Systolic blood pressure in babies of less than 32 weeks gestation in the first year of life. Northern Neonatal Nursing Initiative

Managing severe hypertension in children

Severe childhood hypertension is uncommon and frequently not recognised and is best defined as a systolic blood pressure (SBP) above the stage 2 threshold of the 95th centile + 12 mmHg. If no signs of end-organ damage are present, this is urgent hypertension which can be managed by the slow introduction of oral or sublingual medication, but if signs are present, the child has emergency hypertension (or hypertensive encephalopathy if they include irritability, visual impairment, fits, coma, or facial palsy), and treatment must be started promptly to prevent progression to permanent neurological damage or death. However, detailed evidence from case series shows that the SBP must be lowered in a controlled manner over about 2 days by infusing short-acting intravenous hypotensive agents, with saline boluses ready in case of overshoot, unless the child had documented normotension within the last day. This is because sustained hypertension may increase pressure thresholds of cerebrovascular autoregulation which take time to reverse. A recent PICU study that suggested otherwise was significantly flawed. The target is to reduce the admission SBP by its excess, to just above the 95th centile, in three equal steps lasting about ≥ 6 h, 12 h, and finally ≥ 24 h, before introducing oral therapy. Few of the current clinical guidelines are comprehensive, and some advise reducing the SBP by a fixed percentage, which may be dangerous and has no evidence base. This review suggests criteria for future guidelines and argues that these should be evaluated by establishing prospective national or international databases.

Comparison of clinical outcomes between active and permissive blood pressure management in extremely preterm infants

Background

There remains uncertainty about the definition of normal blood pressure (BP), and when to initiate treatment for hypotension for extremely preterm infants. To determine the short-term outcomes of extremely preterm infants managed by active compared with permissive BP support regimens during the first 72 hours of life.

Method

This is a retrospective medical records review of 23 +0-28 +6 weeks' gestational age (GA) infants admitted to neonatal units (NNU) with active BP support (aimed to maintain mean arterial BP (MABP) >30 mmHg irrespective of the GA) and permissive BP support (used medication only when babies developed signs of hypotension) regimens. Babies admitted after 12 hours of age, or whose BP data were not available were excluded.

Results

There were 764 infants admitted to the participating hospitals; 671 (88%) were included in the analysis (263 active BP support and 408 permissive BP support). The mean gestational age, birth weight, admission temperature, clinical risk index for babies (CRIB) score and first haemoglobin of infants were comparable between the groups. Active BP support group infants had consistently higher MABP and systolic BP throughout the first 72 hours of life (p<0.01). In the active group compared to the permissive group 56 (21.3%) vs 104 (25.5%) babies died, and 21 (8%) vs 51 (12.5%) developed >grade 2 intra ventricular haemorrhage (IVH). Death before discharge (adjusted OR 1.38 (0.88 - 2.16)) or IVH (1.38 (0.96 - 1.98)) was similar between the two groups. Necrotising enterocolitis (NEC) ≥stage 2 was significantly higher in permissive BP support group infants (1.65 (1.07 - 2.50)).

Conclusions

There was no difference in mortality or IVH between the two BP management approaches. Active BP support may reduce NEC. This should be investigated prospectively in large multicentre randomised studies.

Hemodynamic management of the micropreemie: When inotropes are not enough

Managing perfusion in the micropreemie is challenging and should be guided by the patho-physiology, gestational and postnatal age of the baby, perinatal history, and the persistence of fetal shunts. The assessment should incorporate bedside tools such as blood pressure, clinical perfusion markers, and functional echocardiography. The multimodal approach to diagnose and identify the cause of hemodynamic compromise paves the way to a targeted approach to treatment. Characterizing the predominant pathophysiologic cause of low cardiac output and impaired cellular metabolism enables a more accurate use of inotropes, vasopressors, and volume support to suit a particular pathophysiologic situation.

Fifteen-minute consultation: Neonatal hypertension

Neonatal hypertension is a rare but well recognised condition, especially in newborns needing invasive monitoring in the intensive care unit. Recognition of newborns with hypertension remains challenging because of natural variability in blood pressure with postconceptional age and the lack of reference data for different gestational ages. Investigation of neonates with hypertension can be challenging in light of the myriad differing aetiologies. This may be simplified by a systematic approach to investigation. There remains a relative paucity of data to guide the use of pharmacological therapies for hypertension in neonates. Clinicians rely on empirical management protocols based on experience and expert opinion. Much of the information on dosing regimens and protocols has simply been derived from the use of antihypertensive agents in older children and in adults, despite fundamental pathophysiological differences.

Baroreflex Sensitivity and Blood Pressure in Premature Infants – Dependence on Gestational Age, Postnatal Age and Sex

To characterize the differences in baroreflex sensitivity (BRS), blood pressure (BP), heart rate (HR) and respiration rate (RR) in preterm infants with a similar postconceptional age reached by various combinations of gestational and postnatal ages. To detect potential sex differences in assessed cardiovascular parameters. The study included 49 children (24 boys and 25 girls), postconceptional age 34.6±1.9 weeks. Two subgroups of infants were selected with the similar postconceptional age (PcA) and current weight, but differing in gestational (GA) and postnatal (PnA) ages, as well as two matched subgroups of boys and girls. Blood pressure (BP) was recorded continuously using Portapres device (FMS). A stationary segment of 250 beat-to-beat BP values was analyzed for each child. Baroreflex sensitivity (BRS) was calculated by cross-correlation sequence method. Despite the same PcA age and current weight, children with longer GA had higher BRS, diastolic and mean BP than children with shorter GA and longer PnA age. Postconceptional age in preterm infants is a parameter of maturation better predicting baroreflex sensitivity and blood pressure values compared to postnatal age. Sex related differences in BRS, BP, HR and RR were not found in our group of preterm infants.

