What the Anesthesiologist Should Know before the Operative Procedure

The Anesthesiologist needs to know the age of the patient, which valves are affected and the etiology of the lesion. It is important to distinguish between acute and chronic lesions. If the child has had previous cardiac surgery, it is important to know what the nature of procedure was. There are a number of syndromes associated with congenital heart disease, and specifically with several regurgitant lesions.

Regurgitant lesions in pediatric patients can occur in all four heart valves.

There is an important distinction to be made between the acute and chronic regurgitant lesion. Acute lesions (which are predominantly left sided) cause life-threatening hemodynamic instability with ventricular ischemia, low cardiac output syndrome and pulmonary edema. However severe acute regurgitation is extremely rare in children: the commonest etiology is iatrogenic as a result of intervention for aortic stenosis or due to acute endocarditis.

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The hemodynamic significance of the lesions varies with age and etiology. Congenital regurgitant lesions are seldom found in isolation, and acquired lesions are much more common.

It is quite unusual (and thus highly significant) for neonates to present for surgical repair of regurgitant lesions. However infants and young children frequently present for other procedures such as vascular access procedures, gastrostomy placement, MRI or other investigations.

LEFT SIDED REGURGITANT LESIONS

Aortic valve incompetence in isolation requiring surgery is unusual in early childhood; most cases are either iatrogenic (complications of balloon dilation of the much more common aortic stenosis) or due to infective endocarditis, usually of a bicuspid aortic valve, or rheumatic fever. Aortic root dilation (again in association with AS) can also result in valvar regurgitation. It is seldom severe enough to warrant surgical intervention until adolescence or adulthood.

Patients are often asymptomatic.

There is an important association with Marfan’s syndrome and the neonatal form of Marfan’s can be particularly severe. It is also associated with Turner’s and Ehlers Danlos syndrome.

Aortic valve incompetence occurs in association with sub-aortic or subpulmonary VSD as a result of cusp prolapse. It is seldom severe and is usually addressed at the time of VSD closure.

Mitral valve regurgitation is more common. Patients with (AVSD) usually present for surgical repair in infancy, and trisomy 21(T21) is a frequent association. 90% AVSD occurs in Down syndrome.

Atrioventricular valve incompetence occurs quite frequently both preoperatively and as a residual lesion. Cleft mitral valve occurs commonly and is associated with atrial septum primum defects.

Patients with single ventricles who have been palliated in the newborn period with a often have atrioventricular valve (right or left morphology) incompetence secondary to heart failure. The valve de facto is on the systemic side. In this situation the valve repair usually accompanies a staged palliation (cavopulmonary anastomosis or Fontan). This group of patients has a high mortality and is very challenging. The outcomes for newborns with single ventricles in combination with other anomalies is very poor, and the atrioventricular valve regurgitation is usually a manifestation of heart failure, and not a primary pathology.

Dilated cardiomyopathy or myocarditis can present with mitral incompetence, but surgery is seldom required for the valve per se. Children often need anesthetic care for investigations to establish the diagnosis, and for interventions for the management of heart failure, including placement of ventricular assist devices as a bridge to transplantation.

Kawasaki Disease can cause ischemic cardiomyopathy and mitral regurgitation and severe heart failure. Occasionally coronary revascularisation is required, however, more often anesthetic care for these patients is required for non-cardiac surgery.

Papillary muscle rupture is a rare cause of acute severe mitral incompetence. It can occur due to ALCAPA.

In older children and adolescents the world wide incidence of mitral and aortic valve insufficiency is overwhelmingly due to infectious or inflammatory processes notably rheumatic fever, endocarditis and Chagas disease.

Rheumatic fever occurs following Group A hemolytic streptococcus infection, which is readily treated with penicillin, erythromycin or azithromycin. In some parts of the world the prevalence of rheumatic heart disease approaches 4%. In North America this is much less prevalent and CHD lesions predominate.

Older children with Marfan’s syndrome also present for surgical repair of either a dilated aortic root (>4cm) and aortic valve incompetence or mitral valve incompetence.

Children who have residual mitral incompetence after repair of atrioventricular septal defects may present for valve re-repair or replacement during later childhood or adolescence. There is a paucity of appropriate mechanical valves for younger children and the morbidity associated with systemic anticoagulation is considerable.

RIGHT SIDED REGURGITANT LESIONS

Pulmonary Insufficiency as an isolated congenital anomaly is rare and clinically diverse. Hydrops fetalis and intrauterine death have been reported as well as long term survival to age sixty or older.

The commonest etiology of pulmonary insufficiency is as a result of intervention for pulmonary stenosis and as a sequela of repair of Tetralogy of Fallot. It can occur as a result of either balloon dilation or surgical intervention. Initially it was assumed that pulmonary insufficiency was a generally benign and physiologically well tolerated lesion. This is now known to be incorrect. There are defined criteria for intervening for pulmonary insufficiency, and the management of Tetralogy of Fallot has changed as a result.

Pulmonary insufficiency also occurs as a sequela of less frequent anomalies such as truncus arteriosus and pulmonary atresia. It will also complicate late pulmonary hypertension (PHT), when the valves fail to co-apt as a result of dilation of the main pulmonary artery.

Infectious and inflammatory causes of pulmonary regurgitation are rare.

