PEDIATRICS Vol. 106 No. 5 November 2000, pp. 1070-1079

Variations in Practice and Outcomes in the Canadian NICU Network: 1996-1997

Shoo K. Lee, MBBS, FRCPC, PhD^*, , Douglas D. McMillan, MD, FRCPC^§, Arne Ohlsson, MD, FRCPC, MSc, Margaret Pendray, MBBS, FRCPC^*, Anne Synnes, MDCM, FRCPC, MHSc^{*, ¶}, Robin Whyte, MBBS, FRCPC^#, Li-Yin Chien, MPH, ScD^*, , Joanna Sale, MSc, and the Canadian NICU Network^**

From the ^* Department of Pediatrics, University of British Columbia, British Columbia, Canada;  Centre for Community Health and Health Evaluation Research, British Columbia, Canada; ^§ Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada;  Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; ^¶ Department of Pediatrics, McGill University, Montréal, Quebec, Canada; and the ^# Department of Pediatrics, Dalhousie University, Nova Scotia, Canada.

	ABSTRACT

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Background.  Previous reports of variations in outcomes among neonatal intensive care units (NICUs) examined only specific subpopulations of interest (eg, very low birth weight [VLBW] infants <1500 g of birth weight [BW]).

Objectives.  We report on current practice and outcomes variations in a population-based national study of Canadian NICUs from January 8, 1996 to October 31, 1997.

Method.  Information on 20 488 admissions to 17 tertiary level NICUs across Canada was prospectively collected by trained abstractors using a standard manual of operations and definitions. Data were verified and analyzed in concert with a steering committee comprising experienced researchers and neonatologists. Patient information included demographic information, antenatal history, mode of delivery, problems at delivery, status of infant and problems at birth, illness severity (Clinical Risk Index for Babies, Score for Neonatal Acute Physiology, Score for Neonatal Acute Physiology-Version II), therapeutic intensity (Neonatal Therapeutic Intensity Scoring System [NTISS]), selected NICU practices and procedures, use of technology and resources, and selected patient outcomes. Patients were tracked until death or discharge home.

Results.  The mean number of annual admissions to an NICU was 657, with 26% outborn infants. Fifty-three percent were <2500 g BW, 20% were <1500 g BW (VLBW), and 65% were preterm (<38 weeks' gestational age [GA]). Only 2% of mothers received no prenatal care. Antenatal steroids were given to 58%, but there was wide variation in use (23%-76%). Congenital anomalies were present in 14%, and 4% were small for GA (less than the third percentile). Admission illness severity was lowest among infants 33 to 37 weeks of GA and correlated with risk of death. Ninety-six percent of patients survived until discharge, but fewer survived at lower GA. No infant <22 weeks' GA survived. Seven percent of infants had at least 1 episode of infection, but 75% received antibiotics in the NICU. Forty-three percent received respiratory support, and 14% received surfactant. Nitric oxide was given to 150 term infants and to 102 preterm infants. Selected outcomes of VLBW infants were: survival rate (87%); chronic lung disease (26%); stage 3 retinopathy of prematurity (ROP; 11%); grade 3 intraventricular hemorrhage (IVH; 10%); nosocomial infection (22%); necrotizing enterocolitis (NEC; 7%). Sixty-nine percent of VLBW infants survived without major morbidity (grade 3 IVH, chronic lung disease, NEC, grade 3 ROP). The mean duration of NICU stay was 19 days. Forty-seven percent of infants were discharged from the hospital, and 43% were retrotransferred to a community facility before discharge home. Significant variation in practices and outcomes were observed in all aspects of NICU care.

Conclusion.  This study provides population-based information about NICU outcomes. Significant variation in NICU practices and outcomes was observed despite Canada's universal health insurance system. This national database provides valuable information for planning research, allocating resources, designing health and public policy, and serving as a basis for longitudinal studies of NICU care in Canada.  Key words:  neonatal intensive care unit, variations, practice, outcomes.

Advances in neonatal intensive care have significantly increased survival and decreased morbidity among infants admitted to neonatal intensive care units (NICUs).^1-5 There are, however, significant variations in outcomes among NICUs.^6,7 Unfortunately, most reports examine only specific subpopulations of interest (eg, very low birth weight [VLBW] infants weighing 1500 g at birth) and are not population-based.^2,3,6,7 The purpose of this study was to create a national population-based database, which could be used to explore ways of improving quality of care in Canadian NICUs.

