Reducing False Alarm Rates in Neonatal Intensive Care: A New Machine Learning Approach.

In neonatal intensive care units (NICUs), 87.5% of alarms by the monitoring system are false alarms, often caused by the movements of the neonates. Such false alarms are not only stressful for the neonates as well as for their parents and caregivers, but may also lead to longer response times in real critical situations. The aim of this project was to reduce the rates of false alarms by employing machine learning algorithms (MLA), which intelligently analyze data stemming from standard physiological monitoring in combination with cerebral oximetry data (in-house built, OxyPrem). MATERIALS & METHODS: Four popular MLAs were selected to categorize the alarms as false or real: (i) decision tree (DT), (ii) 5-nearest neighbors (5-NN), (iii) naïve Bayes (NB) and (iv) support vector machine (SVM). We acquired and processed monitoring data (median duration (SD): 54.6 (± 6.9) min) of 14 preterm infants (gestational age: 26 6/7 (± 2 5/7) weeks). A hybrid method of filter and wrapper feature selection generated the candidate subset for training these four MLAs. RESULTS: A high specificity of >99% was achieved by all four approaches. DT showed the highest sensitivity (87%). The cerebral oximetry data improved the classification accuracy. DISCUSSION & CONCLUSION: Despite a (as yet) low amount of data for training, the four MLAs achieved an excellent specificity and a promising sensitivity. Presently, the current sensitivity is insufficient since, in the NICU, it is crucial that no real alarms are missed. This will most likely be improved by including more subjects and data in the training of the MLAs, which makes pursuing this approach worthwhile.

Self-perceived health status and mental health outcomes in young adults born with less than 1000 g.

AIM: To assess self-perceived health status and mental health outcomes of former extremely low-birth-weight (ELBW) infants at young adulthood compared with community norms and to analyse predictors of poor outcome. METHODS: Fifty-five ELBW adults, 18 men (33%), with median (range) gestational age of 28.7 (25.0-34.0) weeks and birth weight of 930 (680-990) grams, born in Switzerland, were included. They self-rated their health status and mental health at a mean (range) age of 23.3 (21.8-25.9) years. Health status was measured by the Medical Outcomes Study Short Form-36 questionnaire and mental health by the Brief Symptom Inventory. RESULTS: The mean scores for both outcome measures were in the normal range. However, the study group self-rated significantly higher physical health status and lower mental health status compared with the community norms, and scores for self-perceived mental health tended to be worse in the former. ELBW adults reported more problems in socio-emotional role functioning compared with the community norms. Female sex was associated with poorer and bronchopulmonary dysplasia with better mental health status. CONCLUSION: Health status and mental health of former ELBW adults were overall satisfying. However, the comparison with the community norms revealed differences, which may be important for parental and patient counselling and developing support strategies.

Neonatal morbidity in singleton late preterm infants compared with full-term infants.

AIM: The aim of this study was to test the hypothesis that singleton late preterm infants (34 0/7 to 36 6/7 weeks of gestation) compared with full-term infants have a higher incidence of short-term morbidity and stay longer in hospital. METHODS: In this retrospective, multicentre study, electronic data of children born at five hospitals in Switzerland were recorded. Short-term outcome of late preterm infants was compared with a control group of full-term infants (39 0/7 to 40 6/7 weeks of gestation). Multiple gestations, pregnancies complicated by foetal malformations, maternal consumption of illicit drugs and infants with incomplete documentation were excluded. The results were corrected for gender imbalance. RESULTS: Data from 530 late preterm and 1686 full-term infants were analysed. Compared with full-term infants, late preterm infants had a significant higher morbidity: respiratory distress (34.7% vs. 4.6%), hyperbilirubinaemia (47.7% vs. 3.4%), hypoglycaemia (14.3% vs. 0.6%), hypothermia (2.5% vs. 0.6%) and duration of hospitalization (mean, 9.9 days vs. 5.2 days). The risk to develop at least one complication was 7.6 (95% CI: 6.2-9.6) times higher among late preterm infants (70.8%) than among full-term infants (9.3%). CONCLUSION: Singleton late preterm infants show considerably higher rate of medical complications and prolonged hospital stay compared with matched full-term infants and therefore need more medical and financial resources.

