A comparison of blood pressure measurements in newborns

Arch watch: current approaches and opportunities for improvement

Coarctation of the aorta (CoA) is a ductus arteriosus (DA)-dependent form of congenital heart disease (CHD) characterized by narrowing in the region of the aortic isthmus. CoA is a challenging diagnosis to make prenatally and is the critical cardiac lesion most likely to go undetected on the pulse oximetry-based newborn critical CHD screen. When undetected CoA causes obstruction to blood flow, life-threatening cardiovascular collapse may result, with a high burden of morbidity and mortality. Hemodynamic monitoring practices during DA closure (known as an "arch watch") vary across institutions and existing tools are often insensitive to developing arch obstruction. Novel measures of tissue oxygenation and oxygen deprivation may improve sensitivity and specificity for identifying evolving hemodynamic compromise in the newborn with CoA. We explore the benefits and limitations of existing and new tools to monitor the physiological changes of the aorta as the DA closes in infants at risk of CoA.

Oscillometric arterial blood pressure in haemodynamically stable neonates in the first 2 weeks of life

BACKGROUND

We aimed to provide data on the normal blood pressure of haemodynamically stable neonates. Our study uses retrospective, real-life oscillometric blood pressure measurement values to determine the expected blood pressure in different gestational age, chronological age and birth weight groups. We also investigated the effect of antenatal steroid on neonatal blood pressure.

METHODS

Our retrospective study (2019-2021) was carried out in the Neonatal Intensive Care Unit of the University of Szeged, Hungary. We involved 629 haemodynamically stable patients and analysed 134,938 blood pressure values. Data were collected from electronic hospital records of IntelliSpace Critical Care Anesthesia by Phillips. We used the PDAnalyser program for data handling and the IBM SPSS program for statistical analysis.

RESULTS

We found a significant difference between the blood pressure of each gestational age group in the first 14 days of life. The systolic, diastolic and mean blood pressure rise are steeper in the preterm group than in the term group in the first 3 days of life. No significant blood pressure differences were found between the group with a complete antenatal steroid course and those who received incomplete steroid prophylaxis or did not receive antenatal steroids.

CONCLUSION

We determined the average blood pressure of stable neonates and obtained normative data by percentiles. Our study provides additional data on how blood pressure varies with gestational age and birth weight. A higher resolution version of the Graphical abstract is available as Supplementary information.

Systemic Hypertension in Infants with Bronchopulmonary Dysplasia

PURPOSE OF REVIEW

Neonatal hypertension is increasingly recognized as improvements in neonatal intensive care have led to increased survival of premature infants. Among infants with bronchopulmonary dysplasia (BPD), the rates of hypertension are much higher than the general neonatal population. However, the etiology and pathophysiology of this increased risk of hypertension in neonates with lung disease remain unclear.

RECENT FINDINGS

Among infants with bronchopulmonary dysplasia, the rates of hypertension are much higher than the general neonatal population. New studies suggest outcomes in neonates with BPD with hypertension are usually good, with resolution of hypertension in most infants with lung disease. Several potential mechanisms of hypertension in this patient population have been recently proposed. This review focuses on the recent epidemiologic data on prevalence of hypertension in neonates with bronchopulmonary dysplasia, reviews the typical clinical course, and discusses available strategies for management of infants with bronchopulmonary dysplasia that develop hypertension.

Comparison of Invasive Arterial Blood Pressure Monitoring vs. Non-Invasive Blood Pressure Monitoring in Preterm Infants < 37 Weeks in the Neonatal Intensive Care Unit- A Prospective Observational Study

BACKGROUND

Accurate measurement of blood pressure (BP) is extremely important in the management of sick preterm newborns. The primary objective of this study was to compare non-invasive blood pressure measurement (NIBP) with invasive blood pressure measurement (IBP) using peripheral arterial cannulation (PAC) in preterm neonates < 37 weeks in the neonatal intensive care unit.

METHODS

Preterm neonates needing PAC were prospectively enrolled in the study. NIBP measurements were taken in the same limb as that of peripheral arterial line. Initially IBP was recorded followed by NIBP within 1 min using the same monitor. These were called as paired measurements since they are taken within 1 min of each other.