Blood Pressure Variability and Baroreflex Sensitivity in Premature Newborns-An Effect of Postconceptional and Gestational Age

Introduction: Cardiovascular system is the vitally important system in the dynamical adaptation process of the newborns to the extrauterine environment. To reliably detect immaturity in the given organ system, it is crucial to study the development of the organ functions in relation to maturation process. Objectives: The objective was to determine the changes in the spontaneous short-term blood pressure variability (BPV) and baroreflex sensitivity (BRS) reflecting various aspects of cardiovascular control during the process of maturation in preterm babies and to separate effects of gestational age and postnatal age. Methods: Thirty-three prematurely born infants without any signs of cardio-respiratory disorders (gestational age: 31.8, range: 27-36 weeks; birth weight: 1,704, range: 820-2,730 grams) were enrolled. Continuous peripheral blood pressure signal was obtained by non-invasive volume-clamp photoplethysmography method during supine rest. The recordings of 250 continuous beat-to-beat blood pressure values were processed by spectral analysis of BPV (assessed measures: total power, low frequency and high frequency powers of systolic BPV) and BRS calculation. For each infant we also assessed systolic, diastolic and mean blood pressures, heart rate and respiratory rate. Results: With the postconceptional age, BPV measures decreased (for total power: Spearman correlation coefficient r_s = -0.345, P = 0.049; for low frequency power: r_s = -0.365, P = 0.037; for high frequency power r_s = -0.349; P = 0.046); and BRS increased significantly (r_s = 0.448, P = 0.009). The further analysis demonstrated that these effects were more attributable to gestational age than to postnatal age. BRS correlated negatively with BPV magnitude (r_s = -0.479 to -0.592, P = 0.001-0.005). Mean blood pressure and diastolic blood pressure increased during maturation (r_s = 0.517 and 0.537, P = 0.002 and 0.001, respectively) while heart rate and respiratory rate decreased (r_s = -0.366 and -0.516, P = 0.036 and 0.002, respectively). Conclusion: We conclude that maturation process is accompanied by an increased involvement of baroreflex buffering of spontaneous short-term blood pressure oscillations. Gestational age plays a dominant role not only in BPV changes but also in BRS, mean blood pressure, diastolic blood pressure and heart rate changes.

Single blood pressure chart for children up to 13 years to improve the recognition of hypertension based on existing normative data

OBJECTIVE

To produce a single 'growth-chart-style' blood pressure (BP) chart with clear diagnostic thresholds to assist paediatricians to make prompt and accurate diagnoses of hypertension.

DESIGN

The well-established but complex published data on normal BP ranges in prepubertal children were identified and analysed to determine if it was possible to produce a single, user-friendly, colour-coded chart, showing diagnostic hypertension thresholds for systolic and diastolic BP without losing clinically important information.

RESULTS

There were sufficient published normative childhood BP data available to define systolic and diastolic BP centiles from term onwards but only sufficient to determine systolic BP centiles from 28 weeks of gestation to term. Up to 13 years of age, it was possible to combine boys' and girls' data without loss of precision and to define the threshold between stage 1 and stage 2 (severe) hypertension as the 95th centile +12 mm Hg. This allowed the production of single colour-coded charts for systolic and diastolic BP and to advise on making simple adjustments for the impact of stature on individual children's results.

CONCLUSIONS

A simplified, integrated BP chart with colour-coded diagnostic thresholds was produced to assist the prompt diagnosis of hypertension in prepubertal children. This information could be included into a Paediatric Early Warning System score.

Challenges in developing a consensus definition of neonatal sepsis

Sepsis remains a leading cause of morbidity and mortality in the neonatal population, and at present, there is no unified definition of neonatal sepsis. Existing consensus sepsis definitions within paediatrics are not suited for use in the NICU and do not address sepsis in the premature population. Many neonatal research and surveillance networks have criteria for the definition of sepsis within their publications though these vary greatly and there is typically a heavy emphasis on microbiological culture. The concept of organ dysfunction as a diagnostic criterion for sepsis is rarely considered in neonatal literature, and it remains unclear how to most accurately screen neonates for organ dysfunction. Accurately defining and screening for sepsis is important for clinical management, health service design and future research. The progress made by the Sepsis-3 group provides a roadmap of how definitions and screening criteria may be developed. Similar initiatives in neonatology are likely to be more challenging and would need to account for the unique presentation of sepsis in term and premature neonates. The outputs of similar consensus work within neonatology should be twofold: a validated definition of neonatal sepsis and screening criteria to identify at-risk patients earlier in their clinical course. IMPACT: There is currently no consensus definition of neonatal sepsis and the definitions that are currently in use are varied.A consensus definition of neonatal sepsis would benefit clinicians, patients and researchers.Recent progress in adults with publication of Sepsis-3 provides guidance on how a consensus definition and screening criteria for sepsis could be produced in neonatology.We discuss common themes and potential shortcomings in sepsis definitions within neonatology.We highlight the need for a consensus definition of neonatal sepsis and the challenges that this task poses.

The Relationship between blood pressure parameters and left ventricular output in neonates

OBJECTIVE

To evaluate the relationship between systolic (SBP), diastolic (DBP), mean (MBP) blood pressures and pulse pressure (PP), and left ventricular output (LVO), a surrogate of systemic blood flow.

STUDY DESIGN

This retrospective study included neonates who underwent targeted neonatal echocardiography (TNE) in 3-tertiary NICUs over 2 years. Associations between LVO and BP components were investigated. Analysis was adjusted for relevant covariates.