Interobserver variability in assessment of cranial ultrasound in very preterm infants.

BACKGROUND: Cranial ultrasound (cUS) findings help doctors in the clinical management of preterm infants and in their discussion with parents regarding prediction of outcome. cUS is often used as outcome measure in clinical research studies. Accurate cUS performance and interpretation is therefore required. AIMS: The aims of this study were (i) to assess the interobserver variability in cUS interpretation, and (ii) to evaluate whether level of cUS expertise influences the interobserver variability. METHODS: Fifty-eight cUS image series of preterm infants born below 32 weeks of gestation collected within the Swiss Neonatal Network were sent to 27 observers for reviewing. Observers were grouped into radiologists, experienced neonatologists and less experienced neonatologists. Agreement between observers was calculated using Kappa statistics. RESULTS: When cystic periventricular leukomalacia, intraventricular haemorrhage and periventricular haemorrhagic infarction were combined to one outcome, agreement among all observers was moderate. When divided into subgroups, kappa for the combined outcome was 0.7 for experienced neonatologists, 0.67 for radiologists and 0.53 for inexperienced neonatologists. Marked difference in interobserver agreement between experienced neonatologists and radiologists could be found for haemorrhagic periventricular ifraction (HPI). CONCLUSIONS: Our results suggest that interobserver agreement for interpretation of cUS varies from poor to good varying with the type of abnormality and level of expertise, suggesting that widespread structured training should be made available to improve the performance and interpretation of cUS.

[The early postnatal weight gain as a predictor of retinopathy of prematurity]. / Der frühe postnatale Gewichtsverlauf als Prädiktor einer Frühgeborenenretinopathie.

BACKGROUND: Premature infants are often stressed by the current retinopathy of prematurity (ROP) screening procedure. Additionally, only < 10 % of the screened infants will develop a ROP stadium requiring laser therapy. Therefore the present screening strategy is unsatisfactory. Furthermore, the current guidelines do not take into account postnatal factors. A new method considering postnatal factors is the weight, insulin-like growth factor, neonatal ROP (WINROP) algorithm. This approach is based on the early postnatal weight gain. The aim of this study was to assign the WINROP-algorithm to a preterm population in Switzerland and to analyze its ability for prediction. PATIENTS AND METHODS: In this retrospective study, all preterm infants with a gestational age (GA) < 32 weeks and/or a birth weight (BW) ≤ 1500 g taken care of in the Department of Neonatology at the University Hospital Zurich from January 2003 to December 2008 were included. The weekly postnatal weight gain was analyzed by means of the modified WINROP-algorithm. RESULTS: Altogether 376 preterm infants were analyzed. In 58 infants a "high-risk" alarm was released, thereof eight preterms developed a severe ROP and four of them needed laser therapy. CONCLUSIONS: The high predictive value of the WINROP-algorithm was confirmed in our population of Swiss preterms. This instrument has the potential to simplify the current ROP screening procedure. Accordingly, the amount of ophthalmoscopies could be reduced significantly.

How useful is routine amniotic fluid and neonatal surface swab microbiology at Caesarean section?

BACKGROUND: Our aim was to evaluate the clinical impact of routine amniotic fluid and neonatal surface swab microbiology at Caesarean section. MATERIALS AND METHODS: Microbiology data from 1 537 neonates delivered by Caesarean section were analysed in the light of clinical outcome. RESULTS: 1 340 (87%) neonates had non-pathogenic bacteria or negative culture results from both amniotic fluid and surface swab samples. Of the 197 (13%) neonates with pathogenic bacteria, 22 (1.4%) were diagnosed with infection, but only in 6 (0.4%) were the bacteria presumed to be responsible for the infection. Amniotic fluid and surface swab culture had sensitivities of 54% and 35%, and positive predictive values of 14% and 17%, respectively, for detecting a neonate at risk of infection. CONCLUSION: Amniotic fluid and neonatal surface swab microbiology at Caesarean section contributes little if anything to postnatal management and can be safely dropped from operative routine.

Network based statistics reveals trophic and neuroprotective effect of early high dose erythropoetin on brain connectivity in very preterm infants.

