Douglas K. Richardson

Occurrence of nosocomial bloodstream infections in six neonatal intensive care units.

BACKGROUND Nosocomial bloodstream infections (NBSIs) occur frequently in neonatal intensive care units (NICUs) and are associated with substantial morbidity and mortality. Little has been published regarding variation in NBSI among institutions. OBJECTIVE To determine NBSI incidence among six NICUs and to explore how much variation is explained by patient characteristics and NICU practice patterns. METHODS From October, 1994, to June, 1996, six regional NICUs prospectively abstracted clinical records of all neonates weighing <1,500 g. Occurrence of NBSI, defined as first positive culture occurring >48 h after admission, was analyzed in relation to baseline patient characteristics and several common therapeutic interventions. Variables significant in univariate analyses were analyzed by Cox proportional hazards regression. RESULTS There were 258 NBSIs (incidence, 19.1%) among 1,354 inborn first admissions. Incidence varied significantly by site, from 8.5 to 42%. Birth weight, Broviac catheter use and parenteral nutrition were significantly associated with NBSI (P < 0.05). When controlling for these variables interinstitutional variation in NBSI occurrence decreased but remained significant. CONCLUSIONS Neonatal NBSI incidence varies substantially among institutions despite adjustment for length of stay and some known risk factors. The uses of Broviac catheters and especially intravenous nutrition supplements were significant determinants of NBSI risk.

Declining severity adjusted mortality: evidence of improving neonatal intensive care.

Objectives. Declines in neonatal mortality have been attributed to neonatal intensive care. An alternative to the “better care” hypothesis is the “better babies” hypothesis; ie, very low birth weight infants are delivered less ill and therefore have better survival. Design. We ascertained outcomes of all live births <1500 g in two prospective inception cohorts. We estimated mortality risk from birth weight and illness severity on admission and measured therapeutic intensity. We calculated logistic regression models to estimate the changing odds of mortality between cohorts. Patients and Setting. Two cohorts in the same two hospitals, 5 years apart (1989–1990 and 1994–1995) (totaln = 739). Results. Neonatal intensive care unit mortality declined from 17.1% to 9.5%, and total mortality declined from 31.6% to 18.4%. Cohort 2 had lower risk (higher birth weight, gestational age, and Apgar scores and lower admission illness severity for newborns ≥750 g). Risk-adjusted mortality declined (odds ratio, 0.52; confidence interval, 0.29–0.96). One third of the decline was attributable to “better babies” and two thirds to “better care.” Use of surfactant, mechanical ventilation, and pressors became more aggressive, but decreases in monitoring, procedures, and transfusions resulted in little change in therapeutic intensity. Conclusions. Mortality decreased nearly 50% for infants <1500 g in 5 years. One third of this decline is attributable to improved condition on admission that reflects improving obstetric and delivery room care. Two thirds of the decline is attributable to more effective newborn intensive care, which was associated with greater aggressiveness of respiratory and cardiovascular treatments. Attribution of improved birth weight specific mortality solely to neonatal intensive care may underestimate the contribution of high-risk obstetric care in providing “better babies.”

Intravenous lipid emulsions are the major determinant of coagulase-negative staphylococcal bacteremia in very low birth weight newborns

BACKGROUND Intravenous lipid emulsions and the i.v. catheters through which they were administered were the major risk factors for nosocomial coagulase-negative staphylococcal (CONS) bacteremia among newborns in our neonatal intensive care units a decade ago. However, medical practice is changing, and these and other interventions may have different effects in the current setting. OBJECTIVES We determined the independent risk factors for CONS bacteremia in current very low birth weight newborns after adjusting for severity of underlying illness. METHODS We surveyed 590 consecutively admitted newborns with birth weights < 1500 g hospitalized in 2 neonatal intensive care units and conducted a case-control study in a sample of 74 cases of CONS bacteremia and 74 pairs of matched controls. Adjusted relative odds of bacteremia were estimated for a number of attributes and therapeutic interventions in 2 time intervals before CONS bacteremia: any time before bacteremia and the week before bacteremia. RESULTS Using conditional logistic regression to adjust for indicators of severity of illness, two procedures were independently associated with subsequent risk of CONS bacteremia at any time during hospitalization: i.v. lipids, odds ratio (OR) = 9.4 [95% confidence interval (CI) 1.2 to 74.2]; and any surgical or percutaneously placed central venous catheter, OR = 2.0 (95% CI 1.1 to 3.9). Considering only the week immediately preceding bacteremia, the independent risk factors were: mechanical ventilation, OR = 3.2 (95% CI 1.3 to 7.6); and short peripheral venous catheters, OR = 2.6 (95% CI 1.0 to 6.5). CONCLUSIONS During the last decade exposure to i.v. lipids any time during hospitalization has become an even more important risk factor for CONS bacteremia (OR = 9.4). Of these bacteremias 85% are now attributable to lipid therapy. In contrast the relative importance of intravenous catheters as independent risk factors has declined. Mechanical ventilation in the week before bacteremia has emerged as a risk factor for bacteremia.

