Variability of four limb blood pressure in normal neonates

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.

Clinical, Experimental, and Computational Validation of a New Doppler-Based Index for Coarctation Severity Assessment

BACKGROUND

Long-term morbidity including hypertension often persists in coarctation patients despite current guidelines. Coarctation severity can be invasively assessed via peak-to-peak catheter pressure gradient (PPCG), which is estimated noninvasively via simplified Bernoulli equation and conventionally reported as peak instantaneous Doppler gradient (PIDG). However, underlying simplifications of the equation limit diagnostic accuracy. We studied the diagnostic performance of a new Doppler-based diastolic index called the continuous flow pressure gradient (CFPG) versus conventional indices in assessing coarctation severity.

METHODS

In a rabbit model mimicking human aortic coarctation, temporal blood pressure waveforms revealed the diastolic instantaneous pressure gradients and spectral Doppler features impacted by coarctation severity. We therefore hypothesized that CFPG provides superior correlation with coarctation gradients measured invasively. PIDG and CFPG were quantified using color flow echocardiography in humans and rabbits with discrete coarctations. Results were compared with PPCG in rabbits (n = 34) and arm-leg systolic gradients (n = 25) in humans via 1-way analysis of variance, Pearson's correlation, linear regression, and Bland-Altman analysis.

RESULTS

A threshold of CFPG ≥ 4.6 mm Hg was identified via the Youden index as representative of PPCG ≥ 20 mm Hg (the current guideline value for coarctation intervention) in rabbits, while a CFPG ≥1.0 mm Hg represented an arm-leg systolic gradient ≥20 mm Hg in humans. Accuracy measures revealed superior correlation of CFPG (R2 > 0.80) and mild receiver operating characteristic improvement (area under the receiver operating characteristic curve, 0.94-0.95) compared with PIDG (R2 < 0.63; area under the receiver operating characteristic curve, 0.89-0.95). Inter-/intraobserver variability tested by intraclass correlation coefficient revealed measurement reliability with differences ≤8.2% and 10.7%, respectively. Computational simulations of anesthetized versus conscious hemodynamics showed parameters were minimally impacted by isoflurane inherent in the data used to derive CFPG. These results confirm the potential diagnostic accuracy of CFPG in echocardiography-based coarctation severity assessment. We are optimistic that CFPG will be useful for translation of results from preclinical studies that revisit current guidelines to limit morbidity in humans with aortic coarctation.

Fifteen-minute consultation: Cardiac murmurs in the Newborn Infant Physical Examination (NIPE)

The finding of a cardiac murmur on the initial newborn examination is common but may be a source of anxiety for practitioners due to worries about missing critical congenital heart defects (CHDs). This article aims to provide an approach to this common finding, in particular, reviewing the evidence base behind features of the history, examination and subsequent non-specialist investigations which may increase the likelihood of CHDs. The aim of this structured approach is to give clinicians confidence in dealing with this common clinical finding, to be able to pick out those infants most at risk of having critical CHDs.

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.

Neonatal Hypertension

Neonatal hypertension is uncommon but is becoming increasingly recognized. Normative blood pressure data are limited, as is research regarding the risks, treatment, and long-term outcomes. Therefore, there are no clinical practice guidelines and management is based on clinical judgment and expert opinion. Recognition of neonatal hypertension requires proper blood pressure measurement technique. When hypertension is present there should be a thorough clinical, laboratory, and imaging evaluation to promptly diagnose causes needing medical or surgical management. This review provides a practical overview for the practicing clinician regarding the identification, evaluation, and management of neonatal hypertension.

Management of Acute Kidney Injury in Extremely Low Birth Weight Infants

Acute kidney injury (AKI) is a common problem in the neonatal intensive care unit (NICU). Neonates born at <1,000 g (extremely low birth weight, ELBW) are at an increased risk of secondary associated comorbidities such as intrauterine growth restriction, prematurity, volume restriction, ischaemic injury, among others. Studies estimate up to 50% ELBW infants experience at least one episode of AKI during their NICU stay. Although no curative treatment for AKI currently exists, recognition is vital to reduce potential ongoing injury and mitigate long-term consequences of AKI. However, the definition of AKI is imperfect in this population and presents clinical challenges to correct identification, thus contributing to under recognition and reporting. Additionally, the absence of guidelines for the management of AKI in ELBW infants has led to variations in practice. This review summarizes AKI in the ELBW infant and includes suggestions such as close observation of daily fluid balance, review of medications to reduce nephrotoxic exposure, management of electrolytes, maximizing nutrition, and the use of diuretics and/or dialysis when appropriate.