RESULT

1060 studies from 485 neonates were included, with a mean GA of 28.4 ± 4.6 weeks and birth weight of 1234 ± 840 grams. LVO was associated positively with SBP and PP, and negatively with GA. PP demonstrated the highest predictive value for identifying infants with LVO < 150 ml/kg/min (area under the curve 0.75 [95% CI 0.68, 0.82]). MBP and DBP demonstrated no correlation with LVO.

CONCLUSION

BP parameters correlate poorly with LVO, irrespective of GA and underlying etiology. Narrow PP may be more reflective of low LVO than low SBP.

Hemodynamic instability in the critically ill neonate: An approach to cardiovascular support based on disease pathophysiology

Hemodynamic disturbance in the sick neonate is common, highly diverse in underlying pathophysiology and dynamic. Dysregulated systemic and cerebral blood flow is hypothesized to have a negative impact on neurodevelopmental outcome and survival. An understanding of the physiology of the normal neonate, disease pathophysiology, and the properties of vasoactive medications may improve the quality of care and lead to an improvement in survival free from disability. In this review we present a modern approach to cardiovascular therapy in the sick neonate based on a more thoughtful approach to clinical assessment and actual pathophysiology. Targeted neonatal echocardiography offers a more detailed insight into disease processes and offers longitudinal assessment, particularly response to therapeutic intervention. The pathophysiology of common neonatal conditions and the properties of cardiovascular agents are described. In addition, we outline separate treatment algorithms for various hemodynamic disturbances that are tailored to clinical features, disease characteristics and echocardiographic findings.

Time course study of blood pressure in term and preterm infants immediately after birth

Objective

To describe temporal changes in systolic, diastolic, and mean blood pressure (SBP, DBP, and MBP, respectively) in term and preterm infants immediately after birth.

Methods

Prospective observational two-center study. In term infants SBP, DBP, and MBP were assessed non-invasively every minute for the first 15 minutes, and in preterm infants every minute for the first 15 minutes, as well as at 20, 25, 30, 45, and 60 minutes after birth. Regression analyses were performed by gender and respiratory support in all neonates; and by mode of delivery, cord clamping time, and development of ultrasound-detected brain injury in preterm neonates.

Results

Term infants (n = 54) had a mean (SD) birth weight of 3298 (442) g and gestational age of 38 (1) weeks, and preterm infants (n = 94) weighed 1340 (672) g and were 30 (3) weeks gestation. Term infants’ SBP, DBP and MBP within the first 15 minutes after birth were independent of gender or respiratory support. Linear mixed regression analysis showed that preterm infants, who were female, born vaginally, had delayed cord clamping and did not require positive pressure ventilation nor develop periventricular injury or ventriculomegaly, had significantly higher SBP, DBP, and MBP at some measurement points within the first hour after birth.

Conclusions

We present novel reference ranges of BP immediately after birth in a cohort of term and preterm neonates. They may aid in optimization of cardiovascular support during early transition at all gestations.

Neonatal hypotension: dopamine or dobutamine?

Controversy surrounds the assessment of perfusion and the methods currently utilised to define hypotension, especially blood pressure. There is growing agreement to assess heart function when selecting inotropic therapy and use bedside tools such as echocardiography for assessing at-risk infants. Both dopamine and dobutamine have comparative efficacy, and in certain disease states with immature myocardium there could be potential advantages in using dobutamine. The concomitant use of hydrocortisone has been shown to be beneficial when escalating doses of first-line inotropes are used. Other inotropes require further study through randomised trials for their safety and efficacy to be established.

Critical serum creatinine values in very preterm newborns

Background

Renal failure in neonates is associated with an increased risk of mortality and morbidity. But critical values are not known.

Objective

To define critical values for serum creatinine levels by gestational age in preterm infants, as a predictive factor for mortality and morbidity.

Study Design

This was a retrospective study of all preterm infants born before 33 weeks of gestational age, hospitalized in Nantes University Hospital NICU between 2003 and 2009, with serum creatinine levels measured between postnatal days 3 to 30. Children were retrospectively randomized into either training or validation set. Critical creatinine values were defined within the training set as the 90^th percentile values of highest serum creatinine (HSCr) in infants with optimal neurodevelopmental at two years of age. The relationship between these critical creatinine values and neonatal mortality, and non-optimal neural development at two years, was then assessed in the validation set.

Results and Conclusion

The analysis involved a total of 1,461 infants (gestational ages of 24-27 weeks (n=322), 28-29 weeks (n=336), and 30-32 weeks (803)), and 14,721 creatinine assessments. The critical values determined in the training set (n=485) were 1.6, 1.1 and 1.0 mg/dL for each gestational age group, respectively. In the validation set (n=976), a serum creatinine level above the critical value was significantly associated with neonatal mortality (Odds ratio: 8.55 (95% confidence interval: 4.23-17.28); p<0.01) after adjusting for known renal failure risk factors, and with non-optimal neurodevelopmental outcome at two years (odds ratio: 2.06 (95% confidence interval: 1.26-3.36); p=0.004) before adjustment. Creatinine values greater than 1.6, 1.1 and 1.0 mg/dL respectively at 24-27, 28-29, 30-32 weeks of gestation were associated with mortality before and after adjustment for risk factors, and with non-optimal neurodevelopmental outcome, before adjustment.

Evaluation of cerebral electrical activity and cardiac output after patent ductus arteriosus ligation in preterm infants

OBJECTIVE

To characterize and investigate the relationship between systemic blood flow and pre- and postoperative cerebral electrical activity in preterm neonates undergoing patent ductus arteriosus (PDA) ligation.