Periventricular white matter injury is common in very preterm infants and it is associated with long term neurodevelopmental impairments. While evidence supports the protective effects of erythropoetin (EPO) in preventing injury, we currently lack the complete understanding of how EPO affects the emergence and maturation of anatomical brain connectivity and function. In this case-control study, connectomic analysis based on diffusion MRI tractography was applied to evaluate the effect of early high-dose EPO in preterm infants. A whole brain, network-level analysis revealed a sub-network of anatomical brain connections in which connectivity strengths were significantly stronger in the EPO group. This distributed network comprised connections predominantly in the frontal and temporal lobe bilaterally, and the effect of EPO was focused on peripheral and feeder connections of the core structural connectivity network. EPO resulted in a globally increased clustering coefficient, higher global and average local efficiency, while higher strength and increased clustering was found for regions in the frontal lobe and cingulate gyrus. The connectivity network most affected by the EPO treatment showed a steeper increase graph theoretical measures with age compared to the placebo group. Our results demonstrate a weak but widespread effect of EPO on the structural connectivity network and a possible trophic effect of EPO reflected by increasing network segregation, predominantly in local connections.

Parents' mental health after the birth of an extremely preterm child: a comparison between bereaved and non-bereaved parents.

OBJECTIVE: To assess the impact of extremely preterm birth (24-26 weeks of gestation) on the mental health of parents two to six years after delivery, and to examine potential differences in post-traumatic growth between parents whose newborn infant died and those whose child survived. METHOD: A total of 54 parents who had lost their newborn and 38 parents whose preterm child survived were assessed by questionnaires with regard to depression and anxiety (HADS) and post-traumatic growth (PTGI). RESULTS: Neither group of parents had clinically relevant levels of depression and anxiety. Mothers showed higher levels of anxiety than fathers. Bereaved parents with no other, living child reported higher levels of depression than bereaved parents with one or more children. Mothers reported higher post-traumatic growth compared to fathers. In particular, bereaved mothers experienced the value and quality of their close social relationships more positively compared to the non-bereaved parents. CONCLUSION: In the long term, bereaved and non-bereaved parents cope reasonably well with an extremely preterm birth of a child. Post-traumatic growth appears to be positively related to bereavement, particularly in mothers.

Retrospective cohort study of all deaths among infants born between 22 and 27 completed weeks of gestation in Switzerland over a 3-year period.

OBJECTIVES: The aim of this research is to assess causes and circumstances of deaths in extremely low gestational age neonates (ELGANs) born in Switzerland over a 3-year period. DESIGN: Population-based, retrospective cohort study. SETTING: All nine level III perinatal centres (neonatal intensive care units (NICUs) and affiliated obstetrical services) in Switzerland. PATIENTS: ELGANs with a gestational age (GA) <28 weeks who died between 1 July 2012 and 30 June 2015. RESULTS: A total of 594 deaths were recorded with 280 (47%) stillbirths and 314 (53%) deaths after live birth. Of the latter, 185 (59%) occurred in the delivery room and 129 (41%) following admission to an NICU. Most liveborn infants dying in the delivery room had a GA ≤24 weeks and died following primary non-intervention. In contrast, NICU deaths occurred following unrestricted life support regardless of GA. End-of-life decision-making and redirection of care were based on medical futility and anticipated poor quality of life in 69% and 28% of patients, respectively. Most infants were extubated before death (87%). CONCLUSIONS: In Switzerland, most deaths among infants born at less than 24 weeks of gestation occurred in the delivery room. In contrast, most deaths of ELGANs with a GA ≥24 weeks were observed following unrestricted provisional intensive care, end-of-life decision-making and redirection of care in the NICU regardless of the degree of immaturity.

The impact of a register on the management of neonatal cooling in Switzerland.