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 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.

The effect of including increased arterial stiffness in the upper body when modelling Coarctation of the Aorta

Coarctation of the Aorta is a congenital narrowing of the aorta and diagnosis can be difficult. Treatments result in idiopathic sequelae including hypertension. Untreated patients are known to develop increased arterial stiffness in the upper body, which worsens with time. We present results from simulations with a one-dimensional mathematical model, about the effect of stiffness, stenting, surgery and coarctation severity on blood pressure, Pulsatility and Resistivity Index. One conclusion is that increased stiffness may explain both hypertension in treated patients and why diagnosis can be difficult.

Safe anesthesia for neonates, infants and children

This review provides an overview of the perioperative safety concerns in pediatric anesthesia and exploration of strategies to minimize these risks through education and training in pediatric anesthesia. There is increasing human data on the effects of general anesthesia for surgery and procedures on later neurodevelopment. However, the magnitude and relevance of this remains unclear while the long-term outcomes from recent human studies are awaited. The current known and established risks associated with pediatric anesthesia can be minimized by establishing a robust and safe conduct of anesthesia. This not only includes maintenance of normal physiological variables but also other aspects such as reduction of preoperative fear and anxiety and postoperative care. This can be achieved through effective multidisciplinary team working, cross specialty training and further development of fellowships and secondments.

Defining hypotension in anesthetized infants by individual awake blood pressure values: a prospective observational study

BACKGROUND

Blood pressure (BP) is the most commonly applied clinical surrogate parameter for tissue perfusion and cerebral autoregulation. Hypotension during anesthesia may contribute to unfavorable outcome in young children. Hypotension in anesthetized infants can be defined using BP values relative to individual awake baseline or absolute BP values.

AIM

The aim of this study was to investigate the applicability of the two definitions and to compare the incidences of hypotension.

METHOD

This was a prospective observational study in 151 infants <12 months of age. The percentage of successful awake BP measurements was calculated and related to the infant's behavioral state. Hypotension under sevoflurane anesthesia was defined by a decrease of mean arterial pressure (MAP) relative to awake baseline (>20% in infants <6 months, >40% in infants >6 months) or absolute MAP values (<35 mmHg in infants <6 months, <43 mmHg in infants >6 months). The incidences of hypotension using the two definitions were compared.

RESULTS

Awake BP values were obtained in 85% of the patients. Calm patients were more likely to allow their BP to be measured than anxious patients. Anxious patients had higher preinduction MAP values than calm patients. The relative BP approach resulted in a higher incidence of postinduction hypotension than using absolute BP values.

CONCLUSIONS

Awake BP values were unobtainable in 15% of our patients, resulting in the necessity to define hypotension under anesthesia using absolute BP values. Definitions of hypotension using either absolute MAP or values relative to awake baseline are not interchangeable.

Photoplethysmographic waveform characteristics of newborns with coarctation of the aorta

OBJECTIVE

Fetal echocardiography, physical examination and pulse oximetry detect only half of coarctation of aorta (CoA) cases. We aimed to quantify delayed arrival and diminished amplitude of lower extremity photoplethysmographic (PPG) pulses relative to the right hand in affected patients.

STUDY DESIGN

We studied 8 CoA infants and 32 healthy controls. The pulse arrival time difference between foot and hand (f-hTD) and pulse amplitude ratio (F/H) were measured on PPG signal waveforms by digitally-determining maxima and minima of systolic decrease of light transmission. Mann-Whitney test was used for group comparisons.

RESULTS

In comparison to healthy newborns, CoA infants' PPG waveforms demonstrated prolonged f-hTD (mean±s.d. of 73.2±26.6 versus 35.2±8.3 ms, P<0.001) and lower F/H (0.57±0.26 versus 0.99±0.58, P=0.014).

CONCLUSIONS

F-hTD and F/H are quantifiable from hand- and foot-derived PPG waveforms and are significantly different in CoA versus healthy newborns. Larger studies are needed to validate PPG for improved critical congenital heart disease screening.

Making a diagnosis of hypertension and defining treatment threshold in very low birth weight infants’ need revision?

Introduction: Recent evidence suggests that preterm birth is a possible risk factor for high blood pressure (BP) in later life. The most widely quoted blood pressure centiles for very low birth weight (VLBW, ≤1500 g birth weight) infants at corrected term gestation is based on a cohort with mostly late preterm or term infants (Zubrow curves).

Objectives: The objective of this study was to determine the clinical utility of the Zubrow curves in diagnosis of hypertension in VLBW infants at their term corrected gestational age (CGA).

