HYPERTENSION
Overview
Hypertension in neonates may present insidiously as feeding difficulty, irritability, tachypnea, apnea, or lethargy; may be identified on routine screening; or may present more acutely as congestive heart failure or cardiogenic shock (Flynn, 2000). In infants, as in adults, hypertension is dangerous, particularly when undetected or undermanaged. Preventing organ damage, maintaining healthy function of organ systems, and promoting healthy development depend on early detection and careful management (Kaelber et al., 2016).
Background
Blood pressure (BP) in neonates increases with gestational age, neonatal age, birthweight, and time. Evidence-based BP charts that describe ranges of pressure over time have made it possible to standardize expectations for BP values and help clinicians identify hypertension more consistently and with greater confidence (Flynn, 2000; Flynn & Rosenkrantz, 2016).
Normotension in the neonate is defined as a BP within the 95th percentile on those charts. Conversely, hypertension in the neonate is defined as elevation in systolic BP (on three separate occasions) above the 95th percentile for age, weight, and gender (Watkinson, 2002). By definition then, 5% of all neonates are hypertensive, although in practice, the incidence is closer to 0.2% to 3.0% (Dionne, Abibtol, & Flynn, 2012).
Neonatal hypertension may result from several different causes. It can develop as a result of congenital conditions, including aortic coarctation or structural defects of the renal system; as a consequence of renal disease, including parenchymal or vascular disease; as sequelae to bronchopulmonary dysplasia; as an unintended outcome of medical care, following administration of certain medications, accompanying endocrine disorders such as congenital adrenal hyperplasia and hyperthyroidism; or develop from thromboembolism following umbilical catheterization (Flynn, 2000; Flynn & Rosenkrantz, 2016). Hypertension can progress to cardiovascular disease, kidney disease, and stroke in the adult without proper diagnosis and management (Nickavar & Assadi, 2014).
Among 398,079 children receiving well child care between the ages of 3 and 18 years, 3.3% met diagnostic criteria and were identified as hypertensive and another 10.1% were prehypertensive. These findings agree with prevalence projections described earlier. Regardless, American Academy of Pediatrics recommended treatment was not initiated for the 2,813 infants diagnosed as hypertensive (Kaelber et al., 2016).
A careful history, including both the pregnancy and the neonatal period, is key to evaluating risk, detecting disease, effectively managing the condition, and 166preventing complications. Family history of renal disease or hypertension, in utero exposure to cocaine or other street drugs, and clinical history of bronchopulmonary dysplasia are highly correlated with development of hypertension in the newborn (Flynn & Rosenkrantz, 2016).
Clinical Aspects
ASSESSMENT
Head-to-toe assessment establishes findings to confirm or rule out hypertension. Organ systems impacted by sustained elevated BP are particularly relevant for assessment because microvascular changes in these organs lead to symptoms throughout the body (Nickavar & Assadi, 2014). Important findings include bluish or pale coloration to the skin and rapid respirations, which indicate poor perfusion and oxygenation.
In the primary care setting, weight gain that does not correspond to postnatal age and failure to meet developmental milestones indicate compromised perfusion and oxygenation to vital organs and systems over an extended period. Frequent urinary tract infections point to structural or vascular abnormalities associated with hypertension. Symptoms of pronounced or advanced disease include irritability, seizures, difficulty in breathing, feeding intolerance, and vomiting (Kaelber et al., 2016).
In the neonatal intensive care unit (NICU), routine assessment of respiratory rate and function, heart rate, perfusion, liver function, and oxygenation, as well as systolic, diastolic, and pulse pressures provide useful information to complement BP readings. Observation of the wave formation from arterial lines, urine output, and perfusion to lower extremities provides a picture of vascular conditions. Umbilical arterial lines that are commonly used in the NICU must be discontinued at any sign of complications, including presence of blood in the urine, change in location of the catheter tip on radiography, or compromised perfusion.
Because hypertension in the neonate is defined by three discrete BP measurements that fall above the 95th percentile on standard BP charts, repeated measurement of BP, respiratory rate, heart rate, and pulse oximetry inform the diagnosis (Flynn, 2000; Flynn & Rosenkrantz, 2016). In practice, hypertension is most commonly diagnosed and treated when the BP persistently exceeds the 99th percentile. These data, in combination with the aforementioned clinical findings, indicate need for and effectiveness of the treatment regimen, which is adjusted to the severity and responsiveness of the clinical presentation.
NURSING PROBLEMS, INTERVENTIONS, AND MANAGEMENT
Care for the hypertensive infant in the NICU focuses on promoting comfort, managing medications, monitoring fluid status and renal function, and parent education. Comfort is promoted through careful positioning, providing opportunities for nonnutritive sucking, clustering care to allow time for rest, administration of analgesics as indicated, providing skin-to-skin experiences with 167parents, and maintaining a restive environment. Medications are administered as prescribed. Fluid status is assessed by checking for edema in the extremities and face, strict monitoring of intake and output, testing specific gravity, and monitoring blood urea nitrogen (BUN), creatinine levels, and hematocrit.
