
* Confidential Enquiry Into Maternal and Child Health (CEMACH) Central Office, London, United Kingdom
Medical Statistics Unit, Department of Epidemiology and Public Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
| ABSTRACT |
|---|
|
|
|---|
Methods. A case-control study was conducted of infants who were born at 27 and 28 weeks' gestation in England, Wales, and Northern Ireland during a 2-year period. Cases were neonatal deaths; control subjects were randomly selected survivors at day 28. Main outcome measures were failures of prespecified standards of care or deficiencies in care reported by regional panels assessing anonymized medical records.
Results. Failures of standards of care relating to ventilatory support (adjusted odds ratio [OR]: 3.29; 95% confidence interval [CI]: 1.975.49), cardiovascular support (OR: 2.37; 95% CI :1.364.13), and thermal care (OR: 1.71; 95% CI: 1.212.43) were associated with neonatal death. Frequencies of unmet resuscitation standards (range: 3%46%) and of delays in surfactant administration (range: 38%40%) were similar in cases and control subjects. Panels identified significantly more deficiencies in all aspects of neonatal care in cases with the exception of the management of infection. Stratification by clinical condition of infants at birth showed a stronger association between overall standard of care and death when infants were in a good condition at birth.
Conclusions. Our findings suggest an association between quality of neonatal care and neonatal deaths, most marked for early thermal care and ventilatory and cardiovascular support. Poor overall quality of care was more strongly associated with deaths when the infant was in a good condition at birth.
Key Words: epidemiology neonatology
Abbreviations: CESDI, Confidential Enquiry into Stillbirths and Deaths in Infancy OR, odds ratio CI, confidence interval PPROM, preterm premature rupture of membrane CRIB, clinical risk index for babies
Prematurity (birth before 37 weeks' gestation) accounts for 13% of registrable births in the United Kingdom1 and is the major cause (47%) of neonatal deaths.2 As such, it was chosen in 1997 to be the focus for the national Confidential Enquiry into Stillbirths and Deaths in Infancy (CESDI) program. CESDI, which is now the Confidential Enquiry into Maternal and Child Health, makes national recommendations from its findings aimed at improving the care of these immature infants.3
In the early to mid-1990s, premature infant survival rates in United Kingdom were 39% below 26 weeks' gestation and rose to nearly 80% by 28 weeks and 100% at 36 weeks.1,46 National data in 19982000 showed survival rates at 27 weeks' gestation of 86% and of 90% at 28 weeks.2 We hypothesized that, particularly at these gestations, standards of care may have an effect on survival. This project therefore focused on the maternity and neonatal care of infants who were born between 27 weeks and 0 days (27 + 0) and 28 weeks and 6 days (28 + 6) of gestation, hence the title "Project 27/28."7 The aim of Project 27/28 was to identify variations in standards of antenatal care or neonatal care during the first week of life that might have contributed to death in preterm infants who were born at 27 and 28 weeks' gestation and to make recommendations for future practice on the basis of these findings. We report here on the neonatal findings of the project. Other details are available at www.cemach.org.uk/publications/p2728/mainreport.pdf.
| METHODS |
|---|
|
|
|---|
A case-control design was then used. Detailed information for the enquiry was sought about all the neonatal deaths (cases) and a random sample of infants who survived up to 28 days. Reference numbers for all infants recorded in the logbooks were held in a central database and categorized by gestational age and plurality of pregnancy. A computer program then randomly selected from these categories to ensure appropriate frequency. Infants with lethal congenital anomalies were excluded. For the purposes of comparing characteristics and risk factors of mothers, 2 groups of mothers were also defined: (1) mothers of singleton or multiple births who all survived to day 28 and (2) mothers of singletons who died or of multiple births when 1 or more infants died before day 28.
