Download Practical Approach to Anesthesia for Parturient with Cardiac Disease

Outline

The critical physiological changes of pregnancy.

Predictors of cardiac events during pregnancy

Risk of cardiovascular complications during
pregnancy

Anesthetic management parturient with valvular
diseases.
What are the critical physiological changes
of pregnancy that affects a parturient with
cardiac disease ?

50% increase in the blood volume

40% increase in cardiac output

25% increase in heart rate to
approximately 80-100 beats/min.

Reduced systemic vascular resistance
and pulmonary vascular resistance.

Labor and delivery itself imposes
approximately 50% increase in CO and
oxygen demand.
The main predictors of cardiac
events during pregnancy are:

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Prior cardiac events: (heart failure, transient
ischemic attack, stroke, or dysrrhythmias).
Baseline New York Heart association
functional class≥ II or the presence of
cyanosis.
Left heart obstruction: (mitral valve area ≤
2cm2, aortic valve area ≤ 1.5 cm2, or left
ventricular outflow tract gradient ≥ 30mmHg by
echocardiography).
Reduced left ventricular function (ejection
fraction ≤ 40%).
Many of the signs and symptoms of normal
pregnancy can mimic those of cardiac disease.
For example: Dyspnea due to LV failure
From Labored breathing typical
of normal pregnancy
Leg edema due to CHF
From Venous stasis due to
aortocaval compression
heart murmurs due to
organic lesions
from those due to increased
blood flow
Rotation of the maternal
heart, because of
elevation of the diaphragm
from cardiac hypertrophy.
Circulatory Changes and Co.Existing
HeartDisease
 C.O: 30-50% during gestation
30-45% during labor
After delivery
50%of patients with symptoms of heart disease
during minimal activity or at rest when not
pregnant develop CHF during pregnancy.
Drug administered to the patients with
heart disease may affect fetus:
For Example: Lidocaine
 neonatal depresion
β-blockers  fetal bradycardia and
hypoglycemia
Digoxin  longer elimination halflife in fetus
Electrical cardioversion  no
adverse effects on the fetus
Risk of cardiovascular
complications during pregnancy
Risk of
cardiovascular
complications
during pregnancy
Low risk
of
complications (≤ 1%)
Intermediate risk
of
complications (5-15%)
High risk
of
complications
or death (≥25%)

Low risk of complications (≤ 1%):
Corrected tetralogy of fallot
 Atrial septal defect
 Ventricular septal defect
 Patent ductus arteriosus
 Mild pulmonic or tricuspid valve disease
 Mitral stenosis (NYHA class I, II)
 Mild regurgitant valve lesion
 Bioprosthetic valve
 Compensated heart failure (NYHA class I, II)


Intermediate risk of complications (515%):
Mechanical valve prosthesis
 Aortic stenosis (mild to moderate)
 Mitral stenosis with atrial fibrillation
 Mitral stenosis (NYHA class III, IV)
 Uncorrected cyanotic congenital heart
disease (tetralogy of fallot)
 Uncorrected coarctation of the aorta
 Previous myocardial infarction


High risk of complications or death
(≥25%):
Pulmonary hypertension (severe)
 Eisenminger syndrome
 Marfan disease with aortic root involvement
 Peripartum cardiomyopathy
 Severe aortic stenosis
 NYHA class IV heart failure

One of the most common maternal heart diseases
are:
Acquired valvular heart diseases
included: MS (the most common type of cardiac
valvular defect in pregnant(
MR (the second most common cardiac
valvular defect seen in pregnancy)
AS ( rarely seen in pregnancy)
AI ( is not common in pregnancy)
Valvular Heart Disease:
In general regurgitant valvular lesions
are well tolerated during pregnancy,
where as stenotic lesions have a
greater potential for decompensation.
 Pregnant patients with valvular heart
disease can expect to have worsening
of their New York Heart Association
(NYHA) functional class, while others
may have adverse foetal outcome i.e.
preterm birth or still birth.