BACKGROUND: Therapeutic hypothermia following hypoxic ischaemic encephalopathy in term infants was introduced into Switzerland in 2005. Initial documentation of perinatal and resuscitation details was poor and neuromonitoring insufficient. In 2011, a National Asphyxia and Cooling Register was introduced. AIMS: To compare management of cooled infants before and after introduction of the register concerning documentation, neuromonitoring, cooling methods and evaluation of temperature variability between cooling methods. STUDY DESIGN: Data of cooled infants before the register was in place (first time period: 2005-2010) and afterwards (second time period: 2011-2012) was collected with a case report form. RESULTS: 150 infants were cooled during the first time period and 97 during the second time period. Most infants were cooled passively or passively with gel packs during both time periods (82% in 2005-2010 vs 70% in 2011-2012), however more infants were cooled actively during the second time period (18% versus 30%). Overall there was a significant reduction in temperature variability (p < 0.001) comparing the two time periods. A significantly higher proportion of temperature measurements within target temperature range (72% versus 77%, p < 0.001), fewer temperature measurements above (24% versus 7%, p < 0.001) and more temperatures below target range (4% versus 16%, p < 0.001) were recorded during the second time period. Neuromonitoring improved after introduction of the cooling register. CONCLUSION: Management of infants with HIE improved since introducing the register. Temperature variability was reduced, more temperature measurements in the target range and fewer temperature measurements above target range were observed. Neuromonitoring has improved, however imaging should be performed more often.

Transcutaneous carbon dioxide tension in newborn infants: reliability and safety of continuous 24-hour measurement at 42 degrees C.

In 58 newborn infants a new iridium oxide sensor was evaluated for transcutaneous carbon dioxide (tcPCO2) monitoring at 42 degrees C with a prolonged fixation time of 24 hours. The correlation of tcPCO2 (y; mm Hg) v PaCO2 (x; mm Hg) for 586 paired values was: y = 4.6 + 1.45x; r = .89; syx = 6.1 mm Hg. The correlation was not influenced by the duration of fixation. The transcutaneous sensor detected hypocapnia (PaCO2 less than 35 mm Hg) in 74% and hypercapnia (PCO2 greater than 45 mm Hg) in 74% of all cases. After 24 hours, calibration shifts were less than 4 mm Hg in 90% of the measuring periods. In 86% of the infants, no skin changes were observed; in 12% of infants, there were transitional skin erythemas and in 2% a blister which disappeared without scarring. In newborn infants with normal BPs, continuous tcPCO2 monitoring at 42 degrees C can be extended for as many as 24 hours without loss of reliability or increased risk for skin burns.

Hyperoxemia in newborn infants: detection by pulse oximetry.

Pulse oximetry has been proposed as a noninvasive continuous method for transcutaneous monitoring of arterial oxygen saturation of hemoglobin (tcSO2) in the newborn infant. The reliability of this technique in detecting hyperoxemia is controversial, because small changes in saturation greater than 90% are associated with relatively large changes in arterial oxygen tension (PaO2). The purpose of this study was to assess the reliability of pulse oximetry using an alarm limit of 95% tcSO2 in detecting hyperoxemia (defined as PaO2 greater than 90 mm Hg) and to examine the effect of varying the alarm limit on reliability. Two types of pulse oximeter were studied alternately in 50 newborn infants who were mechanically ventilated with indwelling arterial lines. Three arterial blood samples were drawn from every infant during routine increase of inspired oxygen before intratracheal suction, and PaO2 was compared with tcSO2. The Nellcor N-100 pulse oximeter identified all 26 hyperoxemic instances correctly (sensitivity 100%) and alarmed falsely in 25 of 49 nonhyperoxemic instances (specificity 49%). The Ohmeda Biox 3700 pulse oximeter detected 13 of 35 hyperoxemic instances (sensitivity 37%) and alarmed falsely in 7 of 40 nonhyperoxemic instances (specificity 83%). The optimal alarm limit, defined as a sensitivity of 95% or more associated with maximal specificity, was determined for Nellcor N-100 at 96% tcSO2 (specificity 38%) and for Ohmeda Biox 3700 at 89% tcSO2 (specificity 52%). It was concluded that pulse oximeters can be highly sensitive in detecting hyperoxemia provided that type-specific alarm limits are set and a low specificity is accepted.

Loss of CO2 reactivity of cerebral blood flow is associated with severe brain damage in mechanically ventilated very low birth weight infants.