Canada has universal health insurance coverage, which may increase access to health care and decrease variation in practices and outcomes. However, it also has a highly regionalized system of neonatal-perinatal care, which may increase variation in practices and outcomes between regions. In 1995 the Canadian NICU Network was funded by the Medical Research Council of Canada to establish a standardized national database of practices and outcomes in tertiary level regional NICUs throughout all provinces in Canada, to examine variations in outcomes, and to explore potential ways of improving efficiency and efficacy of treatment in Canadian NICUs. In 1996 Canada had a population of nearly 30 million people⁸ and had over 357 000 births.⁹ The 17 NICUs in the Canadian NICU Network include 75% of all tertiary level NICU beds in Canada and serve a population of ~22 million people. All NICUs, except one, were tertiary level regional NICUs. We report the patient characteristics and selected summary outcomes of admissions to 17 NICUs in Canada during a 21-month period from January 1996 to October 1997. This report profiles the current state of NICU outcomes and practices in Canada and serves as a reference for future reports, which will examine specific outcomes in depth.

	METHODS

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Participating Hospitals

Participating hospitals (Table 1) represent all geographic regions of Canada. Children's Hospital of Eastern Ontario and Ottawa General Hospital were considered as one collaborating center because they are an integrated neonatal-perinatal facility serving the same geographic region. During the study, the Children's Hospital of British Columbia and the Women's Hospital of British Columbia were merged into the Children's and Women's Health Center of British Columbia and were considered as an integrated neonatal-perinatal facility. There were 349 NICU beds (range: 2-45) and 286 intermediate level and continuing care neonatal beds (range: 0-45) in the 17 NICUs. Medical staffing included 96 full-time equivalent (FTE) neonatologists, 76 FTE housestaff (including clinical assistants, neonatal fellows, and pediatric residents), and 31 FTE neonatal nurse practitioners/clinical nurse specialists. Three NICUs did not employ housestaff, and only 6 NICUs used neonatal nurse practitioners/clinical nurse specialists. Four NICUs admitted only outborn infants. General surgery was available in 13 hospitals, cardiac surgery in 9 hospitals, extracorporeal membrane oxygenation (ECMO) in 3 hospitals, and cryotherapy/laser therapy in 11 hospitals. In some hospitals, infants needing general surgery and cardiac surgery were admitted to surgical or pediatric intensive care units instead of NICUs.

Study Population

The study population included 20 488 admissions to the 17 NICUs participating in the Canadian NICU Network during a 22-month period from January 8, 1996 to October 31, 1997 (Table 2). An admission was defined as stay in the NICU for at least 24 hours or death/transfer to another NICU within 24 hours. Eleven admissions were not included because the patients were not yet discharged from hospital at the time the database was closed on June 30, 1998. Readmissions and transfers were tracked as data from the same infant. After accounting for readmissions and transfers, there were 19 507 infants among the 20 488 admissions.

Data Abstraction

Trained research assistants abstracted patient information from the charts of the mothers and infants at each participating hospital on a daily basis. Data were directly entered into laptop computers at the bedside, using a customized data entry program with built-in error checking and a standard manual of operations and definitions. Data were electronically transmitted to the Center for Community Health and Health Evaluation Research, at the British Columbia Research Institute for Children's and Women's Health, for verification. Site research assistants rechecked potential data errors. Data management was conducted by the Center for Community Health and Health Evaluation Research in concert with a steering committee comprising experienced researchers and neonatologists representing each of the 5 geographic regions (British Columbia, Prairie provinces, Ontario, Quebec, and Atlantic provinces) in Canada, and with site investigators representing each of the 17 participating hospitals. Patient information was collected until death or discharge from the NICU. Patients transferred to another hospital were tracked until death or discharge home and outcome information was collected. Data analysis was performed using each infant rather than each admission.

Patient Information

Patient information included demographic information, antenatal history, mode of delivery and problems at delivery, status of infant and problems at birth, illness severity (Clinical Risk Index for Babies [CRIB],¹⁰ Score for Neonatal Acute Physiology [SNAP],¹¹ and Score for Neonatal Acute Physiology-Version II [SNAP-II]¹²), therapeutic intensity (Neonatal Therapeutic Intensity Scoring System [NTISS]¹³), selected NICU practices and procedures, use of technology and resources, and selected patient outcomes. Information on outcomes of all live-born deliveries from 22 to 25 weeks of gestational age (GA) was also obtained at participating hospitals. Transport teams were asked to complete the Alberta Neonatal Transport Score¹⁴ when the transport team first arrived at the transferring hospital and immediately after the transport team arrived at the destination hospital.