RESULTS

Seventy-three preterm infants with 1703 paired measurements were included in the final analysis (median gestational age 32 weeks, IQR 30-34 weeks, median birth weight 1540 g, IQR 1160-2100 g). In preterm infants not receiving vasoactive agents (n = 51, 1428 paired measurements, Bland-Altman analysis for agreement between invasive mean blood pressure (MBP) and non-invasive mean BP revealed a bias of -2.9123 mmHg (SD 7.8074). The 95% limits of agreement were from -18.2157 to 12.3893 mmHg. In preterm infants with hypotension, we detected a bias of -3.9176 mmHg (SD 5.1135) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -13.9401 to 6.1048 mmHg. In normotensive preterm infants receiving vasoactive agents, we detected a bias of -0.7629 mmHg (SD 8.0539) between invasive MBP and non-invasive MBP. The 95% limits of agreement were from -16.5485 to 15.02274 mmHg.

CONCLUSIONS

There is poor level of agreement between IBP and NIBP measurements in sick preterm neonates, leading to overestimation or underestimation of blood pressure. The bias was less for mean BP measurements as compared with systolic BP measurements and also for normotensive neonates as compared with hypotensive neonates. Hence, NIBP may be used as a screening method in haemodynamically stable preterm infants, but infants who are haemodynamically unstable and need to be commenced on vasoactive agents should have IBP monitoring.

Neonatal blood pressure before and after delayed umbilical cord clamping

OBJECTIVE

To describe values of blood pressure (BP) before and after delayed cord clamping (DCC) in healthy term neonates born to low risk pregnancies, examine differences in the temporal patterns of BP during this transition, and assess potential correlation of these parameters with maternal and perinatal clinical and demographic variables.

METHODS

Prospective observational study of term infants eligible for DCC born vaginally from uncomplicated pregnancies. Neonatal BP was estimated noninvasively before DCC, at 30 min and 24 h of life. Median, minimum, maximum, mean and standard deviation, as well as percentiles for BP values were calculated. Pearson correlation assessed the correlation between demographic and clinical variables and BP measurements. Spearman correlation studied the association between BP parameters prior to DCC and Apgar scores. Repeated measures ANOVA and Tukey post hoc analyses were used to compare BP measurements over time. A p-value of <.05 was considered significant.

RESULTS

A total of 54 patients were included. Mean neonatal birthweight was 3185 g and gestational age 39/3 weeks. The mean values for the systolic, diastolic, and mean BP prior to DCC were 97 ± 24.9 mmHg, 58 ± 21.9 mmHg and 67 ± 27.7 mmHg respectively. A statistically significant difference was detected when comparing BP values obtained before DCC with those measured afterwards (Figure 1). A positive correlation was found between SBP and MAP prior to DCC and Apgar scores at 1 min. [Figure: see text].

CONCLUSION

We describe novel values of BP before DCC in healthy term infants following vaginal delivery. Data suggest that neonates whose cord is clamped in a delayed fashion experience an increase blood pressures immediately after birth, followed by a significant drop within 30 min to levels that remain unchanged at 24 h of life. BP values obtained after DCC in our study are similar to those found by previous authors. Further studies are needed to determine the clinical significance of these findings and assess the potential of BP prior to DCC to evaluate immediate postnatal adaptation.

LIMITATIONS

Results generalizability may have been limited by varying degrees of neonatal resuscitation, inability to perform more than one measurement before cord clamping ensued, as well as an unequal distribution of self-reported race in our cohort. Also, noninvasive BP estimates have proven less accurate that invasive methods. Finally, our cohort was comprised by a relatively small sample and larger studies will be required to corroborate our findings.

The hypertensive neonate

Hypertension in neonates is increasingly recognized because of improvements in neonatal intensive care that have led to improved survival of premature infants. Although normative data on neonatal blood pressure remain limited, several factors appear to be important in determining blood pressure levels in neonates, especially gestational age, birth weight and maternal factors. Incidence is around 1% in most studies and identification depends on careful blood pressure measurement. Common causes of neonatal hypertension include umbilical catheter associated thrombosis, renal parenchymal disease, and chronic lung disease, and can usually be identified with careful diagnostic evaluation. Given limited data on long-term outcomes and use of antihypertensive medications in these infants, clinical expertise may need to be relied upon to decide the best approach to treatment. This review will discuss these concepts and identify evidence gaps that should be addressed.

Neonatal Blood Pressure Standards: What Is "Normal"?