STUDY DESIGN

A prospective observational study was conducted in 17 preterm neonates undergoing PDA ligation. All infants had amplitude-integrated electroencephalography (aEEG) recorded continuously from 4 h preoperatively to 24 h postoperatively. Targeted neonatal echocardiography was performed to evaluate myocardial performance and systemic blood flow at four sequential time points: preoperatively; 1, 8 and 24 h postoperatively.

RESULT

PDA ligation was followed by a fall in the lower border of the aEEG trace lower left ventricular output, but recovery of diastolic flow in the middle cerebral artery. Altered lower margin was associated with gestational age and PDA diameter on univariate analysis, but not with low cardiac output.

CONCLUSION

PDA ligation was associated with altered cerebral electrical activity, although these changes were not related to low cardiac output state.

Autonomic cardiovascular control in hypotensive critically ill preterm infants is impaired during the first days of life

BACKGROUND

The first days after preterm birth are a critical period of cardiovascular instability, where hypotension is common. We assessed autonomic cardiovascular function by measuring heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) and hypothesised that these would be impaired in preterm infants born at younger gestational ages. In addition, we speculated that impaired cardiovascular control could be used as a marker of circulatory failure such as is manifest as hypotension.

METHODS

23 preterm infants (11 M/12 F) born between 23 and 35 weeks (mean 27 ± 0.6 weeks) gestational age with indwelling arterial catheters were recruited. Infants were studied over the first 3 days of life with heart rate and blood pressure (BP) analysed beat to beat in the frequency domain in 2 minute epochs of artefact free data during active sleep. Data were compared with one way ANOVA.

RESULTS

Gestational age was correlated with all HRV indices but not BPV or BRS. 9 babies received inotropes. Gestational age between the inotrope group and the non-inotrope group was not different. BP and RR interval were lower in the inotrope group (40.7 ± 1.5 vs 47.1 ± 1.5 mmHg, p<0.05 and 395 ± 14 vs 426 ± 11 ms, p<0.08). BRS was also lower in the inotrope group (3.8 ± 0.9 vs 6.9 ± 1.6 ms/mmHg) as was LF/HF HRV (5.7 ± 1.3 vs 13.6 ± 2.8, p<0.05).

CONCLUSIONS

In the first 3 days after birth, infants receiving inotropes had significantly impaired cardiovascular control compared to those who did not receive treatment, indicating that these infants maybe predisposed to increased vulnerability to circulatory instability.

Use of targeted neonatal echocardiography to prevent postoperative cardiorespiratory instability after patent ductus arteriosus ligation

OBJECTIVES

To investigate the value of targeted neonatal echocardiography (TnECHO) in predicting cardiorespiratory instability after patent ductus arteriosus (PDA) ligation, and to evaluate the impact of TnECHO-directed care.

STUDY DESIGN

We reviewed serial echocardiography evaluations of 62 preterm infants after PDA ligation to investigate the relationship between indices of myocardial performance and postoperative cardiorespiratory instability. A predictive model was developed based on TnECHO criteria, with targeted initiation of intravenous milrinone. A comparative evaluation was performed between matched infants in the previous era (epoch 1; n=25) and current era (epoch 2; n=27) of TnECHO-guided treatment.

RESULTS

Left ventricular output <200 mL/kg/min at 1 hour after PDA ligation was a sensitive predictor of systemic hypotension and the need for inotropes, and was used for initiation of i.v. milrinone infusion in epoch 2. Infants treated with milrinone had a lower incidence of ventilation failure (15% vs 48%; P=.02) and less need for inotropes (19% vs 56%; P=.01), and showed a trend toward improved oxygenation (P=.08).

CONCLUSION

TnECHO facilitates early detection of infants at greatest risk for subsequent cardiorespiratory deterioration. Administration of milrinone to neonates with low cardiac output may lead to improved postoperative stability.

Hyperbilirubinemia and neurodevelopmental outcome of very low birthweight infants: results from the LIFT cohort

Background

Bilirubin-related neurotoxicity is an important clinical issue in very low birthweight (VLBW) infants, and the existing literature is inconsistent.

Objective

To analyze the relationship between maximal serum unconjugated bilirubin levels (SBL) and neurodevelopmental outcome at 2-year corrected age in VLBW infants.

Methods

Phototherapy was initiated in all infants born before 33 weeks of gestation, according to Maisels' recommendations. Neurodevelopmental assessment at 2-year corrected age was performed in all infants that survived. SBLs collected during the first week of life were used to define three tertiles of max-SBL. The first tertile corresponded to infants with the lowest max-SBL.

Results and Conclusions

A total of 724 infants were included in the study, and among them, 631 (87%) were evaluated at two years old. The infants of the first tertile were younger and smaller than the infants of the other two tertiles, in accordance with Maisels' recommendations for very small infants. No difference in the risk of impaired functional outcome among the three groups was observed. However, among infants weighing less than 1001 g, those in the third tertile had a poorer neurodevelopmental prognosis as compared to those in the second tertile (adjusted odds ratio = 6.8, 95% CI: 1.2–36.7, p = 0.03). Considering the results obtained, we propose 196 µmol/L (11.5 mg/dL) when birthweight varies between 1001 and 1500 g, and 170 µmol/L (9.9 mg/dL) when birthweight is less than 1001 g, as recommended max-SBLs (defined as maximal levels of 95^th percentile curves of SBLs in infants with an optimal outcome). When Maisels' recommendations were applied, max SBLs were higher in 8% of infants weighing 1001–1500 g and in 15% of infants weighing less than 1001 g. Our data seems to validate Maisels' recommendations in the overall population of infants born before 33 weeks of gestation, but not in infants weighing less than 1001 g.

