Post on 16-Apr-2017
Anaesthesia for Non-cardiac Surgery in Adults with
Congenital Heart DiseasePresenter- Dr. Ankita Patni
Moderator- Dr. Murlidhar K.
Overview Common congenital heart diseases seen in Adults Long term consequences of congenital heart diseases and effect on Anesthesia management i. Pulmonary Hypertensionii. Bleeding and thrombosis riskiii. Heart failureiv. Dysrhythmias Anaesthetic managementi. Preoperative evaluationii. Pre-medicationiii. Endocarditis Prophylaxisiv. Intraoperative monitoringv. Management strategies for specific defectsvi. Post operative management
Cardiac Sequelae Pulmonary hypertension Ventricular dysfunction Dysrhythmias and conduction defects Residual shunts Valvular lesions-regurgitation or
stenosis Hypertension Aneurysms
Non-cardiac sequelae Secondary erythrocytosis Cholelithiasis Nephrolithiasis Developmental abnormalities Seizure disorders from previous
thromboembolic events or cerebrovascular accidents
Restrictive and obstructive lung disease
Long term consequences of CHD
Pulmonary Hypertension (main etiology)
Presence of long standing large and
non-restrictive defects
Increased pulmonary blood flow and
pressure to near systemic levels
Irreversible vascular changes – hypertrophy of the media, cellular
proliferation in intima, smooth muscle cell migration to sub
endothelium, progressive fibrosis
Obliteration of arterioles and small arteries
Increased pulmonary resistance and
reversal of shunt
Pulmonary Hypertension Other causes of pulmonary venous hypertension-a. Secondary to elevated ventricular end diastolic pressureb. Elevated pulmonary venous atrial pressurec. Pulmonary vein stenosis
Decreased oxygen saturation
Residual shunts
Poor lung function
Persistent decreased pulmonary blood flow
Eisenmenger Syndrome Refers to the development of pulmonary hypertension secondary to long standing left to right shunting. Non cardiac surgery should only be performed if absolutely essential. Perioperative mortality increases Predictors of mortality- Syncope Age at presentation or development of symptoms Poor functional class Supraventricular dysrhythmias Elevated right atrial pressures Low oxygen saturation (<85%> Renal insufficiency Severe right ventricular dysfunction Trisomy 21
Anaesthetic management in patients with pulmonary hypertension Minimize increase in pulmonary vascular resistance and decrease in
systemic vascular resistance. Abrupt increase in PVR precipitate acute right ventricular failure
Decreased cardiac output and oxygen desaturation
Bradycardia and cardiac arrest
Prevention Hyperventilation (with fraction of
inspired oxygen 1.0) Correction of acidosis Avoidance of sympathetic nervous
system stimulation Maintenance of normothermia Minimization of intrathoracic
pressure Use of inotropic support Inhaled nitric oxide
Regional versus general anaesthesia
Regional may produce unacceptable decreases in SVR and could exacerbate Right to left shunt.
General anaesthesia allows for optimal control of ventilation and may be preferable in patients with high risk surgery.
Bleeding and thrombosis risk
cyanosis Chronic hypoxia
Increased erythropoietin
Increased red cell mass
Increased viscosity
Bleeding and thrombosis risk Viscosity Sheer Stress Prostaglandins &
Nitric OxideTissue vascularity and arteriolar dilatation
BLEEDINGFlow in small arterioles(exacerbated by iron deficiency and dehydration)
THROMBOSIS
Bleeding and Thrombosis risk PREVENTION-Adequate hydrationPre-operative phlebotomy if HCT>65%Consider replacement of coagulation factors and plateletsIron deficiency should be corrected pre-operatively
Heart failure
Adults with corrected CHD
Increses ANP, Renin,
Aldosterone , NE
Abnormal cardiac autonomic nervous system regulation
Altered Hemodynamics Heart Failure
Left sided failure Should be Optimized in peri-
operative period with DiureticsDigoxinACE inhibitorsBeta blockers
Right sided failure No evidence based guidelines for
management of heart failure in patients with a systemic right ventricle (congenitally corrected TGA, Mustard or Senning repairs of TGA and single ventricles)
Heart Failure
Dysrhythmias CAUSE- Primary consequence of underlying congenital defect or secondary to surgical repair MOST COMMON FORM- Intraatrial reentrant tachycardia originating from right atrium. ATRIAL TACHYARRHYTHMIAS- often resistant to pharmacological treatment and results in rapid
hemodynamic deterioration. VENTRICULAR DYSRHYTHMIAS- risk factors- Decreased right or left ventricular functionPrevious ventriculotomyOlder age at initial surgery Patients who are repaired late exposed to longer periods of cyanosis, volume overload,
pressure overload Increased myocardial fibrosis and associated slowing of conduction Increased risk of Arrhythmias
Acute hypoxemia can provoke ventricular dysrhythmias as subendocardial myocardial perfusion is already impaired in hypertrophied myocardium
Pre-operative Evaluation Multidisciplinary APPROACH- anesthesiologists, cardiologists,
intensivists, and surgeons Look for echocardiogram and cardiac catheterisation to become
familiar with patient’s anatomy and physiology ANTICIPATE intraoperative events
ASSESS perioperative risk- Increased with Poor functional class
Pulmonary HTNCHFCyanosisMajor surgery ( OLV, changes in position-prone,trendelenberg)
Pre-medication Psychological preparation is important
ANXIOLYTICS and HYPNOTICS
Hypoventilation and Hypercapnia
Cautious!!
