Variation in antibiotic consumption in very preterm infants-a 10 year population-based study.

OBJECTIVES: Wide variations in antibiotic use in very preterm infants have been reported across centres despite similar rates of infection. We describe 10 year trends in use of antibiotics and regional variations among very preterm infants in Norway. PATIENTS AND METHODS: All live-born very preterm infants (<32 weeks gestation) admitted to any neonatal unit in Norway during 2009-18 were included. Main outcomes were antibiotic consumption expressed as days of antibiotic therapy (DOT) per 1000 patient days (PD), regional variations in use across four health regions, rates of sepsis and sepsis-attributable mortality and trends of antibiotic use during the study period. RESULTS: We included 5296 infants: 3646 (69%) were born at 28-31 weeks and 1650 (31%) were born before 28 weeks gestation with similar background characteristics across the four health regions. Overall, 80% of the very preterm infants received antibiotic therapy. The most commonly prescribed antibiotics were the combination of narrow-spectrum ß-lactams and aminoglycosides, but between 2009 and 2018 we observed a marked reduction in their use from 100 to 40 DOT per 1000 PD (P < 0.001). In contrast, consumption of broad-spectrum ß-lactams remained unchanged (P = 0.308). There were large variations in consumption of vancomycin, broad-spectrum ß-lactams and first-generation cephalosporins, but no differences in sepsis-attributable mortality across regions. CONCLUSIONS: The overall antibiotic consumption was reduced during the study period. Marked regional variations remained in consumption of broad-spectrum ß-lactams and vancomycin, without association to sepsis-attributable mortality. Our results highlight the need for antibiotic stewardship strategies to reduce consumption of antibiotics that may enhance antibiotic resistance development.

Inter-rater reliability of the Silverman and Andersen index-a measure of respiratory distress in preterm infants.

BACKGROUND: There are various methods of respiratory support available to optimize respiratory function in preterm infants. Respiratory scoring tools might provide information on which method to choose and the level and duration of support needed. Before implementing a respiratory scoring tool in our clinical practice, we aimed to test the inter- and intra-rater reliability of the Silverman and Andersen index (SA index) among neonatologists and nurses when applied to preterm infants on respiratory support. We also examined the association between the SA index and the electrical activity of the diaphragm (Edi signals). METHODS: This was a multicenter study including three newborn intensive care units in Norway. Four neonatologists and 10 nurses applied the SA index when assessing 80 videos of 44 preterm infants on High Flow Nasal Cannula, Continuous Positive Airway Pressure and Neurally Adjusted Ventilatory Assist. The inter- and intra-rater reliability for the sum scores were measured by the intra-class correlation coefficient (ICC), and Kendall's W was used to assess the degree of agreement for each item. We quantified the association between the Edi signals and the SA index scores by the Spearman's correlation coefficient. RESULTS: We found poor inter-rater reliability with an ICC for absolute agreement of 0.34 (95% CI: 0.20 to 0.53). There was fair agreement measuring each item separately for upper chest movements (Kendall's W 0.30), and moderate for lower chest movements (0.43) and xiphoid retractions (0.44). Expiratory grunting showed substantial agreement (0.67). The intra-rater reliability was good (ICC for absolute agreement 0.77; 95% CI: 0.68 to 0.84). We found a moderate positive correlation (r = 0.468, p = 0.028) between the maximum inspiratory diaphragm activity (Edi peak) and the mean inspiratory SA index scores. CONCLUSION: Our study showed poor inter-rater and good intra-rater reliability of the SA index when nurses and neonatologists assessed videos of preterm infants on various types of respiratory support. Edi peak and SA index had a moderate positive correlation. Formal training might be essential to improve the inter-rater reliability. TRIAL REGISTRATION: Registered 26th June 2017, ClinicalTrials.gov Identifier: NCT03199898.

Associations between unit workloads and outcomes of first extubation attempts in extremely premature infants below a gestational age of 26 weeks.

