Practical Approach to Anesthesia Practical Approach to Anesthesia for Parturient with Cardiac Diseasefor Parturient with Cardiac Disease

CMECCMEC2121stst July 2009 July 2009

bybyNadine Mohamed Mamdouh HabibNadine Mohamed Mamdouh Habib

OutlineOutline

The critical physiological changes of pregnancy.The critical physiological changes of pregnancy.

Predictors of cardiac events during pregnancyPredictors of cardiac events during pregnancy

Risk of cardiovascular complications during Risk of cardiovascular complications during pregnancypregnancy

Anesthetic management parturient with congenital Anesthetic management parturient with congenital and valvular diseases.and valvular diseases.

What are the critical physiological changes What are the critical physiological changes of pregnancy that affects a parturient with of pregnancy that affects a parturient with

cardiac disease ?cardiac disease ? 50% increase in the blood volume50% increase in the blood volume 40% increase in cardiac output40% increase in cardiac output 25% increase in heart rate to 25% increase in heart rate to

approximately 80-100 beats/min. approximately 80-100 beats/min. Reduced systemic vascular resistance Reduced systemic vascular resistance

and pulmonary vascular resistance.and pulmonary vascular resistance. Labor and delivery itself imposes Labor and delivery itself imposes

approximately 50% increase in CO and approximately 50% increase in CO and oxygen demand.oxygen demand.

The main predictors of cardiac The main predictors of cardiac events during pregnancy areevents during pregnancy are::

Prior cardiac events: (heart failure, transient Prior cardiac events: (heart failure, transient ischemic attack, stroke, or dysrrhythmias).ischemic attack, stroke, or dysrrhythmias).

Baseline New York Heart association Baseline New York Heart association functional class≥ II or the presence of functional class≥ II or the presence of cyanosis.cyanosis.

Left heart obstruction: (mitral valve area ≤ Left heart obstruction: (mitral valve area ≤ 2cm2cm22, aortic valve area ≤ 1.5 cm, aortic valve area ≤ 1.5 cm22, or left , or left ventricular outflow tract gradient ≥ 30mmHg by ventricular outflow tract gradient ≥ 30mmHg by echocardiography).echocardiography).

Reduced left ventricular function (ejection Reduced left ventricular function (ejection fraction ≤ 40%). fraction ≤ 40%).

Risk of cardiovascular Risk of cardiovascular complications during pregnancycomplications during pregnancy

Risk of Risk of

cardiovascular

complications complications during pregnancyduring pregnancy

Low risk

of

complications (≤ 1%)

Intermediate risk risk

of of

complications (5-15%)complications (5-15%)

High risk risk

of of

complications complications

or death (≥25%)or death (≥25%)

Low risk of complications (≤ 1%):Low risk of complications (≤ 1%):Corrected tetralogy of fallotCorrected tetralogy of fallotAtrial septal defectAtrial septal defectVentricular septal defectVentricular septal defectPatent ductus arteriosusPatent ductus arteriosusMild pulmonic or tricuspid valve diseaseMild pulmonic or tricuspid valve diseaseMitral stenosis (NYHA class I, II)Mitral stenosis (NYHA class I, II)Mild regurgitant valve lesionMild regurgitant valve lesionBioprosthetic valveBioprosthetic valveCompensated heart failure (NYHA class I, II)Compensated heart failure (NYHA class I, II)

Intermediate risk of complications (5-Intermediate risk of complications (5-15%):15%):Mechanical valve prosthesisMechanical valve prosthesisAortic stenosis (mild to moderate)Aortic stenosis (mild to moderate)Mitral stenosis with atrial fibrillationMitral stenosis with atrial fibrillationMitral stenosis (NYHA class III, IV)Mitral stenosis (NYHA class III, IV)Uncorrected cyanotic congenital heart Uncorrected cyanotic congenital heart

disease (tetralogy of fallot)disease (tetralogy of fallot)Uncorrected coarctation of the aortaUncorrected coarctation of the aortaPrevious myocardial infarctionPrevious myocardial infarction

