Innovation in immediate neonatal care: development of the Bedside Assessment, Stabilisation and Initial Cardiorespiratory Support (BASICS) trolley.

OBJECTIVE: Babies receive oxygen through their umbilical cord while in the uterus and for a few minutes after birth. Currently, if the baby is not breathing well at birth, the cord is cut so as to transfer the newborn to a resuscitation unit. We sought to develop a mobile resuscitation trolley on which newly born babies can be resuscitated while still receiving oxygenated blood and the 'placental transfusion' through the umbilical cord. This would also prevent separation of the mother and baby in the first minutes after birth. DESIGN: Multidisciplinary iterative product development. SETTING: Clinical Engineering Department of a University Teaching Hospital. METHODS: Following an initial design meeting, a series of prototypes were developed. At each stage, the prototype was reviewed by a team of experts in the laboratory and in the hospital delivery suite to determine ease of use and fitness for purpose. A commercial company was identified to collaborate on the trolley's development and secure marking with the Conformité Européenne mark, allowing the trolley to be introduced into clinical practice. RESULTS: The trolley is a small mobile resuscitation unit based on the concept of an overbed hospital table. It can be manoeuvred to within 50 cm of the mother's pelvis so that the umbilical cord can remain intact during resuscitation, irrespective of whether the baby is born naturally, by instrumental delivery or by caesarean section. Warmth for the newborn comes from a heated mattress and the trolley has the facility to provide suction, oxygen and air. CONCLUSIONS: This is the first mobile resuscitation device designed specifically to facilitate newborn resuscitation at the bedside and with an intact cord. The next step is to assess its safety, its acceptability to clinicians and parents, and to determine whether it allows resuscitation with an intact cord.

Use of self-heating gel mattresses eliminates admission hypothermia in infants born below 28 weeks gestation.

INTRODUCTION: Hypothermia at birth is strongly associated with mortality and morbidity in pre-term infants. BACKGROUND: A local audit showed limited effectiveness of occlusive wrapping in preventing admission hypothermia in very pre-term infants. Self-heating acetate gel mattresses were introduced as a result to prevent hypothermia at birth in infants born at or below 28 weeks gestation. METHODS: A retrospective audit was conducted to evaluate the effectiveness of self-heating acetate gel mattresses at resuscitation of infants born at or below 28 weeks to prevent hypothermia at birth. All infants born at or below 28 weeks gestation during 18 months before and 18 months after self-heating acetate gel mattresses were introduced during resuscitation were included. RESULTS: One hundred five babies were born when acetate gel mattresses were not used, and 124 were born during the period when they were. Four (3.3%) babies were hypothermic (temperature <36 degrees C) at admission when the mattresses were used compared to 21 (22.6%) babies who were hypothermic during the period it was not (p < 0.001). Hyperthermia (temperature >37 degrees C) rose from 30.1% prior to use of gel mattresses to 49.6% when they were used (p = 0.004). CONCLUSIONS: Self-heating acetate gel mattresses are highly effective in reducing admission hypothermia in infants born at or below 28 weeks gestation. The use of these mattresses is associated with a significant increase in hyperthermia.

Prophylactic oral nystatin for preterm babies under 33 weeks' gestation decreases fungal colonisation and invasive fungaemia.

BACKGROUND: Invasive fungal infection is an important cause of mortality and morbidity in extremely preterm babies. Colonisation with Candida is a risk factor for systemic infection. A policy of oral nystatin prophylaxis was introduced in November 2000 with the aim of reducing the incidence of invasive fungaemia. AIM: To determine whether this policy had reduced the rates of fungal colonisation and invasive fungal infection. METHODS: All neonates of <33 weeks' gestation born between 1998 and 2003 were studied. Neonates born between January 1998 and October 2000 who did not receive nystatin prophylaxis (group A) were compared with those born between November 2000 and December 2003 who received nystatin prophylaxis (group B). Infant details, blood culture results and the results of weekly surface swabs were recorded. RESULTS: 1459 neonates (group A = 724 , group B = 735) of <33 weeks' gestation were admitted in the study period. There were no differences in birth weight, gestation, gender or proportion of babies transferred in from other units between the groups. There was a reduction in colonisation from 257 (35.5%) in group A to 132 (18%) in group B. The incidence of invasive fungaemia decreased from 30 (4.1%) to 13 (1.8%) between the two groups. There was also a reduction in mortality between the two groups from 17.8% to 11.8%. CONCLUSIONS: The introduction of a prophylactic nystatin administration policy for babies born before 33 weeks was associated with a significant reduction in fungal colonisation and invasive fungal infection.