Objective: The objective was to explore whether high workloads in neonatal intensive care units were associated with short-term respiratory outcomes of extremely premature (EP) infants born <26 weeks of gestational age. Methods: This was a population-based study using data from the Norwegian Neonatal Network supplemented by data extracted from the medical records of EP infants <26 weeks GA born from 2013 to 2018. To describe the unit workloads, measurements of daily patient volume and unit acuity at each NICU were used. The effect of weekend and summer holiday was also explored. Results: We analyzed 316 first planned extubation attempts. There were no associations between unit workloads and the duration of mechanical ventilation until each infant's first extubation or the outcomes of these attempts. Additionally, there were no weekend or summer holiday effects on the outcomes explored. Workloads did not affect the causes of reintubation for infants who failed their first extubation attempt. Conclusion: Our finding that there was no association between the organizational factors explored and short-term respiratory outcomes can be interpreted as indicating resilience in Norwegian neonatal intensive care units.

Predictors of extubation success: a population-based study of neonates below a gestational age of 26 weeks.

OBJECTIVE: The aim of the study was to investigate first extubation attempts among extremely premature (EP) infants and to explore factors that may increase the quality of clinical judgement of extubation readiness. DESIGN AND METHOD: A population-based study was conducted to explore first extubation attempts for EP infants born before a gestational age (GA) of 26 weeks in Norway between 1 January 2013 and 31 December 2018. Eligible infants were identified via the Norwegian Neonatal Network database. The primary outcome was successful extubation, defined as no reintubation within 72 hours after extubation. RESULTS: Among 482 eligible infants, 316 first extubation attempts were identified. Overall, 173 (55%) infants were successfully extubated, whereas the first attempt failed in 143 (45%) infants. A total of 261 (83%) infants were extubated from conventional ventilation (CV), and 55 (17%) infants were extubated from high-frequency oscillatory ventilation (HFOV). In extubation from CV, pre-extubation fraction of inspired oxygen (FiO2) ≤0.35, higher Apgar score, higher GA, female sex and higher postnatal age were important predictors of successful extubation. In extubation from HFOV, a pre-extubation FiO2 level ≤0.35 was a relevant predictor of successful extubation. CONCLUSIONS: The correct timing of extubation in EP infants is important. In this national cohort, 55% of the first extubation attempts were successful. Our results suggest that additional emphasis on oxygen requirement, sex and general condition at birth may further increase extubation success when clinicians are about to extubate EP infants for the first time.

Corrigendum: Can We Optimize Antibiotic Use in Norwegian Neonates? A Prospective Comparison Between a University Hospital and a District Hospital.

[This corrects the article DOI: 10.3389/fped.2019.00440.].

Antibiotic use in children before, during and after hospitalisation.

PURPOSE: To investigate ambulatory antibiotic use in children during 1 year before and 1 year after in-hospital antibiotic exposure compared to children from the general population that had not received antibiotics in-hospital. METHODS: Explorative data-linkage cohort study from Norway of children aged 3 months to 17 years. One group had received antibiotics in-Hospital (H+), and one group had not received antibiotics in-hospital (H-). The H+ group was recruited during admission in 2017. Using the Norwegian Population Registry, 10 children from the H- group were matched with one child from the H+ group according to county of residence, age and sex. We used the Norwegian Prescription Database to register antibiotic use 1 year before and 1 year after the month of hospitalisation. RESULTS: Of 187 children in the H+ group, 83 (44%) received antibiotics before hospitalisation compared to 288/1870 (15%) in the H- group, relative risk (RR) 2.88 (95% confidence interval 2.38-3.49). After hospitalisation, 86 (46%) received antibiotics in the H+ group compared to 311 (17%) in the H- group, RR 2.77 (2.30-3.33). Comorbidity-adjusted RR was 2.30 (1.84-2.86) before and 2.25 (1.81-2.79) after hospitalisation. RR after hospitalisation was 2.55 (1.99-3.26) in children 3 months-2 years, 4.03 (2.84-5.71) in children 3-12 years and 2.07 (1.33-3.20) in children 13-17 years. CONCLUSIONS: Children exposed to antibiotics in-hospital had two to three times higher risk of receiving antibiotics in ambulatory care both before and after hospitalisation. The link between in-hospital and ambulatory antibiotic exposure should be emphasised in future antibiotic stewardship programs.

Are infants exposed to antimicrobials during the first 3 months of life at increased risk of recurrent use? An explorative data-linkage study.