High risk of complications or death High risk of complications or death (≥25%):(≥25%):Pulmonary hypertension (severe)Pulmonary hypertension (severe)Eisenminger syndromeEisenminger syndromeMarfan disease with aortic root involvementMarfan disease with aortic root involvementPeripartum cardiomyopathyPeripartum cardiomyopathySevere aortic stenosisSevere aortic stenosisNYHA class IV heart failureNYHA class IV heart failure

Congenital heart diseaseCongenital heart disease

Prevention of accidental intravenous infusion of Prevention of accidental intravenous infusion of air bubbles air bubbles

A slow onset of epidural analgesia is preferredA slow onset of epidural analgesia is preferred

Supplemental O2 should be given to the patientSupplemental O2 should be given to the patient

Hypercarbia and acidosis should be avoidedHypercarbia and acidosis should be avoided

TOF consists of 4 structural TOF consists of 4 structural abnormalities:abnormalities:• Ventricular septal defect (VSD)Ventricular septal defect (VSD)• Right ventricular hypertrophy Right ventricular hypertrophy

(RVH)(RVH)• Right ventricular outflow Right ventricular outflow

obstructionobstruction• Overriding of the aortaOverriding of the aorta

Tetralogy of Fallot (TOF)Tetralogy of Fallot (TOF)TOF is the most common etiologic factor in TOF is the most common etiologic factor in the right to left shunt.the right to left shunt.

In patients with uncorrected lesion, anaesthetic In patients with uncorrected lesion, anaesthetic considerations must focus on minimizing the considerations must focus on minimizing the haemodynamic changes that would increase right to haemodynamic changes that would increase right to left shunting:left shunting:

decrease in SVR.decrease in SVR. decrease in venous return. decrease in venous return. or myocardial depression.or myocardial depression.

In patients who had successful surgery in infancy or childhood, no special treatment is required; antibiotic prophylaxis is recommended

Anesthtic technique:Anesthtic technique:

Choice of induction agents for general anaesthesia: Choice of induction agents for general anaesthesia: narcotic induction with etomidate.narcotic induction with etomidate. Neonatal depression as a result of narcotic induction Neonatal depression as a result of narcotic induction

can be easily treated with endotracheal intubation can be easily treated with endotracheal intubation Invasive monitoring is mandatory and arterial line or Invasive monitoring is mandatory and arterial line or

CVP line is preferred to pulmonary artery (PA) catheter. CVP line is preferred to pulmonary artery (PA) catheter. CVP may be more useful (as the right ventricle is at the CVP may be more useful (as the right ventricle is at the greatest risk of dysfunction).greatest risk of dysfunction).

Single shot spinal anaesthesia should be avoided. Single shot spinal anaesthesia should be avoided. Slow induction of epidural may be advisable with Slow induction of epidural may be advisable with caution.caution.

A chronic uncorrected left to A chronic uncorrected left to right shunt right shunt produces right produces right ventricular hypertrophy (RVH) ventricular hypertrophy (RVH) elevated pulmonary artery elevated pulmonary artery pressure pressure right ventricular (RV) right ventricular (RV) dysfunction.dysfunction.

The primary lesion is usually The primary lesion is usually ASD, VSD or PDA.ASD, VSD or PDA.

Eisenmenger SyndromeEisenmenger Syndrome

The pulmonary and the RV musculature undergoes The pulmonary and the RV musculature undergoes remodeling in response to the chronic pulmonary remodeling in response to the chronic pulmonary volume overload volume overload the high fixed pulmonary artery the high fixed pulmonary artery pressure limits flow through the pulmonary pressure limits flow through the pulmonary vasculature and when pulmonary artery pressure vasculature and when pulmonary artery pressure exceeds the level of systemic pressure exceeds the level of systemic pressure reversal of reversal of shunt flow occurs. shunt flow occurs.

The initial left to right shunt becomes a right to left The initial left to right shunt becomes a right to left shunt, ultimately leading to the Eisenmenger shunt, ultimately leading to the Eisenmenger syndrome: which includes the sequelae of arterial syndrome: which includes the sequelae of arterial hypoxaemia, and RV failure.hypoxaemia, and RV failure.