Patients and Methods: In a case-control study, we compared BP in 75 VLBW infants at 40 weeks CGA (cases) to 69 full term infants admitted to neonatal intensive care unit (NICU) (controls).

Results: In spite of having lower weights, VLBW infants compared to term infants (2612.8 ± 546 vs. 3308.2 ± 373 g, P ≤ 0.001) had higher average systolic (88.8 ± 7.6 vs. 82.33 ± 8.5 mm Hg; P ≤ 0.001) and mean BP (61.2 ± 6.6 vs. 57.61 ± 6.9, P = 0.01). Although 41% (31/75) VLBW infants would have met the criteria for hypertension according to Zubrow curves only 4% (3/75) were diagnosed with hypertension.

Conclusion: Since Zubrow BP centiles were based on a heterogeneous population of infants including preterm and term infants, new BP centiles based on chronological data from VLBW infants would allow a better definition of hypertension in these infants and identify the threshold BP for initiating treatment.

Comparison of non-invasive vs invasive blood pressure measurement in neonates undergoing therapeutic hypothermia for hypoxic ischemic encephalopathy

OBJECTIVE

To evaluate the accuracy of blood pressure (BP) measured non-invasively (NIBP) compared with invasive arterial BP (IABP) measured by umbilical arterial catheter in neonates undergoing therapeutic hypothermia (TH) for hypoxic ischemic encephalopathy (HIE).

STUDY DESIGN

We conducted a retrospective study of neonates with gestational age (GA)⩾35 weeks with HIE who received TH. Paired NIBP and IABP measurements were obtained during TH and during normothermia.

RESULT

We collected 897 paired measurements from 40 infants, which included 623 pairs during TH and 274 pairs during normothermia. The mean±s.d. differences in BP measured by NIBP compared with IABP in mmHg were -0.2±8.8 (P=0.505) for systolic BP (SBP), -4.5±8.3 (P<0.001) for diastolic BP (DBP) and -5.1±7.5 (P<0.001) for mean BP (MBP) during TH; and -1.3±9.2 (P=0.016) for SBP, -7.5±7.8 (P<0.001) for DBP and -7.3±6.8 (P<0.001) for MBP during normothermia. Overall 466/623 (74.8%), 324/623 (52.0%) and 363/623 (58.3%) of NIBP measurements of SBP, DBP and MBP, respectively, were clinically acceptable (defined as difference ⩽15% of IABP reading) during TH; and 202/274 (73.7%), 118/274 (43.1%) and 148/274 (54.0%), were clinically acceptable during normothermia.

CONCLUSION

In term or near-term neonates with HIE, NIBP measurements are a robust method to determine SBP; however, DBP and MBP are underestimated. Determination of hypotension using the MBP measured non-invasively should be interpreted with caution.

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.

Relationship between sum of the four limbs' pulse pressure and brachial-ankle pulse wave velocity and atherosclerosis risk factors in Chinese adults

The aim of the present study was to analyze the relationship between the sum of the four limbs' pulse pressure (Sum-PP) and brachial-ankle pulse wave velocity (baPWV) and atherosclerosis risk factors and evaluate the feasibility of Sum-PP in diagnosing atherosclerosis systemically. For the purpose, a cross-sectional study was conducted on the basis of medical information of 20748 adults who had a health examination in our hospital. Both Sum-PP and baPWV exhibited significant variations among different human populations grouped by gender, smoking, drinking, and age. Interestingly, Sum-PP had similar varying tendency with baPWV in different populations. And further study in different populations showed that Sum-PP was significantly positively related to baPWV. We also investigated the relationship between Sum-PP, baPWV, and cardiovascular risk factors, respectively. We found that both Sum-PP and baPWV had significant positive correlation with atherosclerosis risk factors while both of them were negatively related to HDL-c. In addition, there was a significant close correlation between Sum-PP and baPWV in the whole population (r = 0.4616, P < 0.0001). Thus, Sum-PP is closely related to baPWV and is of important value for clinical diagnosis of atherosclerosis.