OBJECTIVES: To investigate whether infants exposed to antimicrobials in hospital during the first 3 months of life had an increased risk of ambulatory antimicrobial use during the following year compared with infants not exposed to antimicrobials during the first 3 months of life. METHODS: Norwegian cohort study of infants less than 3 months consisting of one group exposed to antimicrobials recruited during hospitalization and one group not exposed to antimicrobials. Ten unexposed infants were matched with one exposed infant according to county of residence, birth year and month, and sex. The Norwegian Prescription Database was applied to register antimicrobial use from the month after discharge and 1 year onward. We defined comorbidity based on antimicrobials prescribed as reimbursable prescriptions due to underlying diseases. RESULTS: Of 95 infants exposed to antimicrobials during the first 3 months of life, 23% had recurrent use compared with 14% use in 950 unexposed infants [relative risk (RR) = 1.7 (95% CI = 1.1-2.5) and comorbidity-adjusted RR = 1.4 (95% CI = 0.9-2.2)]. The recurrence use rate in exposed term infants (≥37 weeks, n = 70) was 27% compared with 12% in their unexposed matches [RR 2.3 = (95% CI = 1.4-3.7) and comorbidity-adjusted RR = 1.9 (95% CI = 1.2-3.2). Of 25 exposed preterm infants, 3 (12%) had recurrent use. The total antimicrobial prescription rate was 674/1000 in the exposed group and 244/1000 in the unexposed group [incidence rate ratio = 2.8 (95% CI = 1.6-4.9)]. CONCLUSIONS: Infants exposed to antimicrobials during the first 3 months of life had an increased risk of recurrent use during the following year. This increased risk also appeared in term infants without infection-related comorbidity.

European guidelines on perinatal care- Peripartum care Episiotomy.

OF RECOMMENDATIONS1. Episiotomy should be performed by indication only, and not routinely (Moderate quality evidence +++-; Strong recommendation). Accepted indications for episiotomy are to shorten the second stage of labor when there is suspected fetal hypoxia (Low quality evidence ++-; Weak recommendation); to prevent obstetric anal sphincter injury in vaginal operative deliveries, or when obstetric sphincter injury occurred in previous deliveries (Moderate quality evidence +++-; Strong recommendation)2. Mediolateral or lateral episiotomy technique should be used (Moderate quality evidence +++-; Strong recommendation). Labor ward staff should be offered regular training in correct episiotomy techniques (Moderate quality evidence +++-; Strong recommendation).3. Pain relief needs to be considered before episiotomy is performed, and epidural analgesia may be insufficient. The perineal skin needs to be tested for pain before an episiotomy is performed, even when an epidural is in place. Local anesthetics or pudendal block need to be considered as isolated or additional pain relief methods (Low quality evidence ++-; Strong recommendation).4. After childbirth the perineum should be carefully inspected, and the anal sphincter palpated to identify possible injury (Moderate quality evidence +++-; Strong recommendation). Primary suturing immediately after childbirth should be offered and a continuous suturing technique should be used when repairing an uncomplicated episiotomy (High quality evidence ++++; Strong recommendation).

In-Motion-App for remote General Movement Assessment: a multi-site observational study.

OBJECTIVES: To determine whether videos taken by parents of their infants' spontaneous movements were in accordance with required standards in the In-Motion-App, and whether the videos could be remotely scored by a trained General Movement Assessment (GMA) observer. Additionally, to assess the feasibility of using home-based video recordings for automated tracking of spontaneous movements, and to examine parents' perceptions and experiences of taking videos in their homes. DESIGN: The study was a multi-centre prospective observational study. SETTING: Parents/families of high-risk infants in tertiary care follow-up programmes in Norway, Denmark and Belgium. METHODS: Parents/families were asked to video record their baby in accordance with the In-Motion standards which were based on published GMA criteria and criteria covering lighting and stability of smartphone. Videos were evaluated as GMA 'scorable' or 'non-scorable' based on predefined criteria. The accuracy of a 7-point body tracker software was compared with manually annotated body key points. Parents were surveyed about the In-Motion-App information and clarity. PARTICIPANTS: The sample comprised 86 parents/families of high-risk infants. RESULTS: The 86 parent/families returned 130 videos, and 121 (96%) of them were in accordance with the requirements for GMA assessment. The 7-point body tracker software detected more than 80% of body key point positions correctly. Most families found the instructions for filming their baby easy to follow, and more than 90% reported that they did not become more worried about their child's development through using the instructions. CONCLUSIONS: This study reveals that a short instructional video enabled parents to video record their infant's spontaneous movements in compliance with the standards required for remote GMA. Further, an accurate automated body point software detecting infant body landmarks in smartphone videos will facilitate clinical and research use soon. Home-based video recordings could be performed without worrying parents about their child's development. TRIALS REGISTRATION NUMBER: NCT03409978.

