Impact of extremely immature infants on neonatal services

The impact of high intensity care around birth on long-term neurodevelopmental outcomes

BACKGROUND

An equitable and affordable healthcare system requires a constant search for the optimal way to deliver increasingly expensive neonatal care. Therefore, evaluating the impact of hospital intensity around birth on long-term health outcomes is necessary if we are to assess the value of high intensity neonatal care against its costs.

METHODS

This study exploits uneven geographical distribution of high intensity birth hospitals across Canada to generate comparisons across similar Cerebral Palsy (CP) related births treated at hospitals with different intensities. We employ a rich dataset from the Canadian Multi-Regional CP Registry (CCPR) and instrumental variables related to the mother's location of residence around birth.

RESULTS

We find that differences in hospitals' intensities are not associated with differences in clinically relevant, long-term CP health outcomes.

CONCLUSIONS

Our results suggest that existing matching mechanism of births to hospitals within large metropolitan areas could be improved by early detection of high risk births and subsequent referral of these births to high intensity birthing centers. Substantial hospitalization costs might be averted to Canadian healthcare system ($16 million with a 95% CI of $6,131,184 - $24,103,478) if CP related births were assigned to low intensity hospitals and subsequently transferred if necessary to high intensity hospitals.

Perinatal Regionalization and Implications for Long-Term Health Outcomes in Cerebral Palsy

Background: Perinatal regionalization is linked to improved neonatal outcomes; however, the effects on long-term outcomes in cerebral palsy (CP) are not known. We estimate the effect of highest levels of neonatal care available at delivery on the risk of developing a nonambulatory CP status. Methods: Children with CP born in Quebec from the Canadian CP Registry excluding postneonatal causes were included (N=360). We estimate the effect of level of care available at delivery on risk of nonambulatory status among children with CP using propensity score matching and instrumental variables methods to adjust for differences in case mix among the three groups of hospitals. The outcome variable is an indicator for CP nonambulation assigned according to Gross Motor Function Classification System (levels IV and V). This study used data that predated therapeutic hypothermia in Quebec. Results: Propensity score estimates of change in the adjusted risk of having a nonambulatory CP status because of birth at level II versus level I is −0.081, 95% confidence interval (CI; −0.2182 to 0.0562); level III versus level I is −0.072 95% CI (−0.225 to 0.08), and level III versus level II is 0.157 95% CI (0.027 to 0.286). Conclusions: Differences in levels of neonatal care available at hospital where the delivery was carried out are not associated with the risk of a nonambulatory CP phenotype. This suggests that level of care and associated medical technology within the Quebec regionalized neonatal-perinatal system is used efficiently because it does not offer any further marginal benefit in the reduction of severe CP outcomes. The system works well as it is, which is supportive of the perinatal regionalization. The success of the neonatal resuscitation program and referral of high-risk births to regional hospitals with sufficient obstetric and perinatal competence and resources may contribute to this lack of variability.

Babies born at the threshold of viability: changes in survival and workload over 20 years

OBJECTIVE

To assess the care given to the babies born at the threshold of viability over the last 20 years using regional and national data.

DESIGN

Population-based retrospective study.

SETTING

Former 'Trent' health region.

PARTICIPANTS

Babies born between 1 January 1991 and 31 December 2010 at 22(+0) to 25(+6) weeks gestational age.

MAIN OUTCOME MEASURE

Survival and use of respiratory support.

METHODS

Data of all babies born between 1 January 1991 and 31 December 2010 with a gestational age of 22(+0) to 25(+6) weeks and admitted to a neonatal unit were extracted from The Neonatal Survey. Use of respiratory support in terms of ventilation and continuous positive airway pressure (CPAP) for this group of babies was calculated as a proportion of the total used by the whole neonatal intensive care population within the defined study area.

RESULTS

The proportion of babies surviving to discharge increased significantly over time in those born at 24 and 25 weeks (p<0.01) but failed to achieve statistical significance for those at 23 weeks (p=0.08). No babies born at 22 weeks survived. The babies born at 22-25 weeks accounted for 26.3% of all ventilation and 21.5% of CPAP given.

CONCLUSION

Our work concurs with the current UK guidelines. There could be advantages in focusing the care of babies born at 23 weeks to a small number of intensive care units to allow specialist expertise to develop in all aspects of the management of these babies. However, focusing care will not necessarily improve survival or reduce morbidity.

The cost of preterm birth throughout childhood in England and Wales

BACKGROUND

Infants born preterm are at increased risk of adverse health and developmental outcomes. Mortality and morbidity after preterm birth impose a burden on finite public sector resources. This study considers the economic consequences of preterm birth from birth to adult life and compares the costs accruing to those born preterm with those born at term.