In the NICU, pain, agitation, renal output, underlying conditions, interventions such as ventilators and phlebotomy, and medications can influence BP. Pain can complicate assessment and exaggerate the presentation of hypertension. Meticulous pain management is an essential component of treatment especially when hypertension is a consequence of prematurity, which requires a stay in critical care or in the case of congenital anomalies that require surgical intervention.
BP measurements are essential for management of hypertension in the NICU and primary care. Readings can be influenced by many factors, including behavioral state, pain, hunger, and agitation. In order for data to be meaningful, it is useful to measure the BP with the infant in a quiescent state and to note any condition that may have altered the reading at any given time. Proper fit of the cuff to the size of the infant is essential (Nickavar & Assadi, 2014).
In the primary care setting, a variety of medications are prescribed to manage neonatal hypertension, which commonly resolves in the short term in the instance where it presents as a complication of acute illness or medical management. In a meta-analysis of clinical trials conducted on hypertensive infants, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers were most commonly prescribed (35%) followed by diuretics in 22% of the children, calcium channel blockers in 17%, and beta-blockers in another 10% (Kaelber et al., 2016). Infant weight, heart rate, respirations, and BP complete the assessment here as well. Insufficient weight gain may indicate failure to thrive as a result of hypertension and excessive weight gain that presents with edema can also indicate poor BP control.
In cases where hypertension results from renal vascular or parenchymal disease, medications should focus on those disease processes. Management of hypertension that results from kidney disease commonly requires more prolonged treatment under the supervision of a renal specialist.
Lifestyle changes, including diet and exercise, which are among the most effective approaches for adults with hypertension, are ill suited for infants. Evidence supports pharmacologic interventions as most effective for this age group (Chaturvedi, Lipszyk, Licht, Craig, & Parekh, 2014). However, until recently few clinical trials have provided robust data to describe efficacy and long-term outcomes and guide management. This is the reason careful monitoring of BP and other clinical data are very important.
Medications are frequently used to manage hypertension. In a study of more than 2,000 hypertensive children and infants, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers were most commonly prescribed (35%); 22% received diuretics; 17% received calcium channel blockers; and another 10% received beta-blockers (Kaelber et al., 2016).
Parents of infants with hypertension require support and education. Parents must have a clear understanding of the medications they administer, the side 168effects each may cause, and potential interactions between medications and foods. Parents need to understand the importance of follow-up visits, target respiratory rate, goals for growth and development, as well as the symptoms that indicate that the medications and plan of care are effective or failing. Parents must understand the nature of the disease and long-term consequences for their infants. Just as hypertension in adults is a silent disease, so too the negative consequences of hypertension in the infant may be advanced before signs and symptoms are recognizable. For this reason, screening and management are key.
OUTCOMES
Management of hypertension is the priority in avoiding long-term complications, which result from end organ and vascular damage. Such complications include left ventricular hypertrophy, encephalopathy, and retinopathy (Nickavar & Assadi, 2014). Failure to gain weight and failure to thrive can also result when hypertension is not recognized or managed.
Summary
Effective treatment of hypertension in the NICU and in the primary care setting depends on careful assessment, early diagnosis, understanding of the disease, and a familiarity with the evidence. In the case when hypertension results from hospitalization in the NICU and associated conditions, parents need education and support to manage. The same is true when hypertension extends beyond the NICU stay. In both cases, the goal is to prevent end organ damage that can have life-long negative impact. Just as hypertension is a silent disease in adults, so it is for infants. In both situations, vigilance as well as compliance with medication regimens and lifestyle modifications are associated with best outcomes.
Chaturvedi, S., Lipszyc, D. H., Licht, C., Craig, J. C., & Parekh, R. S. (2014). Cochrane in context: Pharmacological interventions for hypertension in children. Evidence-Based Child Health: A Cochrane Review Journal, 9(3), 581–583. doi:10.1002/ebch.1975
Dionne, J. M., Abitbol, C. L., & Flynn, J. T. (2012). Hypertension in infancy: Diagnosis, management and outcome. Pediatric Nephrology, 27(1), 17–32. doi:10.1007/s00467-010-1755-z
Flynn, J. T. (2000). Neonatal hypertension: Diagnosis and management. Pediatric Nephrology, 14(4), 332–341. Retrieved from http://med.stanford.edu/content/dam/sm/pednephrology/documents/secure/5neonatalhypertension.pdf
Flynn, J. T., & Rosenkrantz, T. (2016). Neonatal hypertension. Theheart.org Medscape. Retrieved from https://emedicine.medscape.com/article/979588-overview
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