Neonatal transitional support with intact umbilical cord in assisted vaginal deliveries: a quality-improvement cohort study.

BACKGROUND: Deferring cord clamping has proven benefits for both term and preterm infants, and recent studies have demonstrated better cardio-respiratory stability if clamping is based on the infant's physiology, and whether the infant has breathed. Nevertheless, current guidelines for neonatal resuscitation still recommend early cord clamping (ECC) for compromised babies, unless equipment and competent personnel to resuscitate the baby are available at the mother's bedside. The objective of this quality improvement cohort study was to evaluate whether implementing a new delivery room protocol involving mobile resuscitation equipment (LifeStart™) reduced the prevalence of ECC in assisted vaginal deliveries. METHODS: Data on cord clamping and transitional care were collected 8 months before and 8 months after implementing the new protocol. The Model for Improvement was applied to identify drivers and obstacles to practice change. Statistical Process Control analysis was used to demonstrate signals of improvement, and whether these changes were sustainable. Multivariate logistic regression was used to evaluate the impact of the new protocol on the primary outcome, adjusted for possible confounders. RESULTS: Overall prevalence of ECC dropped from 13 to 1% (P < 0.01), with a 98% relative risk reduction for infants needing transitional support on a resuscitation table (adjusted OR 0.02, P < 0.001). Mean cord clamping time increased by 43% (p < 0.001). Although fewer infants were placed directly on mothers' chest (n = 43 [42%] vs n = 69 [75.0%], P < 0.001), there were no significant differences in needs for immediate transitional care or transfers to Neonatal Intensive Care Unit. A pattern of improvement was seen already before the intervention, especially after mandatory educational sessions and cross-professional simulation training. CONCLUSIONS: A new delivery-room protocol involving mobile resuscitation equipment successfully eliminated early cord clamping in assisted vaginal deliveries of term and near-term infants. A systematic approach, like the Model for Improvement, seemed crucial for both achieving and sustaining the desired results. TRIAL REGISTRATION: The study was approved as a service evaluation as defined by the Regional Committee for Medical and Health Research Ethics ( 2018/1755/REK midt ).

Can We Optimize Antibiotic Use in Norwegian Neonates? A Prospective Comparison Between a University Hospital and a District Hospital.

Background: Worldwide, a large proportion of neonates are prescribed antibiotics without having infections leading to increased antimicrobial resistance, disturbance of the evolving microbiota, and increasing the risk of various chronical diseases. Comparing practice between different hospitals/settings is important in order to optimize antibiotic stewardship. Aim: To investigate and compare the potential for improved antibiotic stewardship in neonates in two Norwegian hospitals with different academic culture, with emphasis on antibiotic exposure in unconfirmed infections, treatment length/doses, CRP values and the use of broad-spectrum antibiotics (BSA). All types of infections were investigated, but the main focus was on early-onset sepsis (EOS). Methods: We conducted a prospective observational cohort study of antibiotic use in a Norwegian university hospital (UH) and a district hospital (DH), 2017. Unconfirmed infections were defined as culture negative infections that neither fulfilled the criteria for clinical infection (clinical symptoms, maximum CRP >30 mg/L, and treatment for at least 5 days). Results: Ninety-five neonates at the DH and 89 neonates at the UH treated with systemic antibiotics were included in the study. In total, 685 prescriptions (daily doses) of antibiotics were given at the DH and 903 at the UH. Among term and premature infants (≥ 28 weeks), 82% (75% at the UH and 86% at the DH, p = 0.172) of the treatments for suspected EOS were for unconfirmed infections, and average treatment length in unconfirmed infections was 3.1 days (both hospitals). Median dose for aminoglycoside was higher for term infants at the UH (5.96, 95% CI 5.02-6.89) compared to the DH (4.98, 95% CI 4.82-5.14; p < 0.001). At the UH, all prescriptions with aminoglycosides were gentamicin, while tobramycin accounted for 93% of all prescriptions with aminoglycosides at the DH. Conclusion: There is a potential for reduction in both antibiotic exposure and treatment length in these two neonatal units, and a systematic risk/observational algorithm of sepsis should be considered in both hospitals. We revealed no major differences between the UH and DH, but doses and choice of aminoglycosides varied significantly.