Blood pressure (BP) is routinely measured in newborn infants. Published BP nomograms demonstrate a rise in BP following delivery in healthy infants at all gestational ages (GA) and evidence that BP values are higher with increasing birth weight and GA. However, the complex physiology that occurs in newborn infants and range of BP values observed at all GA make it difficult to identify "normal" BP for a specific infant at a specific time under specific conditions. As such, complete hemodynamic assessment should include the physical examination, perinatal history, other vital signs, and laboratory values in addition to BP values.

Method of Blood Pressure Measurement in Neonates and Infants: A Systematic Review and Analysis

OBJECTIVES

To determine the recommended blood pressure (BP) measurement methods in neonates after systematically analyzing the literature regarding proper BP cuff size and measurement location and method.

STUDY DESIGN

A literature search was conducted in MEDLINE, PubMed, Embase, Cochrane Library, and CINAHL from 1946 to 2017 on BP in neonates <3 months of age (PROSPERO ID CRD42018092886). Study data were extracted and analyzed with separate analysis of Bland-Altman studies comparing measurement methods.

RESULTS

Of 3587 nonduplicate publications identified, 34 were appropriate for inclusion in the analysis. Four studies evaluating BP cuff size support a recommendation for a cuff width to arm circumference ratio of approximately 0.5. Studies investigating measurement location identified the upper arm as the most accurate and least variable location for oscillometric BP measurement. Analysis of studies using Bland-Altman methods for comparison of intra-arterial to oscillometric BP measurement show that the 2 methods correlate best for mean arterial pressure, whereas systolic BP by the oscillometric method tends to overestimate intra-arterial systolic BP. Compared with intra-arterial methods, systolic BP, diastolic BP, and mean arterial pressure by oscillometric methods are less accurate and precise, especially in neonates with a mean arterial pressure <30 mm Hg.

CONCLUSIONS

Proper BP measurement is critical in neonates with naturally lower BP and attention to BP cuff size, location, and method of measurement are essential. With decreasing use of intra-arterial catheters for long-term BP monitoring in neonates, further studies are urgently needed to validate and develop oscillometric methodology with enhanced accuracy.

Comparison of blood pressure measurements in the upper and lower extremities versus arterial blood pressure readings in children under general anesthesia

Purpose

To compare invasive blood pressure (IBP) readings obtained from an arterial cannula with non-invasive blood pressure (NIBP) measurements from oscillometric cuffs on the upper and lower extremities of infants and children under general anesthesia.

Patients and methods

Patients under 10 years of age were enrolled in our study if they were to receive general anesthesia with planned placement of a radial arterial cannula. At 5 mins intervals, IBP was measured using a fluid-coupled pressure transducer and NIBP was measured with two oscillometers with appropriately sized cuffs placed on the upper arm and lower leg, for 10 readings per patient.

Results

The study enrolled 18 boys and 12 girls, ranging in age from 0 to 8 years. Across 300 data points, the absolute difference between the arm and invasive mean arterial pressure (MAP) measurements was 7±7 mmHg (range: 0–52 mmHg). The absolute difference between the leg and invasive MAP measurements was 8±8 mmHg (range: 0–52 mmHg). Although both non-invasive measurement sites demonstrated frequent deviation from invasive measurement, large deviations were more common when BP was measured at the leg (81 of 298 observations (27%) deviating by >10 mmHg) compared to the arm (60 of 300 observations (20%) deviating by >10 mmHg).

Conclusion

The frequency of clinically significant NIBP deviation in children under general anesthesia supports the importance of IBP monitoring when hemodynamic fluctuations are likely and would be particularly detrimental. NIBP measured at the lower leg is more likely to result in clinically significant deviation from invasively measured MAP than NIBP values obtained from an upper arm.

Binodal, wireless epidermal electronic systems with in-sensor analytics for neonatal intensive care

Existing vital signmonitoring systems in the neonatal intensive care unit (NICU) requiremultiple wires connected to rigid sensors with strongly adherent interfaces to the skin.We introduce a pair of ultrathin, soft, skin-like electronic devices whose coordinated, wireless operation reproduces the functionality of these traditional technologies but bypasses their intrinsic limitations.The enabling advances in engineering science include designs that support wireless, battery-free operation; real-time, in-sensor data analytics; time-synchronized, continuous data streaming; soft mechanics and gentle adhesive interfaces to the skin; and compatibility with visual inspection and with medical imaging techniques used in the NICU. Preliminary studies on neonates admitted to operating NICUs demonstrate performance comparable to the most advanced clinical-standard monitoring systems.