METHODS

A decision-analytic model was constructed to estimate the costs to the public sector over the first 18 years after birth, stratified by week of gestational age at birth. Costs were discounted and reported in UK pounds at 2006 prices. Probabilistic sensitivity analysis was used to examine uncertainty in the model parameters and generate confidence intervals surrounding the cost estimates.

RESULTS

The model estimates the costs associated with a hypothetical cohort of 669601 children and is based on live birth and preterm birth data from England and Wales in 2006. The total cost of preterm birth to the public sector was estimated to be pound2.946 billion (US $4.567 billion), and an inverse relationship was identified between gestational age at birth and the average public sector cost per surviving child. The incremental cost per preterm child surviving to 18 years compared with a term survivor was estimated at pound22885 (US $35471). The corresponding estimates for a very and extremely preterm child were substantially higher at pound61781 (US $95760) and pound94740 (US $146847), respectively.

CONCLUSIONS

Despite concerns about ongoing costs after discharge from perinatal services, the largest contribution to the economic implications of preterm birth are hospital inpatient costs after birth, which are responsible for 92.0% of the incremental costs per preterm survivor.

Outcome following preterm birth

Preterm birth currently occurs in approximately 12% of pregnancies and appears to be increasing despite improvements in obstetric care. Improvements in neonatal care have led to increased survival, particularly at extreme prematurity, but survival may be associated with significant morbidity. This may be acute, reflecting the difficulties in supporting an individual in a hostile extrauterine environment to which they should not be exposed, or chronic, reflecting disturbances to fragile, immature body systems. Brain, lungs, intestines and eyes are particularly vulnerable and damage may be severe. For some infants the consequences of this damage may be permanent disability and impairment. Despite this, the limited information currently available suggests that adult outcomes may be comparable with those for infants born at term.

Morbidity and mortality of infants born at the threshold of viability: ten years' experience in a single neonatal intensive care unit, 1991-2000

BACKGROUND

The purpose of the present paper was to evaluate the mortality and morbidity of infants born at 22-24 weeks gestation.

METHODS

A total of 78 infants born at 22-24 weeks gestation, who were admitted between January 1991 through December 2000, were retrospectively studied.

RESULTS

Seventy-one of 78 infants were enrolled in the present study. One year survival rates at 22, 23 and 24 weeks were 40.0% (2/5), 61.1% (11/18), and 50.0% (24/48), respectively. Failure of response to surfactant and air leak were associated with death in infants born at 23 weeks gestation. Low Apgar score, intraventricular hemorrhage (> or =III), and sepsis were correlated with death in infants born at 24 weeks gestation. The handicap rates of survivors born at 22, 23, and 24 weeks gestation were 100, 36.4, and 26.1%, respectively.

CONCLUSIONS

The present study indicates that infants born at 22 weeks gestation, in whom pulmonary structure is established, that is, a viable lung that can exchange gas with exogenous surfactant, have a chance to survive, but neurological outcome is still poor. Every possible effort should be made to extend gestation beyond 22 weeks.

Cardiopulmonary resuscitation and epinephrine infusion in extremely low birth weight infants in the neonatal intensive care unit

BACKGROUND

Survival of extremely low birth weight (ELBW) infants has improved significantly; however, the aggressiveness of treatment in these infants remains controversial. Critical appraisal of the benefits of cardiopulmonary resuscitation (CPR) and intravenous epinephrine infusion (IV EPI) has not been studied in this population.

OBJECTIVE

To determine if either CPR or continuous IV EPI in NICU is of benefit for surviving in a selected population of infants weighing </=750 g birthweight.

METHODS

Case records of infants </=750 g birthweight were reviewed retrospectively to document episodes of CPR and the use of IV EPI for inotropic support. Demographic data were collected for each infant and severity of illness scores were calculated using the clinical risk index for babies (CRIB).

RESULTS

In all, 91 infants </=750 g birth weight were identified, the overall survival rate was 35/91 (38%). A total of 15 infants received CPR, none of these infants survived to discharge. A total of 47 infants received continuous IV EPI of which 10/47 survived in comparison to 25/44 infants who did not receive this treatment (p<0.001). Increasing dosage of IV EPI was associated with decreased survival. All infants who received epinephrine at a dose >1.0 mcg/kg/hour intravenously died.

CONCLUSIONS

In view of the poor survival after either CPR or high-dose IV EPI in infants </=750 g, extreme caution should be applied to the use of these therapies in this high-risk population of ELBW infants.