BACKGROUND: Early detection of pathophysiological factors associated with permanent and severe brain damage in preterm infants requiring intensive care is a major issue in neonatal neurology. The aim of this study was to investigate if an abnormal CO2 reactivity of cerebral blood flow in high risk very low birth weight infants is associated with severe brain injury demonstrated at autopsy or by neurodevelopment examination at 18 months. METHODS: The CO2 reactivity of cerebral blood flow (xenon-133) was measured in 18 mechanically ventilated, severely ill, very low birthweight infants (gestational age 26-32 weeks, birthweight: 630-1360 g) during the first 36 hours of life. Cerebral outcome was assessed on autopsy findings (n = 8) or at the age of 18 months using Bayley developmental scales (n = 10). RESULTS: Eight infants with normal development at 18 months (within mean +/- 2.5 SD of reference group) and two infants with normal cerebral autopsy findings had a median CO2 reactivity of 24.4%/kPa CO2 (interquartile range 14.7-41.2). Two infants with abnormal development (> 2.5 SD below mean) and six infants with hypoxic-ischaemic encephalopathy at autopsy has a median CO2 reactivity of 3.4%/kPa CO2 (interquartile range 8.0-11.7). CONCLUSION: In mechanically ventilated very low birthweight infants low CO2 reactivity of cerebral blood flow (below 10%/kPa CO2) during the first 36 hours of life was associated with poor neurodevelopmental outcome or hypoxic-ischaemic encephalopathy at autopsy. Loss of CO2 reactivity may play a role in the pathogenesis of hypoxic ischaemic encephalopathy. It is a candidate for predicting early severe brain damage in preterm infants requiring intensive care and for controlling the effect of early interventions.

The influence of a clear layer on near-infrared spectrophotometry measurements using a liquid neonatal head phantom.

It is difficult to test near-infrared spectrophotometry instruments in vivo. Therefore we constructed a liquid phantom which mimics the neonatal head. It consists of a spherical 3.5 mm thick layer of silicone rubber simulating skin and bone and a 0.5 mm thick clear layer of polypropylene imitating cerebrospinal fluid. It acts as container for a liquid solution with Intralipid, 60 micromol l(-1) haemoglobin and yeast. The solution was oxygenated using oxygen and then deoxygenated by the yeast. From the instrumental (Critikon 2020) algorithm, we found that with increasing scattering (0.5%, 1%, 1.5% and 2% Intralipid concentration) the reading was increasingly offset from the expected value of 0 micromol l(-1) by 55.7, 68.6, 76.5 and 80.4 micromol l(-1) (oxyhaemoglobin) and 16.0, 24.4, 29.6 and 31.7 micromol l(-1) (deoxyhaemoglobin). This reduced the range of the oxygen saturation reading from the expected 100% to 31.5, 21.1, 14.3 and 11.5%. Haemoglobin concentration changes were increasingly underestimated by a factor of two to four. For a second algorithm based on the diffusion approximation the offsets were smaller: oxyhaemoglobin 11.4, 17.8, 22.5 and 25.1 micromol l(-1) and deoxyhaemoglobin 1.3, 3.4, 5.2 and 6.0 micromol l(-1). The range of the oxygen saturation reading was higher: 41.3, 29.2, 23.4 and 16.6%. Concentration changes were underestimated by a factor of six to ten. This study demonstrates the need to develop algorithms which take into consideration anatomical structures.

Cyclical fluctuations in blood pressure, heart rate and cerebral blood volume in preterm infants.

Many recently published papers describe cyclical changes of cerebral circulatory variables, mainly in cerebral blood flow velocity (CBFV) performed with Doppler sonography. In this paper we focus on another important variable of cerebral circulation: on cerebral blood volume (CBV) measured by near infrared spectrophotometry (NIRS). In a retrospective analysis of NIRS measurements in 20 preterm infants (median 27 3/7 weeks of gestation), the dominating frequencies and prevalence of cyclical changes of CBV and its possible correlation with peripheral circulatory variables (mean arterial pressure and heart rate) was examined. In 19 out of the 20 infants cyclical changes of CBV were found within a frequency range of 2-4.7 cycles/min which is comparable to the results of the Doppler studies describing fluctuations in CBFV. A dominating frequency of heart rate (HR), was found only in 12 out of 20 infants, and it was with 2.1-3.8 cycles/min in a similar range compared to CBV. In mean arterial blood pressure (MABP), however we detected cycles with longer periods every 1-2.5 min in 14 out of 20 infants. There was a significant coherence between MABP/CBV and HR/CBV. The area under the coherence curve, however, was significantly larger between MABP and CBV as compared to HR and CBV (P = 0.0007, Wilcoxon signed-rank test).

