 surviving very low birth weight infants born in 32 hospitals in Southwest Ontario between January 1982 and December 1986. Multivariate analyses were performed using the proportional odds regression model. Loss to follow-up was more likely among those with mothers < 20 years of age, those with unmarried mothers, and those not born in a tertiary center. Loss to follow-up was less likely for those with neonatal anemia and those of lower birth weight. Motor development of the 369 children who were followed at least 18 months was classified into one of three categories: normal, suspect, or cerebral palsy. Multivariate analysis revealed that factors predictive of poorer outcome were intraventricular hemorrhage, unmarried mother, male sex, recurrent apnea, and hydrocephalus. The finding that unmarried status was associated with loss to follow-up and was also an important predictor of cerebral palsy suggests that it is important for follow-up clinics to identify ways of assisting this population to remain in contact with the clinic.

Cerebral blood flow, cross-brain oxygen extraction, and fontanelle pressure after hypoxic-ischemic injury in newborn infants.

The relationship between mean arterial pressure, intracranial pressure, cerebral blood flow, cross-brain oxygen extraction, cerebral metabolic rate, and outcome was studied during therapy in nine neonates on 3 consecutive days after severe hypoxic-ischemic cerebral injury. Cross-brain oxygen extraction was significantly higher (5.06 +/- 0.5 vs 2.05 +/- 0.8 ml/dl; p = 0.012) in the five neonates who survived with normal neurologic outcome than in the four who died or sustained severe brain damage. In contrast, global cerebral blood flow in the five neonates with normal neurologic outcome was significantly lower (25.6 +/- 8.2 vs 83.2 +/- 44.9 ml/100 gm brain/min; p less than 0.05) during the study period. The differences in cross-brain oxygen extraction and global cerebral blood flow between infants who had neurologic recovery and those who died or sustained brain damage occurred in the presence of acceptable values for intracranial pressure, mean arterial pressure, and cerebral perfusion pressure. Our preliminary data suggest that cross-brain oxygen extraction and possibly global cerebral blood flow may be important variables associated with severe neuronal injury and death after hypoxic-ischemic cerebral injury.

Is perinatal care in southwestern Ontario regionalized?

OBJECTIVE: To determine whether perinatal care in southwestern Ontario is regionalized, to identify trends over time in referral patterns, to quantify trends in perinatal death rates and to identify trends in perinatal death rates that give evidence of regionalization. DESIGN: Cohort study. SETTING: Thirty-two hospitals in southwestern Ontario (1 level III, 1 modified level III and 30 level II or I). PATIENTS: All pregnant women admitted to the hospitals and their infants. MAIN OUTCOME MEASURES: Antenatal and neonatal transfer status, live-born with discharge home alive from hospital of birth, stillborn, and live-born with death before discharge. RESULTS: Between 1982 and 1985 the antenatal transfer rate increased from 2.2% to 2.8% (p less than 0.003). The proportion of births of infants weighing 500 to 1499 g increased from 49% to 69% at the level III hospital. The neonatal transfer rate increased from 26.2% to 47.9% (p less than 0.05) for infants in this birth-weight category and decreased from 10.2% to 7.1% (p less than 0.03) for infants weighing 1500 to 2499 g. The death rate among infants of low birth weight was lowest among those born at the level III centre and decreased at all centres between 1982 and 1985. CONCLUSIONS: Perinatal care in southwestern Ontario is regionalized and not centralized; regionalization in southwestern Ontario increased between 1982 and 1985.

Amikacin pharmacokinetics and suggested dosage modifications for the preterm infant.

The pharmacokinetics of amikacin administered intravenously at currently recommended doses (7.5 mg/kg every 12 h for infants with less than 7 days of life; 7.5 mg/kg every 8 h for infants with greater than 7 days of life) were studied in 28 preterm infants weighing less than 2,500 g (mean +/- standard deviation, 1.38 +/- 0.47 kg; postconceptional age, 30.50 +/- 2.86 weeks). The medication was infused over 45 min. Trough and peak serum samples as well as two additional samples were taken at steady state. The results showed a statistically significant inverse relationship between half-life (8.42 +/- 2.55 h) and postconceptional age (P = 0.002) and a direct correlation between total body clearance (0.84 +/- 0.28 ml/min per kg) and postconceptional age (P = 0.02). These pharmacokinetic data were used to calculate a new dosage schedule for preterm infants. The derived intravenous dosage of amikacin for infants of less than 30 weeks of postconceptional age was 9 mg/kg every 18 h. For infants of greater than 30 weeks of postconceptional age, the dosage was 9 mg/kg every 12 h. Peak and trough levels of amikacin in serum that fell within the therapeutic range were compared by using the currently recommended dosage schedule and the dosage schedule derived from our pharmacokinetic data. There was a reduction in the number of peak and trough levels that fell outside the accepted therapeutic range which was not statistically significant. Extension of the dosing interval and a further increase in the dosage may result in further improvement. Based on these data, the current recommendations are inadequate for the preterm infant. Our derived dosage schedule improved but did not eliminate high trough and low peak levels of amikacin in all infants. The current recommendations should be adjusted for the preterm infant. Ongoing therapeutic drug monitoring is essential to tailor the amikacin dosage to the individual patient.