Increased Pulmonary Vascular Resistance ( particularly in patients with underlying pulmonary HTN or Systemic to Pulmonary shunts)
Endocarditis Prophylaxis AHA has recently published updated guidelines for the prevention of IE. Only patients with cardiac conditions associated with the highest risk of
adverse outcomes should continue antibiotic prophylaxis before surgery- Previous endocarditisUnrepaired CCHD Completely repaired congenital heart defects during the first 6 months
after the procedure Repaired CHD with residual defects at the site (which inhibit
endothelialisation)
Intraoperative Monitoring
Standard conventional monitoring
Direct examination
Pulse oximetry
ECG
Arterial blood pressure
Capnography
Temperature
Signify increase in Pulmonary vascular resistance
Increase Right to left shunt Decrease pulmonary blood flow
through shunts
Increase in left to right shunt may not be detected by pulse oximetry and oxygen saturation may be maintained even if systemic cardiac output is severely compromised.
Pulse oximetry
• EtCO2 underestimates PaCO2 in the case of Right to Left shunting
• Knowledge of the Anatomy and Physiology of specific palliative repairs is important for choosing appropriate monitoring
• Congenital defects associated with inadequate PBF are palliated with systemic to pulmonary shunts
Intraoperative monitoring
Classic Blalock Taussig shunt • End to side anastomosis of
the subclavian and pulmonary arteries
• Significance- Arterial pressure and SpO2 cannot be measured on the ipsilateral side
Glenn shunt• Bidirectional
cavopulmonary anastomosis
• End to side anastomosis of the divided SVC to PA
Fontan shunt• Total cavopulmonary
connection• Pulmonary and systemic
circulations are totally separated by diverting all the systemic venous return to the PA, usu. Without interposition of a sub-pulmonic ventricle.
Monitoring Alterations in intracardiac anatomy complicate the placement of central venous
catheters in palliated adults CVP values interpretation will be different. Eg. In Fontan; CVP ~ mean PAP In Intraatrial Buffle(Mustard or Senning procedure) ; PAC placement is difficult or
impossible. Vascular access --- may be difficult --- previous catheterization Invasive arterial pressure monitoring – Essential – sensitive to sudden changes in
preload, SVR and PVR TEE – might be useful – monitor intravascular volume status and ventricular
function
Major objective- Promote tissue O2 delivery
Prevent arterial desaturation
Maintain a balance between
pulmonary and systemic flows
Optimize HCT
Management strategies for specific defects
Management strategies for specific defects
Management strategies for specific defects
Management strategies for specific defects
Management strategies for specific defects
UNIVENTRICULAR HEART- eg. Fontan – bypasses right ventricle, leaving passive non pulsatile flow from both SVC and IVC to PA• Any factor that increases PVR – decreases PBF – Arterial desaturation.• Fontan patients frequently present with complications – supraventricular dysrhythmias, restrictive lung
disease, thromboembolic complications and hepatic dysfunction.• Both procoagulant and anticoagulant effects are observed with Fontan as a result of liver dysfunction,
factor loss in patients with protein losing enteropathy – Increased Risk of Bleeding• Patients with a Fontan circulation should maintain an arterial saturation above 90%. If <90%, further
evaluation for venovenous collaterals, AVM or residual shunt.
Anesthetic agent of choice
• Maintain hemodynamic stability• Preferred ETOMIDATE
•Increase PVR, maintain SVR and ventricular performance (not used in adults)•Beneficial effects seen in children undergoing sevoflurane anesthesiaKETAMINE•Most depress myocardial contractility and decrease SVR– Adverse effect on tissue oxygen delivery during induction of anesthesia•Choice of a specific volatile or IV agent should be based on patient’s physiology and overall goal of balancing pulmonary and systemic blood flow
OTHERS
Specific intraoperative considerations with shunts All IV lines must be meticulously DEAIRED to decrease the risk of systemic air
embolization Hemodynamic effects of ventilation strategies, positioning, pharmacological agents,
and blood loss must all appropriately BALANCE pulmonary and systemic blood flow. Ventilation with High Airway Pressure can COMPROMISE venous return, increase PVR
and exacerbate Right to Left shunt. Inadequate anesthesia and sympathetic nervous system STIMULATION might increase
SVR and exacerbate Left to Right shunting, reducing systemic cardiac output. TRENDELENBURG position– Increase CVP– Cerebral hypoperfusion in a patient with
Glenn or Fontan. Systemic HYPOTENSION– decrease PBF– Arterial Desaturation, in a patient with a
systemic to pulmonary artery shunt.
Post op management Managed in ICU experienced with caring for adults with CHD Major RISKS include :- BleedingDysrhythmiasThromboembolic events In case of pulmonary HTN, oral PULMONARY VASODILATORS such as
sildenafil and inhaled nitric oxide may be beneficial.
Thank You