Variations in blood transfusions among newborn intensive care units

OBJECTIVES Very low birth weight (< 1500 g) infants frequently require packed red blood cell transfusions, and transfusion rates vary among neonatal intensive care units (NICUs). We analyzed transfusions and compared outcomes among NICUs. STUDY DESIGN In a 6-site prospective study, we abstracted all newborns weighing < 1500 g (total = 825) born between October 1994 and September 1995. Transfusion frequency and volume and phlebotomy number were analyzed by site and adjusted for birth weight and illness severity. We compared rates of intraventricular hemorrhage, necrotizing enterocolitis, bronchopulmonary dysplasia, growth, and length of stay between the high and low transfuser NICUs. RESULTS Sites differed significantly in mean birth weight, illness severity, number of transfusions, pretransfusion hematocrit, blood draws, and donor number. Multivariate adjustment for these risks showed that the highest transfusing NICU transfused an additional 24 cc/kg per baby during the first 14 days and 47 cc/kg per baby after 15 days, relative to the lowest transfusing NICU. The presence of arterial catheters increased the frequency of blood transfusions. The rates of intraventricular hemorrhage, necrotizing enterocolitis, and bronchopulmonary dysplasia were not higher in the 2 lowest transfusing NICUs, nor were there differences in 28-day weight gain or length of stay. CONCLUSIONS Major differences in transfusion practices for very low birth weight infants exist among NICUs. Because clinical outcomes were no different in lower transfuser NICUs, it is likely that transfusion and phlebotomy guidelines could result in fewer transfusions, fewer complications, and reduced cost.

Unstudied infants: outcomes of moderately premature infants in the neonatal intensive care unit

Background: Newborns of 30–34 weeks gestation comprise 3.9% of all live births in the United States and 32% of all premature infants. They have been studied much less than very low birthweight infants. Objective: To measure in-hospital outcomes and readmission within three months of discharge of moderately premature infants. Design: Prospective cohort study including retrospective chart review and telephone interviews after discharge. Setting: Ten birth hospitals in California and Massachusetts. Patients: Surviving moderately premature infants born between October 2001 and February 2003. Main outcome measures: (a) Occurrence of assisted ventilation during the hospital stay after birth; (b) adverse in-hospital outcomes—for example, necrotising enterocolitis; (c) readmission within three months of discharge. Results: With the use of prospective cluster sampling, 850 eligible infants and their families were identified, randomly selected, and enrolled. A total of 677 families completed a telephone interview three months after hospital discharge. During the birth stay, these babies experienced substantial morbidity: 45.7% experienced assisted ventilation, and 3.2% still required supplemental oxygen at 36 weeks. Readmission within three months occurred in 11.2% of the cohort and was higher among male infants and those with chronic lung disease. Conclusions: Moderately premature infants experience significant morbidity, as evidenced by high rates of assisted ventilation, use of oxygen at 36 weeks, and readmission. Such morbidity deserves more research.

Prenatal Consultation Practices at the Border of Viability: A Regional Survey

Objective.We undertook a survey of all practicing neonatologists in New England to determine their attitudes and practices regarding prenatal consultations for infants at the border of viability. Methods.A self-administered anonymous survey, mailed to every practicing neonatologist in the 6 Northeast states of Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont, explored respondent attitudes and practices with respect to a hypothetical clinical scenario of a prenatal consultation for an infant at the border of viability. Results.Our final sample included 149 surveys from 175 eligible neonatologists, giving a response rate of 85%. Seventy-seven percent of respondents indicated that they thought neonatologists and parents should make the decision jointly to withhold resuscitation. Only 40% indicated that the decision actually is made by both parties. A majority of neonatologists (58%) saw their primary role during the prenatal consultation as providing factual information to the parents. Far fewer (27%) thought that their main role was to assist the parents in weighing the risks and benefits of various management options. A majority of respondents indicated that parental understanding of the mothers current medical situation (96%), desired parental role (77%), and parental prior experience with premature or handicapped children (64%) were frequently or always discussed. However, far fewer respondents reported frequently or always asking about parental interpretations of a “good quality of life” (42%), parental prior experiences with death or dying (30%), and parental religious or spiritual beliefs (25%). Short-term outcomes and complications such as the need for surfactant/respiratory distress syndrome (89%) and the risk of intraventricular hemorrhage (81%) were discussed more extensively than long-term outcomes such as motor delays or cerebral palsy (68%), cognitive delays or learning disabilities (63%), and chronic lung disease (61%). Multivariate logistic regression analysis revealed 2 characteristics that were significant predictors of shared decision-making for the final decision regarding resuscitation in the delivery room for extremely premature infants, ie, believing that the main role of the neonatologist during prenatal consultations is to help parents weigh the risks and benefits of each resuscitation option (odds ratio: 4.1; 95% confidence interval: 1.6–10.9) and having >10 years of clinical experience (odds ratio: 3.6; 95% confidence interval: 1.5–8.8). Conclusions.Overall, our results showed that neonatologists are quite consistent in discussing clinical issues but quite varied in discussing social and ethical issues. If neonatologists are to perform complete prenatal consultations for infants at the border of viability as described by the latest American Academy of Pediatrics guidelines, then they will be expected to address quality-of-life values more robustly, to explain long-term outcomes, and to incorporate parental preferences during their conversations. Potential barriers to shared decision-making have yet to be outlined.