Using a period incidence survey to compare antibiotic use in children between a university hospital and a district hospital in a country with low antimicrobial resistance: a prospective observational study.

OBJECTIVES: To describe and compare antibiotic use in relation to indications, doses, adherence rate to guidelines and rates of broad-spectrum antibiotics (BSA) in two different paediatric departments with different academic cultures, and identify areas with room for improvement. DESIGN: Prospective observational survey of antibiotic use. SETTING: Paediatric departments in a university hospital (UH) and a district hospital (DH) in Norway, 2017. The registration period was 1 year at the DH and 4 months at the UH. PARTICIPANTS: 201 children at the DH (mean age 3.8: SD 5.1) and 137 children at the UH (mean age 2.0: SD 5.9) were treated with systemic antibiotics by a paediatrician in the study period and included in the study. OUTCOME MEASURES: Main outcome variables were prescriptions of antibiotics, treatments with antibiotics, rates of BSA, median doses and adherence rate to national guidelines. RESULTS: In total, 744 prescriptions of antibiotics were given at the UH and 638 at the DH. Total adherence rate to guidelines was 75% at the UH and 69% at the DH (p=0.244). The rate of treatments involving BSA did not differ significantly between the hospitals (p=0.263). Use of BSA was related to treatment of central nervous system (CNS) infections, patients with underlying medical conditions or targeted microbiological treatment in 92% and 86% of the treatments, at the UH and DH, respectively (p=0.217). A larger proportion of the children at the DH were treated for respiratory tract infections (p<0.01) compared with the UH. Children at the UH were treated with higher doses of ampicillin and cefotaxime (p<0.05) compared with the DH. CONCLUSION: Our results indicate that Norwegian paediatricians have a common understanding of main aspects in rational antibiotic use independently of working in a UH or DH. Variations in treatment of respiratory tract infections and in doses of antibiotics should be further studied.

Potential for More Rational Use of Antibiotics in Hospitalized Children in a Country With Low Resistance: Data From eight Point Prevalence Surveys.

BACKGROUND: Antimicrobial resistance is low in Norway, but to prevent an increase, the Norwegian Government has launched a National Strategy including a 30% reduction of broad-spectrum antibiotics (BSA) in hospitals within 2020. BSA are defined as second- and third-generation cephalosporins, carbapenems, piperacillin/tazobactam and quinolones. There are no recent studies of antibiotic use in Norwegian hospitalized children. The aim of this study was to describe the use of antibiotics with emphasis on BSA in Norwegian hospitalized children and neonates to detect possibilities for optimization. METHODS: Data were extracted from 8 national point prevalence surveys of systemic antibiotic prescriptions in Norwegian hospitals between 2015 and 2017. The choices of antibiotics were compared with the empirical recommendations given in available Norwegian guidelines. In total, 1323 prescriptions were issued for 937 patients. RESULTS: Twenty-four percent of pediatric inpatients were given antibiotics. Adherence to guidelines was 48%, and 30% (95% confidence interval: 27%-33%) of all patients on antibiotics received BSA. We identified only small variations in use of BSA between hospitals. One-third of the patients on antibiotic therapy received prophylaxis whereof 13% were given BSA. In 30% of prescriptions with BSA, no microbiologic sample was obtained before treatment. CONCLUSIONS: This study reveals an excess of prescriptions with BSA in relation to the low resistance rate in Norway. Our findings reveal areas for improvement that can be useful in the forthcoming antibiotic stewardship programs in Norwegian pediatric departments.

Myocardial function in term and preterm infants. Influence of heart size, gestational age and postnatal maturation.

BACKGROUND: Sparse knowledge exists on the differences in cardiac function between term and preterm infants. This study examines the impact of heart size, gestational age and postnatal maturation on myocardial function. AIM: To assess and compare serial echocardiographic indices of myocardial function in term and moderately preterm infants. METHODS: Longitudinal, prospective, observational echocardiographic cohort study of 45 healthy term infants examined at day three and at 12-20weeks postnatal age and 53 moderately preterm infants (gestational age 31-35weeks) examined at day three and at term equivalent (4-10weeks postnatal age). OUTCOMES: Primary: Systolic mitral and tricuspid annular plane excursions and annular peak systolic pulsed wave tissue Doppler (pwTDI) velocities. Secondary: Indices normalized for heart size. RESULTS: On day three, all indices were higher in the term than in the preterm infants whereas normalized systolic pwTDI velocities were lower in the term infants and normalized excursions showed no difference. All indices increased with advanced postnatal age. The indices in term infants on day three were lower than in preterm infants at term equivalent, with and without normalization. After postnatal maturation in both groups, all indices were higher in the term group (except left pwTDI), whereas normalized indices showed no consistent pattern. CONCLUSIONS: Myocardial function indices increased with gestational age at birth and more profoundly with postnatal maturation. Serial examinations of non-normalized and normalized myocardial function indices showed no sustained differences between the preterm and the term infants. Normalization by heart size may be of value when assessing myocardial function in infants.