The "exposure" was the departure from preset standards of care and panel assessments of deficiencies in care received by infants during the first week of life. Standards of care were preset by a group of 18 senior perinatal clinicians, academics, and epidemiologists (the Project 27/28 working group), who met in 1998 to define standards for the enquiry.8 Not all topics had well-established evidence-based standards. When strong evidence was absent, such as for resuscitation or ventilatory care, the working group set standards using national best practices or guidelines recommended by professional bodies and published either in national reports or in journals (see Appendix, references 3136). Panels reviewed the case notes and considered whether any aspects of neonatal care were substandard. The areas assessed were resuscitation at birth, early thermal care, surfactant therapy, ventilatory and cardiovascular support, management of early and late infection, overall organization of care, and ex utero transfer. Panels were asked each time they identified a deficiency in care to describe it by free text (available at www.cemach.org.uk). At the end of each enquiry, panels were asked to grade the overall obstetric and neonatal care received as good, acceptable, substandard minor, or substandard major. Crude odds ratios (OR) for neonatal death were calculated (with their 95% confidence intervals [CIs]) for different standards of care when poor care was defined as (1) departure from 1 of 10 preestablished standards of neonatal care and (2) as deficiencies in care as recognized by panels' opinion.
|
Obstetric members of the panels were blinded to the outcome, but pediatric members were not, as blinding was not feasible for the assessment of care after the delivery of the infant. They nevertheless applied strictly defined criteria of assessment (available at www.cemach.org.uk).
Recording and collating "opinion" about the quality of patient care is complex. The panel judgments in these enquiries reflect individual health professionals' opinions; therefore, variation in responses is likely. This study built on the experience gained from previous exercises, which used a "second-pass" panel approach, whereby the same case was reviewed by 2 panels separately. These exercises had shown that there could be striking differences in opinion between panels.8,9 As a consequence, the method of Project 27/28 was modified: a structured approach was used with specific questions to the panels, standard documents, clearly predefined standards, and a grading system. A second-pass panel to assess the robustness of the Project 27/28 enquiry was set up for 92 cases and control subjects. Five to 6 second-pass panels were held in each region, and at least 1 neonatologist was available on each panel (range: 13).
Statistical Methods
Differences in categorical variables and trends were compared using the
2 test and in continuous variables using the Student's t test or the Mann-Whitney U test as appropriate. The
statistic was used to define agreement between panels 1 and 2. A
>.6 was considered as good or very good agreement, .4 to .6 as moderate, .2 to .4 as fair, and <.2 as poor.10
Regardless of the quality of care, there are likely to be inherent differences between infants who do and do not survive: sicker infants are more at risk for a poor outcome regardless of the type of care that they receive. We therefore adjusted the analysis to take into account illness severity by using male gender, birth weight
5th centile, and the clinical condition of the infant at 5 minutes of life (defined as absent or ineffective respiration or a persistent heart rate below 100 beats per minute). Because no difference was found in terms of survival across different types of units where mothers and infants were treated,2 no adjustment by types of units was made. Adjusted ORs were obtained using multiple logistic regression, and significance was assessed using the likelihood ratio test.
Sicker infants may also need more medical intervention with the potential for more substandard care or errors. This hypothesis was explored by looking at the interaction between outcomes and standards of care for infants who were considered to be in poor or in good clinical condition at 5 minutes of life. There were varying amounts of missing data for the risk factors and standards, which are indicated in the tables as "not known."
| RESULTS |
|---|
|
|
|---|
|
|
There was more antenatal ultrasound evidence of fetal compromise and of poor fetal growth <5th centile and more urgent cesarean sections (for a clinical situation of impending fetal death) performed in the group of infants who died (Table 3). Infants who died had lower birth weight and were more likely to be male and to have nonlife-threatening congenital malformations (Table 3). All of the recorded parameters reflecting the infants' initial condition (Apgar score, cord pH, temperature, and blood pressure in the first 12 hours; clinical risk index for babies [CRIB] score8) showed that infants who died had been in poorer condition at birth (Table 3).
|
Standards of Neonatal Care
Neonatal standards are described in the Appendix, and patterns of standards of care are summarized in Table 4. There was a high proportion of cases for which these standards were not met.
|
Although most (96%) infants received surfactant, administration within 1 hour after birth was not achieved in 38% of cases and 40% of control subjects. The timing of administration of the first dose of surfactant was similar for infants who died and those who survived at different time ranges (eg, 43% of cases and 40% of survivors received surfactant within half an hour; data not shown). However, exposure to poor care in early resuscitation and surfactant administration was not associated with a significantly increased risk for dying in the study.