Cytochrome P450 (CYP2D6) genotype is associated with elevated systolic blood pressure in preterm infants after discharge from the neonatal intensive care unit

OBJECTIVE

To determine genetic and clinical risk factors associated with elevated systolic blood pressure (ESBP) in preterm infants after discharge from the neonatal intensive care unit (NICU).

STUDY DESIGN

A convenience cohort of infants born at <32 weeks gestational age was followed after NICU discharge. We retrospectively identified a subgroup of subjects with ESBP (systolic blood pressure [SBP] >90th percentile for term infants). Genetic testing identified alleles associated with ESBP. Multivariate logistic regression analysis was performed for the outcome ESBP, with clinical characteristics and genotype as independent variables.

RESULTS

Predictors of ESBP were cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6) (rs28360521) CC genotype (OR, 2.92; 95% CI, 1.48-5.79), adjusted for outpatient oxygen therapy (OR, 4.53; 95% CI, 2.23-8.81) and history of urinary tract infection (OR, 4.68; 95% CI, 1.47-14.86). Maximum SBP was modeled by multivariate linear regression analysis: maximum SBP=84.8 mm Hg + 6.8 mm Hg if cytochrome P450, family 2, subfamily D, polypeptide 6 (CYP2D6) CC genotype + 6.8 mm Hg if discharged on supplemental oxygen + 4.4 mm Hg if received inpatient glucocorticoids (P=.0002).

CONCLUSIONS

ESBP is common in preterm infants with residual lung disease after discharge from the NICU. This study defines clinical factors associated with ESBP, identifies a candidate gene for further testing, and supports the recommendation to monitor blood pressure before age 3 years, as is suggested for term infants.

Blood pressures in newborns with twin-twin transfusion syndrome

OBJECTIVE

In addition to unbalanced flow through placental anastomoses, evidence suggests that transfer of circulating vasoactive elements from the donor to the recipient contribute to the pathological process of twin-twin transfusion syndrome (TTTS). The objective of this study was to test the hypothesis that TTTS recipients have higher blood pressure (BP) at birth than donors.

STUDY DESIGN

Chart review of all TTTS infants born from 1996 to 2007 with both twins alive 24 h (51 pairs; average gestational age 30±3 weeks).

RESULTS

Both systolic and diastolic neonatal BPs were significantly higher in recipients. When expressed relative to predicted BP for birth weight (BW), BP were lower than expected in donors and higher in recipients.

CONCLUSIONS

Data indicate that TTTS recipients have BP significantly higher than donors and than BP expected for BW. The long-term impact of these early hemodynamic perturbations remains to be determined.

Etiology and outcome of acute kidney injury in children

The aim of this prospective, multicenter study was to define the etiology and clinical features of acute kidney injury (AKI) in a pediatric patient cohort and to determine prognostic factors. Pediatric-modified RIFLE (pRIFLE) criteria were used to classify AKI. The patient cohort comprised 472 pediatric patients (264 males, 208 females), of whom 32.6% were newborns (median age 3 days, range 1-24 days), and 67.4% were children aged >1 month (median 2.99 years, range 1 month-18 years). The most common medical conditions were prematurity (42.2%) and congenital heart disease (CHD, 11.7%) in newborns, and malignancy (12.9%) and CHD (12.3%) in children aged >1 month. Hypoxic/ischemic injury and sepsis were the leading causes of AKI in both age groups. Dialysis was performed in 30.3% of newborns and 33.6% of children aged >1 month. Mortality was higher in the newborns (42.6 vs. 27.9%; p < 0.005). Stepwise multiple regression analysis revealed the major independent risk factors to be mechanical ventilation [relative risk (RR) 17.31, 95% confidence interval (95% CI) 4.88-61.42], hypervolemia (RR 12.90, 95% CI 1.97-84.37), CHD (RR 9.85, 95% CI 2.08-46.60), and metabolic acidosis (RR 7.64, 95% CI 2.90-20.15) in newborns and mechanical ventilation (RR 8.73, 95% CI 3.95-19.29), hypoxia (RR 5.35, 95% CI 2.26-12.67), and intrinsic AKI (RR 4.91, 95% CI 2.04-11.78) in children aged >1 month.

Patent ductus arteriosus ligation is associated with impaired left ventricular systolic performance in premature infants weighing less than 1000 g

OBJECTIVE

Patent ductus arteriosus ligation is often complicated by systemic hypotension and oxygenation failure. The ability of the immature myocardium to compensate for altered afterload is poorly understood. The aim of this study was to characterize the effects of patent ductus arteriosus ligation on myocardial performance in preterm infants.

METHODS

Serial echocardiographic analysis was performed before and after patent ductus arteriosus ligation. Characteristics of the patent ductus arteriosus, myocardial performance (fractional shortening, mean velocity of circumferential fiber shortening, and left ventricular output) and left ventricular afterload (end-systolic wall stress) were assessed. The stress-velocity relationship was measured as a preload-independent, afterload-adjusted measure of myocardial contractility.

RESULTS

Forty-six preterm infants were assessed at 28.5 +/- 11.3 days and a weight of 1058 +/- 272 g. Patent ductus arteriosus ligation was followed by increased left ventricular exposed vascular resistance temporally coinciding with reduced left ventricular preload, decreased left ventricular contractility, and low left ventricular output. Neonates weighing 1000 g or less had a higher rate of low fractional shortening (<25%) or low left ventricular output (<170 mL x kg(-1) x h(-1)) and increased need for cardiotropes and demonstrated a trend toward an impaired stress-velocity relationship. Neonates with impaired left ventricular systolic performance were more likely to require cardiotropes and have low systolic arterial pressure, increased heart rate, and abnormal base deficit.