Use of plastic bags to prevent hypothermia at birth in preterm infants--do they work at lower gestations?

BACKGROUND: Hypothermia at birth is strongly associated with mortality and morbidity in preterm infants. Occlusive wrapping of preterm infants during resuscitation, including polythene bags have been shown to prevent hypothermia. OBJECTIVES: To evaluate the effectiveness of the introduction of polythene bags at resuscitation of infants born below 30 weeks gestation in a large tertiary neonatal centre. METHODS: Retrospective audit of admission temperatures of all infants born below 30 weeks gestation for two years before and two years after the introduction of polythene bags. Hypothermia was defined as admission axillary temperature < 36 degrees C. RESULTS: A total of 334 eligible infants were born during the study period. Two hundred and fifty-three (75.8%) had admission temperatures recorded. The incidence of hypothermia fell from 25% to 16%(p = 0.098) for the whole group since the introduction of polythene bags. The main reduction in hypothermia was seen in infants born above 28 weeks gestation (19.4% vs. 3.9%, p = 0.017). There was no significant effect in infants born between 28 weeks and 30 weeks (29.3% vs. 24.8%, p = 0.58). CONCLUSIONS: Polythene bags are effective in reducing the incidence of hypothermia at admission in infants born below 30 weeks gestation. The benefit in infants born below 28 weeks gestation was only marginal. This is in contrast to previously published studies. This may be related to the comparatively low incidence of hypothermia at the study centre even prior to introduction of polythene bags.

Does sustained lung inflation at resuscitation reduce lung injury in the preterm infant?

BACKGROUND: Bronchopulmonary dysplasia (BPD) is a common outcome of preterm birth. Experimental animal work has shown that initial ventilation strategies injure the immature lung and may lead to BPD. Studies with asphyxiated babies have shown that, if tidal ventilation at birth is preceded by sustained lung inflation, larger inflation volumes can be achieved, which is thought to lead to clearance of lung fluid and formation of the functional residual capacity (FRC). OBJECTIVE: To see if sustained lung inflation at initial resuscitation of preterm babies would facilitate the removal of lung fluid, establish the FRC, and allow an even distribution of alveolar opening, permitting less aggressive ventilation, leading to a reduction in pulmonary inflammation and subsequent BPD. METHOD: The outcomes of 52 babies of less than 31 weeks gestation, resuscitated at birth using either a sustained lung inflation of five seconds or a conventional lung inflation of two seconds for the first assisted breath of resuscitation, were examined. Evidence of pulmonary inflammation was determined by quantification of interleukins 6, 10, and 1beta and tumour necrosis factor alpha in bronchoalveolar lavage fluid by enzyme linked immunosorbent assay. RESULTS: There were no significant differences in any of the cytokines. Death occurred in 3/26 babies in the conventional group and 6/26 babies in the sustained lung inflation group. Survival without BPD occurred in 13/26 and 14/26 respectively. CONCLUSION: The use of sustained lung inflation at resuscitation did not reduce lung injury, as measured by inflammatory markers.

Does the use of 50% oxygen at birth in preterm infants reduce lung injury?

BACKGROUND: Bronchopulmonary dysplasia is an inflammatory fibrotic condition produced as a consequence of injurious influences in the neonatal lung. Exposing the premature lung to high concentrations of oxygen is thought to play an important part in lung injury pathogenesis. OBJECTIVE: To see if the amount of oxygen used during resuscitation at birth triggers events that lead to the subsequent lung injury and if a reduction in oxygen used leads to a reduction in lung injury. METHOD: The outcomes of newborn babies less than 31 weeks gestation who were resuscitated using either 50% or 100% oxygen were examined. Eight of the babies receiving 50% oxygen required an increase in their oxygen concentration. Evidence of pulmonary inflammation was determined by quantifying interleukin 6, 1beta, and 10 and tumour necrosis factor alpha in bronchoalveolar lavage fluid by enzyme linked immunosorbent assay. RESULTS: There were no significant differences in any of the cytokines studied in either of the groups. Death occurred in 5/26 (19%) babies who received 100% oxygen and 4/26 (15%) babies who received 50% oxygen. Survival without bronchopulmonary dysplasia at 36 weeks postmenstrual age occurred in 14/26 (54%) and 13/26 (50%). CONCLUSION: Reducing the oxygen to 50% at resuscitation did not influence either short or long term outcomes, but a small benefit could not be excluded. There was no increase in adverse clinical outcomes in babies who received 100% oxygen.