Neonatal hypertension: an educational review

Hypertension is encountered in up to 3% of neonates and occurs more frequently in neonates requiring hospitalization in the neonatal intensive care unit (NICU) than in neonates in newborn nurseries or outpatient clinics. Former NICU neonates are at higher risk of hypertension secondary to invasive procedures and disease-related comorbidities. Accurate measurement of blood pressure (BP) remains challenging, but new standardized methods result in less measurement error. Multiple factors contribute to the rapidly changing BP of a neonate: gestational age, postmenstrual age (PMA), birth weight, and maternal factors are the most significant contributors. Given the natural evolution of BP as neonates mature, a percentile cutoff of 95% for PMA has been the most common definition used; however, this is not based on outcome data. Common causes of neonatal hypertension are congenital and acquired renal disease, history of umbilical arterial catheter placement, and bronchopulmonary dysplasia. The treatment of neonatal hypertension has mostly been off-label, but as evidence accumulates, the safety of medical management has increased. The prognosis of neonatal hypertension remains largely unknown and thankfully most often resolves unless secondary to renovascular disease, but further research is needed. This review discusses important factors related to neonatal hypertension including BP measurement, determinants of BP, and management of neonatal hypertension.

Neonatal hypertension: cases, causes, and clinical approach

Neonatal hypertension is increasingly recognized as dramatic improvements in neonatal intensive care, advancements in our understanding of neonatal physiology, and implementation of new therapies have led to improved survival of premature infants. A variety of factors appear to be important in determining blood pressure in neonates, including gestational age, birth weight, and postmenstrual age. Normative data on neonatal blood pressure values remain limited. The cause of hypertension in an affected neonate is often identified with careful diagnostic evaluation, with the most common causes being umbilical catheter-associated thrombosis, renal parenchymal disease, and chronic lung disease. Clinical expertise may need to be relied upon to decide the best approach to treatment in such patients, as data on the use of antihypertensive medications in this age group are extremely limited. Available data suggest that long-term outcomes are usually good, with resolution of hypertension in most infants. In this review, we will take a case-based approach to illustrate these concepts and to point out important evidence gaps that need to be addressed so that management of neonatal hypertension may be improved.

Discrepancy between invasive and non-invasive blood pressure readings in extremely preterm infants in the first four weeks of life

Background

The agreement between invasive and non-invasive blood pressure (BP) readings in the first days of life of preterm infants is contentiously debated.

Objective

To compare mean, systolic and diastolic invasive (IBP) and non-invasive BP (NBP) readings obtained during routine care in the first four weeks of life of extremely preterm infants.

Methods

We extracted pairs of IBP and NBP readings obtained from preterm infants born below 28 weeks of gestation from the local database. After exclusion of erroneous measurements, we investigated the repeated measures correlation and analyzed the agreement (bias) and precision adjusted for multiple measurements per individual.

Results

Among 335 pairs of IBP and NBP readings obtained from 128 patients, we found correlation coefficients >0.65 for mean, systolic and diastolic BP values. The bias for mean BP readings was -0.4 mmHg (SD 6.1), for systolic BP readings 6.2 mmHg (SD 8.1), and for diastolic BP readings -4.3 mmHg (SD 6.5). Overestimation of systolic IBP and underestimation of diastolic IBP by the non-invasive measurement were found both in the group with gestational age from 23 to 25.9 weeks and in the group with gestational age from 26 to 27.9 weeks. Systolic NBP readings tended to exceed invasive readings in the range <50 mmHg (bias 9.9 mmHg) whereas diastolic NBP readings were lower than invasive values particularly in the range >30 mmHg (bias -5.5 mmHg).

Conclusion

The disagreement between invasive and non-invasive BP readings in infants extends to the first four weeks of life. Biases differ for mean, systolic and diastolic BP values. Our observation implies that they may depend on the range of the blood pressure. Awareness of these biases and preemptive concomitant use of IBP and NPB readings may contribute to reducing over- or under-treatment.