Poor care in relation to 3 neonatal standards was associated with a significantly increased risk for dying: temperature control, ventilation, and cardiovascular support. Thus, a temperature
36.0°C on admission to the neonatal unit was reported in two thirds of all infants (73% of infants who died and 59% of control subjects) and was associated with a 70% increased risk for death. Poor ventilatory and cardiovascular standards were defined as failure to monitor or properly document blood gases or blood pressure and failure to make therapeutic adjustment to maintain blood gases or blood pressure within predefined limits (Appendix). Standards of cardiovascular support failed to be achieved in 15% of infants who died and 7% of control subjects. Similarly, there was a failure to achieve adequate ventilatory support in 20% of infants who died and 7% of control subjects, and this was associated with a 2- to 3-fold increase in the risk for death.
Panels' Opinion of Deficiency of Neonatal Care
Except for the management of infection, deficiencies in the standards of care were identified for between 7% and 51% of infants, and these were consistently and significantly more frequent in cases than in control subjects (Table 5).
|
|
|
| DISCUSSION |
|---|
|
|
|---|
In keeping with the findings of others,14,15 mothers whose infants died were characterized by a lower incidence of preterm labor and earlier PPROM than control subjects. Bacteriuria was less frequent among mothers of infants who died, possibly because of its association with spontaneous preterm labor.16 The marked similarities between the maternal groups (Table 2) highlighted the difficulties of identifying the mother of an "at risk" infant before delivery. There were 3 notable differences between the mothers of infants who were born at 27 and 28 weeks' gestation compared with the general British maternity population: (1) there were more multiple births17; (2) there was a higher proportion of smokers17; and (3) there was a different distribution of ethnicity (not shown in Table 2): the study population comprised 79% white, 9% black, 8% Asian, and 5% others, compared with the general maternity population, which comprised 91% white, 2% black, 3% Asian, 1% mixed, and <1% others.18 In contrast to the maternal characteristics, there were multiple differences between the 2 groups of infants studied, which are shown in Table 3.
Population characteristics may affect outcome,19,20 and a variety of measures may be used to adjust for differences in risk-specific hospital performance. It was believed to be inappropriate to use the CRIB score,21 which is based on routine data recorded within 12 hours of life and can be used to describe risk-adjusted mortality, because it is partly dependent on early management.2123 Furthermore, infants for whom the CRIB score was recorded were unrepresentative of the whole group in that they were older when they died and had higher Apgar scores and lower systolic blood pressure. Because other measures of illness severity may also be affected by inadequate care,2123 we restricted adjustments in this study to the infant's gender, birth weight, and clinical condition within 5 minutes of birth. We considered the proportion of infants who were in poor clinical condition at 5 minutes of age in different neonatal settings where they were treated and found no significant differences (test for trend with tertiary units as reference: P = .26, data available but not shown).
There was a high proportion of cases overall for whom standards of neonatal care were not met (Table 4). However, exposure to poor care in early resuscitation and surfactant administration were not associated with a significantly increased risk for dying in the study. This might be a true finding or a consequence of a lack of power of the study, which had sufficient power to detect only differences between cases and control subjects of >7% in the proportion exposed to poor care at a 5% significance level.24 Our findings relating to delayed surfactant administration were similar to those from the Vermont-Oxford network during the same study period 19982000,25 and the conclusion of that study that there was a gap between the evidence from randomized trials and clinical practice may also apply to the United Kingdom.25 Overall, there was a high proportion of poor care in resuscitation and late surfactant administration, which, even if not directly causing death, might have had an impact on the quality of survival.
