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NEONATAL HYPERTENSION. MARIFI DE JESUS U. CABALUNA, MD PL-2 NOVEMBER 28, 2006. QUESTIONS TO BE ANSWERED. What is the proper way of obtaining BP in the neonate? Does the device used in getting the BP matters? What is the primary determinant of
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NEONATAL HYPERTENSION MARIFI DE JESUS U. CABALUNA, MD PL-2 NOVEMBER 28, 2006
QUESTIONS TO BE ANSWERED • What is the proper way of obtaining BP in the neonate? • Does the device used in getting the BP matters? • What is the primary determinant of BP in both Term and Preterm infants?
QUESTIONS TO BE ANSWERED • What are the common causes of Hypertension among the neonates? • Does catheter tip placement play a role in the incidence of Hypertension among the neonates? • What are the “RED FLAGS” in history and PE that points to neonatal hypertension?
QUESTIONS TO BE ANSWERED • What initial laboratory studies are important? • Who should receive treatment ? • How do we choose a suitable agent? • Are there any medications to avoid? • Long term outcome and prognosis depend on which factor?
DEFINITION • Systolic and/or diastolic BP >/= 95% (> 2 SD above the mean) • Stage 1 : BP at 95 to < 99 % • Stage 2 : BP >/= 99% + 5 mm Hg
BLOOD PRESSURE MEASUREMENT Nwankwo et al • LBW and PT infants • BP is significantly lower in the prone than supine position • First reading is significantly higher than the third reading.
BLOOD PRESSURE MEASUREMENT STANDARDIZED PROTOCOL • Check blood pressure 1.5 hours after the last feeding or intervention • Apply appropriately sized cuff • 2/3 the length of the limb segment • 75% of the limb circumference
BLOOD PRESSURE MEASUREMENT • Wait 15 minutes or more of stillness • 3 successive readings at 2-minute interval.
BLOOD PRESSURE MEASUREMENT Intra-arterial catheters • most accurate technique • placed in aorta or radial artery • continuous readings Oscillometric devices • non-invasive ; continuous • measure systolic and mean and calculate diastolic pressure.
BLOOD PRESSURE MEASUREMENT INTRA-ARTERIAL CATHETERS VS. OSCILLOMETRIC DEVICES Low et al (study on 31 newborns) • Average oscillometric pressures significantly lower than intra-arterial pressures. • Systolic lower by 1 mm HG • Mean pressure lower by 5.3 mm Hg • Diastolic pressure lower by 4.6 mm HG
BLOOD PRESSURE MEASUREMENT • Leg pressures are higher than arm pressures • Normal BP increases with gestational age, post-conceptual age and birthweight.
BLOOD PRESSURE MEASUREMENT Zubrow et al (695 PT infant) • D1 – Systolic and Diastolic correlate strongly with BW and GA • First 5 days after birth – • Systolic increase by 2.2-2.7 mm Hg/day • Diastolic increase by 1.6-2 mm Hg/ day regardless of BW and GA
BLOOD PRESSURE MEASUREMENT Zubrow et al (695 PT infant) • After 5th Day – more gradual increments • Systolic – 0.24-0.27 mm Hg/day • Diastolic – 0 – 0.15 mm Hg/day
BLOOD PRESSURE MEASUREMENT Zubrow et al (695 PT infant ) • generated standard curves for mean BP + upper and lower 95% confidence limits • regression lines developed based on • Birthweight • Gestational age • Postconceptual age
BLOOD PRESSURE MEASUREMENT • Postconceptual age/Postmenstrual age (GA + postnatal age) – primary determinant of BP in this population RECOMMENDATION • BP consistently > 95% confidence limit by ZUBROW CURVES.
INCIDENCE • General NICU population • .08% (26/3,179) • NICU admissions • 2% ( 20/988) • 0.7 to 3 % in three studies
INCIDENCE More common in patients with certain diagnoses : • BPD – 6 % • PDA – 3 % • IV hemorrhage – 3 % • Umbilical catheterization – 9 %
CAUSES OF NEONATAL HYPERTENSION • RENOVASCULAR • most common • thromboembolism • umbilical artery catheters as theoretical sources of thomboembolic events • studies established an association between local thrombi and development of hypertension • renal artery stenosis • renal venous thrombosis • compression of renal artery
CAUSES OF NEONATAL HYPERTENSION THROMBOEMBOLISM • COCHRANE STUDY • analysis of 11 randomized clinical trials • one study using alternate assignments • To compare the incidence of morbidity and mortality for HIGH Vs. LOW catheter tip placement.