The Pathophysiology of Low Systemic Blood Flow in the Preterm Infant

Assessment and treatment of the VLBW infant with cardiovascular impairment requires understanding of the underlying physiology of the infant in transition. The situation is dynamic with changes occurring in systemic blood pressure, pulmonary pressures, myocardial function, and ductal shunt in the first postnatal days. New insights into the role of umbilical cord clamping in the transitional circulation have been provided by large clinical trials of early versus later cord clamping and a series of basic science reports describing the physiology in an animal model. Ultrasound assessment is invaluable in assessment of the physiology of the transition and can provide information about the size and shunt direction of the ductus arteriosus, the function of the myocardium and its filling as well as measurements of the cardiac output and an estimate of the state of peripheral vascular resistance. This information not only allows more specific treatment but it will often reduce the need for treatment.

Management of severe hypertension in the newborn

Blood pressure is considered a vital sign, as values too low or too high can be related with serious morbidity and mortality. In neonates, normal blood pressure values undergo rapid changes, especially in premature infants, making the recognition of abnormal blood pressures more challenging. Severe hypertension can occur in neonates and infants and is a medical emergency, often manifesting with congestive heart failure or other life-threatening complications. The cause or risk factors for the hypertension can usually be identified and may guide management. Most classes of antihypertensive medications have been used in the neonatal population. For severe hypertension, intravenous short-acting medications are preferred for a controlled reduction of blood pressure. In this article, we focus on identification, aetiology and management of severe hypertension in the newborn.

Coarctation Index Predicts Recurrent Aortic Arch Obstruction Following Surgical Repair of Coarctation of the Aorta in Infants

Recurrent aortic arch obstruction (RAAO) remains a major cause of morbidity following surgical neonatal repair of coarctation of the aorta (CoA). Elucidating predictors of RAAO can identify high-risk patients and guide postoperative management. The Coarctation index (CoA-I), defined as the ratio of the diameter of the narrowest aortic arch segment to the diameter of the descending aorta, has been used to help diagnose RAAO in neonates following the Norwood Procedure. We sought to assess the predictive value of the CoA-I on RAAO after CoA repair in infants with biventricular circulation. Clinical, surgical, and echocardiographic data of infants with biventricular circulation following neonatal CoA repair between 2010 and 2014 were evaluated. RAAO was defined using a composite quantitative outcome variable: a blood pressure gradient >20, a peak aortic arch velocity >3.5 m/s by echocardiogram, or a catheter-measured peak-to-peak gradient >20 within 2 years of surgery. Univariate and multivariate logistic regression analyses were used. Of the 68 subjects included in the analysis, 15 (22%) met criteria for RAAO. In the multivariate model, only CoA-I (OR 35.89, 95% CI 6.08-211.7, p < 0.0001) and use of patch material (OR 9.26, 95% CI 1.57-54.66, p = 0.014) were associated with increased risk of RAAO. The odds of developing RAAO was higher in patients with a CoA-I less than 0.7 (OR 33.8, 95% CI 5.7-199.5, p < 0.001). Postoperative CoA-I may be used to predict RAAO in patients with biventricular circulation after repair of CoA. Patients with a CoA-I less than 0.7 or patch aortoplasty warrant close follow-up.

Does measurement of four-limb blood pressures at birth improve detection of aortic arch anomalies?

OBJECTIVE

To determine normal four-extremity blood pressure (BP) in the neonatal intensive care unit (NICU) at birth and the utility of upper (UE) and lower extremity (LE) BP difference to screen for coarctation of the aorta (Co-A) and interrupted the aortic arch (IAA).

STUDY DESIGN

Retrospective study of BP at birth (n=866), and case-control study of Co-A/IAA infants and matched controls (1:2).

RESULT

Although BP increased with gestational age (R(2)=0.3, P<0.0001), the pressure gradient between UE and LE did not change with gestation (P=0.68). Forty-six cases of Co-A/IAA were identified, with 92 controls. Pressure gradient was significantly higher in patients with Co-A/IAA (7.6±14.8 versus 0.4±10 mm Hg, P=0.004). However, there was overlap between cases and controls resulting in low sensitivity (41.3% with ⩾10 mm Hg gradient cutoff).

CONCLUSION

Evaluation of UE-LE BP gradient at birth is a poor screening test for Co-A/IAA with low sensitivity. Repeating four-limb BP after ductal closure at 24 to 48 h along with SpO2 screening for critical congenital heart disease may increase sensitivity.

The effects of umbilical cord milking on hemodynamics and neonatal outcomes in premature neonates

OBJECTIVE

To determine whether umbilical cord milking (UCM) improves systemic blood flow and reduces neonatal morbidities compared with immediate cord clamping (ICC).