The value of Bilicheck as a screening tool for neonatal jaundice in term and near-term babies.

AIMS: To determine the accuracy of Bilicheck in assessing serum bilirubin. To evaluate the effectiveness of Bilicheck as a screening device in a population of jaundiced term and near-term babies. METHODS: Prospective evaluation of paired Bilicheck measurements and serum bilirubin in 300 babies. RESULTS: There was a strong correlation between Bilicheck and serum bilirubin. The mean difference between Bilicheck and serum bilirubin was -10.7 micromol/l, but the 95% limits of agreement were wide at -80 micromol/l to +60 micromol/l. Bilicheck identified significant jaundice (serum bilirubin above 250 micromol/l) with a sensitivity (95% confidence interval) of 91% (88% to 94%) and specificity of 66% (60% to 71%). The area under the receiver operator characteristic curve was 0.85. There were five false negatives, all of whom had a serum bilirubin below 300 micromol/l. If Bilicheck had been used as a screening device, there would have been a 55% decrease in blood samples taken in these babies. CONCLUSION: Bilicheck cannot be used to measure serum bilirubin in term and near-term babies with jaundice, but is an effective screening method, which can be used to safely reduce the number of blood tests in these babies.

Concentrations of cardiac troponin T in neonates with and without respiratory distress.

AIMS: To establish a practical postnatal reference range for cardiac troponin T in neonates and to investigate concentrations in neonates with respiratory distress. METHODS: Prospective investigation in a tertiary neonatal unit, recruiting infants with and without respiratory distress (sick and healthy infants respectively). Concentrations of cardiac troponin T were compared between sick and healthy infants, accounting for confounding variables. RESULTS: A total of 162 neonates (113 healthy and 49 sick infants) had samples taken. The median (interquartile range) cardiac troponin T concentration in the healthy infants was 0.025 (0.01-0.062) ng/ml, and the 95th centile was 0.153 ng/ml. There were no significant relations between cardiac troponin T and various variables. The median (interquartile range) cardiac troponin T concentration in the sick infants was 0.159 (0.075-0.308) ng/ml. This was significantly higher (p < 0.0001) than in the healthy infants. In a linear regression model, the use of inotropes and oxygen requirement were significant associations independent of other basic and clinical variables in explaining the variation in cardiac troponin T concentrations. CONCLUSIONS: Cardiac troponin T is detectable in the blood of many healthy neonates, but no relation with important basic and clinical variables was found. Sick infants have significantly higher concentrations than healthy infants. The variations in cardiac troponin T concentration were significantly associated with oxygen requirement or the use of inotropic support in a regression model. Cardiac troponin T may be a useful marker of neonatal and cardiorespiratory morbidity.

Right ventricular volume measurements in ventilated preterm neonates.

Pulmonary hypertension is associated with worse perinatal outcomes in infants with respiratory disorders. In these infants, right ventricular dysfunction may result in poor pulmonary blood flow. The objective of this study was to follow changes in right ventricular volumes during the first 2 days of life in infants with respiratory distress syndrome. Serial echocardiographic examinations were performed on days 0-2 on infants ventilated for respiratory distress syndrome. Two-dimensional echocardiography with the ellipsoid approximation was used to calculate systolic and diastolic volumes. In 17 ventilated preterm infants, right ventricular volumes were significantly lower on day 2 compared with day 0 and decreased from a median (interquartile range) end systolic volume of 0.80 ml/kg (0.66-0.91 ml/kg) to 0.45 ml/kg (0.39-0.54 ml/kg) ( p < 0.001). End diastolic volume decreased from a median (interquartile range) of 1.54 ml/kg (1.44-1.65 ml/kg) to 1.30 ml/kg (1.22-1.60 ml/kg) ( p = 0.039). Right ventricular ejection fraction increased from a median (interquartile range) of 0.48 ml/kg (0.44-0.56 ml/kg) to 0.62 ml/kg (0.58-0.71 ml/kg) during the same period ( p < 0.001), as did right ventricular output from a median (interquartile range) 120 ml/kg/min (96-125 ml/kg/min) to 140 ml/kg/min (113-168 ml/kg/min) ( p = 0.044). Right ventricular volume decreases during the first 2 days of life in ventilated preterm infants. However, right ventricular performance is maintained.