Eisenmenger Syndrome (cont.)Eisenmenger Syndrome (cont.)

Clinical manifestations:Clinical manifestations:

Dyspneoa, Dyspneoa, Clubbing of nails, Clubbing of nails, PolycythemiaPolycythemia Peripheral oedema Peripheral oedema Cynosis. Cynosis.

In an established case of Eisenmenger In an established case of Eisenmenger syndrome, surgical correction of the defect syndrome, surgical correction of the defect is unhelpful and may increase mortality.is unhelpful and may increase mortality.

Anaesthetic consideration:Anaesthetic consideration:

Avoid any decrease in Avoid any decrease in the SVRthe SVR insufficient insufficient RV pressure required to perfuse the RV pressure required to perfuse the hypertensive pulmonary arterial bed and may hypertensive pulmonary arterial bed and may result in sudden death of the patient.result in sudden death of the patient.

Acute arrhythmiasAcute arrhythmias are particularly dangerous are particularly dangerous as these patients have little or no cardiac as these patients have little or no cardiac reserve and need a normal sinus rhythm to reserve and need a normal sinus rhythm to keep up with the increased workload. keep up with the increased workload.

Ampicilin and gentamycin i.v.Ampicilin and gentamycin i.v. should be should be given as prophylaxis against infective given as prophylaxis against infective endocarditis and repeated eight hourly after endocarditis and repeated eight hourly after the initial dose.the initial dose.

Anesthetic technique: O2 should be administered to all patients undergoing surgery O2 should be administered to all patients undergoing surgery

under regional anaesthesia, as O2 reduces pulmonary vascular under regional anaesthesia, as O2 reduces pulmonary vascular resistance, which benefits the patient with Eisenmeneger.resistance, which benefits the patient with Eisenmeneger.

Caesarean section can also be conducted under general Caesarean section can also be conducted under general anaesthesiaanaesthesia (but several disadvantages): (but several disadvantages):

• Effects of IPPV on venous returnEffects of IPPV on venous return• ventilation/perfusion mismatchventilation/perfusion mismatch• high pulmonary artery pressurehigh pulmonary artery pressure• increased shunt through the anatomic defect increased shunt through the anatomic defect • myocardial depression by halogenated agentsmyocardial depression by halogenated agents

Monitoring includes invasive blood pressure monitoring (A-line), Monitoring includes invasive blood pressure monitoring (A-line), and central venous pressure (CVP) monitoring (Pulmonary and central venous pressure (CVP) monitoring (Pulmonary artery catheter (PA) use is controversial).artery catheter (PA) use is controversial).

The blood loss should be promptly replaced by crystalloids, The blood loss should be promptly replaced by crystalloids, colloids, or packed cells. Postpartum autotransfusion may colloids, or packed cells. Postpartum autotransfusion may cause intravascular volume overload in these patients. Regional cause intravascular volume overload in these patients. Regional anaesthesia may reduce the risk of postoperative deep vein anaesthesia may reduce the risk of postoperative deep vein thrombosis. thrombosis.

Titrated epidural anaesthesia is probably the prefered regional Titrated epidural anaesthesia is probably the prefered regional technique, a dilute solution of phenylephrine may be given as technique, a dilute solution of phenylephrine may be given as needed to maintain maternal SVR. needed to maintain maternal SVR.

Valvular Heart Disease:Valvular Heart Disease:

In general regurgitant valvular lesions In general regurgitant valvular lesions are well tolerated during pregnancy, are well tolerated during pregnancy, where as where as stenotic lesionsstenotic lesions have a have a greater potential for decompensationgreater potential for decompensation. .

Pregnant patients with valvular heart Pregnant patients with valvular heart disease can expect to have disease can expect to have worseningworsening of their New York Heart Association of their New York Heart Association (NYHA) functional class(NYHA) functional class, while others , while others may have adverse foetal outcome i.e. may have adverse foetal outcome i.e. preterm birth or still birth.preterm birth or still birth.