Blood pressure screening for critical congenital heart disease in neonates

Pulse oximetry (POx) screening for critical congenital heart disease (CCHD) in neonates is less effective in identifying aortic arch obstruction than in detecting other forms of CCHD. This study was performed to assess the use of neonatal blood pressure (BP) screening to detect CCHD. A retrospective review of BP and POx measurements performed at the age of 24 h or before discharge in asymptomatic term neonates was undertaken. The charts of infants readmitted younger than 30 days with a diagnosis of CCHD also were reviewed to identify infants with a missed diagnosis. The screening process was completed for 10,012 of 10,436 infants. Because of an abnormal initial result, 164 neonates required a repeat screening (139 due to abnormal BP). A total of 12 infants failed the BP screening component, and 1 infant failed both the BP and Pox components. The average final right arm-to-leg BP gradient was 25 mmHg in these 13 babies. For nine infants, CCHD was excluded by echocardiography. Three patients were normal at their 1-year well-child exam, and one patient was lost to follow-up evaluation. No infants were identified who had been discharged home with a missed diagnosis of CCHD. Neonatal BP screening to detect CCHD was responsible for more inappropriately performed screenings, repeated screenings, and screening failures than the POx component of the screening protocol and had a highest possible positive predictive value of 1 in 13. These data suggests that BP screening at the time of routine newborn hospital discharge is of limited value in the detection of unrecognized CCHD.

Comparison of calf and brachial blood pressures in infants: is there a difference between calf and brachial blood pressures?

The standard of care is to obtain a noninvasive blood pressure (NIBP) measurement from the right upper arm. However, in the pediatric population it is common practice to take blood pressure (BP) measurements from the calf/upper ankle. Nurses commonly take calf NIBPs for many reasons, but there is little evidence to support calf BPs as a reliable site for BP measurement. Furthermore, there is conflicting evidence. Some studies suggest no difference between the calf and the upper arm BPs, whereas others conclude great variability between the two. The purpose of this study was to demonstrate the reliability of calf BPs, by showing no difference between brachial and calf BP measurements in neonates and infants ≤ 1 year old. From July 2008 to December 2008, a convenience sample of 52 subjects admitted to the Neonatal and Infant Critical Care Unit were enrolled into the study. Limb selection was not randomized. Three BPs were taken from the arm and 3 BPs were taken from the calf. Data were analyzed using a mixed analysis of variance (P = 0.05). The difference was not significant for systolic (P = 0.6159) or mean BP (P = 0.1298), but it was significant for diastolic (P = 0.0263). The authors concluded that these results support the current practice of bedside nurses and contribute to the limited knowledge on this topic. Because there was a difference in the diastolic BPs, further investigation is needed.

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.

Cerebral blood flow in the neonate

Ensuring adequate oxygenation of the developing brain is the cornerstone of neonatal critical care. Despite decades of clinical research dedicated to this issue of paramount importance, our knowledge and understanding regarding the physiology and pathophysiology of neonatal cerebral blood flow are still rudimentary. This review primarily focuses on currently available human clinical and experimental data on cerebral blood flow and autoregulation in the preterm and term infant. Limitations of systemic blood pressure values as surrogates for monitoring adequate cerebral oxygen delivery are discussed. Particular emphasis is placed on the high interindividual variability in cerebral blood flow values, vasoreactivity, and autoregulatory thresholds making the applications of normative values highly questionable. Technical and ethical difficulties to conduct such trials leave us with a near complete lack of knowledge on how pharmacological and surgical interventions impact on cerebral autoregulation. The ensemble of these works argues for the necessity of highly individualized care by taking advantage of continuous bedside monitoring of cerebral circulation. They also point to the urgent need for further studies addressing the exciting but difficult issue of cerebral blood flow autoregulation in the neonate.

Management of asymptomatic cardiac murmurs in term neonates

Approximately 2 % of newborn infants are noted to have cardiac murmur on routine postnatal examination. Our aim was to look at current evidence and practice in the management of asymptomatic cardiac murmur in term neonates. We performed a systematic literature review and a telephone survey of all neonatal units in the United Kingdom (UK). The systematic review of the literature did not support the routine practice of four-limb blood pressure (BP), chest X-ray (CXR), and electrocardiogram (ECG) in the assessment of asymptomatic cardiac murmur in term neonates. The survey had participation from 132 (68 %) of 193 neonatal units in the UK. In an asymptomatic term neonate with cardiac murmur, 124 (94 %) units perform pulse oximetry, 100 units (76 %) measure four-limb BP, 36 units (27 %) perform a CXR, and 52 units (39 %) perform an ECG. Eight-six units (65 %) have availability of in-house echocardiography services provided mainly by paediatricians with cardiology interest in special care units and neonatologists in neonatal intensive care units. Currently there is wide variation in practice in the management of asymptomatic cardiac murmur in term neonates. There is no evidence to support the routine use of four-limb BP, CXR, and ECG in the assessment of asymptomatic cardiac murmur in term neonates. Based on the evidence available, both structured clinical examination (including determining presence and quality of bilateral femoral pulses) and universal use of pulse oximetry are most important in identifying CHD in asymptomatic term neonates with cardiac murmur before discharge home.