STUDY DESIGN

Women admitted to a tertiary care center and delivering before 32 weeks' gestation were randomized to receive UCM or ICC. Three blinded serial echocardiograms were performed in the first 2 days of the infant's life. The primary outcome was measured systemic blood flow (superior vena cava flow) at each time point.

RESULTS

Of the 60 neonates who were enrolled and randomized, 30 were assigned to cord milking and 30 to ICC. Neonates randomized to cord milking had greater measures of superior vena cava flow and right ventricular output in the first 6 hours and 30 hours of life. Neonates receiving UCM also had greater serum hemoglobin, received fewer blood transfusions, fewer days on oxygen therapy, and less frequent use of oxygen at 36 weeks' corrected postmenstrual age.

CONCLUSIONS

We demonstrate greater systemic blood flow with UCM in preterm neonates compared with ICC. Future large prospective trials are needed to determine whether UCM reduces intraventricular hemorrhage and other long-term morbidities.

Beyond survival; influences of blood pressure, cerebral perfusion and anesthesia on neurodevelopment

Neonates have a higher perioperative mortality risk largely due to the degree of prior illness of the infants, the complexity of their surgeries, and infant physiology. It is important to consider contributing anesthetic factors during the perioperative period that may affect cerebral perfusion and neurocognitive outcome, such as alterations in hemodynamics and ventilation. Limitations of blood pressure as a marker for cerebral perfusion are discussed, as well as the effect of hypocapnia on the brain.

Neonatal blood pressure monitoring: visual assessment is an unreliable method for selecting cuff sizes

AIM

To compare current practice of cuff size selection for noninvasive blood pressure measurement in a single-centre, tertiary-level neonatal intensive care unit (visual assessment of bladder width/limb length closest to 2/3) with common recommendations for appropriate cuff selection.

METHODS

Visual assessment of the appropriate cuff size ('2/3 rule') for upper arm, forearm and calf in 103 neonates (309 cuff selections) was compared with the following recommendations: (i) Method A - guidelines of the cuff manufacturer, (ii) Method B - cuff width/limb circumference ratio 0.44-0.60 and (iii) Method C - cuff width/limb length ratio closest to 0.66.

RESULTS

The upper arm cuff size was correctly chosen in 84% of cases (Method A), 43% (Method B) and 56% (Method C). The forearm cuff size was correctly chosen in 94% of cases (Method A), 68% (Method B) and 54% (Method C). The calf cuff size was correctly chosen in 96% of cases (Method A), 72% (Method B) and 63% (Method C).

CONCLUSION

The accuracy of selecting cuff size by visual assessment is low. Further research on accurate cuff selection for neonates, including at the forearm and calf, is warranted.

Hypertension in the neonatal period

PURPOSE OF REVIEW

Continued interest in neonatal hypertension has led to generation of new data on normal blood pressure (BP) values in neonates, identification of new causes of hypertension in the neonatal period, and improved insights into therapy.

RECENT FINDINGS

Normal BP in neonates depends on a variety of factors, including gestational age, postnatal age, and birth weight, and may be influenced by other antenatal conditions. The incidence of neonatal hypertension is low, and it is most often seen in infants with concurrent conditions such as chronic lung disease (CLD) or renal disease, or in those that have undergone umbilical arterial catheterization. Although few data exist on efficacy and safety of antihypertensive medications in neonates, a wide variety of medications have been utilized in those who do require treatment. Hypertension resolves over time in most infants, although robust long-term outcome data are lacking.

SUMMARY

Our understanding of neonatal hypertension continues to evolve. Although better data are available on normal BP and the incidence of hypertension, we still need studies focused on appropriate treatment and long-term prognosis.

Comparison between oscillometric and invasive blood pressure measurements in critically ill premature infants

AIM

Blood pressure (BP) measurement techniques in neonates generally involve noninvasive measurements with a cuff (oscillometric) or invasive measurements through an arterial catheter. The aim of this study was to determine the reliability of the noninvasive oscillometric method in critically ill preterm infants when results were compared with the invasive technique.

METHOD

Twenty-seven premature infants with a mean birth weight of 1138 ± 552 g were enrolled in the prospective study. Invasive and noninvasive mean arterial pressure (MAP) levels were recorded simultaneously at each measurement in all patients. Low or lower range mean invasive MAP values (MAP ≤30) were evaluated separately as we aimed to assess the value of noninvasive measurements in hypotensive sick premature infants.