Variable Definitions

Study variables were defined according to the Canadian NICU Network SNAP Project Abstractor Manual. GA was defined as the best obstetric estimate based on early prenatal ultrasound, obstetric examination, and obstetric history, unless the postnatal pediatric estimate of gestation differed from the obstetric estimate by >2 weeks. In that case, the pediatric estimate of GA based on the Ballard Score¹⁵ was used instead. An infant was defined as small for GA (SGA) if the birth weight (BW) was less than the third percentile for GA according to the British Columbia provincial growth charts established by Whitfield¹⁶ in 1992 for the Canadian population. Prenatal care was defined as receipt of pregnancy-related care from a physician on at least one occasion (not related to a visit for diagnosis of pregnancy) during pregnancy. SNAP-II¹² is a neonatal illness severity score calculated from 6 empirically weighted physiologic measurements made during the first 12 hours of admission to the NICU. NTISS¹³ is a score of neonatal therapeutic intensity calculated from a checklist of 63 NICU therapies used in a 24-hour period, weighted according to invasiveness and cost. Chronic lung disease (CLD) was defined as oxygen dependency at 36 weeks' corrected GA (CGA) for an infant who was born at 32 weeks' gestation.¹⁷ Intraventricular hemorrhage (IVH) was defined according to the criteria of Papile et al¹⁸ from head ultrasound performed before 14 days of life. Necrotizing enterocolitis (NEC) was defined according to the criteria of Bell et al¹⁹ (stage 2 or higher) and was classified as medical (clinical symptoms and signs plus evidence of pneumatosis on abdominal radiographs) or surgical (histologic evidence of NEC on surgical specimen of intestine). Retinopathy of prematurity (ROP) was defined according to the International Classification for Retinopathy of Prematurity²⁰ and the Reese Classification of cicatrical disease.²¹ Nosocomial infection was defined using blood and cerebrospinal fluid (CSF) culture results according to criteria by Freeman et al.²² Patent ductus arteriosus (PDA) was defined as clinical diagnosis plus treatment with indomethacin or surgical ligation or both. Seizures were defined as clinically significant episodes witnessed by a nurse or physician and for which anticonvulsant treatment was given. Congenital anomalies were classified according to the International Classification of Diseases, Ninth Revision of the World Health Organization.²³

	RESULTS

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Patient Profile

Table 2 shows the perinatal risks and patient characteristics of the study population. Missing data for each variable ranged from .6% to 2% (except for prenatal care [6%] and maternal hypertension [7%]). The mean number of annual admissions to a participating NICU was 657 (range: 133-1129). Overall, 26% of infants admitted were outborn, with the highest prevalence among term infants (37%).

BW Distribution Figure 1A shows the distribution of all infants admitted by BW. Fifty-three percent (n = 9361) were <2500 g of BW (low BW) and 20% (n = 3779) were <1500 g of BW (VLBW).

View larger version (56K): [in this window] [in a new window]   Fig. 1.   A, NICU population distribution by BW. B, NICU population distribution by GA.

GA Distribution Figure 1B shows the distribution of all infants admitted by GA. Sixty-five percent (n = 12 592) were preterm (<38 weeks' GA) and 2% (n = 396) were 24 weeks' GA.

Perinatal Risks

Prenatal Care Two percent (range: 1%-8%) of mothers with infants admitted to the NICU received no prenatal care before delivery.

Maternal Hypertension/Preeclampsia

Maternal hypertension was reported in 13% of infants admitted to the NICU. The prevalence among preterm infants was 2.5 times higher than among term infants.

Antenatal Steroids Overall, 58% of infants 34 weeks' GA received antenatal steroids. There was wide variation in antenatal steroid use among participating centers (range: 23%-76%). Among those who received antenatal steroid treatment, 61% received a complete course of 2 doses before delivery.

Birth Presentation The prevalence of breech presentation increased with decreasing GA (5% at >37 weeks' GA, 16% at 33-37 weeks' GA, 27% at 28-32 weeks' GA, and 34% at <28 weeks' GA).

Mode of Delivery The overall cesarean section rate was 39%. Delivery by cesarean section was most prevalent among infants between 28 and 32 weeks' GA (50%) and least prevalent among term infants (31%) and infants 24 weeks' GA (21%).

