e3 86 Zierer A, El Sayed Ahmad A, Papadopoulos N, et al Selective an tegrade cerebral perfusion and mild (28°C–30°C) systemic hypo thermic circulatory arrest for aortic arch replacement results from 1[.]
e3 86 Zierer A, El-Sayed Ahmad A, Papadopoulos N, et al Selective antegrade cerebral perfusion and mild (28°C–30°C) systemic hypothermic circulatory arrest for aortic arch replacement: results from 1002 patients J Thorac Cardiovasc Surg 2012;144:1042-1049 87 Corno AF, Bostock C, Chiles SD, et al Comparison of Early Outcomes for Normothermic and Hypothermic Cardiopulmonary Bypass in Children Undergoing Congenital Heart Surgery Frontiers in pediatrics 2018;6:219 88 Xiong Y, Sun Y, Ji B, Liu J, Wang G, Zheng Z Systematic Review and Meta-Analysis of benefits and risks between normothermia and hypothermia during cardiopulmonary bypass in pediatric cardiac surgery Paediatric anaesthesia 2015;25(2):135-142 89 Murkin JM, Farrar JK, Tweed WA, et al Cerebral autoregulation and flow/metabolism coupling during cardiopulmonary bypass: the influence of PaCO2 Anesth Analg 1987;66:825-832 90 Abdul Aziz KA, Meduoye A Is pH-stat or alpha-stat the best technique to follow in patients undergoing deep hypothermic circulatory arrest? Interact Cardiovasc Thorac Surg 2010;10:271-282 91 Melrose DG, Dreyer B, Bentall HH, Baker JB Elective cardiac arrest Lancet 1955;269:21-22 92 Shiroishi MS Myocardial protection: the rebirth of potassiumbased cardioplegia Tex Heart Inst J 1999;26:71-86 93 Follette DM, Mulder DG, Maloney JV, Buckberg GD Advantages of blood cardioplegia over continuous coronary perfusion or intermittent ischemia Experimental and clinical study J Thorac Cardiovasc Surg 1978;76:604-619 94 Barner HB Blood cardioplegia: a review and comparison with crystalloid cardioplegia Ann Thorac Surg 1991;52:1354-1367 95 Bartels C, Gerdes A, Babin-Ebell J, et al Cardiopulmonary bypass: evidence or experience based? J Thorac Cardiovasc Surg 2002;124:20-27 96 Kotani Y, Tweddell J, Gruber P, et al Current cardioplegia practice in pediatric cardiac surgery: a North American multiinstitutional survey Ann Thorac Surg 2013;96:923-929 97 Chambers DJ, Fallouh HB Cardioplegia and cardiac surgery: pharmacological arrest and cardioprotection during global ischemia and reperfusion Pharmacol Ther 2010;127:41-52 98 Matte GS, del Nido PJ History and use of del Nido cardioplegia solution at Boston Children’s Hospital J Extra Corpor Technol 2012;44:98-103 99 Ginther RM Jr, Gorney R, Forbess JM Use of del Nido cardioplegia solution and a low-prime recirculating cardioplegia circuit in pediatrics J Extra Corpor Technol 2013;45:46-50 100 Allen BS, Barth MJ, Ilbawi MN Pediatric myocardial protection: an overview Semin Thorac Cardiovasc Surg 2001;13:56-72 101 Butler J, Rocker GM, Westaby S Inflammatory response to cardiopulmonary bypass Ann Thorac Surg 1993;55:552-559 102 Levy JH, Tanaka KA Inflammatory response to cardiopulmonary bypass Ann Thorac Surg 2003;75:S715-S720 103 Wan S, LeClerc JL, Vincent JL Inflammatory response to cardiopulmonary bypass: mechanisms involved and possible therapeutic strategies Chest 1997;112:676-692 104 Allan CK, Newburger JW, McGrath E, et al The relationship between inflammatory activation and clinical outcome after infant cardiopulmonary bypass Anesth Analg 2010;111:1244-1251 105 Hovels-Gurich HH, Vazquez-Jimenez JF, Silvestri A, et al Production of proinflammatory cytokines and myocardial dysfunction after arterial switch operation in neonates with transposition of the great arteries J Thorac Cardiovasc Surg 2002;124:811-820 106 Appachi E, Mossad E, Mee RB, Bokesch P Perioperative serum interleukins in neonates with hypoplastic left-heart syndrome and transposition of the great arteries J Cardiothorac Vasc Anesth 2007;21:184-190 107 Graham EM, Atz AM, McHugh KE, et al Preoperative steroid treatment does not improve markers of inflammation after cardiac surgery in neonates: results from a randomized trial J Thorac Cardiovasc Surg 2014;147:902-908 108 Scrascia G, Rotunno C, Guida P, et al Perioperative steroids administration in pediatric cardiac surgery: a meta-analysis of randomized controlled trials Pediatr Crit Care Med 2014;15: 435-442 109 Fudulu DP, Gibbison B, Upton T, et al Corticosteroids in Pediatric Heart Surgery: Myth or Reality Frontiers in pediatrics 2018;6:112 110 Dreher M, Glatz AC, Kennedy A, Rosenthal T, Gaynor JW A Single-Center Analysis of Methylprednisolone Use during Pediatric Cardiopulmonary Bypass The Journal of extra-corporeal technology 2015;47(3):155-159 111 Darling E, Searles B, Nasrallah F, et al High-volume, zero balanced ultrafiltration improves pulmonary function in a model of postpump syndrome J Extra Corpor Technol 2002;34:254-259 112 Huang H, Yao T, Wang W, et al Continuous ultrafiltration attenuates the pulmonary injury that follows open heart surgery with cardiopulmonary bypass Ann Thorac Surg 2003;76:136-140 113 Sever K, Tansel T, Basaran M, et al The