Tricuspid Insufficiency is uncommon and most frequently occurs as part of the spectrum of Ebstein’s anomaly, first described in 1866. It is seen as an isolated lesion or as part of more complex anomalies. The clinical course is quite variable, but cyanosis in early life is a prognostic indicator for adverse outcomes and death (10%). The pathophysiology includes arrhythmias, congestive heart failure, cyanosis and functional tricuspid or pulmonary atresia.

Patients with Ebstein’s anomaly should be evaluated by a cardiologist and electrophysiologist: the severity of the tricuspid regurgitation is very variable. There can be massive cardiomegaly and arrhythmias which may be life threatening. The patient may be taking anti-arrhythmic drugs, or medications to treat heart failure. The surgical options range from isolated repair of the tricuspid valve, to oversewing the valve and converting the patient to a single ventricle. Invasive treatment of arrhythmias may be open, with atrial reduction or maze procedures (so-called because there is a “maze” cut into the atrium to prevent the propagation of re-entrant impulses) or catheter based interventions, for example using radiofrequency.

Sickle cell disease (SCD) and secondary pulmonary hypertension may also result in tricuspid insufficiency. Children with SCD present for vascular access procedures, diagnostic imaging including MRI for stroke, cholecystectomy and unrelated surgery. It was originally thought that PHT was a late presenting complication (ie adults and adolescents), but more recent data suggests that there is evidence of elevated PVR in children, especially those with a history of frequent chest crises.

Neonatal valvar regurgitation

All the following anomalies are rare and have a high mortality:

Truncus arteriosus with truncal valve regurgitation has an operative mortality of 5-10% and was identified as having an odds ratio of 17 for anesthesia related cardiac arrest during cardiac surgery.

Congenital or acquired aortic incompetence, eg as a result of balloon dilation of critical AS occurs occasionally in the neonatal period. Emergency surgery for acute aortic incompetence superimposed on aortic stenosis has a significant mortality from coronary ischemia, myocardial injury and low cardiac output syndrome. The physiologic management of these patients is difficult but it is important to decrease myocardial oxygen demand while maintaining adequate supply. This means avoiding tachycardia, even though quicker heart rates diminish the regurgitant fraction. Maintaining reasonable perfusion pressure is important as is adequate oxygenation. This can be very difficult in a baby who is likely in pulmonary edema, hypotensive and tachycardic and whose cardiac output is heart rate dependent.

Mitral incompetence as an isolated lesion is rare. The associated lesions are frequently severe. The mechanism of mitral regurgitation is often left ventricular ischemia, infarction or global dysfunction as a result of critical aortic stenosis, or coarctation.

Neonatal Marfan’s syndrome is associated with aortic and mitral regurgitation.

Tetralogy of Fallot with absent pulmonary valve. Severely affected neonates present with respiratory symptoms due to airway compression by aneurysmal pulmonary arteries.

Neonatal Ebstein’s anomaly of the tricuspid valve presents with cyanosis and occasionally tachyarrhythmia in infancy.

All these scenarios carry the possibility of significant mortality as well as major morbidity.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

Surgical urgency depends on the proposed procedure.

Emergency cardiac surgery is very infrequent, and most other surgery in childhood can be temporised to allow for appropriate diagnosis.

The fact that the mortality for non-cardiac surgical procedures and general anesthesia is doubled in children under 2 years of age should prompt a reasonable approach for clarifying the cardiac diagnosis in even the most enthusiastic surgeon.

If emergency is defined as any delay at all causes harm: ie the patient needs to be in the operating room within the hour then airway emergencies, and acute subdural hematoma are the obvious candidates. Subdural bleeds often occur in young children because of falls, but the rare child who is anticoagulated with coumadin is at particular risk. Children on low molecular weight heparin or anti-platelet drugs also present a management challenge for emergency neurosurgery. Other childhood trauma such as fractures can be temporised unless there is a vascular injury. Most abdominal blunt trauma is also managed conservatively in the current era.

Bilious vomiting and malrotation are also true emergencies and are associated with congenital heart disease but not regurgitant lesions except atrioventricular septal defect. Malrotation is also more frequently observed in children with syndromes, notably trisomy 21, heterotaxia.

Important information that should be obtained is the most recent echo report, any symptoms and particularly any change or new onset of symptoms. In young children tachypnea, growth retardation feeding difficulties and sweating are concerning. In older children, fatigue, chest pain, changes in exercise tolerance may occur. Monosyllabic responses and denial are relatively normal in adolescents but this should be gently ignored and persistent questioning is necessary to ascertain a clear history. It is quite common for patients and parents to be vague about the diagnosis. “A hole in the heart” covers a lot of ground, but the most frequent important diagnosis to exclude is Tetralogy of Fallot.

Late Tetralogy of Fallot and Severe Pulmonary Incompetence

Tetralogy of Fallot is the commonest form of complex CHD, and has the most variability in the postoperative course.

The outcomes and pathophysiology depends on the nuances of the diagnosis, the age of the patient, the era they were operated on, the management algorithm, and the substrate of the right ventricle.

Tetralogy varies from “pink” TOF where the pulmonic stenosis is mild and the VSD relatively large, (so the shunt is predominantly L to R), to pulmonary atresia plus VSD where the stenosis is 100% and the child is dependent on a patent ductus arteriosus or a shunt for pulmonary blood flow until a more definitive repair is performed. There is also every variation between these two extremes.