CONCLUSION

Patent ductus arteriosus ligation is sometimes associated with impaired left ventricular systolic performance, which is most likely attributable to altered loading conditions. Neonates weighing 1000 g or less are at increased risk of impaired left ventricular systolic performance, which might relate to maturational differences and decreased tolerance to altered loading conditions.

The role of systemic hemodynamic disturbances in prematurity-related brain injury

Premature infants who experience cerebrovascular injury frequently have acute and long-term neurologic complications. In this article, we explore the relationship between systemic hemodynamic insults and brain injury in this patient population and the mechanisms that might be at play.

Normative blood pressure data in non-ventilated premature neonates from 28-36 weeks gestation

Blood pressure (BP) measurement in the premature neonate is an essential component of neonatal intensive care. Despite significant advances in neonatal care, the data available on BP in the premature neonate are limited. The aim of this study was to determine normative BP measurements for non-ventilated stable premature neonates of gestation age 28-36 weeks in the first month of life using an oscillometric method. Neonates born at 28-36 weeks gestation who did not require ventilation for >24 h or inotrope support for >24 h were enrolled into the study. Blood pressure measurements were taken on days 1, 2, 3, 4, 7, 14, 21 and 28 where possible prior to discharge. A total of 147 infants were included in the study, and 10th and 90th percentiles BPs were obtained for gestation as well as birthweight. Changes in BP over time for each gestational week were determined. A significant difference in BP from day 1 to day 7 and from day 7 to 14 was observed in those born at less than 31 weeks gestation, and from day 1 to 7 in those born at more than 31 weeks gestation, but not from day 14 to 21 and from day 21 to 28 for any gestation period. Data on BP for stable non-ventilated premature infants using an oscillometric method provide useful information for determining hypotension and hypertension in the premature neonate. Premature neonates stabilize their BP after 14 days of life, and at this time they have a BP similar to that of term infants.

Congenital heart disease in twin-to-twin transfusion syndrome treated with fetoscopic laser surgery

OBJECTIVE

To determine the incidence of congenital heart disease (CHD) and right ventricular outflow tract obstruction (RVOTO) in twin-to-twin transfusion syndrome (TTTS) treated with fetoscopic laser surgery and evaluate the role of increased afterload by determining the difference in blood pressure and endothelin-1 at birth between donor and recipient twins.

DESIGN

Prospective study.

SETTING

Tertiary medical center, serving as the national referral center for fetoscopic laser surgery for TTTS in The Netherlands.

PATIENTS

All consecutive cases of monochorionic twins with TTTS treated with laser (n = 46 twin pairs) and monochorionic twins without TTTS (n = 55 twin pairs) delivered at our center between June 2002 and June 2005 were included in the study.

INTERVENTIONS

Echocardiography was performed within 1 week after delivery. At birth, blood pressure was measured in all survivors and endothelin-1 was determined in umbilical cord blood. Data on RVOTO in TTTS treated with laser surgery at our center but delivered elsewhere were reviewed retrospectively from medical records.

RESULTS

The incidence of CHD in the TTTS group and non-TTTS group was 5.4% (4/74) and 2.3% (2/87) (P = .42), respectively. RVOTO was diagnosed in 1 recipient twin delivered at our center and 2 recipient twins delivered elsewhere. The incidence of RVOTO in recipients was 4% (3/75). Mean systolic blood pressure at birth was similar in donor and recipient twins, respectively, 53 mm Hg vs. 56 mm Hg (P = .42). Mean endothelin-1 level at birth was also similar between donors and recipients, respectively, 14.3 ng/L and 13.2 ng/L (P = .64).

CONCLUSION

The incidence of CHD in TTTS treated with fetoscopic laser surgery is higher than in the general population (5.4% vs. 0.5%). We found no difference in afterload parameters between donors and recipients after laser treatment.

Neonatal arterial hypertension in nephro-urological malformations in a tertiary care hospital

An increase in the survival of neonates with antenatal diagnosis of malformations was achieved by the recent technical advances in neonatal intensive care units. The aim of this article is to describe the experience with neonatal arterial hypertension, in newborns with nephro-urological malformations, in a tertiary care referral Nursery, in a period of 4 years. Newborn medical records from the Nursery Annex to the Maternity of Hospital das Clinicas, School of Medicine, University of Sao Paulo, with the diagnosis of nephro-urological malformations and systemic arterial hypertension (SAH) at hospital discharge, in a period from January 1999 to January 2003, were retrospectively analysed. Among 10.278 live newborns in the studied period, 15 (0.15%) newborns were compatible with our inclusion criteria. Of these 15 newborns, 12 (80%) were male and three were premature (20%). In relation to aetiology, 13 (87%) showed urological malformations, 1 (6%) chronic renal insufficiency secondary to kidney dysplasia and one (6%) autosomal recessive polycystic kidney disease. SAH control was achieved with monotherapy in eight patients (53%), five patients (33%) needed an association of two drugs (calcium-channel blocker and angiotensin converting enzyme (ACE) inhibitor), one child used three types of antihypertensive drugs (calcium-channel blocker, ACE inhibitor and hydrochlorothiazide) for pressoric control and one child's blood pressure (BP) was controlled exclusively by peritoneal dialysis. The incidence of nephro-urological malformations in our service during the studied period was 0.89%. SAH incidence among these newborns was 19%. Our data reinforce previous studies pointing to the necessity to consider children with nephro-urological malformations as a risk group for SAH, who should have the BP evaluated since the neonatal period.