Multiple Births Multiple birth was most prevalent among infants <33 weeks' GA (26%) and least prevalent among term infants (1.7%).

Apgar Score Less Than Seven at Five Minutes Fifteen percent of infants had Apgar scores <7 at 5 minutes. The prevalence was highest among infants <28 weeks' GA (39%) and >37 weeks' GA (16%).

Infant Characteristics

Sex More males (58%) than females were admitted to an NICU.

SGA Four percent of all admissions were SGA (weight less than the third percentile for GA). The prevalence was highest among infants at 28 to 32 weeks' GA (5%).

Congenital Anomalies Overall prevalence of congenital anomalies was 14%. The prevalence among term infants was 2.2 times that among infants 28 weeks' GA.

Admission Illness Severity

Mean admission day SNAP-II¹² was 6.9 (Table 3). Mean admission day illness severity was lowest among infants at 33 to 37 weeks' GA (SNAP-II: 4.2), but increased with higher (SNAP-II: 5.0 at >37 weeks' GA) and lower GA groups (SNAP-II: 21.5 at <28 weeks' GA). The mortality rate increased with increasing perinatal extension of SNAP-II¹² (Fig 2).

View larger version (27K): [in this window] [in a new window]   Fig. 2.   Mortality rate in the NICU related to admission day perinatal extension of SNAP-II.

Survival to Discharge From NICU

Overall, 96% (range: 89%-99%) of patients admitted to an NICU survived until discharge. Table 3 shows illness severity and selected practices and outcomes (by GA) for all NICU infants. The prevalence of missing data for each variable ranged from .6% to 2%. Figure 3 shows survival of infants admitted to the NICU until discharge by GA of the infant. Of admissions to NICUs, there were no survivors (n = 0/5) <22 weeks' GA. Intercenter variations in survival rates were largest among infants 24 weeks' GA (50% variation) and decreased with increasing GA.

View larger version (12K): [in this window] [in a new window]   Fig. 3.   Birth GA and survival of admitted infants until discharge from NICU.

Selected Outcomes and Practices

Bacterial Infection Seven percent of all infants had at least one episode of bacterial infection proven by positive blood or CSF culture (Table 3). Prevalence was highest among infants <28 weeks' GA (30%) and lowest among infants 33 to 37 weeks' GA (3%). However, adjustment for duration of hospitalization (ie, episodes of infection per 100 NICU patient days) significantly reduced the difference between the different GA groups. Only 25% of infants did not receive antibiotics at least once during their stay in the NICU.

Respiratory Support Forty-three percent of all NICU infants received assisted respiratory support (including mechanical ventilation and continuous positive airway pressure). The mean duration of assisted respiratory support increased with decreasing GA.

Surfactant Treatment Surfactant use was most prevalent among the most preterm infants (52% at <28 weeks' GA) and decreased with increasing GA (4% at term GA).

Nitric Oxide Treatment Nitric oxide was given to 150 term infants (2%) and to 102 preterm infants (1%) <37 weeks' GA.

Pneumothorax Pneumothorax occurred in 4% of infants but was most prevalent among term infants (6%) and infants <28 weeks' GA (6%).

ECMO ECMO was only used in infants over 32 weeks' GA. Sixty-six percent of the infants who received ECMO were >37 weeks' GA.

Surgery Surgery (excluding therapy for ROP) was performed in 11% of NICU infants. Prevalence was highest among infants <28 weeks' GA (31%) and lowest among infants 28 to 37 weeks' GA (8%).

Parenteral Nutrition Parenteral nutrition was used in 24% of all NICU infants but use was most prevalent among infants <28 weeks' GA (74%).

Blood Transfusion Thirteen percent of infants received at least 1 blood transfusion, with the prevalence rising from 5% in term infants to 73% in infants <28 weeks' GA.

Indwelling Catheter Use Arterial catheters were used in 27% of all infants in the NICU. Umbilical venous catheters were used in 18%, percutaneous long venous catheters in 8%, and surgically inserted central venous cathethers in 2% of NICU infants. Use of all types of catheters was more prevalent among infants of lower GA groups.

Selected Outcomes of VLBW (<1500 g of BW) Infants

Table 4 shows selected practices and outcomes for NICU infants <1500 g of BW. Prevalence of missing data for each variable ranged from .05% to 2%.

Survival Rate Survival rate for infants admitted to the NICU was 98% for infants 1500 g of BW, but 31% for infants <500 g of BW.

