Download Cardiac Assessment in the Operating Room (Part 1)

Cardiac Assessment in the
Operating Room
Allison K. Cabalka, MD
Associate Professor of Pediatrics
Consultant, Pediatric Cardiology
Mayo Clinic
Objectives
1. Rhythm issues encountered in the
operating room
2. Discuss the use of echocardiography
in the OR
Objectives
1. Rhythm issues encountered in the
operating room
2. Discuss the use of echocardiography
in the OR
Rhythm Issues in the OR
• Tachyarrhythmias
– Supraventricular tachycardia (SVT)
– Atrial flutter/fibrillation (AF/Fib)
– VT/VF
• Junctional Rhythm
– Too fast OR too slow
• Conduction abnormalities
– Advanced 2° or 3° (complete) heart block
Diagnosis: Monitor Strips
•
•
•
•
Evaluate rate, regularity, rhythm
Is every QRS preceded by a P wave?
Narrow or wide complex?
What is the rate compared to what you
expect?
Normal Sinus Rhythm
• Look for a P wave in front of every QRS
– But not so far in front that it is ‘behind’
• Change leads to be sure
Junctional Ectopic Tachycardia
• Common post-operative arrhythmia
– Originates from AV node
– Particularly in postop TOF/Fontan patient
• Heart rates >150 beats per minute
• Loss of AV synchrony
– Look for AV dissociation
• Slower P wave rate
– Easy to diagnose with pacing wires postop
Junctional Ectopic Tachycardia
Junctional Ectopic Tachycardia
• Treat with IV Amiodarone
– Load 5-10 mg/kg IV
– Drip infusion of total of 10 mg/kg/24 hrs
• Alternative or complimentary
– Cooling
– Reduction of sympathetic stimulation
(Epinephrine)
– Correct Ca++ and Mg+ levels
– Volume replacement
AV Node Independent Re-Entry
• Atrial fibrillation
– Irregularly irregular
– No organized atrial contractility
– Easy to see on direct visualization or by
TEE
• Atrial flutter
– Regular atrial rate, variable conduction
– Also can be seen by TEE or visualization
Diagnosis
AV node independent re-entry
Atrial flutter
Complete AV Block
• Common postop complication
– 3.7-6% incidence of surgical postoperative
complete AV block
– Recognition of AV dissociation with slower
escape rate
• P wave rate is greater than QRS rate
• Otherwise this may be AV dissociation with
accelerated junctional rhythm!
Postoperative Complete AVB
Complete AV Block
• Temporary pacing wires used in interval
– Daily threshold checks
– Pulse oximeter monitoring
• ECG monitor picks up pacing spike
• Recommendation for observation to see
if resolves within 7-10 days
– If not, permanent pacing system warranted
Objectives
1. Rhythm issues encountered in the
operating room
2. Discuss the use of echocardiography
in the OR
Echo: Background
• Echo has been utilized in the OR for the last
20 years
– Miniaturization of probe allows application of TEE
to all pts coming to the OR for CHD surgery
• Mini-TEE, mini-multiplane, Acunav longitudinal imaging
• Performed by either the cardiologist or the
anesthesiologist
– The key to this is proper training and experience
with the diagnosis and evaluation of congenital
heart disease
Echo in the OR
• Echocardiography is a key part of noninvasive imaging in the operating room
– Evaluate the preoperative anatomy
• Be sure nothing was ‘missed’
• Confirm the surgical plan
– Evaluate the repair before leaving the OR
• Residual defects
• Guide revision
• Available modalities: TTE or Epicardial
Randolph G, Hagler D et al J Thorac Cardiovasc Surg 2003
Utility of TEE?
