Gas Prices on the Rise…. Misty Ellis, MSN, APRN 2015 Annual SPCS Conference Disclosure Statement I do not have any relevant financial relationships with any commercial interests to disclose. Pulmonary Hypertension Definition Elevation in pulmonary artery pressures (PAP) and pulmonary vascular resistance (PVR) Systolic pulmonary arterial pressure >35 mm Hg or a mean PAP >25 mm Hg Often we compare the PAP to the systemic blood pressure; if the systolic PAP is >1/2 the systemic blood pressure, the patient is at higher risk for a pulmonary hypertensive event crisis *Simple definition: elevated BP in the lungs* Suesaowalak, et al, 2010 Pulmonary Hypertension Pathophysiology Endothelial cell dysfunction creates increased vascular tone and pulmonary artery vasoconstriction Increased pulmonary venous pressure may be due to mitral valve disease, left ventricular systolic or diastolic dysfunction Increased pulmonary blood flow through the pulmonary vasculature may be due to congenital heart defects with left-to-right shunt Hazinski, 2013 Pulmonary Hypertension Event vs Crisis Condition PHT Event PHT Crisis Definition Acute rise in PAP but stable BP Acute event in which PAP systolic pressures match or exceed systemic pressures, causing RV failure and a fall in LA preload and systemic hypotension HR Increased Increased; late bradycardia BP Stable Decreased O2 sats Decreased or Stable Cyanotic CVP / RT atrial pressure Stable or slightly Increased Increased LA pressure Stable Decreased to increased as LV end diastolic pressure rises Lactic Acid Normal >2.0 Perfusion Decreased Severely decreased Hazinski, 2013 Pulmonary Hypertension Epidemiology Incidence of congenital heart disease is approximately 8/1,000 live births It is estimated that 3 million children worldwide are at risk for the development of pulmonary vascular disease due to congenital heart disease. Adatia, et al, 2010) Question: What patient would you anticipate to be most at risk for pulmonary hypertension post operatively? A. 1 year s/p ASD repair B. 5 day old s/p CoA repair C. 4 month old Down’s Syndrome boy s/p CAVC repair Pulmonary Hypertension At Risk Populations Congenital heart disease Highest risk- cyanotic lesions with increased pulmonary blood flow at high pressure (ex. Truncus Arteriosus) Lesions with increased pulmonary blood flow at high pressure without cyanosis (ex. Unrestrictive VSD, large PDA) Pulmonary venous outflow obstruction (ex. Mitral stenosis pulmonary vein obstruction (TAPVR), cor traiatriatum) Neonates in first 2-6 weeks of life are still transitioning from fetal circulation ie. Elevated pulmonary venous pressure Premature infants with bronchopulmonary dysplasia Children with abnormal pulmonary reactivity (ex. Trisomy 21) Suesaowalak, et al, 2010 Pulmonary Hypertension Most common anatomic lesions and conditions associated with PH after surgical repair and Cardiopulmonary bypass Unrestrictive VSD in children > 6 months AVC in children > 6 months TAPVR in infants < 8 weeks old TAPVR with obstruction Truncus arteriosus Cardiac transplantation Did your patient have a pre-op cardiac catheterization? PVR? > 3 Wood units concern for PHT Checchia, P. et al. 2011 Date of download: 6/1/2015 Copyright © American College of Chest Physicians. All rights reserved. From: Pulmonary Arterial Hypertension: Baseline Characteristics From the REVEAL Registry Chest. 2010;137(2):376-387. doi:10.1378/chest.09-1140 Epidemiology of PHT Figure Legend: World Health Organization (WHO) Group I pulmonary arterial hypertension classification of REVEAL patients at enrollment. (A) WHO Group I PAH classification. (B) Breakdown of associated pulmonary arterial hypertension subgroup. APAH = associated PAH; CHD = congenital heart disease; CVD/CTD = collagen vascular disease/connective tissuedisease; FPAH = familial PAH; HT = hypertension; IPAH = idiopathic PAH; PAH = pulmonary arterial hypertension; PCH = pulmonary capillary hemangiomatosis; PPHN = pulmonary hypertension of the newborn; PVOD = pulmonary venoocclusive disease; REVEAL = Registry to EValuate Early And Long-term PAH disease management. Management of Post operative PHT • First is ..Prevention! • Anticipate the patients that are at risk for PHT • Avoid the following in high risks patients • Hypoxia • Acidosis • Hypoventilation • Endotracheal Suctioning • Second.. Encourage factors that LOWER PVR by pulmonary vasodilation • Oxygen • Alkalosis / Hypocarbia • Sedation: Fentanyl • Normal FRC • Nitric Oxide Nitric Oxide • What is it? • Endogenous gaseous cell mediator involved in neurotransmission, inflammatory cell activation, and vascular smooth muscle relation • Therapeutically, inhaled NO (iNO) is a Selective Pulmonary Vasodilator • Enhances V/Q matching • Treats pulmonary arteriolar hypertension (PPHN in newborn babies) • Reduces pulmonary vascular resistance and right ventricular cardiac work ie.. Post op heart patients Nitric Oxide Pharmacology • Nitric oxide activates guanylyl cyclase (GC) • GC takes GTP and turns it into cGMP • Increase in cGMP activates to cellular signaling pathways which lead to DECREASE in intracellular calcium levels • Decreased calcium leads to smooth muscle relation and pulmonary arteriolar vasodilation **potent pulmonary vasodilator without systemic vasodilatory effect** Googleimages.com Nitric Oxide • Delivery Method • Intubated patients • Can be delivered to non-intubated patients with a tight-fitting face mask or nasal cannula • Injected directly into the inspiratory limb of the ventilator circuit in synchrony with each inspiratory breath • Half- life is only 15-30 seconds so, to ensure flow is not interrupted in the event of a disconnected ventilator, a separate connector is used to facilitate iNO delivery via a manual bag system Nitric Oxide • Dosing • Doses between 5 and 20 ppm should produce a clinically apparent response in oxygenation or pulmonary vascular resistance • Doses > 40 ppm do not produce greater benefit and it puts patients at greater risk for methemoglobinemia and raises levels of nitrogen dioxide Suesaowalak, et al, 2010 Nitric Oxide • Complications • Methemoglobinemia • A condition in which the iron within hemoglobin is oxidized from the Fe2+ state to the Fe3+ state • Iron needs to be in the Fe2+ state to allow hemoglobin to bind oxygen • Methemoglbinemia results in cyanosis because the Hgb can’t bind oxygen • Methemoglobin > 10% results in clinical cyanosis • Rebound PHTN • Typically occurs when weaning the final 5 ppm • Associated with elevation of PA pressure, difficulty with ventilation, severe hypoxia, and cardiovascular instability Nitric Oxide • Rebound HTN Mechanism • iNO actually leads to down regulation of guanalyl cyclase so stopping iNO causes acute reduction in cGMP levels, an increase in intracellular calcium and can lead to pulmonary arteriolar vasoconstriction until cGMP levels become naturally replete (over a few hours) • There is also a reduced production of endogenous NO during iNO administration Nitric Oxide • Rebound PHT Prevention • Slow weaning of nitric oxide may ameliorate rebound PHTN • Evidence shows progressive rebound of symptoms can occur if patient has had long-term treatment with iNO • Slow weaning can be done with a weaning protocol Nitric Oxide: Protocol • Why have a protocol? • Determine if the patient is a responder or not • This prevents use of potentially dangerous or expensive drug on patients who will no benefit • Utilize the drug only when it is needed • Reduces practice variation • Limit costs attributable to unnecessary use of nitric U gotta be oxide kidding • At our institution it costs $175 / 30 minutes me!$!$ Simsic ,et al 2014 Nitric Oxide: Protocol Nitric Oxide: Protocol Barr, et al, 2010 Nitric Oxide: Protocol • Key Components • Avoid metabolic & respiratory acidosis • If the patient becomes unstable at any time notify MD/NP to evaluate • Be proactive in asking / using the Protocols • RN to avoid doing other “things” during the weaning process or doing any unnecessary suctioning • Do not wean FiO2 during weaning • The most critical time in weaning iNO is the last 5ppm, can potentially see rebound PHT during this weaning phase Summary • CHD lesions that predispose children to PHT are: VSD, PDA, ASD, truncus arteriosus, TAPVR and AVC • Be prepared; know the pre-op cath data • Clinical s/s PHT: HR, CVP, BP, O2 sats, perfusion • One management strategy for PHT is to start iNO • Use iNO to ensure the patient really benefits from it, reduce provider practice variation, and reduce cost References • Adatia, I., Kothari, S., & Feinstein, J. (2010). Pulmonary Hypertension Associated with Congenital Heart Disease. Pulmonary Vascular Disease: The Global Perspective. CHEST 137(6) (Supple):52S-61S. • Barr, F., & Macrae, D. (2010). Inhaled Nitric Oxide and Related Therapies. Pediatr Crit Care Med 11 (2 Suppl): S30-S36. • Checchia, P., Bronicki, R., & Goldstein, B. (2012). Review of Inhaled Nitric Oxide in the Pediatric Cardiac Surgery Setting. Pediatr Cardiol 33:493-505 • Simsic, J., Harrison S., Evans, L., et al. (2014). Reducing Variation in the Use of Inhaled Nitric Oxide. Pediatrics 133: 31753-e1758 • Hazinski, M.F. (2013). Pulmonary Hypertension. In Nursing Care of the Critically Ill Child. (3rd ed.) (pp265-273). St. Louis, Missouri: Mosby Elsevier. • Tzanetos, D.T., Housley, J., et al. (2015). Implementation of an Inhaled Nitric Oxide Protocol Decreases Direct Cost Associated With Its Use. Respiratory Care 60(5) 64450.