RESULTS

Totally, 431 paired BP measurements were taken during the first week of life. There was no statistically significant difference between invasive and noninvasive readings. However, noninvasive measurements were found significantly higher compared with invasive measurements in the presence of hypotension (p < 0.05).

CONCLUSION

This study showed good agreement between oscillometric and invasive readings in critically ill premature infants, and further, comparable mean MAP values were found with the two methods. However, the accuracy of the oscillometric BP measurement technique fails in preterm infants with BP within the lower limits.

Hypertension in infancy: diagnosis, management and outcome

Advances in the ability to identify, evaluate, and care for infants with hypertension, coupled with advances in the practice of Neonatology, have led to an increased awareness of hypertension in modern neonatal intensive care units. This review will present updated data on blood pressure values in neonates, with a focus on the changes that occur over the first days and weeks of life in both term and preterm infants. Optimal blood pressure measurement techniques as well as the differential diagnosis of hypertension in the neonate and older infants will be discussed. Recommendations for the optimal immediate and long-term evaluation and treatment, including potential treatment parameters, will be presented. We will also review additional information on outcome that has become available over the past decade.

Early postnatal hypotension and developmental delay at 24 months of age among extremely low gestational age newborns

OBJECTIVES

To evaluate in extremely low gestational age newborns, relationships between indicators of hypotension during the first 24 postnatal hours and developmental delay at 24 months of age.

METHODS

The 945 infants in this prospective study were born at <28 weeks, were assessed for three indicators of hypotension in the first 24 postnatal hours, and were evaluated with the Bayley Mental Development Index (MDI) and Psychomotor Development Index (PDI) at 24 months corrected age. Indicators of hypotension included: (1) mean arterial pressure in the lowest quartile for gestational age; (2) treatment with a vasopressor; and (3) blood pressure lability, defined as the upper quartile for the difference between the lowest and highest mean arterial pressure. Logistic regression was used to evaluate relationships between hypotension and developmental outcomes, adjusting for potential confounders.

RESULTS

78% of infants in this cohort received volume expansion or vasopressor; all who received a vasopressor were treated with volume expansion. 26% had an MDI <70 and 32% had a PDI <70. Low MDI and PDI were associated with low gestational age, which in turn, was associated with receipt of vasopressor treatment. Blood pressure in the lowest quartile for gestational age was associated with vasopressor treatment and labile blood pressure. After adjusting for potential confounders, none of the indicators of hypotension were associated with MDI <70 or PDI <70.

CONCLUSIONS

In this large cohort of extremely low gestational age newborns, we found little evidence that early postnatal hypotension indicators are associated with developmental delay at 24 months corrected gestational age.

Early postnatal hypotension is not associated with indicators of white matter damage or cerebral palsy in extremely low gestational age newborns

OBJECTIVE

To evaluate, in extremely low gestational age newborns (ELGANs), relationships between indicators of early postnatal hypotension and cranial ultrasound indicators of cerebral white matter damage imaged in the nursery and cerebral palsy diagnoses at 24 months follow-up.

STUDY DESIGN

The 1041 infants in this prospective study were born at <28 weeks gestation, were assessed for three indicators of hypotension in the first 24 postnatal hours, had at least one set of protocol cranial ultrasound scans and were evaluated with a structured neurological exam at 24 months corrected age. Indicators of hypotension included: (1) lowest mean arterial pressure (MAP) in the lowest quartile for gestational age; (2) treatment with a vasopressor; and (3) blood pressure lability, defined as the upper quartile of the difference between each infant's lowest and highest MAP. Outcomes included indicators of cerebral white matter damage, that is, moderate/severe ventriculomegaly or an echolucent lesion on cranial ultrasound and cerebral palsy diagnoses at 24 months gestation. Logistic regression was used to evaluate relationships among hypotension indicators and outcomes, adjusting for potential confounders.

RESULT

Twenty-one percent of surviving infants had a lowest blood pressure in the lowest quartile for gestational age, 24% were treated with vasopressors and 24% had labile blood pressure. Among infants with these hypotension indicators, 10% percent developed ventriculomegaly and 7% developed an echolucent lesion. At 24 months follow-up, 6% had developed quadriparesis, 4% diparesis and 2% hemiparesis. After adjusting for confounders, we found no association between indicators of hypotension, and indicators of cerebral white matter damage or a cerebral palsy diagnosis.