Evaluation of echocardiography on the neonatal unit.

BACKGROUND: Echocardiography is an investigation that is being used increasingly on the neonatal unit. There is some controversy as to whether this service can be provided safely and effectively by neonatologists or whether it should only be performed by paediatric cardiologists. AIMS: To describe (a) the indications for an echocardiogram, (b) the yield and range of positive findings, (c) the resulting changes in clinical management, and (d) the reliability of echocardiography in the hands of neonatologists when it is performed on the neonatal unit. METHODS: Information about all echocardiograms performed on the neonatal unit was collected prospectively. Indications for performing echocardiography, echocardiographic findings, and any resulting changes in clinical management were determined. The concordance of findings in infants who underwent echocardiograms performed by both a neonatologist and a paediatric cardiologist was described. RESULTS: A total of 157 echocardiograms were performed in 82 infants. Echocardiography identified 44 infants with a structural cardiac abnormality and a further 17 infants with a trivial abnormality. In addition, 13 babies were found to have an important functional abnormality. Echocardiography prompted a specific change in clinical management in 64 (78%) babies. In 31 of the 38 infants who had paired scans performed, there was complete concordance between the two examinations. No infants had scans that were completely different. Some discrepancy was identified in seven infants, but this did not prevent appropriate immediate clinical management. CONCLUSIONS: Echocardiography on the neonatal unit has a high yield for the diagnosis of structural and functional cardiac abnormalities, often results in a change in clinical management, and can be a reliable tool in the hands of neonatologists.

Peri-operative blood lactate concentrations in pre-term babies with necrotising enterocolitis.

AIM: Hyperlactaemia has been shown to predict mortality in preterm babies undergoing intensive care. The value of such measurement has not been evaluated in babies undergoing laparotomy for necrotising enterocolitis (NEC). The aim of this study was to determine whether peri-operative blood lactate measurements (L) can be used to predict outcome in preterm babies with necrotising enterocolitis. METHODS: Clinical and laboratory data in 24 babies who underwent laparotomy for NEC over 3 years were collected. The data were analysed to correlate blood lactate level with the clinical outcome. RESULTS: There were no statistically significant differences between babies who died and those who survived in terms of gestation, birth weight, condition at birth, etc. There was no difference in pre-operative acid-base status parameters between the groups. Median (range) of pre- and post-operative blood lactate measurements (L) are shown: Pre-op Lactate: 0.9 (0.3 to 2.4) n = 15 (Survivors); 2.7 (0.5 to 10.9) n = 5, p = 0.05 (Non-survivors). Post-op Lactate: 1.2 (0.5 to 6) n = 19 (Survivors); 4.7 (0.2 to 19.5) n = 5, p = 0.06 (Non-survivors). Babies with pre-operative hyperlactaemia ([L] > 1.6 mmol/L) were more likely to die. (Odd's Ratio 22, Confidence Interval 1.54 to 314.3, p = 0.04). Pre-operative L was not higher in babies who subsequently had bowel resection compared to those who had no bowel resection ([L] = 0.88 mmol/L [0.3 to 10.9] vs. 1.6 mmol/L [0.6 to 2.7], [p = 0.2]). Post-operative L was generally higher than pre-operative L but was a less useful predictor of death. CONCLUSION: This study suggests that elevation of L in the pre-operative period carries a poor prognosis in babies with NEC. As L was not significantly different between babies who had necrotic bowel and those who had a healthy bowel, we postulate that it reflects inadequate global tissue oxygen delivery rather than local disease process. Pre-operative optimisation of oxygen delivery has been shown to reduce mortality in high-risk adult surgical patients. Babies with NEC may also benefit from further peri-operative resuscitation.

Measurement of right ventricular volume in healthy term and preterm neonates.