The age of the patient in part dictates the management algorithm. Helen Taussig and Alfred Blalock pioneered the palliative surgery in 1944, and primary repairs in older survivors were being undertaken a decade later. However it was 20 years after that when primary repairs were done in infants. At that time, the pulmonary valve was laid wide open with a transannular patch, and the VSD was closed through a right ventriculotomy. The combination of free PI and possibly residual pulmonary arterial stenosis, in combination with right ventricular dysfunction is very disadvantageous. Thus young adults, particularly if they had a shunt first, are at risk of right heart failure and arrhythmias.

In the more recent era, patients with other co-morbidities, or more complex disease may still be managed with a shunt, for example to encourage the growth of diminutive pulmonary arteries.

Pulmonary insufficiency over time, will cause right ventricular dilation, decrease in exercise tolerance, disability and death. However it usually takes at least a decade to develop. Sudden death also occurs because of arrhythmias. The adult with CHD who presents for emergency procedures has a high risk of death or needing heart transplantation within the next 3 years according to one study.

This is most likely due to presentation with symptomatic arrhythmias. The outcomes in patients of any age with severe right ventricular dilation are poor, and the current indications for PV replacement include RV dilation measured by cardiac MRI. The presence of tricuspid incompetence, EKG changes and patient symptoms are all important measures of potential morbidity. The significant EKG findings are atrial or ventricular ectopy and right bundle branch block pattern with a qRS duration greater than 180msec.

  • Emergent- As an absolute minimum, a reliable history, careful physical examination, functional ability, other anomalies or health issues, and any drugs the patient is taking should be obtained. If there are any concerns or contradictions arrangements should be made for urgent cardiology consultation, in the operating room if necessary. A chest X-ray, EKG and relevant bloodwork should be considered. Reversal of anticoagulation can be a problem and may need a hematology consult. Drug interactions may also be a concern. Afro-Caribbean children should have sickle-cell screening and hemoglobin electrophoresis as indicated.

  • Urgent-Patients who have had regular follow up, are doing well and have no new symptomatology, other than whatever non-cardiac issue has brought them to surgery, should have review of their most recent clinic findings, appropriate bloodwork (eg electrolytes for patients on chronic diuretic therapy, PTT/INR if anticoagulated) and consideration as to whether endocarditis prophylaxis is needed. Patients who have been identified as having limited cardiac reserve should have an urgent cardiology consult, and patients at risk of coronary events should have an EKG. (eg Kawasaki’s, late Tetralogy, severe AI, or Marfan’s). Anyone lost to follow up, who has new symptoms, or is presenting for major surgery should have a cardiology consult, EKG, transthoracic echocardiography, and whatever other investigations the cardiologist deems appropriate.

  • Elective- Patients presenting for elective surgery should have all the appropriate information related to their heart disease available for review. There should be documentation from the last clinic visit, an EKG, the most recent echocardiogram report, and the results of any relevant blood tests. If there are any concerns then a discussion or formal consultation from either the patient’s cardiologist or a pediatric cardiologist is indicated. The variability and complexity of congenital heart disease mandates a close working relationship with a pediatric cardiologist, or a cardiologist with a specialist interest in CHD for adolescent and older patients.

2. Preoperative evaluation

The most common medical conditions to evaluate are the associated syndromes and their implications.

The child with Down’s syndrome should be evaluated for any airway issues and particularly signs and symptoms of obstructive sleep apnea. Sometimes children with T21 are difficult to bag and mask ventilate, so any past anesthetic events should be reviewed.

Children with 22q11deletion (DiGeorge syndrome and associated or similar syndromes such as Schprintzen syndrome, velocardiofacial syndrome, Takao syndrome) have multiple medical issues.

The Online Mendelian Inheritance in Man website (OMIM) is a very useful resource for unusual syndromes and congenital anomalies. It is found at http://omim.org/, and is also accessible via the tool bar in PubMed. http://www.nslij-genetics.org/search_pubmed.html

Sickle cell disease, and related hemoglobinopathies, including SC disease and thalassemia. Tricuspid regurgitation and pulmonary regurgitation are associated with sickle cell disease and the development of pulmonary hypertension.

Cardiomyopathy and heart failure need careful assessment for any changes in symptoms or evidence of overt low cardiac output syndrome.

Bacterial Endocarditis occurs in both normal and abnormal hearts, but is much more common in the latter. It is an acute life-threatening illness that requires long term antibiotic therapy, occasional emergency cardiac surgery, and very rarely emergency neurosurgery for drainage of septic intra-cranial abscess.

Medically unstable conditions warranting further evaluation include:

Arrhythmias: particularly in the context of moderate to severe valve regurgitation. On the systemic side of the heart aortic incompetence is rarely associated with arrhythmias, but mitral incompetence causes left atrial dilation and supra-ventricular tachyarrhythmias are relatively common. Atrial flutter is more prevalent in children (atrial fibrillation in adults) and there is often a high rate of conduction so that the hemodynamic consequences are severe. Right ventricular dilation (late Tetralogy see above) is associated with bundle branch block and ventricular tachyarrhythmias. Ebstein’s anomaly echos the pathophysiology of mitral incompetence with right atrial enlargement and supraventricular and atrial ectopic tachycardia. In the case of Ebstein’s (see below), there may be less hypotension and more cyanosis as the right atrial pressure will rise and the shunt at the ASD may increase.

Dilated cardiomyopathy with valve incompetence can be difficult to distinguish from acute myocarditis, and the prognostic difference and management makes it likely that young children will present for investigations, including endomyocardial biopsy, which require anesthesia care.