CONCLUSION

The absence of an association between indicators of hypotension and cerebral white matter damage and or cerebral palsy suggests that early hypotension may not be important in the pathogenesis of brain injury in ELGANs.

Prediction of recurrent coarctation by early postoperative blood pressure gradient

OBJECTIVE

Blood pressure gradients that are noted early after repair of coarctation in neonates and infants are often attributed to proximal arch hypoplasia. Rapid growth of the hypoplastic proximal arch is usually observed, although in some individuals an early gradient predicts the subsequent need for reintervention. To define the predictive reliability of blood pressure gradients between arms and legs and to identify predictors of arch growth, we undertook a retrospective study.

METHODS

Between January 2000 and June 2008, 77 infants underwent surgical repair of coarctation. Data collected included preoperative dimensions of aortic segments. Blood pressure gradients between arms and legs determined by cuff were compared intraoperatively and postoperatively, as well as 2-dimensional echocardiographic dimensions of the aorta between those who did not require reintervention for recoarctation (group A) and those who did (group B). Receiver operating characteristic curve analysis was applied to evaluate discrimination of the systolic gradient in differentiating the 2 groups of patients.

RESULTS

At surgery, patients' median age was 10 days and weight was 3.3 kg. There was 1 early death. Median follow-up was 40 months (interquartile range, 24-63 months). Recoarctation developed in 11 patients (14.3%), defined as a resting blood pressure gradient of greater than 20 mm Hg with a corresponding decrease in the diameter of the aorta by 50%. Freedom from recoarctation was 87% at 1 year and 85% at 5 years. Multivariable logistic regression analysis identified the size of the ascending aorta as a risk factor for recoarctation. Blood pressure gradient at the end of surgery was not predictive of recoarctation. The ascending aorta and transverse arch showed rapid growth in group A, and this was associated with a decrease in blood pressure gradient over time. In comparison, the growth of the ascending aorta and arch in group B was significantly less than in group A and associated with worsening of gradients. Receiver operating characteristic curve analysis revealed that gradients at the time of hospital discharge (>13 mm Hg) had excellent discriminative accuracy in identifying patients in whom subsequent recoarctation developed.

CONCLUSIONS

Small size of the ascending aorta is a risk factor for recoarctation. Limb gradient in the operating room at completion of surgery is not a reliable tool to assess repair of coarctation, although the gradient at the time of hospital discharge can be used to accurately predict recoarctation. Rapid growth of both the ascending and the transverse aorta is frequently observed and associated with improvement in gradients over time.

The need for noninvasive biomarkers for drug safety in neonatal circulation

The new EU Pediatric Drug Regulation covers the development of new drugs to include studies in children and newborn babies. An important part of the evaluation of a new drug will be data on efficacy and safety related to short-term and possible long-term effects. Owing to the special circumstances of studying drugs, especially in newborn babies, new, preferably noninvasive, biomarkers are required that can be used for assessment and monitoring in this vulnerable patient population. Feedback from expert groups and public stakeholders should be taken into account when introducing biomarkers into the study design. New noninvasive biomarkers for monitoring cardiovascular circulation in newborns will be used to illustrate an example of their practical use and implementation.

Comparison of noninvasive and central arterial blood pressure measurements in ELBW infants

OBJECTIVE

The objective of this study was to evaluate the difference between noninvasive and central arterial blood pressure measurements in extremely low-birth-weight (ELBW) infants.

STUDY DESIGN

We conducted a retrospective cohort study of infants with birth weight <or=1000 g and who were admitted to a single center in 2005. Paired noninvasive and umbilical arterial blood pressure measurements obtained in the first 72 h were compared. The primary outcome was the differential between the paired measurements. Noninvasive blood pressure (NBP) measurements were defined as clinically acceptable if the differential between the pairs was 15% or lower.

RESULT

We obtained 146 pairs of measurements from 38 infants. The median absolute differences between noninvasive and arterial systolic, mean and diastolic blood pressure measurements were +18.5, +12 and +10 mm Hg, respectively (percentage differential of 43, 39 and 41%, respectively). In total 75% of the noninvasive measurements of mean blood pressure were clinically unacceptable. No patient or measurement characteristic was significantly associated with clinically unacceptable noninvasive measurements.

CONCLUSION

In ELBW infants, NBP measurements substantially overestimate systolic, mean and diastolic blood pressures compared with central arterial measurements.