Survival of very preterm infants: Epipage, a population based cohort study

OBJECTIVE

To evaluate the outcome for all infants born before 33 weeks gestation until discharge from hospital.

DESIGN

A prospective observational population based study.

SETTING

Nine regions of France in 1997.

PATIENTS

All births or late terminations of pregnancy for fetal or maternal reasons between 22 and 32 weeks gestation.

MAIN OUTCOME MEASURE

Life status: stillbirth, live birth, death in delivery room, death in intensive care, decision to limit intensive care, survival to discharge.

RESULTS

A total of 722 late terminations, 772 stillbirths, and 2901 live births were recorded. The incidence of very preterm births was 1.3 per 100 live births and stillbirths. The survival rate for births between 22 and 32 weeks was 67% of all births (including stillbirths), 85% of live births, and 89% of infants admitted to neonatal intensive care units. Survival increased with gestational age: 31% of all infants born alive at 24 weeks survived to discharge, 78% at 28 weeks, and 97% at 32 weeks. Survival among live births was lower for small for gestational age infants, multiple births, and boys. Overall, 50% of deaths after birth followed decisions to withhold or withdraw intensive care: 66% of deaths in the delivery room, decreasing with increasing gestational age; 44% of deaths in the neonatal intensive care unit, with little variation with gestational age.

CONCLUSION

Among very preterm babies, chances of survival varies greatly according to the length of gestation. At all gestational ages, a large proportion of deaths are associated with a decision to limit intensive care.

Ethical considerations in the management of infants born at extremely low gestational age

With ongoing improvements in technology and the understanding of neonatal physiology, there has been increasing debate regarding the gestational age and birth weight limits of an infants' capability of sustaining life outside the womb and how this is to be determined. The objective of this review was to address this issue with an analysis of current data (following the introduction of surfactant therapy in 1990) from published studies of survival in extremely low gestational age infants. We found that survival was possible at 22 completed weeks of gestation but only in < 4% of live births reported. Survival increased from 21% at 23 weeks gestational age to 46% at 24 weeks gestational age. Historically, despite continual advances in neonatology, the mortality at 22 weeks has not improved over the past three decades. Combining the data from studies on survival with evidence from developmental biology, we believe that it is not worthwhile to pursue aggressive support of infants born at < 23 weeks gestational age. Given the complicated issues related to morbidity and mortality in infants born at 22 to 25 weeks gestational age and the ethical implications of the available evidence, we propose the need for a consensus derived framework to help in decision-making.

Evidence-based ethics and the care and outcome of extremely premature infants

The care of extremely premature infants involves a number of complex clinical and ethical issues. The ethical and scientific quality of decisions made in the care of these infants has profound long-term consequences for these infants and their families. In circumstances when it is unclear whether intensive care should be initiated or continued, evidence-based ethics provides an approach to facilitate treatment decisions that over time will be progressively better informed, better justified, and more broadly acceptable to parents, caregivers, and the general public.

Perinatal substance abuse intervention in obstetric clinics decreases adverse neonatal outcomes

OBJECTIVE

To evaluate the effect of Early Start, a managed care organization's obstetric clinic-based perinatal substance abuse treatment program, on neonatal outcomes.

STUDY DESIGN

Study subjects were 6774 female Kaiser Permanente members who delivered babies between July 1, 1995 and June 30, 1998 and were screened by completing prenatal substance abuse screening questionnaires and urine toxicology screening tests. Four groups were compared: substance abusers screened, assessed, and treated by Early Start ("SAT," n=782); substance abusers screened and assessed by Early Start who had no follow-up treatment ("SA," n=348); substance abusers who were only screened ("S," n=262); and controls who screened negative ("C," n=5382).

RESULTS

Infants of SAT women had assisted ventilation rates (1.5%) similar to control infants (1.4%), but lower than the SA (4.0%, p=0.01) and S groups (3.1%, p=0.12). Similar patterns were found for low birth weight and preterm delivery.

CONCLUSION

Improved neonatal outcomes were found among babies whose mothers received substance abuse treatment integrated with prenatal care. The babies of SAT women did as well as control infants on rates of assisted ventilation, low birth weight, and preterm delivery. They had lower rates of these three neonatal outcomes than infants of either SA or S women.

Preterm delivery

Preterm delivery and its short-term and long-term sequelae constitute a serious problem in terms of mortality, disability, and cost to society. The incidence of preterm delivery, which has increased in recent years, is associated with various epidemiological and clinical risk factors. Results of randomised controlled trials suggest that attempts to reduce these risk factors by use of drugs are limited by side-effects and poor efficacy. An improved understanding of the physiological pathways that regulate uterine contraction and relaxation in animals and people has, however, helped to define the complex processes that underlie parturition (term and preterm), and has led to new scientific approaches for myometrial modulation. The continuing elucidation of the mechanisms that regulate preterm labour, combined with rigorous clinical assessment, offer hope for future solutions.