benefits of continuous ultrafiltration in pediatric cardiac surgery Scand Cardiovasc J 2004; 38:307-311 114 Song LO, Yinglong LI, Jinping LI Effects of zero-balanced ultrafiltration on procalcitonin and respiratory function after cardiopulmonary bypass Perfusion 2007;22:339 e4 Abstract: Cardiopulmonary bypass (CPB), which originated in the mid-twentieth century, was designed to allow for the repair of congenital heart defects Its history has since been characterized by perpetual technological advancements that have been instrumental in sustaining the momentum of clinical progress of this field The current guidelines for use of CPB to treat congenital heart defects are designed to meet the metabolic demands of the patient throughout the repair while minimizing the impact of associated nonphysiologic effects The progress of CPB in repair of congenital heart defects has played a major role in the steady reduction of morbidity and mortality associated with cardiac surgery in children Pediatric mortality rates are now comparable to those in adult patients Key words: Cardiopulmonary bypass, perfusionist, congenital heart defect, oxygenation, anticoagulation, ultrafiltration, hypothermia, myocardial protection, systemic inflammatory response 36 Critical Care After Surgery for Congenital Cardiac Disease PAULA HOLINSKI, JENNIFER TURI, VEERAJALANDHAR ALLAREDDY, V BEN SIVARAJAN, AND ALEXANDRE T ROTTA • • Congenital anomalies account for the largest diagnostic category among causes of infant mortality in the United States.1 Structural heart disease leads the list of congenital malformations Of the more than million children born each year in the United States, nearly 40,000 have some form of congenital heart disease (CHD) Approximately half of these children appear for therapeutic intervention within the first year of life; the majority require critical care expertise in pediatric intensive care units (PICUs) We recognize that many centers have developed separate specialized pediatric cardiac intensive care units to care for these patients, while some continue to cohort cardiac patients within a general PICU In this chapter, the PICU designation is used interchangeably to denote the unit caring for critically ill patients necessitating care following surgery or procedures to treat congenital cardiac conditions These patients now represent a major diagnostic category for admissions in large PICUs across the country, accounting for 30% to 40% or more of PICU admissions in many centers In addition 380 • • The neonatal myocardium is less compliant than that of the older child, less tolerant of increases in afterload, and less responsive to increases in preload A predictable decrease in cardiac index typically occurs to 12 hours after separation from cardiopulmonary bypass, but milrinone administration during the early postoperative period may attenuate this phenomenon Patients with postoperative low cardiac output (CO) require careful evaluation for unanticipated residual lesions Patients with restrictive physiology from hypertrophy and diastolic dysfunction of the right ventricle may require high right-sided filling pressures to achieve adequate cardiac output, making them prone to hepatic congestion, anasarca, pleural effusions, and ascites Inhaled nitric oxide plays an important role in the management of postoperative pulmonary hypertension in the cardiac intensive care unit Hypoxemia after bidirectional cavopulmonary anastomosis generally is a sign of decreased pulmonary blood flow related to reduced cardiac output • • • • PEARLS Liberation from positive-pressure mechanical ventilation should be accomplished as soon as feasible, particularly in patients after a cavopulmonary anastomosis (bidirectional Glenn) or Fontan operation because spontaneous breathing improves pulmonary blood flow, arterial oxygen saturation, and ventricular preload Ventricular ectopy and elevated atrial pressures after the arterial switch operation should raise suspicion of myocardial ischemia from insufficient coronary blood flow Postoperative care of the patient with hypoplastic left heart syndrome after stage I palliation (Norwood procedure) may require delicate balancing of the pulmonary and systemic blood flows A high arterial oxygen saturation denotes excessive pulmonary blood flow and in patients with impaired ventricular output is generally accompanied by inadequate systemic blood flow, acidosis, and end-organ dysfunction to the traditional pediatric-age patients, many PICUs now also care for young adult survivors of congenital heart disease, since these patients now outnumber children with congenital heart disease in the general population.2 Neonatal Considerations Care of the critically ill neonate requires an appreciation of the special structural and functional features of immature organs, the interactions of the transitional neonatal circulation, and the secondary effects of the congenital heart