Pulmonary Hypertension in the Intensive Care Unit
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Pulmonary vascular disease ORIGINAL ARTICLE Heart: first published as 10.1136/heartjnl-2015-307774 on 6 April 2016. Downloaded from Pulmonary hypertension in the intensive care unit. Expert consensus statement on the diagnosis and treatment of paediatric pulmonary hypertension. The European Paediatric Pulmonary Vascular Disease Network, endorsed by ISHLT and DGPK Michael Kaestner,1 Dietmar Schranz,2 Gregor Warnecke,3,4 Christian Apitz,1 Georg Hansmann,5 Oliver Miera6 For numbered affiliations see ABSTRACT heterogeneous underlying conditions.1 Distinction end of article. Acute pulmonary hypertension (PH) complicates the between precapillary and postcapillary aetiologies Correspondence to course of several cardiovascular, pulmonary and other (or establishment of a combination of the two) is Dr. Oliver Miera, Department systemic diseases in children. An acute rise of RV important to initiate specific individual therapy. of Congenital Heart Disease afterload, either as exacerbating chronic PH of different and Paediatric Cardiology, aetiologies (eg, idiopathic pulmonary arterial Pathophysiology of acute PH and RV failure Deutsches Herzzentrum Berlin, hypertension (PAH), chronic lung or congenital heart Augustenburger Platz 1, Chronic PH causes adaptation and remodelling of Berlin 13353, Germany; disease), or pulmonary hypertensive crisis after corrective the RV to increased loading conditions. Pulmonary [email protected] surgery for congenital heart disease, may lead to severe hypertensive crisis (PHC) occurs when compensatory circulatory compromise. Only few clinical studies provide mechanisms fail, RV systolic function decompensates This manuscript is a product of evidence on how to best treat children with acute severe and LV preload acutely decreases resulting in abol- the writing group of the 23 European Paediatric Pulmonary PH and decompensated RV function, that is, acute RV ished cardiac output and coronary perfusion. Vascular Disease (PVD) failure. The specific treatment in the intensive care unit Acute elevation of afterload (pulmonary artery pres- Network (Writing Group Chair: should be based on the underlying pathophysiology and sure (PAP)) is poorly tolerated by the unprepared RV. G. Hansmann, Writing Group not only be focused on so-called ‘specific’ or ‘tailored’ In healthy adult individuals, the RV cannot acutely Co-Chair: C. Apitz). ISHLT, drug therapy to lower RV afterload. In addition 4 International Society of Heart generate a mean PAP >40 mm Hg. Adaptive and Lung Transplantation; therapeutic efforts should aim to optimise RV preload, changes of the RV microstructure and function do http://heart.bmj.com/ DGPK, German Society of and to achieve adequate myocardial perfusion, and not work in the setting of acute rise of RV afterload. Paediatric Cardiology. cardiac output. Early recognition of patients at high risk Thus, although myocardial contractility may initially and timely initiation of appropriate therapeutic measures Received 6 March 2015 rise with RV concentric hypertrophy and preserved Revised 28 June 2015 may prevent the development of severe cardiac systolic and diastolic function, excessive pressure Accepted 29 June 2015 dysfunction and low cardiac output. In patients not overload results in maladaptive remodelling with RV responding adequately to pharmacotherapy, (1) novel dilatation and failure.5 Among many others, arrhyth- surgical and interventional techniques, temporary mia, myocardial ischaemia and/or pulmonary disease mechanical circulatory support with extracorporeal such as infections or pulmonary arterial embolism on September 24, 2021 by guest. Protected copyright. membrane oxygenation, (2) pumpless lung assist devices may trigger an acute rise of PAP and PVR (figure 1). (3) and/or lung or heart-lung transplantation should be With subsequent RV dilatation, the contractile sarco- timely considered. The invasive therapeutic measures can mere apparatus is damaged, resulting in RV failure. be applied in a bridge-to-recovery or bridge-to-lung The combination of right-to-left septal shift with sub- transplant strategy. This consensus statement focuses on sequent LV compression, related to limited space the management of acute severe PH in the paediatric within the pericardial sac, results in low LV output, intensive care unit and provides an according treatment systemic arterial hypotension and elevated LVand RV algorithm for clinical practice. end-diastolic pressure. With or without RV hyper- trophy, these factors decrease coronary perfusion leading to myocardial ischaemia that perpetuates RV INTRODUCTION failure.6 The resulting metabolic acidosis further Despite recent advances in the specific treatment of increases PVR and PAP.Moreover, a sudden