Evidence of selection bias in preterm survival studies: a systematic review

OBJECTIVE

To determine by how much selection bias in preterm infant cohort studies results in an overestimate of survival.

DESIGN

Systematic review of studies reporting survival in infants less than 28 weeks of gestation published 1978-1998. Studies were graded according to cohort definition: A, stillbirths and live births; B, live births; C, neonatal unit admissions. Proportions of infants surviving to discharge were calculated for each week of gestation.

RESULTS

Sixty seven studies report data on 55 cohorts (16 grade A, 23 grade B, 16 grade C). Studies that are more selective report significantly higher survival between 23 and 26 weeks of gestation (grade C > grade B > grade A, p < 0.01), exaggerating survival by 100% and 56% at 23 and 24 weeks respectively.

CONCLUSION

To minimise the potential for overestimating survival around the limits of viability, future studies should endeavour to report the outcome of all pregnancies for each week of gestation (terminations, miscarriages, stillbirths, and all live births).

The EPICure study: outcomes to discharge from hospital for infants born at the threshold of viability

OBJECTIVE

To evaluate the outcome for all infants born before 26 weeks of gestation in the United Kingdom and the Republic of Ireland. This report is of survival and complications up until discharge from hospital.

METHODOLOGY

A prospective observational study of all births between March 1, 1995 and December 31, 1995 from 20 to 25 weeks of gestation.

RESULTS

A total of 4004 births were recorded, and 811 infants were admitted for intensive care. Overall survival was 39% (n = 314). Male sex, no reported chorioamnionitis, no antenatal steroids, persistent bradycardia at 5 minutes, hypothermia, and high Clinical Risk Index for Babies (CRIB) score were all independently associated with death. Of the survivors, 17% had parenchymal cysts and/or hydrocephalus, 14% received treatment for retinopathy of prematurity (ROP), and 51% needed supplementary oxygen at the expected date of delivery. Failure to administer antenatal steroids and postnatal transfer for intensive care within 24 hours of birth were predictive of major scan abnormality; lower gestation was predictive of severe ROP, while being born to a black mother was protective. Being of lower gestation, male sex, tocolysis, low maternal age, neonatal hypothermia, a high CRIB score, and surfactant therapy were all predictive of oxygen dependency. Intensive care was provided in 137 units, only 8 of which had >5 survivors. There was no difference in survival between institutions when divided into quintiles based on their numbers of extremely preterm births or admissions.

CONCLUSIONS

This study provides outcome data for this geographically defined cohort; survival and neonatal morbidity are consistent with previous data from the United Kingdom and facilitate comparison with other geographically based data.

Outcomes of children of extremely low birthweight and gestational age in the 1990s

Advances in perinatal care have improved the chances for survival of extremely low birthweight (<800 grams) and gestational age (<26 weeks) infants. A review of the world literature reveals that among regional populations, survival at 23 weeks' gestation ranges from 2 to 35%, at 24 weeks' gestation 17 to 62% and at 25 weeks' gestation 35 to 72%. These wide variations may be accounted for by differences in population descriptors, in the criteria used for starting or withdrawing treatment, in the reported duration of survival and differences in care. Major neonatal morbidity increases with decreasing gestational age and birthweight. At 23 weeks' gestation, chronic lung disease occurs in 57 to 86% of survivors, at 24 weeks in 33 to 89% and at 25 weeks' gestation in 16 to 71% of survivors. The rates of severe cerebral ultrasound abnormality range from 10 to 83% at 23 weeks' gestation, 9 to 64% at 24 weeks and 7 to 22% at 25 weeks' gestation Of 77 survivors at 23 weeks' gestation, 26 (34%) have severe disability (defined as subnormal cognitive function, cerebral palsy, blindness and/or deafness). At 24 weeks' gestation, the rates of severe neurodevelopmental disability range from 22 to 45%, and at 25 weeks' gestation 12 to 35%. When compared with children born prior to the 1990s, the rates of neurodevelopmental disability have, in general, remained unchanged. We conclude that, with current methods of care, the limits of viability have been reached. The continuing toll of major neonatal morbidity and neurodevelopmental handicap are of serious concern.