lesion on other organ systems.3–5 The neonate responds more quickly and profoundly to physiologically stressful circumstances, such as rapid changes in pH, lactic acid, blood glucose, and temperature Neonates have diminished fat and carbohydrate reserves compared with older children; however, they have a higher metabolic rate Immaturity of the liver and kidney may be associated with reduced protein CHAPTER 36 Critical Care After Surgery for Congenital Cardiac Disease synthesis and glomerular filtration such that drug metabolism is altered and hepatic synthetic function is reduced These issues may be compounded by the normal increased total body water of the neonate compared with the older patient, along with the propensity for capillary leakage This is especially prominent in the immature lung of the neonate, in which the pulmonary vascular bed is nearly fully recruited at rest, and the lymphatic recruitment required to handle elevated mean capillary pressures associated with increases in pulmonary blood flow may be suboptimal.5 The neonatal myocardium is less compliant than that of the older child, less tolerant of increases in afterload, and less responsive to increases in preload Younger age also predisposes the myocardium to the adverse effects of cardiopulmonary bypass (CPB) and hypothermic ischemia implicit in support techniques used during cardiac surgery These factors not preclude intervention in the neonate but rather simply dictate that extraordinary vigilance be applied to the care of these children and that intensive care management plans account for the immature physiology The observed benefits of neonatal reparative operations in patients with two ventricles are numerous (Box 36.1) Elimination of cyanosis and congestive heart failure (CHF) early in life optimizes conditions for normal growth and development Palliative procedures such as pulmonary artery banding and creation of systemic-to-pulmonary artery shunts not fully address cyanosis or CHF and may introduce their own set of physiologic and anatomic complications Examples of improved outcomes with a single reparative operation rather than staged palliation as a newborn are well known and evoke little controversy Approaches that have been abandoned include banding the pulmonary arteries in truncus arteriosus,6 staging repair of type B interrupted aortic arch (IAA),7 and staging repair of transposition of the great arteries with IAA.8 In other conditions (e.g., severely cyanotic newborn with tetralogy of Fallot [TOF]), the risks and benefits of neonatal repair versus a palliative shunt are debatable.9 Whereas the neonate may be more labile than the older child, there is ample evidence that this age group is more resilient in its response to various forms of stress, including metabolic or ischemic injury Tolerance of hypoxemia in the neonate is characteristic of many species,10 and the plasticity of the neurologic system in the neonate is well known.11 It is the rule rather than the exception that neonates presenting with shock secondary to obstructive left heart lesions can be effectively resuscitated without persistent endorgan impairment The pliability and mobility of vascular structures in the neonate improve the technical aspects of surgery Reparative operations in neonates take advantage of normal postnatal changes, allowing more normal growth and development in crucial areas such as myocardial muscle, pulmonary parenchyma, and coronary and pulmonary angiogenesis Postoperative pulmonary hypertensive events are more common in the infant who has been exposed to weeks or months of high pulmonary pressure and flow.6 This is especially true for such • BOX 36.1 Advantage of Neonatal Repair Early elimination of cyanosis Early elimination of congestive heart failure Optimal circulation for growth and development Reduced anatomic distortion from palliative procedures Reduced hospital admissions while awaiting repair Reduced parental anxiety while awaiting repair 381 lesions as truncus arteriosus, complete atrioventricular (AV) canal defects, and transposition of the great arteries (TGA) with ventricular septal defects (VSDs) Finally, cognitive and psychomotor abnormalities associated with months of hypoxemia or abnormal hemodynamics may be diminished or eliminated by early repair However, if early reparative surgery results in more exposures to CPB (e.g., repeated conduit changes) and associated adverse effects on cognitive or motor function, then the risk-to-benefit assessment must be modified accordingly Preoperative Care Optimal preoperative care involves (1) initial stabilization, airway management, and establishment of adequate vascular access; (2) complete and thorough noninvasive delineation of the anatomic defect(s); (3) initiation/termination of prostaglandin therapy, as appropriate; (4) evaluation and treatment of secondary organ dysfunction, particularly the brain, kidneys, and liver; and (5) cardiac