CLD Twenty-six percent of infants surviving to 36 weeks' CGA had CLD. The prevalence was inversely related to BW. Twenty-five percent (range: 1%-41%) of infants received postnatal steroids for CLD, and the prevalence increased with decreasing GA. Duration (days) of assisted ventilation increased with decreasing BW. A similar pattern was noted with duration (days) of supplemental oxygen.

ROP Fifty-three percent of infants <1500 g of BW had eye examinations for ROP before discharge or transfer from the NICU. Results of eye examinations conducted after retrotransfer to a community facility were not available. Of those with eye examination results available, 43% of infants <1500 g of BW developed ROP, but only 11% were stage 3 or higher, and only 3% required treatment. The prevalence of ROP and treatment for ROP increased with decreasing GA.

IVH Eighty-two percent of infants <1500 g of BW had cranial ultrasound examination before 14 days of life. Overall prevalence of IVH (any grade) was 32%. Grade 3 or higher IVH occurred in 10% and the prevalence increased with decreasing BW. Treatment with surgical shunts was required in 1%.

PDA Twenty-eight percent of infants developed PDA requiring treatment. Seventy-five percent were treated with indomethacin alone, 8% with surgical ligation alone, and 17% required both indomethacin and surgical ligation. Infants with lower BW were more likely to be treated surgically.

Nosocomial Infection Twenty-two percent of infants had at least 1 episode of nosocomial infection. The infection rate among infants <1000 g of BW was 2.2 times that among infants 1250 to 1499 g of BW.

NEC Four percent of infants developed medical NEC and 3% developed surgical NEC. The prevalence was higher in infants of lower GA.

Survival Without Major Morbidity (>Grade 3 IVH, CLD, NEC, or >Grade 3 ROP) Sixty-nine percent of infants <1500 g of BW who survived until discharge did not have major morbidity. The prevalence was 37% at <750 g of BW, 56% at 750 to 999 g of BW, 75% at 1000 to 1249 g of BW, and 86% at 1250 to 1499 g of BW.

Resource Consumption and Discharge Disposition

Table 5 shows resource consumption by GA group. Prevalence of missing data for each variable was <1%.

NTISS Score The mean NTISS score was 10 for term infants and increased to 20 among infants <28 weeks' GA (see Table 5).

Mean Duration of NICU Stay The mean duration of NICU stay until discharge home or transfer to a community hospital was 19 days (rising from 9 days for term infants to 60 days for infants <28 weeks' GA).

Mean GA at Discharge Mean GA at discharge was 39 weeks' CGA. It was lowest (37 weeks' CGA) for infants born at 29 to 36 weeks' GA and increased with lower (42 weeks' CGA for infants 24 weeks' GA at birth) and higher (41 weeks' CGA for infants born at term) GA.

Disposition at Discharge Forty-seven percent of NICU infants were discharged from the hospital. Forty-three percent were transferred to a community hospital and 6% were transferred to another level 3 hospital.

Special Support at Discharge At discharge home, 1% of infants were on some form of therapy with diuretics, methylxanthines, supplemental oxygen, or assisted respiration (continuous positive airway pressure or intermittent mandatory ventilation).

	DISCUSSION

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Canada has a highly regionalized system of neonatal-perinatal care.²⁴ Tertiary level NICU and perinatal services are mostly located at university-affiliated teaching hospitals in major cities and serve distinct geographic regions. Regional tertiary level institutions coordinate care with a network of primary and secondary level facilities throughout each geographic region. Centralized transport systems are coordinated either by regional tertiary level institutions or through a single provincial transport coordinating service. Health services are provided through a tax-funded universal health insurance system. We found that 98% of all NICU admissions received prenatal care before delivery, nearly two thirds of NICU admissions (65%) were for preterm infants and nearly one half of NICU admissions (43%) were retrotransferred to a community facility before discharge home. These results suggest that Canadians generally have good access to a highly organized perinatal health care (including preventive prenatal care) system, referral NICU facilities seem to be appropriately used primarily for preterm or very sick infants requiring tertiary level care, and community and tertiary level neonatal-perinatal facilities seem to be well-coordinated in their referral and retrotransfer functions to provide as much care as possible closer to home.