Health status of a population of infants born before 26 weeks gestation derived from routine data collected between 21 and 27 months post-delivery

This retrospective study was designed: (a) to determine the extent to which routine data sources in the UK can provide data relating to the later health status of selected groups of infants; and (b) to use such an approach to describe the outcome of a geographically defined population of infants born before 26 weeks gestation. All infants of less than 26 weeks gestation admitted for neonatal intensive care during the period 1/1/91 and 31/12/93 whose mother's address at the time of birth was within the boundaries of the Trent Health Region were included. Health status was assessed against a previously described simple scheme and using information from existing sources only. During the 3-year period 249 infants of less than 26 weeks gestation were admitted for intensive care. Of these 66 (26.5%) survived to be discharged from the neonatal service. A further seven infants died before the age of 2 years. Of the remaining 59 four were lost to follow up (three could not be traced; one was living abroad). Of the 55 infants reviewed, 36 demonstrated no features, pre-defined in the classification scheme, of severe disability. However, only 30 children appeared to be considered entirely normal.

CONCLUSION

Infants born before 26 weeks gestation and admitted for neonatal intensive care had, approximately, a 12% chance of normal survival to 2 years. A slightly smaller proportion of infants survived with significant disability. Existing routine data sources could be adapted to provide useful public health information about the outcome of 'high risk' groups of infants.

Outcomes of children of extremely low birthweight and gestational age in the 1990's

Advances in perinatal care have improved the chances for survival of extremely low birthweight (< 800 g) and gestational age (< 26 weeks) infants. A review of the world literature and our own experience reveals that at 23 weeks gestation survival ranges from 2% to 35%. At 24 weeks gestation the range is 17% to 58%, and at 25 weeks gestation 35% to 85%. Differences in population descriptors, in the initiation and withdrawal of treatment and the duration of survival considered may account for the wide variations in the reported ranges of survival. Major neonatal morbidity increases with decreasing gestational age and birthweight. The rates of severe cerebral ultrasound abnormality range at 23 weeks gestation from 10% to 83%, at 24 weeks from 17% to 64% and at 25 weeks gestation from 10% to 22%. At 23 weeks gestation, chronic lung disease occurs in 57% to 70% of survivors, at 24 weeks in 33% to 89%, and at 25 weeks gestation in 16% to 71% of survivors. When compared to children born prior to the 1990's, the rates of neurodevelopmental disability have, in general, remained unchanged. Of 30 survivors reported at 23 weeks gestation nine (30%) are severely disabled. At 24 weeks gestation the rates of severe neurodevelopmental disability (including subnormal cognitive function, cerebral palsy, blindness and deafness) range from 17% to 45%, and at 25 weeks gestation 12% to 35% are similarly affected. In Cleveland, Ohio, we compared the outcomes of 114 children with birthweight 500-749 g born 1990-1992 to 112 infants born 1993-1995. Twenty month survival was similar (43% vs 38%). The use of antenatal and postnatal steroids increased (10% vs 54% and 43% vs 84%, respectively, P< 0.001), however the rates of chronic lung disease increased from 41% to 63% (P = 0.06). There was a significant increase in the rate of subnormal cognitive function at 20 months corrected age (20% vs 48%, P < 0.02) and a trend to an increase in the rate of cerebral palsy (10% vs 16%) and neurodevelopmental impairment. We conclude that, with current methods of care, the limits of viability have been reached. The continuing toll of major neonatal morbidity and neurodevelopmental handicap are of serious concern.

Are neonatal brain lesions due to intrauterine infection related to mode of delivery?

Studies of antenatal and intrapartum factors involved in the development of cerebral palsy have identified intrauterine infection and chorioamnionitis as high risk situations for white matter damage, especially periventricular leukomalacia. To characterise adverse or protective perinatal factors further, we undertook a multiple regression analysis of selected perinatal events in a population of 110 inborn premature neonates with documented chorioamnionitis. In the total population of 110 infants delivered at between 25 and 32 weeks, 101 (92%) survived the first week of life and two were subsequently excluded. Of the 99 remaining infants, 20 (20%) developed periventricular leukomalacia including 16 (80%) cystic lesions. Forty-five (45%) babies were born by lower segment caesarean section, and for 37 of these, this was carried out before labour. Fetal presentation at delivery was breech in 14 (26%) of those born vaginally and 23 (52%) of those born by lower segment caesarean section (OR 3 [95% CI 1.3-7]). Among predetermined perinatal risk factors for periventricular leukomalacia, logistic regression analysis showed that delivery by caesarean section was associated with a dramatic decrease in the incidence of periventricular leukomalacia (OR 0.15 [95% CI 0.04-0.57]). These preliminary results warrant confirmation and preferably a prospective study before considering caesarean section as a protective perinatal factor of periventricular leukomalacia.