Cerebral blood flow in preterm infants affected by sex, mechanical ventilation, and intrauterine growth.

Sex differences in cerebral blood flow (CBF) values have been demonstrated in adults but not in newborns. This study evaluated the influence of sex, intrauterine growth, and need of mechanical ventilation on resting cerebral blood flow in preterm neonates. Sixty-eight preterm infants with gestational ages of less than 34 weeks and birth weights of less than 1,500 gm were enrolled into the study. Cerebral blood flow was measured by the noninvasive intravenous xenon 133 method 3 times. Measurements were classified into 3 groups: group 1: measurement at 2-36 hours (n = 46); group 2: measurement at 36-108 hours (n = 39); and group 3: measurement at 108-240 hours (n = 41). In all 3 groups, the CBF in girls was significantly lower than in boys (group 1: 11.5 +/- 2.8 ml/100 gm/min vs 14.0 +/- 4.1 ml/100 gm/min; group 2: 13.4 +/- 2.9 ml/100 gm/min vs 16.3 +/- 4.3 ml/100 gm/min; group 3: 12.9 +/- 3.2 ml/100 gm/min vs 15.3 +/- 3.1 ml/100 gm/min). In group 1, the CBF in neonates requiring mechanical ventilation was significantly lower (P < .05) than in patients who were spontaneously breathing (11.5 +/- 3.7 ml/100 gm/min vs 14.2 +/- 3.1 ml/100 gm/min), and the CBF in neonates who were too small for gestational age was significantly higher (P < .005) than in children with appropriate intrauterine growth (16.1 +/- 4.1 ml/100 gm/min vs 11.5 +/- 2.6 ml/100 gm/min). It is concluded that in preterm neonates CBF is substantially affected by sex, intrauterine growth retardation, and the need of mechanical ventilation.

Sleep state changes associated with cerebral blood volume changes in healthy term newborn infants.

In order to assess the possible effects of sleep states on cerebral haemodynamics in healthy term infants, we measured cerebral oxyhaemoglobin, deoxyhaemoglobin and total haemoglobin concentration using near infrared spectroscopy. Thirty-seven sleep state changes in seventeen infants (gestational age: 37 to 41 4/7 weeks), aged between two and eight days were continuously registrated during 1-3 h. Transcutaneous PaO2, PaCO2, arterial O2 saturation and heart rate were simultaneously recorded and sleep states were clinically defined. There was a close relationship between sleep state changes and changes in total cerebral haemoglobin concentration, which increased from active to quiet sleep and decreased from quiet to active sleep. Changes in total cerebral haemoglobin were due, in the most part, to changes in the cerebral oxyhaemoglobin concentration. In conclusion, sleep states influence the cerebral haemoglobin concentration. Studies on cerebral haemodynamics should take sleep state into account in term newborn infants.

Artificial sweetener reduces nociceptive reaction in term newborn infants.

BACKGROUND: Sucrose has been shown to have an analgesic effect in preterm and term neonates. Sucrose, however, has a high osmolarity and may have deleterious effects in infants with fructose intolerance. Furthermore, it may favour caries. We therefore investigated the effects of a commercially available artificial sweetener (10 parts cyclamate and 1 part saccharin), glycine (sweet amino acid) or breast milk in reducing reaction to pain as compared with a placebo. SUBJECTS: Eighty healthy term infants, four days old, with normal birth weight. INTERVENTIONS: The infants were randomly assigned to one of four groups: 2 ml sweetener, glycine, expressed breast milk or water were given 2 min before a heel prick for the Guthrie test. The procedure was filmed with a video camera and analysed by two observers who did not know which medication the infant had received. RESULTS: Using a multivariate regression analysis, the following variables had significant correlation with relative crying time and recovery time: behavioural state before the intervention, the pricking nurse, and the type of medication. Relative crying time and recovery time were significantly less in the sweetener group but not in the glycine and the breast milk group. CONCLUSIONS: The artificial sweetener used in our study reduces pain reaction to a heel prick in term neonates, and thus provides an alternative to sucrose. In contrast, glycine tends to increase pain reaction whereas breast milk has no effect.