Congestive heart failure in children is often not considered and can be difficult to distinguish from lower respiratory tract infections or reactive airways disease. Children with CHD may have all respiratory symptoms ascribed to their cardiac disease, but in fact bronchiolitis and pneumonia are recognised complications of heart failure. Cardiac “asthma” occurs with mitral incompetence by two mechanisms: a dilated left atrium can compress the left main stem bronchus causing air-trapping, atelectasis, expiratory noise and forced exhalation. Pulmonary edema causes tachypnea and wheeze.

Bronchiolitis and pneumonia. Down syndrome is a risk factor for respiratory syncytial virus bronchiolitis as is heart disease. Both conditions increases the likelihood of severe lower respiratory tract infection needing mechanical ventilation. While many children with heart disease are given prophylaxis (palivizumab), it is not universal. Bacterial pneumonia also occurs relatively frequently and will exacerbate breathlessness from heart failure.

Acute endocarditis: the incidence is about 1:1000 hospital admissions and there is a strong association with CHD and the indwelling catheters such as PICC lines. It has significant mortality (15-20%) mostly due to heart failure, especially with acute aortic incompetence and also to the secondary pathology from septic emboli. Neonates are most prone to develop severe embolic disease. Every organ system can be affected and the classic diagnostic signs such as splinter hemorrhage may not be present

Cyanosis should provoke a detailed assessment of the cardiorespiratory system in children with two ventricles. Mild desaturation may arise in the context of cardiac failure and respiratory disease. It is an ominous finding in the absence of respiratory illness. In the context of PI, or cardiomyopathy it implies inadequate cardiac output and oxygen delivery, and very limited cardiac reserve. Under those circumstances, inotropic support, critical care admission and mechanical support are all potential interventions. Children with Ebstein’s are often chronically cyanosed (and would be expected to have polycythemia: see below), but there is usually a “normal” for that child. Falling saturations are an indication for surgical intervention to the tricuspid valve.

Anemia may arise from multiple etiologies. Hemoglobinopathy has already been mentioned, and iron deficiency is common in the infant and young child usually as a result of dietary deficiency. Children can also have anemia of chronic disease. Children with cyanosis should have hemoglobin levels that are at least high normal. It is important to check MCV and MCHC, iron and ferritin levels in these patients regardless of hemoglobin levels because there is an increased risk of stroke in microcytic polycythemic patients.

3. What are the implications of co-existing disease on perioperative care?

Trisomy 21:

Occasionally children with T21 have atlanto axial instability, however there is a conundrum: in order to obtain the relevant radiological images to confirm this the children frequently have to be sedated or given a general anesthetic, and the neck is then placed in precisely the position likely to cause injury. The ordinary care of a child having a surgical procedure including laryngoscopy and endotracheal intubation does not put them at risk, so it is not necessarily routine practice to evaluate them in the absence of long tract signs or symptoms.

Hypothyroidism is quite common with T21 and can be difficult to clinically evaluate, so blood work needs to be drawn.

There is an increased risk of leukemia in T21, and other hematological disorders including polycythemia.

There is a higher risk of pulmonary hypertension in children with T21, and AVSD and mitral regurgitation both predispose towards the early development of increased pulmonary vascular resistance.

Developmental delay is very variable, and so is the likelihood of co-operation. Hearing loss is relatively frequent. The child should be assessed regarding the need for premedication. The normal growth curves for children with T21 are lower than normal children, and their airways are smaller.

Vascular access is often difficult even if the child has had no previous hospitalisation.

Snoring, and symptoms suggestive of obstructive sleep disorder my well predict an unstable course in the recovery room, and difficult managing pain and behavior.

22q11deletion:

Children with the spectrum of disease associated with this genetic abnormality, and including velo-cardio-facial syndrome, can be a difficult airway, both for bag mask ventilation and endotracheal intubation.

As well as the airway concerns, there is frequently thymic hypoplasia, hypocalcemia in infancy and auto-immune disorders including Graves disease and juvenile rheumatoid arthritis.

There are neurological anomalies, including structural brain abnormalities such as absent corpus callosum. The children have hearing loss, ophthalmic abnormalities and dysmorphism. Children with absent thymus need to have irradiated blood products and may present with thrombocytopenia.

Cardiomyopathy/Myocarditis:

A recent echocardiogram is important to evaluate the degree of mitral or tricuspid regurgitation and as a trend compared to previous examinations. Ejection fractions are not terribly useful (although numbers less than 25% are uniformly poor), and symptoms may be a better guide. Loss of appetite, nausea, change in mental state, desaturation are all indicators of severe disease. The Ross scale is a modified version of the NYHA functional status specifically for children. The incidence of cardiac arrest associated with anesthesia in children with cardiomyopathy varies between 1-10%

Sickle Cell Disease:

This hereditary hemoglobinpathy is associated with chronic hemolytic anemia, small vessel vaso-occlusive disease, and the secondary effects of these two problems. The clinical presentation is very variable and at its worst requires bone marrow transplantation. Cardiomyopathy and tricuspid regurgitation arise as a result of chest crises, chronic hypoxemia and pulmonary hypertension. Iron overload causing cardiomyopathy is mostly a historic concern, since transfusion therapy has become much more conservative, and there are other available therapies, including hydroxyurea, simple transfusion, angiotensin converting enzyme inhibitors and inhaled nitric oxide.

A hematology consult should be obtained and advice sought regarding transfusion, hydration and drug therapy in the perioperative period. These children frequently have pain issues and should be managed by a specialist pain team.