Mitral stenosis (MS):Mitral stenosis (MS):

Normal mitral valve orifice has a Normal mitral valve orifice has a surface area of4-6cms2, in mild surface area of4-6cms2, in mild stenosis the valve area stenosis the valve area (1.5 to 3 cm(1.5 to 3 cm22),), moderate mitral stenosis the valve moderate mitral stenosis the valve area area (1.1 to 1.5 cm(1.1 to 1.5 cm22),), while severe while severe mitral stenosis the valve area mitral stenosis the valve area (less (less than 1cmthan 1cm22).).

Mitral valve Mitral valve stenosis prevents stenosis prevents emptying of the left emptying of the left atrium (LA), with atrium (LA), with increased left atrial increased left atrial and pulmonary and pulmonary artery pressure, artery pressure, resulting in resulting in dyspnoeadyspnoea, , haemoptysishaemoptysis and and pulmonary pulmonary oedemaoedema..

Mitral stenosis (cont.):Mitral stenosis (cont.):

Peripartum considerations:Peripartum considerations:The hyperdynamic state of pregnancy is The hyperdynamic state of pregnancy is

poorly tolerated by women with poorly tolerated by women with severe mitral stenosis:severe mitral stenosis:

Increased plasma volume can cause Increased plasma volume can cause pulmonary edema and worsen the left pulmonary edema and worsen the left atrial enlargement.atrial enlargement.

Tachycardia decreases the left Tachycardia decreases the left ventricular diastolic filling through ventricular diastolic filling through the stenotic valve.the stenotic valve.

AF is common with MS, with loss of AF is common with MS, with loss of the atrial kick; which accounts for = the atrial kick; which accounts for = 30% of the left ventricular stroke 30% of the left ventricular stroke volume. Medical management of AF volume. Medical management of AF by a beta-adrenergic blocking agent.by a beta-adrenergic blocking agent.

Anesthetic considerations:Anesthetic considerations:

Should be based on the severity of the Should be based on the severity of the lesion,( according to the valve area, and the lesion,( according to the valve area, and the hemodynamic stability of the patient).hemodynamic stability of the patient).

Avoid increased heart rate.Avoid increased heart rate. Maintain venous return and SVR.Maintain venous return and SVR. Avoid aorto-caval compression.Avoid aorto-caval compression. Treat atrial fibrillation (AF) aggressively.Treat atrial fibrillation (AF) aggressively. Maintain sinus rhythm.Maintain sinus rhythm. Prevent pain, hypoxaemia, hypercarbia and Prevent pain, hypoxaemia, hypercarbia and

acidosis as these can increase PVR.acidosis as these can increase PVR.

Anesthetic techniqueAnesthetic techniqueSlow epidural anaesthesiaSlow epidural anaesthesia may be may be

conducted with caution to maintain conducted with caution to maintain hemodynamics.hemodynamics.

Prophylactic ephedrine administration Prophylactic ephedrine administration should be avoided. If a need for should be avoided. If a need for vaspressor arises, the drug of choice in vaspressor arises, the drug of choice in patients with MS is low dose patients with MS is low dose phenylephrine.phenylephrine.

General anaesthesiaGeneral anaesthesia

The cardiovascular effects associated with laryngoscopy and The cardiovascular effects associated with laryngoscopy and intubation and oral suction should be minimized.intubation and oral suction should be minimized.

Induction agent should not produce wide swings in the Induction agent should not produce wide swings in the haemodynamics( haemodynamics( Etomidate is a suitable induction agentEtomidate is a suitable induction agent). A ). A beta-blocker such as beta-blocker such as esmololesmolol and and a modest dose of opioida modest dose of opioid should be administered before or during the induction of should be administered before or during the induction of general anaesthesia. general anaesthesia.

Oxytocin should be used with care, a dilute solution instead of Oxytocin should be used with care, a dilute solution instead of bolus dose is recommended.bolus dose is recommended.

Emergence must be carefully controlled to avoid tachycardia.Emergence must be carefully controlled to avoid tachycardia.

Regurgitation of blood Regurgitation of blood through an incompetent mitral through an incompetent mitral valve valve chronic volume over chronic volume over load and dilatation of the LVload and dilatation of the LV

In the acute type, there is In the acute type, there is acute pulmonary congestion acute pulmonary congestion and pulmonary edema results.and pulmonary edema results.