The Canadian NICU Network includes 75% of tertiary level NICU beds in Canada, and the NICUs are organized in a highly regionalized geographic referral system. Our dataset is, therefore, unique in being able to yield population-based information about patient outcomes linked to clinical practice, individual patient risks, and illness severity. The demographic profile of patients admitted to Canadian NICUs reveals several points of interest. The predominance of male infants (57.5%) admitted to Canadian NICUs contrasts with previous reports by the National Institute of Child Health and Human Development (NICHD) Neonatal Network (49% male)^2,7 and the Vermont-Oxford Trials Network (VOTN; 51% male).²⁵ Because our data are population-based (whereas the US reports are not), it is likely that they more accurately reflect the higher morbidity rates associated with male newborn infants.²⁶ Although 7 years separate the reports of the Canadian NICU Network (1996/1997) and the NICHD Neonatal Network (1989/1990 and 1993/1994),^2,7 the BW-specific distribution of infants <1500 g of BW who were admitted to the NICU are strikingly similar (Canada vs NICHD 1989/1990 and 1993/1994, respectively, for <750 g of BW: 19% vs 18%-21%; for 750-999 g of BW: 23% vs 23%-23%; for 1000-1249 g of BW: 28% vs 28%-25%; for 1250-1499 g of BW: 29% vs 31%-30%), and suggests that our ability to delay preterm delivery has not changed much during this time. A large percentage (20%) of term infants treated in the NICU had major congenital anomalies, which represents a significant burden on NICU resources and utilization.

Outcomes of the Canadian NICU Network compare favorably with those previously published by the NICHD Neonatal Network,⁷ the VOTN,^6,25 and the Australia-New Zealand NICU Network (ANZNN).²⁷ BW-specific survival of the Canadian NICU Network and the ANZNN are similar and show significant improvement over those of the NICHD Neonatal Network^2,7 and VOTN.^6,25 Mortality of infants >32 weeks' GA is very low (2%). Also striking are improvements in survival of the smallest infants <750 g of BW (survival rate 62% Canada vs 49% NICHD Neonatal Network). These differences are most likely the result of improvements in neonatal care over time but may also be attributable to changes in organization, staffing, training, and attitudes toward active treatment of extremely low BW infants. Therefore, it is important to report trends over time. It is noteworthy that more recent reports from the Canadian NICU Network, ANZNN,²⁷ and NICHD Neonatal Network⁷ reported significantly higher BW-specific prevalence of CLD than did earlier reports of the NICHD Neonatal Network² and VOTN.²⁵ These difference are likely attributable to improved survival of preterm infants but may also be attributable to differences in clinical practice over time (eg, higher threshold for discontinuing oxygen, surfactant, high-frequency ventilation, and postnatal steroid use). It is unclear whether, and how, intercountry differences in health care systems, socioeconomic status, cultural factors, and social income disparities impact on NICU outcomes.

Benchmarking using illness severity adjustment is critical for studying variations in outcomes. Residual variation, after adjusting both for individual patient risk factors and illness severity, may then be used to identify differences in care, which may increase costs but not improve outcomes. Clinical trials of efficacy can then be conducted to test these findings. Consequently, valid comparisons of outcomes can be used not only for audit of NICU care, but also for improving patient outcomes and reducing costs. SNAP-II measures illness severity of newborn infants admitted to the NICU and is highly predictive of NICU mortality and morbidity.^12,28 It was derived using the Canadian NICU Network cohort and validated in both the Canadian NICU Network cohort and in 2 separate NICU cohorts in the United States.¹² SNAP-II is, therefore, highly suitable for benchmarking NICU outcomes. In future publications, we will adjust outcomes using individual patient risks and SNAP-II and examine risks associated with poor outcomes.

Although Canada has a universal health insurance system and a highly regionalized system of neonatal-perinatal care, variations in patterns of NICU usage and of patient outcomes among Canadian NICUs seem to be as wide as those reported by the NICHD Neonatal Network^2,7 and VOTN.^6,25 For instance, annual admissions to Canadian NICU Network units ranged from 134 to 1129 infants, and NICU survival varied between centers from 89% to 99%. This suggests that small area variations in the practices of groups of physicians persist even with universal health care access and a uniform health care financing system. Variations in NICUs are important because they are natural experiments, reflecting the practice patterns of small groups of physicians. Wennberg et al²⁹ showed that small area variations can be used to study the relative effectiveness of differing medical practices and technologies. In future publications, we will examine the sources of variation in outcome among Canadian NICUs to gain insight into ways of improving care for NICU infants.