CAUSES OF NEONATAL HYPERTENSION • HIGH – in the descending aorta above the diaphragm (T6 and T9) • LOW – above the bifurcation but below the renal arteries (L3 and L5) CONCLUSION • High catheter positions caused fewer ischemic complications and possibly decreased the frequency of aortic thrombosis • Hypertension appears with equal frequency
CAUSES OF NEONATAL HYPERTENSION RENAL ARTERY STENOSIS • caused by fibromuscular dysplasia • if present there also may be mid- aortic coarctation and cerebral vascular stenosis • may be due to congenital rubella
CAUSES OF NEONATAL HYPERTENSION RENAL VEIN THROMBOSIS • Hypertension • gross hematuria • abdominal/flank mass • thrombocytopenia
CAUSES OF NEONATAL HYPERTENSION CONGENITAL RENAL DISEASE • Polycystic kidney disease • autosomal dominant and recessive • enlarged kidney and hypertension • multicystic-dysplastic kidney disease • non-functional • ureteropelvic junction obstruction • Activation of Renin-angiotensin system
CAUSES OF NEONATAL HYPERTENSION ACQUIRED RENAL DISEASE • ATN/Interstitial nephritis/cortical necrosis • due to volume overload/hyperreninemia • HUS • Obstruction by a tumor
CAUSES OF NEONATAL HYPERTENSION BRONCHOPULMONARY DYSPLASIA • 13- 43% of infants develop systemic hypertension • cause unclear : chronic hypoxia • severity (greater need for diuretics) of BPD related to likelihood of developing increased BP. • sickest infant require the closest monitoring
CAUSES OF NEONATAL HYPERTENSION COARCTATION OF THE AORTA • early repair improves the long term outcome • hypertension may persist even after surgical repair
CAUSES OF NEONATAL HYPERTENSION ENDOCRINE • seizures and increased intracranial pressure are common causes of episodic hypertension • CAH • HYPERALDOSTERONISM • HYPERTHYROIDISM
CAUSES OF NEONATAL HYPERTENSION IATROGENIC • NICU meds • Dexamethasone • Theophylline • Caffeine • Pancuronium • Phenylephrine • Prolonged TPN • lead to salt and water overload/hypercalcemia • Under treatment of pain
CAUSES OF NEONATAL HYPERTENSION MATERNAL CAUSES • Cocaine use • harm the developing kidneys • Heroine use • with neonatal withdrawal
CAUSES OF NEONATAL HYPERTENSION NEOPLASMS • from compression of renal vessels and ureters • production of vasoactive substances • Neuroblastoma • Wilm’s tumor • Mesoblastic nephroma
CAUSES OF NEONATAL HYPERTENSION MISCELLANEOUS CAUSES • closure of abdominal wall defect • adrenal hemorrhage • hypercalcemia • ECMO • birth asphyxia
EVALUATION • Life-threatening presentation • CHF • Cardiogenic shock • Seizures • Presentation of less ill infants • feeding difficulties • unexplained tachypnea • lethargy, apnea, irritability • mottling of the skin
EVALUATION RED FLAGS IN THE HISTORY • prenatal exposures to heroin and cocaine • predisposing conditions – BPD, CNS disorders, PDA, hypervolemia (post BT) • Medications/ Umbilical artery catheterizations
EVALUATION RED FLAGS IN THE PHYSICAL EXAMINATION • BP in lower extremities/non-palpable femoral pulses – CoA • dysmorphic features – CAH/Turner Sy • Flank mass – UPJ obstruction • Epigastric bruit – renal artery stenosis
EVALUATION RED FLAGS IN THE PHYSICAL EXAMINATION • Abdominal distention – obstructive uropathy, PKD, tumors • Peripheral thrombi – UAC related HTN • Tachycardia/flushing/LBW – hyperthyroidism • Ambiguous genitalia - CAH
LABORATORY EXAMINATIONS • Urinalysis • CBC • Electrolytes, BUN, Crea, Ca • Urine culture if UTI is suspected • Plasma renin level – significantly elevated level indicates renovascular disease
LABORATORY EXAMINATIONS Additional tests • Thyroid studies • VMA/Homovanillic acid • Aldosterone • Cortisol
IMAGING STUDIES • CXRay/2D echo – CHF • US of genitourinary tract • should be performed in all hypertensive infants • to rule out UPJ obstruction, renal vein thrombosis • Doppler flow studies • Abdominal/pelvic US • VCUG
IMAGING STUDIES • Radionuclide imaging - Abnormal kidney displays: • decreased effective renal plasma flow • decreased urine flow rate • increased isotope concentration • MRA – gold standard for diagnosis of reno vascular hypertension • must be 3 kg
MANAGEMENT • optimal management uncertain • threshold for starting antihypertensive has not been well defined • idiosyncratic responses to certain drugs due to developmental immaturity of liver and kidney function.
MANAGEMENT RECOMMENDATION • Asymptomatic /Mild Hypertension (Systolic 95th to < 99th %) • observation • resolves in time • Moderate to Severe (Systolic >/= 99th %) • antihypertensive therapy
MANAGEMENT • Address correctible causes of hypertension • treat pain • correct volume overload • wean inotropic infusion • Choose a suitable agent • depends on specific clinical situation
TREATMENT ACUTELY ILL INFANTS • continuous IV infusion • intermittently administered agents cause wide fluctuation in BP • PT are at increased risk for cerebral ischemia and hemorrhage from rapidly falling BP’s. • allows titration for desired effect
TREATMENT ACUTELY ILL INFANTS • continuous IV infusion • Nicardipine - DOC • Nitroprusside • Labetalol – cathecholamine and CNS mediated hypertension - avoid in BPD • monitor BP Q 10-15 minutes
TREATMENT NICARDIPINE • calcium channel blocker • peripheral vasodilator • short half life : 10-15 minutes • IV infusion 0.5 mcg/kg/min if normal BP not achieved in 15 minutes increase infusion to max of 3 mcg/kg/min. If still elevated, add Sodium nitroprusside then stop Nicardipine.
TREATMENT NITROPRUSSIDE • potent vasodilator • rapid onset of action short duration of effect • complications : hypotension and thiocyanate toxicity.
TREATMENT LABETALOL • combined alpha-1 and beta-blocker • rapid onset of action • duration of action : 2-3 hours • do not cause tachycardia, cerebral vasodilatation or changes in intracranial pressure.
TREATMENT(NeoReviews) LESS SEVERE HYPERTENSION NOT READY FOR ORAL • Intermittent IV agents • Hydralazine • Labetalol • sometimes doses at lower end of recommended range cause significant hypotension
TREATMENT HYDRALAZINE • peripheral vasodilator • relaxes vascular smooth muscle