Bacterial Endocarditis:

Acute bacterial endocarditis can require anesthesia and surgical intervention for life threatening complications such as subarachnoid hemorrhage. Starting with the need for appropriate imaging, the anesthesiologist may be faced with a patient in septic shock, with hemodynamic instability, renal impairment, acute or worsened valvular insufficiency. The development of acute coagulopathy is a particular concern in neurosurgical procedures.

  • Perioperative evaluation-

  • The particular history to be obtained includes any previous cardiac surgery, and cardiac diagnosis, as well as a detailed current cardiovascular status. A surprising number of patients and parents do not know their diagnosis, so this can be trickier than one would imagine. In young children an evaluation of growth, feeding and activity levels is a good indicator of cardiovascular reserve. In adolescents, denial and stereotyping can mean that symptoms such as increasing fatigue, decreased exercise are overlooked or dismissed. Specific questions to elicit worrisome symptoms include direct questioning of adolescents about palpitations, lightheadedness and syncope. These may reflect hemodynamically significant arrhythmias. In children at risk for myocardial ischemia (eg severe AI, or mixed aortic disease), questions about unexpected inconsolable crying may be significant, as well as parents noting sudden pallor or episodes of sweating. Questions regarding recent or frequent hospitalisation for “asthma” or “chest infection” may in fact reveal undiagnosed heart failure. It can be an indicator of the severity of diagnosed CHF.

  • The physical findings are specific to each lesion and concomitant issues and prior interventions.

  • Aortic Incompetence usually presents with a murmur in an asymptomatic child, and the classic waterhammer pulses can be felt. There may be cardiomegaly on chest X-ray and the EKG will have findings of left axis deviation. Echocardiography will reveal a dilated left ventricle, and the regurgitant jet and flow reversal are indicators of disease severity. Flow reversal in the abdominal aorta is indicative of severe AI. Aortic root dilatation may be primary or secondary, and if severe, may be an indication for cardiac intervention in and of itself.

  • Mitral incompetence often presents with respiratory symptoms such as tachypnea. It may also be asymptomatic, such as with mitral valve prolapse and resultant regurgitation. There is a mid-systolic murmur and the CXR may show pulmonary venous engorgement and left atrial enlargement. If the valve lesion is secondary, then the globular cardiomegaly of dilated cardiomyopathy (DCM) may be seen on X-ray. Presenting signs and symptoms of heart failure, including displaced apex and thoracic deformity may be found. Transthoracic echocardiography is used to evaluate both the severity of the regurgitation and the detailed anatomic configuration of the valve. Increasingly, 3 dimensional images and models are used to help guide surgical intervention.

  • Pulmonary incompetence causes a diastolic murmur. Patients may show right ventricular dilatation which may cause a thoracic deformity. The patient who has had a previous tetralogy repair may have both a thoracotomy and sternotomy scar as evidence of staged surgical management. These patients are at increased risk of RV dysfunction and adverse outcomes from PI. The “gold standard’ imaging for PI is cardiac MRI, and there are defined criteria for intervention based on RV volumes, measured by MRI. Echocardiography is also useful to assess for other residual lesions, and it does have the very considerable advantage that the equipment is portable.

  • Tricuspid incompetence in the context of Ebsteins anomaly may be asymptomatic or present with cyanosis, fatigue, and growth retardation. The murmur is described as early systolic. The presence of an ASD or patent foramen ovale is required for desaturation to occur. The classical jugular pulse findings can be difficult to assess in an upset toddler, but echocardiography demonstrates the dimensions of the regurgitant jet and flow reversal into the inferior vena cava is a significant finding. The presence of a TR jet also permits an assessment of RV pressure as a surrogate for PA pressure in other lesions (eg MR) where pulmonary hypertension may be a concern. The chronically cyanosed patient will have clubbing.

  • In the current era, the major indications for cardiac catheterisation are either to obtain physiological measurements, such as evaluation of pulmonary vascular resistance, or to permit an intervention. The majority of patients discussed in this chapter would have no indication for cardiac catheterisation other than transvenous pulmonary valve replacement. The vast majority of imaging information is obtained through echocardiography, but there is an increasing role for cardiac magnetic resonance imaging for both congenital and acquired heart disease.

  • Perioperative risk reduction strategies- infants children adolescents cardiac drugs. Children with hemodynamically significant heart disease who are presenting for elective surgery but meet criteria for cardiac intervention should have their heart disease addressed as the priority, before undergoing non-cardiac surgery. For the occasional practitioner, all but the mildest of problems should at very least have a cardiac consultation from a pediatric cardiologist.

b. Cardiovascular system

  • Acute/unstable conditions:

  • Arrhythmias

  • Uncontrolled heart failure

  • Acute cardiac illness such as rheumatic fever or endocarditis, or viral myocarditis

  • Goals of management: The goals of management should be to appropriately manage any rhythm disturbance, preferably returning to sinus rhythm, using either cardioversion, drug therapy or both. The advice of a cardiologist and in complex situations (eg late tetralogy) an electrophysiologist should be sought. In this circumstance the predominant problems are tachyarrhythmias, but previous surgery can make EKG interpretation difficult. The “normal” EKG configurations for children change from the newborn period into adolescence, even without cardiac disease so computerised reports should be viewed with suspicion as these are based on adult criteria.