This study also demonstrates the impact of changing technology on clinical practice and the need for evidence-based practice guidelines. Of interest nitric oxide treatment was given to 150 term and 102 preterm infants, although randomized, controlled trials have only demonstrated its safety and efficacy in term infants.³⁰ In contrast, the use of antenatal steroids in infants <34 weeks' GA varied from 23% to 76% among participating NICUs, although its efficacy was unequivocally demonstrated over 25 years ago.³¹ Even established technologies (eg, cranial ultrasound screening) reveal large variations in usage patterns, which show the lack of uniform criteria for optimal use. Evidence-based practice guidelines (eg, criteria for cranial ultrasound screening) need to be articulated so that clinical practice can be made more coherent. Monitoring practice patterns longitudinally can provide important insights into identifying clinical practice trends that may be inconsistent with the existing evidence. Interventions can then be targeted to change practices that may not improve outcomes or reduce costs.

Longitudinal studies on a population basis act as sentinels to changes in disease and practice patterns. They provide an objective way of auditing care and outcomes on an ongoing basis and can provide important insights into how to improve efficacy and efficiency of care. They provide useful information for planning research, allocating resources, and designing health and public policy. In this study, we successfully established a national NICU database and established population-based benchmarks for examining practice and outcome variation as well as the sources of variation. This database will also serve as a basis for longitudinal studies of NICU care in Canada for research, audit, and quality improvement. Using this database, we also previously developed and validated SNAP-II^12,28 as a benchmarking instrument for measuring illness severity in newborn infants.

	APPENDIX

The members of the Canadian NICU Network are: Shoo K. Lee, MBBS, FRCPC, PhD (coordinator; Centre for Community Health and Health Evaluation Research, Vancouver, British Columbia); Wayne Andrews, MD, FRCPC (Charles A. Janeway Child Health Centre, St John's, Newfoundland); Ranjit Baboolal, MBChB, FRCPC (North York Hospital, North York, Ontario); Jill Boulton, MD, FRCPC (St Joseph's Health Centre, London, Ontario; formerly Mt Sinai Hospital, Toronto, Ontario); David Brabyn, MBChB, FRACP, FRCPC (Royal Columbian Hospital, New Westminster, British Columbia); David S. C. Lee, MBBS, FRCPC (St Joseph's Health Centre, London, Ontario); Derek Matthew, MRCS, FRCPC, SM (Victoria General Hospital, Victoria, British Columbia); Douglas D. McMillan, MD, FRCPC (Foothill's Hospital, Calgary, Alberta); Christine Newman, MD, FRCPC (Hospital for Sick Children, Toronto, Ontario); Arne Ohlsson, MD, FRCPC, MSc (Mt Sinai Hospital, Toronto, Ontario; formerly Women's College Hospital, Toronto, Ontario); Abraham Peliowski, MD, FRCPC (Royal Alexandra Hospital, Edmonton, Alberta); Margaret Pendray, MBBS, FRCPC (Children's and Women's Health Centre of British Columbia, Vancouver, British Columbia; formerly Montreal Children's Hospital, Montreal, Quebec); Koravangattu Sankaran, MBBS, FRCPC (Royal University Hospital, Saskatoon, Saskatchewan); Barbara Schmidt, MD, FRCPC, MSc (Hamilton Health Sciences Corporation, Hamilton, Ontario); Mary Seshia, MBChB, FRCPC (Health Sciences Centre, Winnipeg, Manitoba); Anne Synnes, MDCM, FRCPC, MHSc (Children's and Women's Health Centre of British Columbia, Vancouver, British Columbia); Paul Thiessen, MD, FRCPC (Children's and Women's Health Centre of British Columbia, Vancouver, British Columbia); Robin Walker, MD, FRCPC (Children's Hospital of Eastern Ontario and Ottawa General Hospital, Ottawa, Ontario); and Robin Whyte, MBBS, FRCPC (Izaak Walton Killam-Grace Health Centre for Women, Children and Families, Halifax, Nova Scotia).

Coordinating Centre: Li-Yin Chien, MPH, ScD; Joanna Sale, MSc; Herbert Chan, MSc; and Shawn Stewart, BA.

	ACKNOWLEDGMENTS

This study was supported by Grants 40503 and 00152 from the Medical Research Council of Canada.