BACKGROUND: Pulmonary hypertension is associated with worse perinatal outcomes in infants with respiratory disorders. In such infants right ventricular dysfunction may result in poor pulmonary blood flow. OBJECTIVE: To evaluate the practicability and repeatability of echocardiographic measurements of right ventricular volume in healthy term and preterm neonates, and to follow changes in right ventricular volume over the first 2 days of life. METHODS: Serial echocardiographic examinations were performed on day 0, 1, and 2 on healthy term and preterm neonates. Two methods of estimating right ventricular volume were assessed: the ellipsoid approximation and Simpson's stacked discs methods. Systolic and diastolic volumes on days 1 and 2 were compared with baseline values on day 0. Term and preterm volumes were compared at the same time points. RESULTS: Thirty five infants were recruited, 18 term and 17 preterm. Right ventricular volumes were significantly lower on day 1 and day 2 than baseline in both term and preterm infants. Median (interquartile range) end systolic and diastolic volumes for term infants on days 0, 1, and 2 were 1.04 (0.88-1.44), 0.82 (0.70-1.03), 0.92 (0.72-0.97) ml/kg and 2.21 (2.10-2.75), 2.05 (1.81-2.38), 1.91 (1.81-2.13) ml/kg respectively. In preterm infants the values were 1.09 (0.91-1.16), 0.72 (0.54-0.91), 0.61 (0.54-0.76) ml/kg and 2.09 (1.71-2.25), 1.47 (1.23-1.98), 1.43 (1.22-1.78) ml/kg respectively. CONCLUSION: Right ventricular volume decreases over the first 2 days of life in healthy term and preterm infants.

Can transcutaneous bilirubinometry reduce the need for blood tests in jaundiced full term babies?

BACKGROUND: Previous studies have suggested that transcutaneous bilirubinometry (TcB) may provide a useful method for screening for significant jaundice, thereby reducing unnecessary blood tests. These studies have not allowed an estimation of the magnitude of such a benefit. OBJECTIVES: To evaluate the accuracy of TcB as a method of determining the need for serum bilirubin (SBR) measurements in full term babies and to quantify the magnitude of any benefit. SUBJECTS: Babies born at more than 34 weeks gestation who had not previously been exposed to phototherapy and were requiring blood sampling in the first week of life. METHOD: TcB measurements were made at the same time as blood sampling. SBR was measured in all blood samples. For jaundiced babies, the ability of TcB to detect significant jaundice (SBR > 249 micromol/l) was evaluated. RESULTS: There was a correlation between SBR and TcB measurements (n = 303, r = 0.76, p < 0.0001), but the 95% prediction interval for SBR from TcB was wide (+/- 88.3 micromol/l). For the 285 jaundiced babies, the area under the receiver operator characteristic curve was 0.89. A TcB value of 18 detected significant jaundice with a sensitivity of 100% and a specificity (95% confidence interval) of 45% (39% to 51%). If blood samples had only been taken from babies with a TcB value greater than 18, the number of samples taken would have been reduced by 34%. CONCLUSIONS: SBR cannot be measured accurately by TcB. However, TcB measurements can be used to determine the need for blood sampling in jaundiced babies and will reduce the number of blood samples taken. Recent improvements in TcB may improve the performance of this method.

Right ventricular performance in hypotensive preterm neonates treated with dopamine.

Systemic hypotension with left ventricular dysfunction is a common complication of neonatal respiratory distress syndrome and is often treated with inotropic agents. Although pulmonary hypertension with elevated pulmonary vascular resistance is also an important pathophysiological finding in respiratory distress syndrome, the effect of inotropes on the right ventricle has not been studied. The aim of this study was to assess changes in right ventricular dimensions and function with inotropic therapy in hypotensive preterm infants. Hypotensive neonates with respiratory distress syndrome were studied before and 1 hour after the initiation of a dopamine infusion. Right ventricular performance was assessed by two-dimensional echocardiography using the ellipsoid approximation method. Eight hypotensive neonates were recruited with a median (interquartile range) gestation of 27 weeks (26 to 27 weeks). Right ventricular end systolic volume decreased significantly from a median (interquartile range) of 1.06 ml/kg (0.81-1.50 ml/kg) to 0.73 ml/kg (0.51-0.99 ml/kg) (p < 0.01) 1 hour following dopamine therapy. Right ventricular end diastolic volume did not change significantly. Right ventricular ejection fraction increased significantly from 0.36 (0.29-0.46) to 0.51 (0.43-0.53) ( p < 0.01). There was a trend toward an increase in right ventricular output from 90 ml/kg/min (67-115 ml/kg/min) to 112 ml/kg/min-143 ml/kg/min) (p=0.07). Dopamine increases right ventricular ejection fraction through a reduction in right ventricular end systolic volume.

A pilot randomised controlled trial of peripheral fractional oxygen extraction to guide blood transfusions in preterm infants.