  • The child presenting with decompensated heart failure should be deferred, if at all possible until the heart failure has been medically managed using diuretics as a first line therapy. The management of heart failure in children involves the off-label use of drugs and does not have strong evidence to support therapy that adult heart failure does. Furosemide is commonly used to relieve symptoms of pulmonary congestion. Carvedilol has not been shown to be helpful in DCM, or single ventricle patients and angiotensin-converting enzyme drugs also have very limited evidence demonstrating efficacy. None the less the use of such agents is increasing in children and there is the potential for interactions with anesthetic drugs.

c. Pulmonary

  • Children with Down syndrome, 22q11del and similar syndromes with facial anomalies are at increased risk of airway obstruction and obstructive sleep apnea. The typical facial differences, large tongue, small airway and hypotonia put children with T21 at particular risk.

  • Children with heart failure have an increased incidence of pneumonia and lower respiratory tract infections. Children with MR are at risk of left lower lobe atelectasis and pneumonia due to external compression of the left main-stem bronchus by the enlarged left atrium. RSV bronchiolitis can be particularly severe in the context of pediatric heart disease so prophylaxis is recommended. The threshold to cancel a child with a respiratory tract infection should be lower in children with cardiac disease.

  • Reactive airway disease (Asthma): Children with regurgitant lesions can also have reactive airways disease, and it can be impossible to sort out whether or not the child with MR wheezes because of asthma or cardiac causes. It is more likely to be a separate pathology in the patient with right sided regurgitation. There are also association between RSV infection and wheezing, smoke exposure in the home and allergy. Adolescents should be questioned about smoking habits of both legal and illegal substances, in the absence of their parents.

d. Renal-GI:

Infants with heart failure frequently display signs and symptoms of gastro-esophageal reflux and there is an incidence feeding aversion and swallowing difficulties in children with severe cardiac disease. Patients are commonly on such medications as omeprazole and domperidone to control symptoms. Nutritional support is therapeutic in severe heart failure and therefore nasogastric or transabdominal gastric tube feeding with calorie enhanced feeds is frequent.

e. Neurologic:

Children with CHD and cardiac disease are at risk of neurological injury through multiple mechanisms from hypoxia and low cardiac output syndrome, to paradoxical emboli via intracardiac shunts, or stroke. Children with prosthetic valves are at risk of both hemorrhage and thrombosis as a result of anticoagulation. Infective endocarditis frequently causes neurological symptoms from septic emboli. Focal stroke is known to occur, as is white matter injury, delayed motor skills and learning disability.

Children with syndromes have well recognised patterns of neurologic deficit and developmental delay.

f. Endocrine:

Hypothyroidism is a feature of T21. Hypocalcemia and hypoparathyroidism is associate with thymic hypoplasia and 22q11del but is most troublesome in the neonatal period.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (eg. musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

Behavioral issues are common and there is an increasing recognition that some hospitalised children suffer from post-traumatic stress disorder. Crying and upset behavior are probably not good for children with limited cardiac reserve, so consideration should be given to premedicating children using oral agents. The use of oral midazolam syrup is safe and effective. There is a low incidence of dysphoric reactions.

4. What are the patient's medications and how should they be managed in the perioperative period?

As part of the preoperative history parents should be specifically asked about the use of natural and over-the-counter medicines and these should be checked for pharmacological action. Children taking thyroid replacement therapy should have relevant blood work drawn. Children with left sided valve regurgitation may be on afterload reducing drugs which in general should be continued as should any antiarrhythmia medications. The decision to discontinue low molecular weight heparin administration is made on a case by case basis. It is most frequently discontinued for 1 or 2 doses preoperatively. The management of coumadin anticoagulation is also governed by circumstance: a child with a prosthetic valve undergoing EUA of ears, should continue their anticoagulation. On the other hand the same child needing drainage of a subdural hematoma will need a hematology consultation, and Factor VIII concentrate. Most commonly children undergoing elective procedures are admitted and transitioned to unfractionated heparin which is then discontinued for the procedure.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

There is an increased incidence of sevoflurane related bradycardia in children with Down syndrome with or without CHD. This is hemodynamically disadvantageous in mitral regurgitation and should be promptly corrected. Consideration of pre-emptive prophylaxis with atropine (10mcg/kg) or glycopyrrolate (10mcg/kg) should be considered.

i. What should be recommended with regard to continuation of medications taken chronically?

  • Cardiac: In general cardiac medications should be continued into the perioperative period. In the hope of making vascular access easier, the morning dose of diuretic can be withheld.

  • Pulmonary: Children who are on chronic bronchodilator therapy should continue these medicines especially inhaled medications

  • Renal: Most children are not on any renal medicines except furosemide: see above

  • Neurologic: children taking antiseizure medication should take their regular dose at the normal time regardless of NPO restrictions. The only exception would be the child whose medication is given with food.

  • Anti-platelet medications

  • Psychiatric: this is generally not applicable to children with the exception of medicines for attention deficit hyperactivity disorder. Based on no evidence I would favor giving such medicines as it is easier for both the child and the treating team if there is a certain amount of focus and listening happening.

  • Anti-reflux medications are generally withheld prior to surgery

j. How To modify care for patients with known allergies –

Antibiotics and muscle relaxant changes outline current endocarditis guidelines

Children who are allergic to muscle relaxants can generally be managed without them, and intubated if necessary with the use of deep vapor, propofol or remifentanil. All these strategies are suitable for regurugitant lesions as they all tend to cause vasodilation and decrease afterload. The bradycardia induced by remifentanil ( and also sevoflurane) can be counteracted with glycopyrrolate.