• Mayo Clinic: 1002 pts during CHD surgery
– Mean age 9 yrs; range 4d to 85 yrs
• Prebypass or postbypass major impact in
~14% of cases
– 52 pts had immediate revision (“cost-effective”)
• Most useful in complex valve repairs or in
complex outflow tract reconstructions
– Less impact in PAPVR, ASD, simple tricuspid
valve repair, aortic arch repair
Echo in the OR
• Pre-operative echo evaluation
– Document baseline ventricular function
– Assessment of AV valve function
– Confirmation of anatomy and surgical plan
– Are there any additional defects that need
to be addressed surgically?
• Especially atrial septal defect
• ?Bubble study to confirm intact atrial septum
Post-Bypass Echo: Function
• Evaluation of air in the left heart
– Adequate venting
• Ventricular function
– Comparison with pre-bypass imaging
– Evaluation of intervention with medications
and inotropic support
• Volume status
– Is the heart underfilled or distended?
Post-Bypass Echo: Anatomy
• Critical for evaluation of residual defects
– Outflow tract stenosis
• Alignment as parallel as possible (often
transgastric views needed)
– Valve repair
• Be sure volume status is sufficient, BP stable
– Residual shunts
– Atrioventricular valve
• Critical if repair undertaken
• Leaflet motion/paravalve leak in replacement
Post-operative Evaluation
• Echo can be correlated with surgeon’s
evaluation
– Pressure line monitoring
• i.e. RV to PA pressure post-TOF repair
– Blood gas sampling for shunt
• i.e. SVC line and PA blood gas sampling
• Review of TEE and applications to
pediatric CHD
– Intraoperative TEE
– Catheterization and TEE guidance
– TEE during non-cardiac surgery in the
CHD patient
• Description of typical probe positions
and views obtained
Kamra K, et al, Pediatr Anes, 2011
Mid-Esophageal View (0-30º)
• Typical 4-chamber
view
– AV valves
• Ventricular function
• Atrial septum
• Segments of
ventricular septum
– Inlet
Mid-Esophageal View (60-90º)
• Typical long-axis
view
– AV valves in different
plane
• Ventricular function
• Atrial septum
• Segments of
ventricular septum
• Outflow tracts
– RVOT and LVOT
Mid-Esophageal (30º)
• Typical view to
see aortic leaflets
• Coronary origins
• Proximal RVOT
and pulmonary
valve
• PA bifurcation
Deep Trans-Gastric View (0º)
• Left ventricle
• LVOT
• Right ventricle
(rotate rightward)
• RVOT
• Ventricular
function
Deep Trans-Gastric View (90º)
• Anteflex probe and
rotate right/left
• LVOT and aortic
valve
• Outlet ventricular
septum
• Tricuspid valve
inflow/function
Epicardial Echo
• When TEE not available
• Standard use transthoracic probes
– Sterile sleeve
– Surgeon images in epicardial position
• Image orientation may not be quite
‘standard’
– Understanding of baseline anatomy and
surgical repair
Epicardial Echo
• Reported use of
Epicardial or
Epi+TEE in 8% of
CHD OR cases
• May be useful for
difficult to see
‘areas’ such as PA
branches and
coronaries
Dragalescu A, et.al, JCVTS 2011 in press
Use of Epicardial Echo JCVTS
Hospital for Sick Children
Toronto
2007-2009
Epicardial Echo
RVOT Free wall:
“PLAX view”
Aorto-PA Sulcus:
“PLAX view”
Epicardial Echo
RVOT Free wall:
“PLAX view”
Aorto-PA Sulcus:
“PLAX view”
Epicardial Echo
RV Free wall:
“Subcostal view”
SVC-Aorto Sulcus:
“Subcostal long axis”
Epicardial Echo
RV Free wall:
“Subcostal view”
SVC-Aorto Sulcus:
“Subcostal long axis”
Conclusion
• One must pay careful attention to
rhythm issues in the operating room
– Most will involve a decision about
placement of pacing wires
• Intraoperative echo is very useful for pre
and post-bypass evaluation of anatomy,
surgical repair and cardiac function
– Epicardial echo may be used if TEE is
unavailable