catheterization if necessary, typically for (a) physiologic assessment (e.g., vascular response to oxygen or another pulmonary vasodilator), (b) interventions such as balloon atrial septostomy or valvotomy, or (c) anatomic definition not possible by echocardiography (e.g., coronary artery distribution in pulmonary atresia with intact ventricular septum or delineation of aorticopulmonary collaterals in TOF with pulmonary atresia) Magnetic resonance imaging (MRI) and magnetic resonance angiography have emerged as important adjuvant diagnostic modalities in the evaluation of the cardiovascular system, including qualitative assessments of valve and ventricular function, and quantification of flow, ventricular volume, mass, and ejection fraction.12,13 Congenital heart defects can be complex and difficult to categorize or conceptualize Rather than trying to determine the management for each individual anatomic defect, a physiologic approach can be taken The following questions should be asked: How does the systemic venous return reach the systemic arterial circulation to maintain cardiac output? What, if any, intracardiac mixing, shunting, or outflow obstruction exists? Are the pulmonary and systemic circulations in series or parallel? Are the defects amenable to a two-ventricle or single-ventricle repair? Is pulmonary blood flow increased or decreased? Is there a volume load or pressure load on the ventricles? Appropriate organization of preoperative data, patient preparation, and decisions about monitoring, anesthetic agents, and postoperative care are best accomplished by focusing on a few major pathophysiologic problems, beginning with whether the patient is cyanotic, is in CHF, or both Most pathophysiologic mechanisms that are pertinent to optimal patient preparation and to the perioperative plan focus on one of the following major problems: severe hypoxemia, excessive pulmonary blood flow, CHF, obstruction of blood flow from the left heart, and poor ventricular function Although some patients with congenital heart disease present with only one of these problems, many have multiple interrelated issues Severe Hypoxemia In the first few days of life, many of the cyanotic forms of CHD present with severe hypoxemia (Pao2 ,50 mm Hg) in the absence of respiratory distress Infusion of prostaglandin E1 (PGE1) in 382 S E C T I O N I V Pediatric Critical Care: Cardiovascular patients with decreased pulmonary blood flow maintains or reestablishes pulmonary flow through the ductus arteriosus This may also improve mixing of venous and arterial blood at the atrial level in patients with transposition of the great arteries.14 Consequently, neonates rarely require surgery while severely hypoxemic PGE1 dilates the ductus arteriosus of the neonate with lifethreatening ductus-dependent cardiac lesions and improves the patient’s condition before surgery PGE1 can reopen a functionally closed ductus arteriosus even several days after birth, or it can be used to maintain patency of the ductus arteriosus for several months postnatally.14,15 The common side effects of PGE1 infusion—apnea, hypotension, fever, central nervous system (CNS) excitation—are easily managed in the neonate when normal therapeutic doses of the drug (0.01–0.05 mg/kg per minute) are used.16 However, PGE1 is a potent vasodilator; thus, intravascular volume may require augmentation at higher doses Patients with intermittent apnea resulting from administration of PGE1 may require mechanical ventilation preoperatively, although apnea can resolve with the concomitant administration of aminophylline or caffeine.17 PGE1 usually improves the arterial oxygenation of hypoxemic neonates who have poor pulmonary perfusion as a result of obstructed pulmonary flow (critical pulmonic stenosis or pulmonary atresia) by providing pulmonary blood flow from the aorta via the ductus arteriosus The improved oxygenation reverses the lactic acidosis that often develops during episodes of severe hypoxia, and clinical improvement is seen in a matter of minutes to hours.18 Excessive Pulmonary Blood Flow Excessive pulmonary blood flow is frequently the primary problem of patients with CHD The intensivist must carefully evaluate the hemodynamic and respiratory impact of left-to-right shunts and the extent to which it contributes to the perioperative course in the ICU Children with left-to-right shunts may have chronic low-grade pulmonary infection and congestion that cannot be eliminated despite optimal preoperative preparation If so, surgery should not be postponed further Respiratory syncytial viral infections are particularly prevalent in this population, but advances in intensive care have markedly improved outcomes with this and other viral pneumonias.19 Aside from the respiratory impairment caused by increased pulmonary blood flow, the left heart must dilate to accept pulmonary venous return that might be several times normal If the body requires