Endocarditis Guidelines:

The current endocarditis guidelines are based on the principle that there are competing risks of allergic reactions and the development of antibiotic resistant organisms, versus the likelihood of acute endocarditis. Therefore, the current recommendations are much more limited, and based on the fact that wound prophylaxis is generally aimed at the likely pathogens in contaminated procedures, so further coverage is not required.

Children with congenital or acquired valvular heart disease are not felt to be at high risk of endocarditis: with the following exceptions: anyone with a past history of endocarditis or rheumatic fever, complex cyanotic heart disease (notably tetralogy of Fallot), patients with prosthetic valves and heart transplant patients with valulopathy.

Dental procedures that involve manipulation of gingival tissue, periapical procedures or perforation of oral mucosa; ampicillin or amoxicillin 50mg/kg po or iv. Clarithromycin or azithromycin (15mg/kg) are suitable oral alternatives for penicillin allergic patients.

k. Latex allergy- If the patient has a sensitivity to latex (eg. rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

This is not an at risk group for latex allergy

l. Does the patient have any antibiotic allergies- – Common antibiotic allergies and alternative antibiotics]

Common antibiotic allergies include penicilins, cephalosporins and

Penicillin allergic patients may have cephalexin (50mg/kg) clindamycin(20mg/kg) or cefazolin or ceftriaxone (50mg/kg).

It is important to avoid cephalosporins in patients with a history of anaphylaxis, urticaria or angioedema to penicillins

m. Does the patient have a history of allergy to anesthesia?

  • Malignant hyperthermia:

    Documented- avoid all trigger agents such as succinylcholine and inhalational agents:

    Proposed general anesthetic plan: The issue for young children with bona fide family history of MH is vascular access. The general strategy in a child without an iv in place would be to put local anesthetic cream (maxilene) on the most promising sites and administer 50% nitrous oxide from a suitably prepared anesthetic machine, to minimise any upset. The child can then be induced with propofol and managed with either benzodiazepines, narcotics and nitrous oxide, or a TIVA technique. If appropriate regional techniques can be added.

    Family history or risk factors for MH: Muscular dystrophy, central core disease, nemaline rod myopathy. Exertional rhabdomyolysis or heat stroke in the non-obese patient.

    Insure MH cart available:

    [- MH protocol]

  • Local anesthetics/ muscle relaxants:

5. What laboratory tests should be obtained and has everything been reviewed?

NA

Common laboratory normal values will be same for all procedures, with a difference by age and gender.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

Pediatric anesthesia is mostly general anesthesia, and monitored anesthesia care is mostly deep sedation verging on general anesthesia with a few exceptions. Regional techniques in pediatric patients are almost always as an adjunct to general anesthesia. Infants and children and especially T21 patients are much more flexible than adults so it is easy to position them in ways that are inappropriate, eg arms straight above the head for cardiac catheterisation, hyperextended frog leg position. The infants larger head is surprisingly heavy, and particular care is need prevent hyperflexion or extension in Down syndrome.

a. Regional anesthesia – They are very useful in circumstances where the avoidance of narcotics may be beneficial, such as the child with a difficult airway. There is a compelling role for the use of regional techniques as part of a multimodal pain strategy, and there is evidence that infants who have undergone painful procedures have exaggerated pain responses. Therefore, all efforts ranging from wound infiltration to neuraxial techniques should be considered for relevant surgical procedures. In children in whom neuraxial blocks are contra-indicated, directly place paravertebral catheters can be used for thoracotomy, and transversus abdominis plane blocks are useful for abdominal procedures.

The use of neuraxial techniques in patients who are going to be anticoagulated has been reported eg for cardiac surgery, but remains controversial. There are guidelines regarding the placement of epidural catheters in patients taking aspirin and non-steroidal agents which state that neuraxial blocks are safe.

Unfractionated heparin at therapeutic levels is a contra-indication to neuraxial block and the aPTT should be normal prior to placement or catheter removal. LMWH for thromboprophylaxis (rather than therapeutic anticoagulation) should be stopped for 12 hrs prior to central or peripheral nerve block.

All the published evidence currently addresses risk benefit ratios for adults with coronary stents and not pediatric patients. The primary principle of “do no harm” should probably guide pediatric practice.

  • Neuraxial

    Benefits: avoidance of narcotics, excellent analgesia, possible afterload reduction

    Drawbacks: Added risk, technical issues, local anesthetic toxicity

  • Issues

  • Peripheral Nerve Block

    Benefits; Lower dose of local anesthetic, avoidance of issues around motor block

    Drawbacks; Neuropraxia, shorter duration, catheters may not be suitable or may be less stable

    Issues

b. General Anesthesia

  • Benefits: Control, there is by definition a still, silent, pain-free patient, with no recollection of the proceedings

  • Drawbacks; cardiac depression, positive pressure ventilation and cardiorespiratory interactions

  • Other issues; recovery, post-operative pain management

  • Airway concerns; T21, 22q11del, other syndromes

c. Monitored Anesthesia Care is only suitable for some adolescent patients and a few procedures in infants, eg PICC lines and percutaneous G-tube insertion.