Morphine, hypotension, and adverse outcomes among preterm neonates: who's to blame? Secondary results from the NEOPAIN trial

OBJECTIVES

Hypotension occurs commonly among preterm neonates, but its cause and consequences remain unclear. Secondary data analyses from the NEOPAIN trial identified the clinical factors associated with hypotension and examined the contributions of morphine treatment or hypotension to severe intraventricular hemorrhage (IVH) (grades 3 and 4), any IVH (grades 1-4), or death.

METHODS

In the NEOPAIN trial, 898 ventilated neonates between 23 and 32 weeks of gestation were enrolled, with equal numbers randomized to receive masked morphine or placebo infusions. Additional doses of open-label morphine were administered as necessary by medical staff members. IVH was diagnosed with centralized readings of early and late cranial ultrasonograms. Hypotension was assessed before study drug infusion, during the loading dose, and at 24 and 72 hours during study drug infusion. Logistic regression analyses with stepdown elimination identified the predictor factors associated with the hypotension, severe IVH, any IVH, or death outcomes at each time point.

RESULTS

Hypotension was associated with 23 to 26 weeks of gestation, morphine infusions, severity of illness, additional morphine doses, and prior hypotension. Severe IVH was associated with shorter gestation, higher Clinical Risk Index for Babies scores, no prenatal steroids, pulmonary hemorrhage, hypotension before the loading dose, and morphine doses before intubation and at 25 to 72 hours. Neonatal deaths were associated with 23 to 26 weeks of gestation, higher Clinical Risk Index for Babies scores, pulmonary hemorrhage, patent ductus arteriosus, thrombocytopenia, and hypotension before the loading dose. Morphine infusions were not a significant factor in logistic models for severe IVH, any IVH, or death.

CONCLUSIONS

Preemptive morphine infusions, additional morphine, and lower gestational age were associated with hypotension among preterm neonates. Severe IVH, any IVH, and death were associated with preexisting hypotension, but morphine therapy did not contribute to these outcomes. Morphine infusions, although they cause hypotension, can be used safely for most preterm neonates but should be used cautiously for 23- to 26-week neonates and those with preexisting hypotension.

Low blood pressure among very-low-birth-weight infants with fetal vessel inflammation

OBJECTIVE

To test the hypothesis that fetal vessel inflammation (FVI: funisitis and/or fetal vasculitis) is associated with lower blood pressure (BP) over the first week of life and an increased risk of periventricular leukomalacia (PVL) among premature infants.

STUDY DESIGN

A total of 255 infants born at <1350 g to normotensive mothers were stratified by gestational age (GA) and grouped by presence/absence of FVI on placental pathology. Daily highest (Hi) and lowest (Lo) systolic BP (BP(sys)), mean BP (BP(mn)) and diastolic BP (BP(dia)) over first 7 days of life were analyzed by repeated measures ANOVA and regression analysis. Cranial ultrasounds were obtained at 2 weeks of life.

RESULTS

Infants > or =30 weeks gestation with FVI had lower HiBP(sys), HiBP(mn), HiBP(dia), LoBP(sys), LoBP(mn) and LoBP(dia) (p<0.001) than did infants without FVI. Infants with PVL (all < or =27 weeks gestation) had lower LoBP(mn) and LoBP(dia) (p<0.01) than controls. FVI did not increase the risk of PVL in these infants.

CONCLUSION

FVI and PVL are associated with reduced BP over the first week of life.

Long-term neurodevelopmental outcome in twin-to-twin transfusion syndrome

OBJECTIVE

The purpose of this study was to determine the long-term neurodevelopmental outcome in children after twin-to-twin transfusion syndrome.

STUDY DESIGN

Maternal and neonatal medical records of all twin-to-twin transfusion syndrome patients who were admitted to our center between 1990 and 1998 were reviewed. Neurologic and mental development at school age was assessed during a home visit in all twin-to-twin transfusion syndrome survivors.

RESULTS

A total of 33 pregnancies with twin-to-twin transfusion syndrome were identified. Four couples opted for termination of pregnancy. All other pregnancies were treated conservatively, 18 pregnancies (62%) with serial amnioreductions and 11 pregnancies (38%) without intrauterine interventions. Mean gestational age at delivery was 28.6 weeks (range, 20-37 weeks). The perinatal mortality rate was 50% (29/58 infants). The birth weight of the donor twins was less than the recipient twins (P<.001). Systolic blood pressure at birth was lower in donors than in recipients (P=.023), and donors required inotropic support postnatally more frequently than did recipients (P=.008). The incidence of hypertension at birth was higher in recipients than in donors (P=.038). Abnormal cranial ultrasonographic findings were reported in 41% of the neonates (12/29 neonates). All long-term survivors (n=29 neonates) were assessed during a home visit. Mean gestational age at birth of the surviving twin was 31.6 weeks (range, 25-37 weeks). The mean age at follow-up was 6.2 years (range, 4-11 years). The incidence of cerebral palsy was 21% (6/29 infants). Five of 6 children with cerebral palsy had an abnormal mental development. The incidence of cerebral palsy in the group of survivors who were treated with serial amnioreduction was 26% (5/19 infants). Four children were born after the intrauterine fetal demise of their co-twin, 2 of which had cerebral palsy.

CONCLUSION

The incidence of adverse neurodevelopmental outcome in twin-to-twin transfusion syndrome survivors is high, especially after the intrauterine fetal demise of a co-twin.

Fetal hypertension: an insight into the pathogenesis of the twin-twin transfusion syndrome

OBJECTIVES

To investigate if systemic hypertension occurs in fetuses with twin-to-twin transfusion syndrome (TTTS).

