A guideline on Neonatal Hypertension

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1 A guideline on Neonatal Hypertension Authors: Dr Aravind Shastri, Consultant (Neonatology and Cardiology), Colchester General Hospital For use in: Eastern Neonatal Units Guidance specific to the care of neonatal patients Used by: Medical Staff and neonatal nurses, Neonatal Nurse Practitioners, pharmacists, and on children s ward for children below Term+4 weeks age. Key Words: neonatal, hypertension, BP, renal, Date of Ratification: May 2016 Review due: May 2019 (or earlier in the light of new evidence) Registration No: NEO-ODN Approved by: Neonatal Clinical Oversight Group 15 April 2016 Clinical Lead Mark Dyke Approved Ratified by ODN Board: Date of meeting 4 May 2016 Page 1 of 10

2 Document Reader Information Document Purpose Title Authors Guideline Guideline on Neonatal Hypertension Dr Aravind Shastri, Consultant Neonatology and paediatric cardiology, Colchester East of England Neonatal ODN Publication Date May 2016 Target Audience Circulation List Medical Staff and nursing staff, Neonatal Nurse Practitioners, pharmacists, All of the above. East of England Neonatal ODN Clinical Oversight Group. Description Superceded Docs Action required Guideline on neonatal hypertension None For dissemination and implementation in EoE neonatal units Timing Implementation May 2016 Contact details East of England Neonatal ODN Box 402 Cambridge University Hospitals NHS FT Hills Road Cambridge CB2 0SW Page 2 of 10

3 1. INTRODUCTION EOE Neonatal ODN Neonatal medical and nursing staffs are used to diagnosing and treating hypotension on a day to day basis. However, hypertension is rare in neonatal units: advances in the practice of neonatal medicine have led to increased awareness of hypertension in neonatal units. The incidence of Hypertension is quoted to be ranging from 0.7% to 2% in infants discharged from neonatal units 1. There is a subgroup of neonates managed in NICU who are particularly at risk of hypertension and may need pharmacologic treatment. The guideline gives a brief synopsis on definition of neonatal hypertension, measurement of BP in neonates, investigations and management of hypertension. 2. DEFINITIONS Epidemiological Definition Hypertension is defined by a systolic blood pressure in a neonate which is 95 th percentile for age and sex on 3 separate occasions. Clinically significant hypertension which needs treatment 1 High blood pressure > 95 th centile and there is end-organ involvement Or BP > 99 th centile for age consistently (generally this is taken as systolic BP > 110 mm Hg in term babies) Or Hypertensive emergency (systolic BP > 130 mm Hg in term baby) 3. NORMAL DATA The American Second Task Force on Blood Pressure Control in Children 2 incorporated data from over American and British children into its centiles. Two large British studies produced reference ranges for preterm babies, recording mean blood pressure using indwelling arterial catheters 3, and systolic pressure by Doppler ultrasound 4. Incorporating the above evidence, the following table gives normal data across various gestations as below. Page 3 of 10

4 Guidance values for 95 th and 97 th centile BP values in first 2 weeks of life Gestation Age Systolic Blood Pressure 95 th % 97 th % Term (AAP task force) Term (Brompton study) Day 1 Day 8-30 Day 4 6 weeks (awake) Term Day 1 Day weeks Day 1 Day weeks Day 1 Day weeks Day 1 Day weeks Day 1 Day 10 Northern nursing initiative study The fourth report based on an article Dionne et al 7 provides a table with estimated values for blood pressures after two weeks of age in infants from 26 to 44 weeks post-conceptual age. The 95th and 99th percentile values are intended to serve as a reference to identify infants with persistent hypertension that may require treatment. Page 4 of 10

5 Normal data; Estimated BP values in neonates after 2 weeks of age in neonates Page 5 of 10

6 4. MEASUREMENT OF BLOOD PRESSURE EOE Neonatal ODN The gold standard for blood pressure measurement is an appropriately calibrated intra-arterial catheter. However, for babies who do not have or require invasive monitoring, the most frequently used technique is via an oscillometric manometer (e.g Dinamap). Blood pressure should be taken when babies are quiet and not feeding (systolic BP is 5mmHg lower in sleeping babies) with an appropriate sized cuff. Appropriate sized cuff is one where the cuff bladder should cover % of the upper arm circumference and its width should be 40% of that same circumference. Use right arm for measuring BP; where high BP is noted in one arm, undertake BP with same instrument in other arm and a lower limb for confirmation. Right arm and lower limb BP to be undertaken in those babies where coarctation of aorta is suspected Use Doppler sphygmomanometry to confirm hypertension 5. INCIDENCE AND ETIOLOGY OF HYPERTENSION The reported incidence varies from 0.2% in healthy term new-borns to 2.6 % in babies at discharge from NICU. Cumulative data from various studies show that 80% of babies with hypertension had an umbilical catheter in situ before the hypertension was picked up. Aortic or renal artery thromboses are common causes. Renal vein thrombosis and structural kidney anomalies constitute the next largest group. Chronic lung disease, particularly when dexamethasone is used, is associated with systemic hypertension. Dexamethasone is known to increase median systolic BP by 27 mm Hg and usually resolves 2 weeks after treatment is stopped. Following table gives various causes of hypertension. Causes of Hypertension in neonate 1. Renal Renal artery thrombosis (particularly if a UAC has been in place) Renal vein thrombosis Renal artery stenosis or compression (e.g. from tumour) Parenchymal renal disease Severely obstructed urinary tract Page 6 of 10