If the patient survives this If the patient survives this episode of acute mitral episode of acute mitral regurgitation, pulmonary regurgitation, pulmonary artery pressure continues to artery pressure continues to increase and right heart increase and right heart failure occurs.failure occurs.

Mitral Regurgitation (MR):Mitral Regurgitation (MR):

Anesthetic consideration:Anesthetic consideration:

Primary considerations are:Primary considerations are:Maintain slightly increased heart rateMaintain slightly increased heart ratePrevent increase in SVR.Prevent increase in SVR. Increase in the central blood volume.Increase in the central blood volume.Prevent hypoxemia, hypercarbia, Prevent hypoxemia, hypercarbia,

acidosis which may increase PVR.acidosis which may increase PVR.Avoid aortocaval compression and Avoid aortocaval compression and

myocardial depression.myocardial depression.

Anesthetic technique:Anesthetic technique:

Epidural anaesthesiaEpidural anaesthesia prevents increase in SVR, prevents increase in SVR, promotes forward flow of blood and helps to prevent promotes forward flow of blood and helps to prevent pulmonary congestion.pulmonary congestion.

If general anaesthesia is required: If general anaesthesia is required: ketamine andketamine and pancuronium pancuronium are desirable agents in are desirable agents in these patients. these patients.

Atrial fibrillation (AF) must be treated promptly, and Atrial fibrillation (AF) must be treated promptly, and haemodynamic instability associated with AF haemodynamic instability associated with AF warrants immediate cardioversion.warrants immediate cardioversion.

Invasive (intra-arterial) BP monitoring, and Invasive (intra-arterial) BP monitoring, and pulmonary artery catheter monitoring are advisable pulmonary artery catheter monitoring are advisable in severe cases.in severe cases.

Aortic stenosis (AS):Aortic stenosis (AS):

The pathophysiology of The pathophysiology of severe ASsevere AS entail a entail a narrowing of the valve to narrowing of the valve to less than 1 cmless than 1 cm22 associated with a trans-valvular gradient of associated with a trans-valvular gradient of 50mmHg with significant increase in after 50mmHg with significant increase in after load to the LV. load to the LV.

A valvular gradient which exceeds 100mmHg A valvular gradient which exceeds 100mmHg carries an increased risk of myocardial carries an increased risk of myocardial ischemia as the LV hypertrophies ischemia as the LV hypertrophies significantly.significantly.

In aortic stenosis In aortic stenosis transvalvular gradient transvalvular gradient increasesincreases progressively progressively throughout throughout pregnancypregnancy, due to increasing blood volume , due to increasing blood volume and decreasing SVRand decreasing SVR

Avoid tachycardia (decrease Avoid tachycardia (decrease time for coronary perfusion of time for coronary perfusion of the hypertrophied LV), and the hypertrophied LV), and bradycardia (slow heart rate bradycardia (slow heart rate decreases CO).decreases CO).

Maintain intravascular volume Maintain intravascular volume and venous return.and venous return.

Avoid aortocaval compression Avoid aortocaval compression and myocardial depression. and myocardial depression.

Arrhythmias are not well Arrhythmias are not well tolerated and should be tolerated and should be promptly treated.promptly treated.

Patients with Patients with trans-valvular trans-valvular gradient more than 50mmHggradient more than 50mmHg with symptomatic AS should with symptomatic AS should have have invasive monitoring i.e. invasive monitoring i.e. A-line and PA catheter in place.A-line and PA catheter in place.

Anaesthetic considerations:

Anesthetic technique:Anesthetic technique:

General Anaesthesia :Drugs of choice are General Anaesthesia :Drugs of choice are a combination of a combination of etomidate and modest dose of opioidsetomidate and modest dose of opioids with with succinylcholine succinylcholine for for rapid sequence intubation.rapid sequence intubation.

Myocardial depression associated with volatile anaesthetic Myocardial depression associated with volatile anaesthetic agents should be avoided.agents should be avoided.