A significantly increased risk for dying was associated with poor-quality neonatal care in 3 areas (temperature control, ventilation, and cardiovascular support). Although hypothermia may indicate a preterminal condition rather than poor care, when the infants who died in the first 24 hours were removed from the analysis, a low admission temperature was still associated with death. The strength of the association (OR: 1.71) between hypothermia
36°C on admission to the neonatal unit and death in this study of infants who were born at 27 and 28 weeks' gestation was similar to that found by the EPICure study of infants <26 weeks' gestation when a cutoff point of
35°C was used4 and emphasizes the importance of good temperature control for these small infants.
The condition of an infant at 5 minutes of age is a marker of illness severity and of the amount of resuscitation required and hence of cold exposure. After adjustment for the condition of the infant 5 minutes after birth, there were only minor changes in ORs (from 1.91 to 1.71), but mortality was reduced when the incubator temperature was adjusted to maintain an anterior abdominal skin temperature above 36°C.26 This standard therefore remains an objective of good care in very preterm infants. Simple measures, such as occlusive wrapping in the delivery room, improve early temperature control in infants who are born at <28 weeks' gestation.27,28 An appropriate environmental temperature is also important, and the temperature of the delivery room should be at least 25°C.29
Three limitations of this study need to be considered. First, the proxy measure chosen for adjustment for illness severity might not properly reflect disease severity. Adjustment for illness severity resulted in only minor changes in ORs, and increased exposure of sicker infants to substandard care or errors may have had only a limited effect on the association between death and standards of care. In considering the possibility that substandard care and errors might be reduced by the presence of a senior clinician, we found that consultants (attending physicians) were more likely to be present at the resuscitation of sick infants (data available, not shown). This observation may explain the tendency for substandard care in resuscitation to be less frequently observed in infants who died than in those who survived (Table 4). The hypothesis that there was a bias because sicker infants were more likely to be exposed to potential errors was explored by looking at the interaction among outcome, clinical condition at birth, and standard of care. There was an increased risk for dying when infants who were in good condition were exposed to a lower overall grade of care compared with infants who were in poor clinical condition at birth (Tables 6 and 7).
A second potential limitation is that appraising the standard of care was difficult in the absence of a strong evidence base or easily measured criteria (Appendix). For instance, evidence for recommending the timing of prophylactic surfactant at 27 and 28 weeks' gestation was lacking at the time the Project 27/28 working group convened before the study. The cutoff of 1 hour after birth was chosen to define delay because a UK neonatal staffing study30 had observed that surfactant was more likely to be administered within the first hour after delivery in well-staffed units of medium activity, where guidelines stated that prophylaxis should be given as soon as possible after birth. A standards document was compiled by the Project 27/28 Working Group2,8 to guide panel members and to improve the consistency of the assessment process. Analysis of the second-pass panel results suggested an overall robustness and consistency by the enquiry panels, especially when quantitative criteria were available.
A third potential limitation of the study was that pediatric members of the panels were not blind to the outcome. The knowledge that an infant had died may also have resulted in more stringent assessment of the quality of care that was given to infants who died. However, panels followed a strict protocol and had to justify their opinions using free text; most comments related to areas of care, such as ventilatory care, for which there was a strong association between poor care and death.
| CONCLUSIONS |
|---|
|
|
|---|
| ACKNOWLEDGMENTS |
|---|
| FOOTNOTES |
|---|
Reprint requests to (D.A.) Confidential Enquiry into Maternal and Child Health (CEMACH) Central Office, 188 Baker St, London NW1 5SD. E-mail: dominique.acolet{at}cemach.org.uk
No conflict of interest declared.
| REFERENCES |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
A M Groves, C A Kuschel, D B Knight, and J R Skinner Echocardiographic assessment of blood flow volume in the superior vena cava and descending aorta in the newborn infant Arch. Dis. Child. Fetal Neonatal Ed., January 1, 2008; 93(1): F24 - F28. [Abstract] [Full Text] [PDF] |
||||
![]() |
N. Marlow and A Bryan Gill Establishing neonatal networks: the reality Arch. Dis. Child. Fetal Neonatal Ed., March 1, 2007; 92(2): F137 - F142. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||