METHODS

We conducted an observational cohort study in a tertiary care centre in 23 pregnant women with TTTS. Polyhydramnios stuck twin sequence occurred at a median gestational age of 22 weeks (range 15-27). Biventricular myocardial hypertrophy was diagnosed in 22/23 recipient fetuses. In cases with atrioventricular valve regurgitation (AVR), it was possible to estimate the fetal systolic systemic blood pressure by ultrasound, on the basis of the simplified Bernouilli equation. The diagnosis of fetal hypertension (FHT) was made when the estimated systolic arterial pressure was equal to or above 1.6-fold the expected value.

RESULTS

In 10 pregnancies (group A), fetal blood pressure could be assessed in recipients with AVR. The maximum velocities ranged from 2.9 to 5 m/s, leading to estimates of systemic fetal arterial pressure from 37 to 104 mmHg, that is, 1.6- to 2.8-fold the expected values. In 13 pregnancies (group B), fetal blood pressure could not be assessed in the absence of AVR. In group A, perinatal death (16/20) and hydrops (7/20) were significantly more frequent than in group B (8/26 and 1/26 respectively).

CONCLUSION

Fetal systemic hypertension may occur in recipient twins and could play a role in the pathophysiology of TTTS.

Safety of benzodiazepines in newborns

BACKGROUND

Benzodiazepines are being used in neonatal intensive care units for sedation and control of seizures. However, anecdotal reports suggest that their use in infants may be associated with serious adverse effects (AEs).

OBJECTIVE

To determine the incidence of AEs from benzodiazepine use in preterm and full-term infants.

METHODS

Retrospective chart review of 63 infants who received benzodiazepines as a sedative or anticonvulsant over a 16-month period.

RESULTS

Mean +/- SD gestational age of the infants was 33.1 +/- 6.2 weeks, and birth weight was 2.3 +/- 1.2 kg. Median (range) postnatal age at commencement of drug administration was 19 (5-54) days. Forty-one infants received lorazepam, 8 received midazolam, and 14 received both. Ten (16%) of the infants had 14 documented adverse events: seizures (n = 6), hypotension (n = 5), and respiratory depression (n = 3). Using a validated adverse drug reaction probability scale, a probable association with benzodiazepine use was demonstrated in 12 of the AEs. Due to the retrospective nature of the data, a score for definite association was not attainable. Anticonvulsant administration was required for 4 of 6 infants and, in all cases of respiratory depression, ventilatory support was initiated or increased. Two cases of significant hypotension were treated with inotropes. There was no statistically significant correlation between AEs and benzodiazepine dose or concomitant use of inotropes or analgesics (morphine), although most infants had underlying medical conditions or received multiple drugs that may have predisposed them to experience AEs.

CONCLUSIONS

Administration of benzodiazepines was frequently associated with AEs in full-term and preterm infants. It is possible that underlying illnesses and concomitant drug use predisposed these effects. Until the benefit-to-risk ratio is determined by further studies, judicious use of benzodiazepines is recommended in this vulnerable population.

Controversies in the diagnosis and management of hypotension in the newborn infant

Although close to half of the newborns admitted to neonatal intensive care units receive treatment for "hypotension," the normal physiologic blood pressure range ensuring appropriate organ perfusion in the neonate is unknown. Thus, the decision to treat hypotension in the newborn is based on statistically defined gestational and postnatal age-dependent normative blood pressure values and physicians' beliefs rather than on data bearing physiologic reference. Dopamine is the most widely used sympathomimetic amine in the treatment of neonatal hypotension, and it is more effective than dobutamine in raising blood pressure. Volume administration is less effective in the immediate postnatal period, and its extensive use is associated with significant untoward effects, especially in preterm infants. During the course of their disease, some of the sickest hypotensive newborns become unresponsive to volume and pressor administration. This phenomenon is caused by the desensitization of the cardiovascular system to catecholamines by the critical illness and relative or absolute adrenal insufficiency. The findings that steroids rapidly up-regulate cardiovascular adrenergic receptor expression and serve as hormone substitution in cases of adrenal insufficiency explain their effectiveness in stabilizing the cardiovascular status and decreasing the requirement for pressor support in the critically ill newborn with volume-and pressor-resistant hypotension. Finally, despite recent advances in our understanding of the pathophysiology and management of neonatal hypotension, there are few data on the impact of the treatment on organ blood flow and tissue perfusion and on neonatal morbidity and mortality.

The role of size at birth and postnatal catch-up growth in determining systolic blood pressure: a systematic review of the literature

OBJECTIVE

To conduct a systematic review in order to (i) summarize the relationship between birthweight and blood pressure, following numerous publications in the last 3 years, (ii) assess whether other measures of size at birth are related to blood pressure, and (iii) study the role of postnatal catch-up growth in predicting blood pressure.

DATA IDENTIFICATION

All papers published between March 1996 and March 2000 that examined the relationship between birth weight and systolic blood pressure were identified and combined with the papers examined in a previous review.

SUBJECTS

More than 444,000 male and female subjects aged 0-84 years of all ages and races.

RESULTS

Eighty studies described the relationship of blood pressure with birth weight The majority of the studies in children, adolescents and adults reported that blood pressure fell with increasing birth weight, the size of the effect being approximately 2 mmHg/kg. Head circumference was the only other birth measurement to be most consistently associated with blood pressure, the magnitude of the association being a decrease in blood pressure by approximately 0.5 mmHg/cm. Skeletal and non-skeletal postnatal catch-up growth were positively associated with blood pressure, with the highest blood pressures occurring in individuals of low birth weight but high rates of growth subsequently.

CONCLUSIONS

Both birth weight and head circumference at birth are inversely related to systolic blood pressure. The relationship is present in adolescence but attenuated compared to both the pre- and post-adolescence periods. Accelerated postnatal growth is also associated with raised blood pressure.