Oxytocin should be avoided as it is known to cause marked Oxytocin should be avoided as it is known to cause marked vasodilation, with hypotension. The drug of choice for uterine vasodilation, with hypotension. The drug of choice for uterine contraction is ergometrine at the end of delivery.contraction is ergometrine at the end of delivery.

PA catheter monitoring is controversial, as it entails a high risk PA catheter monitoring is controversial, as it entails a high risk of ventricular arrhythmias of ventricular arrhythmias

CVP monitoring is desirable and should be maintained at a CVP monitoring is desirable and should be maintained at a high normal level to protect cardiac output during unexpected high normal level to protect cardiac output during unexpected peri-partum haemorrhage.peri-partum haemorrhage.

Regional anesthesia better avoided due to the risk of fall in Regional anesthesia better avoided due to the risk of fall in SVR, that is poorly tolerated in patients with a fixed cardiac SVR, that is poorly tolerated in patients with a fixed cardiac output.output.

Aortic regurge (AR):Aortic regurge (AR):

The pathophysiology is chronic The pathophysiology is chronic volume overload of the LV, with volume overload of the LV, with hypertrophy and dilatation and hypertrophy and dilatation and increase in LV End Diastolic increase in LV End Diastolic Volume (LVEDV), decrease in Volume (LVEDV), decrease in ejection fraction (EF) and signs and ejection fraction (EF) and signs and symptoms of pulmonary edema. symptoms of pulmonary edema.

Patients with aortic insufficiency Patients with aortic insufficiency tolerate pregnancy well as tolerate pregnancy well as pregnancy results in a modest pregnancy results in a modest increase in heart rate.increase in heart rate.

Anaesthetic considerations:Anaesthetic considerations:Prevent catecholamine – induced Prevent catecholamine – induced

increases in SVR due to pain, and increases in SVR due to pain, and avoid bradycardia, which may avoid bradycardia, which may increase regurgitant flow.increase regurgitant flow.

Anesthetic technique:Anesthetic technique: Epidural anaesthesia decreases the after-load, and Epidural anaesthesia decreases the after-load, and

prevents increases in SVR and acute LV volume prevents increases in SVR and acute LV volume overload in these patients. overload in these patients.

General anaesthesia may be induced with General anaesthesia may be induced with etomidateetomidate to prevent severe haemodynamic swings, followed to prevent severe haemodynamic swings, followed by intubation of the trachea with by intubation of the trachea with suxamethonium.suxamethonium.

Remi-fentanilRemi-fentanil can be used as an infusion during can be used as an infusion during induction and maintenance of anaesthesia and induction and maintenance of anaesthesia and provides haemodynamic stability. provides haemodynamic stability.

Neonatal respiratory depression is known to occur Neonatal respiratory depression is known to occur with remi-fentanil. It is treated with with remi-fentanil. It is treated with endotracheal endotracheal intubationintubation and no further medical management is and no further medical management is required for the neonate.required for the neonate.

Postoperative period in parturients with cardiac Postoperative period in parturients with cardiac disease:disease:

In the postoperative period, patients with severe In the postoperative period, patients with severe cardiac dysfunction delivered by Caesarean section cardiac dysfunction delivered by Caesarean section should be kept in the High Dependent Unit (HDU) / should be kept in the High Dependent Unit (HDU) / intensive care unit (ICU) for aggressive monitoring intensive care unit (ICU) for aggressive monitoring of fluid therapy, oxygen saturation and of fluid therapy, oxygen saturation and haemodynamics. During the first 24-72 hours haemodynamics. During the first 24-72 hours significant fluid shift occurs, which may lead to CCF.significant fluid shift occurs, which may lead to CCF.

Adequate post-operative analgesia should be Adequate post-operative analgesia should be provided in the form of continuous epidural provided in the form of continuous epidural analgesia or patient controlled IV analgesia. Early analgesia or patient controlled IV analgesia. Early ambulation to minimize the risk of deep venous ambulation to minimize the risk of deep venous thrombosis should be weighed against the risk of thrombosis should be weighed against the risk of cardiovascular stress.cardiovascular stress.

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