Two years outcome of very pre-term and very low birthweight infants in Switzerland.

BACKGROUND: There are only few reports worldwide on the outcome of very pre-term infants and very low birthweight infants for a whole country. In Switzerland official population statistics are based on birthweight only, gestational age not yet being documented. AIM: The aim of the present study was to assess the outcome at two years of age for a geographically defined high-risk neonatal population based on both birthweight and gestational age. METHODS: All infants born in 1996 included in the Swiss Neonatal Network (a national anonymous registry established by the Swiss Society of Neonatology for liveborn infants before 32 completed gestational weeks or weighing less than 1500 g) were divided into three groups according to gestational age and birth weight: Group 1: born <32 completed gestational weeks and weighing =1500 g; group 2: born after 32 completed gestational weeks and weighing <1500 g; group 3: born <32 gestational weeks and weighing <1500 g. Information at 24 months corrected age about growth, neurological outcome, frequency of respiratory infections, prescription of antibiotics and medical consultations during this period was obtained from the paediatricians caring for the infants. Fair outcome was defined as survival without serious neonatal complications or abnormal neurological findings at 24 months corrected for prematurity. RESULTS: 723 infants were born alive in Switzerland between 1.1. and 31.12.1996 before 32 completed weeks or weighing less than 1500 g at birth. Mortality was 4.3% for a total of 163 infants in group 1 (<32 weeks, =1500 g), 4.6% for 108 infants in group 2 (>32 weeks, <1500 g) and 18.6% for 452 infants in group 3 (<32 weeks, <1500 g). 6.5% of group 1 survivors followed up to 24 months corrected age had a poor neurological outcome as compared to 9.3% in group 2 and 10.9% in group 3. Infants in group 1 needed antibiotics less often after hospital discharge (interquartile range IQR: 0-2 courses) than infants in group 2 (0-3 courses) and 3 (0-3 courses). Infants in group 2 suffered from fewer airway infections (interquartile range 2-5 times) than in group 1 (2-6 times) and 3 (1-7 times). Infants in group 3 needed more medical consultations (IQR 12-21) than those in group 1 (10-16) and 2 (11-16). The overall fair outcome at 24 months corrected age was 85.3% in group 1, 80.7% in group 2 and 59.6% in group 3. A close correlation between overall fair outcome and gestational age at birth on the one hand and with birthweight on the other can be observed. CONCLUSIONS: This study gives estimates for mortality, poor and fair outcome at 24 months corrected age for very low birth weight infants (<1500 g) and for very pre-term infants (<32 completed gestational weeks). Gestational age is as important for predicting outcome as birthweight and should therefore be integrated into national statistics.

Reflectance pulse oximetry in neonates.

OBJECTIVE: To test the feasibility and reliability in neonates of an in-house reflectance pulse oximetry (RPOX) system as an alternative method of non-invasive oxygen saturation monitoring when transmission pulse oximetry (TPOX) cannot be used, as in fetal scalp oxygen saturation monitoring during delivery. STUDY DESIGN: The study population consisted of 31 intensive care neonates. The RPOX sensor was attached by suction to the forehead, cheek, occiput and back; recordings were under simultaneous TPOX control. RESULTS: There was close agreement between RPOX and TPOX oxygen saturation and heart rate values, even in periodic breathing. RPOX signals from the back were unreliable because of breathing artifacts. Differences in mean absolute RPOX and TPOX oxygen saturation values were due to different calibrations. Both systems were equally sensitive to motion artifacts. CONCLUSION: As a feasible and reliable method of non-invasive oxygen saturation monitoring in neonates, RPOX has potential applications in fetal scalp monitoring.