BACKGROUND: Peripheral fractional oxygen extraction (FOE) may be a better indicator of the need for transfusion than the haemoglobin concentration (Hb) because it is a measure of the adequacy of oxygen delivery to meet demand. A randomised controlled trial of the use of peripheral FOE to guide the need for blood transfusions in preterm infants was carried out to test this hypothesis. METHOD: Infants less than 1500 g birth weight who were stable and less than 2 weeks old were randomised to receive transfusions guided by either a conventional protocol based on Hb (conventional group) or a protocol based on measurements of peripheral FOE made by near infrared spectroscopy (NIRS group). Measurements of Hb and FOE were made on all infants from randomisation until discharge. The primary outcome measures were number of transfusions received, rate of weight gain, and postmenstrual age at discharge. RESULTS: Thirty seven infants were randomised to each group. Birth weight (median, range) (1200, 1004-1373 v 1136, 1009-1285 g) and Hb (median, range) at randomisation (160, 149-179 v 155, 145-181 g/l) did not differ between the two groups. The total number of transfusions given to the NIRS group was 56 and to the conventional group 84. The median number of transfusions per infant, the median volume of blood transfused to each group, and the total number of donors to which infants were exposed were similar in the two groups. Infants transfused according to the conventional protocol were more likely to be transfused earlier and at a higher Hb than those transfused in the NIRS group. Infants in the conventional group spent a significantly shorter period than those in the NIRS group with Hb < 100 g/l. Of the 56 transfusions given to the NIRS group, 33 (59%) were given because of clinical concerns rather than because of high FOE. There was no difference in the rate of weight gain, rate of linear growth, postmenstrual age at discharge, or the incidence of chronic lung disease or retinopathy of prematurity. CONCLUSIONS: FOE measurements failed to identify many infants felt by clinicians to require blood transfusion. This may have been because clinicians relied on conventional indicators of transfusion that are vague and non-specific, or a peripheral FOE of 0.47 alone may not be a sensitive enough predictor of the need for transfusion. This requires further study.

Dependency level of babies on the neonatal unit: a comparison of two different classification systems.

BACKGROUND: Monitoring activity on the neonatal unit is important for planning service provision and as part of monitoring quality of care. The dependency level of the patients cared for must be taken into account as well as the number of patients. Two different systems for determining dependency level are in common use. AIM: To develop a system that would allow the accurate determination of dependency level for babies in our care using both the British Association for Perinatal Medicine and Neonatal Nurses Association definitions and the Northern Neonatal Network definitions and to perform a comparison between these two systems. METHOD: Forty details relating to current clinical status and treatment being given were recorded daily for every patient on two neonatal units over a 17 month period. These details were recorded in a computer database, and dependency levels were calculated for each patient day using both systems. RESULTS: A total of 21 905 patient days were recorded for 1555 patients. There was good agreement between the two systems on what constituted the highest level of dependency, but overall comparability was poor, with the two systems assigning comparable dependency levels to only 76% of patient days. CONCLUSIONS: There is limited comparability in dependency levels between these two widely used systems. There is a need for a standardisation of definitions to allow meaningful comparisons to be made between units.

Time to positivity of neonatal blood cultures.

AIM: To determine how long it takes neonatal blood cultures to become positive. METHODS: Data were collected retrospectively on 451 positive blood cultures from babies on a tertiary neonatal unit between January 1997 and December 1998. During the study period, the laboratory used the BacT/Alert microbial detection system. RESULTS: Complete information was available on 416 blood cultures. Twelve became positive after 72 hours, none of which were considered to be clinically significant. Of the 404 remaining cultures, 86% were positive at 36 hours, 96% at 48 hours, and 98.5% by 60 hours. If definite bacterial pathogens are considered alone, the time to positivity was 90% by 36 hours, 93% by 48 hours, and 98% by 60 hours. If definite and possible bacterial pathogens are considered (coagulase negative staphylococci taken as possible bacterial pathogens), the time to positivity was 89% at 36 hours and 97% at 48 hours. The negative predictive value, for isolation of any organism before 72 hours, of a negative blood culture was 97% at 36 hours and 99% at 48 hours. The negative predictive value for the isolation of definite bacterial pathogens only was 99.7% at 36 hours and 99.8% at 48 hours. CONCLUSIONS: A period of 36 hours is enough to rule out sepsis in the asymptomatic neonate, and a three day incubation period is sufficient to detect all clinically important infections using the BacT/Alert microbial detection system.