Mitral stenosis (MS):

Normal mitral valve orifice has a
surface area of4-6cms2, in mild
stenosis the valve area (1.5 to 3 cm2),
moderate mitral stenosis the valve
area (1.1 to 1.5 cm2), while severe
mitral stenosis the valve area (less
than 1cm2).
Mitral stenosis (cont.):

Mitral valve
stenosis prevents
emptying of the
left atrium (LA),
with increased left
atrial and
pulmonary artery
pressure, resulting
in dyspnoea,
haemoptysis and
pulmonary
oedema.
Peripartum considerations:
The hyperdynamic state of pregnancy is
poorly tolerated by women with
severe mitral stenosis:
 Increased plasma volume can cause
pulmonary edema and worsen the left
atrial enlargement.
 Tachycardia decreases the left
ventricular diastolic filling through
the stenotic valve.
 AF is common with MS, with loss of
the atrial kick; which accounts for =
30% of the left ventricular stroke
volume. Medical management of AF
by a beta-adrenergic blocking agent.
Anesthetic considerations:
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Should be based on the severity of the
lesion,( according to the valve area, and the
hemodynamic stability of the patient).
Avoid increased heart rate.
Maintain venous return and SVR.
Avoid aorto-caval compression.
Treat atrial fibrillation (AF) aggressively.
Maintain sinus rhythm.
Prevent pain, hypoxaemia, hypercarbia and
acidosis as these can increase PVR.
Pregnant patients with Mitral Stenosis
There are increased incidence of:
Pulmonary edema
Atrial fibrilation
Paroxismal atrial tachycardia
Control of the heart rate is critical
Excessive perioperative fluid administration
Trendelenburg position
Autotransfusion (via uterine contraction)  central
blood volume  CHF.
Monitoring
Invasive monitoring is usually not necessary in the
absence of cardiac symptoms.
Exceptions are parturients with:
Pulmonary hypertension
Right-to-left intracardiac shunts
Coarctation of the aorta
invasive cardiac monitoring should be continued
for 48 hours after delivery
Anesthetic technique
Spinal anesthesia
For most elective and urgent C/S
Epidural anesthesia
Decrease likelihood of hypotension
Combined Spinal-Epidural anesthesia
General anesthesia
Neuraxial anesthesia techniques
Advantages :
-A decreased risk of failed intubation and aspiration
of gastric contents
-Avoidance of depressant agents
-The ability of the mother to remain awake
and enjoy the birthing experience
- Reduced blood loss
Disadvantages:
- Dural puncture
- Reduced SVR & BP
- Slower onset
General anesthesia technique
Advantages:
- Speed of induction
- Control of the airway
- Superior homodynamic
Disadvantages:
- Failed intubation
- Pulmonary aspiration of gastric contents
- Neonatal depression
- Maternal awareness
Mitral Regurgitation (MR):

Regurgitation of blood
through an incompetent mitral
valve  chronic volume over
load and dilatation of the LA

In the acute type, there is
acute pulmonary congestion
and pulmonary edema results.

If the patient survives this
episode of acute mitral
regurgitation, pulmonary
artery pressure continues to
increase and right heart
failure occurs.
Anesthetic consideration:
Primary considerations are:
 Maintain slightly increased heart rate
 Prevent increase in SVR.
 Prevent
hypoxemia,
hypercarbia,
acidosis which may increase PVR.
 Avoid aortocaval compression and
myocardial depression.
Aortic stenosis (AS):
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The pathophysiology of severe AS entail a
narrowing of the valve to less than 1 cm2
associated with a trans-valvular gradient of
50mmHg with significant increase in after
load to the LV.
A valvular gradient which exceeds 100mmHg
carries an increased risk of myocardial
ischemia as the LV hypertrophies
significantly.
In aortic stenosis transvalvular gradient
increases progressively throughout
pregnancy, due to increasing blood volume
and decreasing SVR
Anaesthetic considerations:
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Avoid tachycardia (decrease
time for coronary perfusion of
the hypertrophied LV), and
bradycardia (slow heart rate
decreases CO).
Maintain intravascular volume
and venous return.
Avoid aortocaval compression
and myocardial depression.
Arrhythmias are not well
tolerated and should be
promptly treated.
Patients with trans-valvular
gradient more than 50mmHg
with symptomatic AS should
have invasive monitoring i.e.
A-line and PA catheter in place.
Aortic regurge (AR):

The pathophysiology is chronic
volume overload of the LV, with
hypertrophy and dilatation and
increase in LV End Diastolic
Volume (LVEDV), decrease in
ejection fraction (EF) and signs and
symptoms of pulmonary edema.

Patients with aortic insufficiency
tolerate pregnancy well as
pregnancy results in a modest
increase in heart rate.
Anaesthetic considerations:
 Prevent catecholamine – induced
increases in SVR due to pain, and
avoid bradycardia, which may
increase regurgitant flow.