increase pulmonary hypertension (PH), RV failure following in PAP causes airway obstruction due to arterial dis- or in the context of severe rise of pulmonary vascu- tension of the smaller intrapulmonary arteries and lar resistance (PVR) is a challenging complication lung oedema. The resulting dead space ventilation of PH and is associated with substantial morbidity and ventilation/perfusion mismatch causes hypoxia and mortality. and respiratory acidosis, eventually resulting in even PH leading to a decompensation of the cardio- more elevated PAP and PVR (figure 1).237 To cite: Kaestner M, vascular system can be considered a syndrome with In children with congenital heart disease (CHD) Schranz D, Warnecke G, non-specific signs and symptoms presenting late in and systemic-to-pulmonary shunt, PH crisis may et al. Heart 2016;102: the disease process and may be strongly associated occur following corrective surgery. Factors that – ii57 ii66. with, or directly caused by several, very promote the development of postoperative PH are Kaestner M, et al. Heart 2016;102:ii57–ii66. doi:10.1136/heartjnl-2015-307774 ii57 Pulmonary vascular disease Heart: first published as 10.1136/heartjnl-2015-307774 on 6 April 2016. Downloaded from Figure 1 Schematic drawing of PAH crisis and contributing factors. Pulmonary hypertensive crisis develops with an acute increase of PAP. This leads to an increase in RV pressure and volume causing a shift of the interventricular septum towards the left side and reducing LV volume. Filling http://heart.bmj.com/ pressures of ventricles rise, compensatory tachycardia and the drop in systemic blood pressure compromise coronary perfusion pressure and flow, leading to low cardiac output and metabolic acidosis. Furthermore, the increase in PAP causes decreased pulmonary blood flow and airway obstruction related to arterial distension of the smaller intrapulmonary arteries and lung oedema. Consequently dead space ventilation increases; together with a mismatch of pulmonary ventilation and perfusion this causes hypoxia and respiratory acidosis. PAH, pulmonary arterial hypertension; RVEDV, RV end-diastolic volume; RVEDP, RV end-diastolic pressure; LVEDP, LV end-diastolic pressure; V/Q, pulmonary ventilation and perfusion; PAH, pulmonary arterial hypertension; PAP, pulmonary artery pressure; PVR, pulmonary vascular resistance; CHD, congenital heart disease; NO, nitric oxide; CPB, cardiopulmonary bypass; LR-Shunt, left-to-right shunt; PBF, pulmonary blood flow. on September 24, 2021 by guest. Protected copyright. not yet completely understood, however, endothelial cell dys- unit (PICU), including concise recommendations and a treat- function was found to be a contributing factor preoperatively ment algorithm for clinical practice. – and postoperatively.8 10 Inflammatory response to cardiopul- monary bypass, and ischaemia-reperfusion injury and its impact METHODS on heart-lung function contribute to the rise in PVR.11 Pain, The recommendations given in table 2 relate to the grading awakening reactions in mechanically ventilated children, tracheal system currently suggested by the European Society of secretions or tracheal suctioning may trigger acute severe eleva- Cardiology (ESC) and the American Heart Association (AHA), tion of PVR presenting as PHC and potentially leading to cardi- and was based on paediatric data only (class of recommenda- ocirculatory collapse and death (figure 1). tion, level of evidence). The grading and voting process within In this consensus statement, we distinguish between and elab- the writing group is outlined in the executive summary13 of this orate on three common scenarios: (1) acute PH crisis after online supplement. Computerised searches of the PubMed/ cardiac surgery for CHD, with different management strategies MEDLINE bibliographical database were conducted between subdivided for patients with univentricular and biventricular 1990 and June 2015. Clinical trials, guidelines and reviews physiology (2) acute deterioration in a child with previously limited to paediatric data were searched using the terms ‘pul- known chronic PH (eg, a child with chronic parenchymal lung monary hypertension’ and ‘intensive care’, ‘heart failure’, ‘con- disease and acute viral chest infection and acute deterioration in genital heart’, ‘postoperative’, ‘surgery’, ‘ECMO’, ‘lung assist’, a child with new diagnosis of group 1 PH (pulmonary arterial ‘ventricular assist’, ‘mechanical circulatory support’, ‘cardiopul- hypertension (PAH), eg, idiopathic PAH), and (3) secondary monary bypass’, and ‘pulmonary hypertensive crisis’. The PH.12 We finally focus on the rapid assessment and efficient primary focus of this manuscript is on group 1 PH according to management of acute severe PH in the paediatric intensive care the World Symposium on Pulmonary Hypertension