Perioperative central nervous system injury in neonates

Anaesthetic-induced developmental neurotoxicity (AIDN) has been clearly established in laboratory animal models. The possibility of neurotoxicity during uneventful anaesthetic procedures in human neonates or infants has led to serious questions about the safety of paediatric anaesthesia. However, the applicability of animal data to clinical anaesthesia practice remains uncertain. The spectre of cerebral injury due to cerebral hypoperfusion, metabolic derangements, coexisting disease, and surgery itself further muddles the picture. Given the potential magnitude of the public health importance of this issue, the clinician should be cognisant of the literature and ongoing investigations on AIDN, and raise awareness of the risks of both surgery and anaesthesia.

Comparison of femoral and carotid blood pressure during laparoscopy in piglets

PURPOSE

The impact of a capnoperitoneum on the known blood pressure (BP) difference of the upper and lower limb was studied in piglets.

METHODS

Eleven German Landrace piglets (body weight, 4.3-7.4 kg; mean body weight, 6.2 kg) were studied. Arterial lines were placed in the right carotid and right femoral artery for pressure monitoring. Intraabdominal pressure levels were increased in steps of 6 mm Hg up to 24 mm Hg.

RESULTS

We found that elevated intraabdominal pressures up to 24 mm Hg did not change the preexisting systolic BP difference between the carotid and femoral arteries. Systolic femoral artery pressure constantly remained 5% higher than its carotid counterpart. In addition, mean and diastolic values were not affected.

CONCLUSIONS

Arterial BP measurements recorded at the legs of piglets when abdominal pressure is increased by up to 24 mm Hg can be used for intraoperative assessment of systemic arterial BP.

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 of arm and calf automatic noninvasive blood pressures in pediatric intensive care patients

The purpose of this study was to compare upper arm and calf automatic blood pressures (BPs) in a convenience sample of 221 children, ages 1 to 8 years, admitted to a pediatric intensive care unit of a 180-bed teaching hospital in the Mid-Atlantic region of the United States. Subjects were positioned in bed, with the head of bed elevated 30° and extremities resting on the bed. BP cuff size was based on arm and calf circumferences. BPs were measured simultaneously using bedside and portable Spacelabs monitors. Calf BPs were greater than arm BPs in approximately 73% of the sample. Paired t tests show statistically significant differences for systolic BPs and mean arterial pressures. Influence of demographics, agitation levels, medical diagnoses, and current medications was explored. Calf and arm BPs were not interchangeable in acutely ill children, ages 1 to 8 years.

Coarctation of the aorta: a case presentation

Coarctation is a constriction or narrowing of the aorta and presents most commonly within the first two weeks of life. This article reviews a case study of an infant diagnosed with coarctation of the aorta on day 8 of life. It includes an overview of the etiology, clinical presentation, and management plus an account of the infant's transport to a regional pediatric intensive care unit (PICU).

Epidemiologic features of the presentation of critical congenital heart disease: implications for screening

OBJECTIVE

Critical congenital heart disease has been proposed as a target of newborn screening. This study aimed to define the incidence and timing of significant physiologic compromise attributable to critical congenital heart disease as well as the distribution of vulnerable lesions. These descriptive parameters must be defined to evaluate the impact and feasibility of any proposed screening strategy.

METHODS

A retrospective cohort study of neonates who had critical congenital heart disease and were admitted to a single institution was conducted. Critical congenital heart disease was defined as congenital heart disease that required invasive intervention or resulted in death in the first 30 days of life. Significant physiologic compromise was defined by severe metabolic acidosis, seizure, cardiac arrest, or laboratory evidence of renal or hepatic injury before invasive intervention. Significant physiologic compromise was classified as potentially preventable when it occurred as a result of undiagnosed congenital heart disease after 12 hours of life.

RESULTS

Significant physiologic compromise occurred in 76 (15.5%) of 490 patients, and potentially preventable significant physiologic compromise occurred in 33 (6.7%) of 490 patients. Most (83%) significant physiologic compromise as a result of unrecognized congenital heart disease occurred after 12 hours of age. A total of 90.9% of cases of potentially preventable significant physiologic compromise had aortic arch obstruction. The incidence of potentially preventable significant physiologic compromise as a result of congenital heart disease in the general population is estimated to be 1 per 15,000 to 1 per 26,000 live births.

CONCLUSIONS

The incidence and timing of significant physiologic compromise as a result of critical congenital heart disease seems amenable to postnatal screening. Any viable screening strategy must be sensitive for lesions with aortic arch obstruction.