  • Benefits; Some adolescents (very few) prefer to be awake, lower drug doses, increased sympathetic tone

  • Drawbacks; Cooperation, increased sympathetic tone

  • Other Issues; surgeon comfort, movement

6. What is the author's preferred method of anesthesia technique and why?

General anesthesia is the favored technique for most procedures, as anesthetic drugs are generally favorable in regurgitant lesions. If there is right sided regurgitation, particularly in the context of poor RV function I will make every effort to keep the patient breathing spontaneously with pressure support or minimise inspiratory times and peak pressures to try to mitigate the cardiopulmonary interactions seen with positive pressure ventilation.

  • What prophylactic antibiotics should be administered? – Depends on the type of surgery: see above re endocarditis prophylaxis but the majority of patients are given cefazolin (30mg/kg) when wound prophylaxis is indicated. For bowel surgery cefoxitin(30mg/kg), or gentamycin(2.5mg/kg) and metronidazole(10mg/kg) may be added. Neurosurgery protocols depend on the procedure, and in the case of an intracerebral abscess than antibiotics are therapeutic. Urological surgery employs co-trimoxazole(6-10mg/kg trimethoprim) as a second line agent, and otherwise, clindamycin(15mg/kg) or vancomycin(15mg/kg) are used for patients with beta-lactam allergy. There are modified regimens for neonates.

  • What do I need to know about the surgical technique to optimize my anesthetic care? – All anesthesiologists need to know what surgeons are doing; the point of the anesthetic is to shepherd the patient through the surgical procedure in such a way as to keep them safe and minimise the physiological insult.

  • What can I do intraoperatively to assist the surgeon and optimize patient care? Examples: Controlled hypotension, Cell Saver.

  • What are the most common intraoperative complications and how can they be avoided/treated? Prioritize them by urgency.

  • Cardiac complications-.

  • Pulmonary-

  • Neurologic: Unique to procedure: EXAMPLE: Cement Implantation Syndrome (CIS) in the ORIF of the hip.

a. Neurologic:

  • Unique to procedure: EXAMPLE: Cement Implantation Syndrome (CIS) in the ORIF of the hip

b. If the patient is intubated, are there any special criteria for extubation?

The incidence of laryngospasm is higher in children and their minute ventilation, oxygen consumption and disadvantageous respiratory mechanics mean that they desaturate disconcertingly rapidly. The presence of a PFO will speed up desaturation by permitting right to left shunting during valsalva type maneuvers. This is usually a transient problem. On the other hand a child with poor RV function who is allowed to cough and strain on an endotracheal tube for any length of time, may well desaturate and become hypotensive because of impedance to cardiac output.

c. Postoperative management

  • What analgesic modalities can I implement? The possibility for multimodal analgesia should always be considered for painful procedures, and those techniques that are contra-indicated or inappropriate discarded. Thus local anesthesia, plus oral or rectal tylenol, plus non-steroidal drugs, plus narcotics as indicated.

  • What level bed acuity is appropriate? Children with hemodynamically significant cardiac disease should be cared for on the cardiac ward if they have undergone minor procedures. For more extensive surgery then shared care in either an intensive care unit or a high-intensity ward setting are appropriate. The complexity of congenital heart disease is such that expert care should be available throughout the child’s hospitalisation.

  • What are common postoperative complications, and ways to prevent and treat them? Common postoperative complications for children with heart disease include volume overload and exacerbation of heart failure as well as pre-renal azotemia due to over-enthusiastic diuresis. Atelectasis and postoperative oxygen requirement is frequent. Children given narcotics frequently itch, and often have bad dreams. Post-operative delirium is reportedly more common in children.

What's the Evidence?

Freedom, Robert M. The Natural and Modified History of Congenital Heart Disease. 2004. (The most useful resource for me in preparing this text. This text reviews the patholgy and outcomes in all forms of congenital heart disease.)

Rosenthal, DN, Hammer, GB. “Cardiomyopathy and heart failure in children: anesthetic implications”. Paediatr Anaesth. vol. 21. 2011. pp. 577-84.

Knauth, AL, Gauvreau, K, Powell, AJ, Landzberg, MJ, Walsh, EP, Lock, JE, del Nido, PJ, Geva, T. “Ventricular size and function assessed by cardiac MRI predict major adverse clinical outcomes late after tetralogy of Fallot repair”. Heart. vol. 94. 2008. pp. 211-6.

Kaemmerer, H, Fratz, S, Bauer, U, Oechslin, E, Brodherr-Heberlein, S, Zrenner, B, Turina, J, Jenni, R, Lange, PE, Hess, J. “Emergency hospital admissions and three-year survival of adults with and without cardiovascular surgery for congenital cardiac disease”. J Thorac Cardiovasc Surg. vol. 126. 2003. pp. 1048-52.

Clarizia, NA, Chahal, N, Manlhiot, C, Kilburn, J, Redington, AN, McCrindle, BW. “Transition to adult health care for adolescents and young adults with congenital heart disease: perspectives of the patient, parent and health care provider”. Can J Cardiol. vol. 25. 2009. pp. e317-22.

Farbod, F, Kanaan, H, Farbod, J. “Infective endocarditis and antibiotic prophylaxis prior to dental/oral procedures: latest revision to the guidelines by the American Heart Association published April 2007”. Int J Oral Maxillofac Surg. vol. 38. 2009. pp. 626-31.

Bai, W, Voepel-Lewis, T, Malviya, S. “Hemodynamic changes in children with Down syndrome during and following inhalation induction of anesthesia with sevoflurane”. J Clin Anesth. vol. 22. 2010. pp. 592-7.

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