Additional funding was provided by the Children's Hospital Foundation of British Columbia; Calgary Regional Health Authority; Dalhousie University Neonatal-Perinatal Research Fund; Division of Neonatology, Children's Hospital of Eastern Ontario; Child Health Program, Health Care Corporation of St John's; the Neonatology Program, Hospital for Sick Children; Lawson Research Institute; Midland Walwyn Capital Inc; Division of Neonatology, Hamilton Health Sciences Corporation; Mount Sinai Hospital; North York General Hospital Foundation; Saint Joseph's Health Center; University of Saskatchewan Neonatal Research Fund; University of Western Ontario; and Women's College Hospital.

	FOOTNOTES

^** Members of the Canadian NICU Network and Coordinating Center are listed in the "Appendix."

Findings from this study were presented in part at the Annual Meeting of the American Pediatric Society/Society for Pediatric Research; May 1-4, 1999; San Francisco, CA; and at the Annual Meeting of the Canadian Pediatric Society; June 22-27, 1999, Winnipeg, Manitoba, Canada.

Received for publication Dec 2, 1999; accepted May 22, 2000.

Reprint requests to (S.K.L.) Canadian NICU Network Centre for Community Health and Health Evaluation Research, 4480 Oak St, Rm E-414, Vancouver, British Columbia, Canada V6H 3V4. E-mail: shool{at}interchange.ubc.ca

	ABBREVIATIONS

NICU, neonatal intensive care unit; VLBW, very low birth weight; FTE, full-time equivalent; ECMO, extracorporeal membrane oxygenation; CRIB, Clinical Risk Index for Babies; SNAP, Score for Neonatal Acute Physiology; SNAP-II, Score for Neonatal Acute Physiology-Version II; NTISS, Neonatal Therapeutic Intensity Scoring System; GA, gestational age; SGA, small for gestational age; BW, birth weight; CLD, chronic lung disease; CGA, corrected gestational age; IVH, intraventricular hemorrhage; NEC, necrotizing enterocolitis; ROP, retinopathy of prematurity; CSF, cerebrospinal fluid; PDA, patent ductus arteriosus; NICHD, National Institute of Child Health and Development; VOTN, Vermont Oxford Trials Network; ANZNN, Australia-New Zealand Neonatal Network.

	REFERENCES

Top Abstract Methods Results Discussion References

1. Stahlman MT Newborn intensive care: success or failure? J Pediatr 1984; 105:162-167 [CrossRef][Medline]
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6. Horbar JD, Badger J, Lewit EM, Rogowski J, Shiono PH Hospital and patient characteristics associated with variation in 28-day mortality rates for very low birth weight infants. Pediatrics 1997; 99:149-156 [Abstract/Free Full Text]
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11. Richardson DK, Gray JE, McCormick MC, Workman K, Goldman DA Score for neonatal acute physiology: a physiologic severity index for neonatal intensive care. Pediatrics 1993; 91:617-623 [Abstract/Free Full Text]
12. Richardson DK, Corcoran JD, Escobar GJ, Lee SK, for the Canadian NICU Network, the Kaiser Permanente Neonatal Minimum Data Set Wide Area Network, and the SNAP-II Study Group. SNAP-II and SNAPPE-II: simplified newborn illness severity and mortality risk scores. J Pediatr. 2000;137
13. Gray JE, Richardson DK, McCormick MC, Workman-Daniels K, Goldman DA Neonatal therapeutic intervention scoring system (NTISS): a therapy-based severity of illness assessment tool. Pediatrics 1992; 90:561-567 [Abstract/Free Full Text]
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20. American Academy of Pediatrics Committee members: an international classification of retinopathy of prematurity. Pediatrics 1984; 74:127-133 [Abstract/Free Full Text]
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25. The Investigators of the Vermont-Oxford Trials Network Very low birth weight outcomes for 1990. Pediatrics 1993; 91:540-545 [Abstract/Free Full Text]
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28. Chien LY, Lee SK, Thiessen P, Whyte R, the Canadian NICU Network Validation of the SNAP and SNAP-II on morbidity of infants less than 33 weeks gestational age. Pediatr Res 1999; 45:240A
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30. Neonatal Inhaled Nitric Oxide Study Group Inhaled nitric oxide in full-term and nearly full-term infants with hypoxic respiratory failure. N Engl J Med 1997; 336:597-604 [Abstract/Free Full Text]
31. Liggins GC, Howie RN A controlled trial of antepartum glucocorticoid treatment for the prevention of respiratory distress syndrome in premature infants. Pediatrics 1972; 50:515-525 [Abstract/Free Full Text]