Diagnostic tests in obstetrics: a method for improved evaluation.

With the proliferation of diagnostic tests in obstetrics, several recurrent questions arise. How does one determine whether one diagnostic test is superior to another available test? What test cutoff value best separates diseased from nondiseased patients? How much does performance of additional tests assist in arriving at a correct diagnosis? This article reviews a simple yet sophisticated analytic technique, the receiver operating characteristic curve, and demonstrates its application to several obstetric diagnostic tests. Receiver operating characteristic curve analysis is used to select a cutoff value for the 1-hour glucose tolerance test, to compare amniotic fluid tests of fetal lung maturity, and to determine the optimal combinations of factors and overall performance of the fetal biophysical profile. The value of receiver operating characteristic curve analysis lies in providing a clear graphic analysis of the performance of diagnostic tests over their entire range of values. It also provides the starting point for evaluating the costs and benefits of alternative cutoff points in differing clinical settings.

Interneonatal intensive care unit variation in growth rates and feeding practices in healthy moderately premature infants

BACKGROUND:Variation in care and outcomes of very low birth weight infants (VLBW) in neonatal intensive care units (NICU) has been widely reported in the past decade. Less is known about care provided to healthy premature infants born between 30 and 35 weeks gestational age (GA). We have previously reported inter-NICU variation in discharge (D/C) timing and achievement of maturational milestones in this population.OBJECTIVE:To compare inter-NICU growth outcomes and feeding practices in healthy, moderately premature infants.METHODS:Records of 450 infants, 30 to 35 weeks gestation, without medical or surgical complications, and consecutively discharged from 15 Massachusetts NICUs (nine Level II and six Level III) were reviewed. Final analyses included 382 infants with hospital length of stay >6 days (d).RESULTS:GA at birth and birth weight (BW) were 33.2 weeks (SD 1.2) and 2024 g (389). Mean Z-score decreased 0.67z (0.37) from birth to D/C. Weight loss from birth to 7 d averaged 4.0%. Mean growth velocity from 7 d to D/C was 13.3 g/k/d (5.2) with net growth velocity of 5.5 g/k/d (5.6). Mean net growth velocity ranged from 0.1 to 8.4 g/k/d (p<0.001) among study NICUs. Time of initiation, rate of advancement and caloric density of feedings also varied significantly between NICUs.CONCLUSION:Mean NICU growth velocity of healthy, moderately premature infants did not achieve in utero growth standards. There was significant inter-NICU variation in growth outcomes and feeding practices. Further study is needed to identify practices associated with better growth in this healthy moderately premature infant population.

Perinatal risk and severity of illness in newborns at 6 neonatal intensive care units.

OBJECTIVES This multisite study sought to identify (1) any differences in admission risk (defined by gestational age and illness severity) among neonatal intensive care units (NICUs) and (2) obstetric antecedents of newborn illness severity. METHODS Data on 1476 babies born at a gestational age of less than 32 weeks in 6 perinatal centers were abstracted prospectively. Newborn illness severity was measured with the Score for Neonatal Acute Physiology. Regression models were constructed to predict scores as a function of perinatal risk factors. RESULTS The sites differed by several obstetric case-mix characteristics. Of these, only gestational age, small for gestational age. White race, and severe congenital anomalies were associated with higher scores. Antenatal corticosteroids, low Apgar scores, and neonatal hypothermia also affected illness severity. At 2 sites, higher mean severity could not be explained by case mix. CONCLUSIONS Obstetric events and perinatal practices affect newborn illness severity. These risk factors differ among perinatal centers and are associated with elevated illness severity at some sites. Outcomes of NICU care may be affected by antecedent events and perinatal practices.

Access to Neonatal Intensive Care

The birth of a high-risk infant is still a relatively rare, not totally predictable event; and the management of high-risk newborns requires highly skilled personnel and sophisticated technology. In the early days of neonatal intensive care, scarce resources led to regionalized systems of neonatal and, later, perinatal services, generally based on voluntary agreements but sometimes reinforced by planning legislation. At present, a vastly increased pool of skilled professionals and technical resources is available in the context of a rapidly changing medical care system characterized by intense competition, coalescence of services under large managed care plans, and substantial cost pressures. The evidence suggests that, in many areas, these forces have led to the dismantling of regional networks; however, the full potential for these changes to hinder or facilitate access to neonatal intensive care remains to be assessed.