more systemic blood flow, the neonatal heart responds inefficiently, as most of the increment in cardiac output is recirculated to the lungs Eventually, symptoms of CHF appear Medical management with inotropes, systemic vasodilators, and diuretics may improve the patient’s condition, but the diuretics may induce profound hypochloremic alkalosis and potassium depletion that often persist after surgery Obstruction of Left Heart Outflow Patients who require surgery to relieve obstruction to outflow from the left heart are among the most critically ill children in the ICU These lesions include interruption of the aortic arch, critical coarctation of the aorta, aortic stenosis (AS), and mitral stenosis or atresia as part of the hypoplastic left heart syndrome (HLHS) spectrum These neonates present with inadequate systemic perfusion and profound metabolic acidosis The initial pH may be below despite a low partial pressure of arterial carbon dioxide (Paco2) Systemic blood flow is largely or completely dependent on blood flow into the aorta from the ductus arteriosus; thus, its closure causes a dramatic worsening of the patient’s condition The patient suddenly becomes critically ill, and survival requires PGE1 infusion to allow blood flow into the aorta from the pulmonary artery.18,20 PGE1 infusion improves perfusion and metabolism in neonates with acidosis, metabolic derangements, and renal failure because of inadequate systemic perfusion so that surgery generally can be deferred until stability is achieved Ventilatory and inotropic support and correction of metabolic acidosis— along with calcium, glucose, and electrolyte abnormalities— should occur preoperatively Adequacy of stabilization, rather than severity of illness at presentation, appears to influence postoperative outcome the most.21 Ventricular Dysfunction Ideally, the intensivist should participate in the preoperative care of all patients who are expected to recover in the ICU after surgery Understanding the extent of ventricular dysfunction preoperatively provides considerable insight into intraoperative and postoperative events Although patients with large shunts may have only mild-to-moderate hypoxemia as a result of excessive pulmonary blood flow, the price paid for near-normal arterial oxygen saturation is chronic ventricular dilation and dysfunction and pulmonary vascular obstructive disease Older patients with CHD and poor ventricular function as a result of chronic ventricular volume overload (aortic or mitral valve regurgitation or longstanding systemic-to-pulmonary arterial shunts) present a different challenge, mitigated to some extent by afterload reduction However, great care must be exercised in hearts with chronic volume overload as there is a propensity for ventricular fibrillation during sedation, anesthesia, or intubation of the airway For patients with significantly increased pulmonary-to-systemic flow ratio (Qp/Qs), systemic blood flow should be optimized without further augmenting pulmonary flow during induction of anesthesia in the ICU or in the operating room Postoperative Care Assessment When the clinical course of patients after cardiac surgery deviates from the usual expectation of uncomplicated recovery, our first responsibility is to verify the accuracy of the preoperative diagnosis and the adequacy of surgical repair For example, a young infant who is acidotic, hypotensive, and cyanotic after surgical repair of TOF may tempt us to ascribe these findings to the vagaries of ischemia/reperfusion injury caused by CPB or transient, postoperative stiffness of the right ventricle However, the real culprit may be an additional VSD undetected preoperatively and therefore not closed, a significant surgical patch leak, or residual right ventricle (RV) outflow obstruction Correct postoperative assessment is imperative, and treatment follows accordingly Evaluation of the postoperative patient relies on examination, monitoring, interpretation of vital signs, and imaging Only when the accuracy of the diagnosis and adequacy of the repair are established can a CPB-related low–cardiac output state be presumed and treatment optimized Treating low–cardiac output states and preventing cardiovascular collapse often are the central features of pediatric cardiac intensive care and are the focus of this chapter ... care units to care for these patients, while some continue to cohort cardiac patients within a general PICU In this chapter, the PICU designation is used interchangeably to denote the unit caring... syncytial viral infections are particularly prevalent in this population, but advances in intensive care have markedly improved outcomes with this and other viral pneumonias.19 Aside from the respiratory... technological advancements that have been instrumental in sustaining the momentum of clinical progress of this field The current guidelines for use of CPB to treat congenital heart defects are designed