Longitudinal assessment of atrioventricular annulus excursion by grey-scale m-mode and colour tissue Doppler imaging in premature infants.

BACKGROUND: There is a lack of standardized echocardiographic parameters to quantify ventricular function in newborn infants. Long-axis systolic ventricular shortening is a useful parameter of global ventricular function. AIMS: Serial assessment of long-axis systolic atrioventricular annulus excursion in premature infants. METHODS: Two-centre, prospective observational study. Fifty-seven premature infants (26 girls), median (range) gestational age 33(+5) (31(0)-34(+6)) weeks(+days), birth weight 1925 (1127-2836) grams were included. Echocardiographic examinations were performed at the first three days of life and at expected term. OUTCOME MEASURES: Systolic annulus excursion by grey-scale m-mode and colour tissue Doppler imaging (cTDI). RESULTS: A consistent longitudinal pattern was found for annulus excursion by grey-scale m-mode and cTDI. All parameters showed a pronounced increase at expected term (p < 0.001). After normalizing for ventricular size the increase at term was less pronounced. Results were lower by cTDI than by grey-scale m-mode for the left and right ventricular walls (p < 0.001). Intraobserver variability (range 1.5-9.8%) was lower than interobserver variability (5.5-18%). CONCLUSIONS: Serial assessment of longitudinal ventricular shortening in premature infants by grey-scale m-mode and cTDI was feasible and the measurements displayed a consistent pattern. cTDI excursion measurements were lower and more dependent on image quality than m-mode measurements. Lower intraobserver variability suggests that repeated measurements should preferably be performed by the same observer. Annulus excursion varies with ventricular size and we suggest normalizing measurements by ventricular size.

Myocardial function in premature infants: a longitudinal observational study.

OBJECTIVES: Gestational and chronological age may have an impact on myocardial function. We studied the longitudinal changes of the atrioventricular tissue Doppler velocities in premature infants through the neonatal transitional period and at expected term and explored the reproducibility of the measurements. DESIGN: Prospective, observational and longitudinal cohort study. SETTING: Two-centre study, from a secondary and a tertiary neonatal intensive care unit. PARTICIPANTS: 55 infants (29 males) with gestational age 31-35 weeks and birth weight 1127-2836 grams. PRIMARY AND SECONDARY OUTCOME MEASURES: Pulsed-wave atrioventricular left, septum and right ventricular annulus tissue Doppler systolic (S'), early diastolic (E') and late diastolic (A') velocities measured by repeated echocardiographic examinations days 1, 2 and 3 and at expected term. RESULTS: All velocities increased significantly from the neonatal period to expected term (p<0.001). We found a significant correlation between gestational age and right-sided S', E' and A' on day 1 (Pearson correlation 0.32-0.46, p<0.05), for S' in all three walls and septal E' and A' on day 2 (Pearson correlation 0.27-0.49, p<0.05). There was a moderate linear correlation between left ventricle end-diastolic length and septal and right S' at term and for septal E' and A' at day 1 (Pearson correlation 0.30-0.56, p<0.05). We found no correlation between heart rate and tissue Doppler velocities when controlling for the effect of fusion. Continuous positive airway pressure showed moderate effect where as persistence of the ductus arteriosus showed no effect on the tissue Doppler velocities. The E'/A' relationship was consistently reversed throughout the study with frequently fused diastolic tissue velocity signals. CONCLUSIONS: Pulsed-wave atrioventricular annulus tissue Doppler velocities were related to gestational age, postnatal age and ventricular size. Right ventricle velocities showed more pronounced increase with postnatal maturation than left ventricle velocities. The degree of E'/A' fusion influenced the diastolic tissue Doppler velocities and should be reported if present.