7 2. Cardiovascular Coarctation of the aorta Interrupted aortic arch Distal aortic thrombosis (particularly if a UAC has been in place) Fluid overload 3. Endocrine Congenital Adrenal Hyperplasia Hyperaldosteronism Hyperthyroidism Adrenal haemorrhage Hypercalcaemia 4. Neonatal Chronic Lung Disease May manifest late after discharge from NICU; hence undertake BP even in Out-patient clinics 5. Drugs Dexamethasone Adrenergic agents Caffeine 6. Neurological Pain Seizures Intracranial hypertension Drug Withdrawal 6 HOW OFTEN SHOULD BLOOD PRESSURE TO BE MEASURED IN NICU? There is no accurate guidance on this. Routine screening with blood pressure in every term healthy baby is certainly not indicated. In the absence of any guidance, following rationale is recommended (this is guidance only) All critically unwell babies in NICU usually have BP recorded either through central/peripheral arterial line mainly to monitor for hypotension; if on inotropes, it s important to titrate inotropes making sure that systolic BP is < 97 th centile. All ITU babies without an arterial line to have BP recorded 4 hourly as part of observations or more frequently if concerns about BP. All HDU babies without an arterial line to have BP recorded 12 hourly at least or more frequently if clinically indicated. All well SCBU babies with risk factors for hypertension as above to have one BP recording twice a week ( eg previous UAC, previous CLD) All stable SCBU babies who have not needed any HDU/ITU support to have BP at least once on admission and one at discharge. Page 7 of 10

8 7. INVESTIGATIONS First Line Investigations: 1. Repeat clinical examination and blood pressure by Doppler sphygmomanometry; pay attention to cuff size. Particularly focus on aspects as below Are there any abdominal masses? Can you feel the kidneys? Feel the pulses! Are the femoral pulses the same as the brachial pulses? Are the fontanelle and sutures normal? 2. 4-limb blood pressures Dinamap BP can be normal in the lower limbs in a baby with coarctation of aorta. Do not rely on four limb Dinamap BP measurement to exclude coarctation - use fingers to feel pulses and use ideally Doppler sphygmomanometry 3. Electrolytes, urea, and creatinine 4. Urinalysis for proteinuria 5. Renal ultrasound scan 6. Chest radiograph (if cardiac murmur or signs of congestive cardiac failure) Second Line Investigations (when history/examination suggests): 1. Echocardiogram to exclude co-arctation of aorta or interrupted aortic arch. Also useful to assess cardiovascular function and complications in longstanding or severe hypertension. 2. Plasma renin activity Plasma Renin Activity levels(pra) are higher in new-born infants than in older children and adults and an elevated PRA may not indicate underlying renal disease 3. Plasma cortisol, urinary steroid profile, aldosterone, or thyroxine (as indicated) 4. Cranial ultrasound or MRI if any suspicion of an intracranial cause 5. Renal artery Doppler especially where baby had UAC during early NICU stay. This is a specialised skill and done mainly in tertiary centres. Please discuss with tertiary renal team. Page 8 of 10

9 8 OUTCOMES/TREATMENT EOE Neonatal ODN Most neonates where hypertension is idiopathic do well and do not need any specific treatment Where there is cause identified, eg-renal artery thrombosis or a structural kidney problem, consultation with tertiary paediatric nephrology team is essential and should guide further management. Medications are recommended if there is persistently elevated BP where Systolic BP is > 99 th centile OR Systolic BP is 95 th 99 th centile and there is end organ involvement (heart. kidneys, eyes) OR Hypertensive emergency (systolic BP > 130 mmhg in a term baby) Many oral/intravenous medications have been used; many of the drugs are not licensed for children, have different pharmacokinetics in neonates, and experience with them in this age group is limited. All drugs should be started at their lowest doses and after consultation with tertiary nephrology team. Following table gives medications used in neonates and BNF dosages; please refer to BNF for Children for full details of medications, side-effects etc. Indication Medication Route Dosage Comments Non - emergency Hypertension plus Chronic lung disease Frusemide/ Spironolactone PO/IV PO 0.5 to 2 mg/kg every hours 0.5 to 1 mg/kg bd Monitor electrolytes Captopril PO 0.01 to 0.5 mg/kg tds Start at low dose. Monitor serum creatinine and electrolytes Propranolol PO 250 micrograms/kg Monitor BP every tds and gradually 30 minutes after increase to 1 mg/kg first dose tds Nifedipine PO micrograms/kg Monitor BP ½ hourly post-dose Hypertensive emergency Labetolol IV 0.2 to 1 mg/kg bolus or 0.25 to 3 mg/kg/hr infusion Heart-failure and, bronchopulmonary dysplasia (BPD) relative contraindications Page 9 of 10

10 References EOE Neonatal ODN 1. Watkinson M. Hypertension in the newborn baby. Arch Dis Child Fetal Neonatal Ed 2002; 86: F78-F81 2. Task force on blood pressure control in children. Report of the Second Task Force on Blood Pressure Control in Children Pediatrics, 1987; 79: Northern Neonatal Nursing Initiative. Systolic blood pressure in babies less than 32 weeks gestation in the first year of life. Arch Dis Child Fetal Neonatal Ed1999;80: F Cunningham S, Symon AG, Elton RA, et al. Intra-arterial blood pressure reference ranges, death and morbidity in very low birthweight infants during the first seven days of life. Early Hum Dev1999; 56: Flynn JT. Neonatal hypertension: diagnosis and management. Pediatr Nephrol 2000;14(4): Flynn JT. Neonatal hypertension and management. Emedicine.com 7. Dionne JM, Abitbol CL, Flynn JT. Hypertension in infancy: diagnosis, management, and outcomes. Pediatr Nephrol 2012 Page 10 of 10

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