cardiac assessment in the operating room

Cardiac Assessment in the Cardiac Assessment in the Operating RoomOperating 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

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


• 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

DiagnosisAV 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 non-invasive 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

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

Randolph G, Hagler D et al J Thorac Cardiovasc Surg 2003

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

Use of Epicardial Echo JCVTSHospital for Sick Children

Toronto 2007-2009

Dragalescu A, et.al, JCVTS 2011 in press

Epicardial EchoRVOT Free wall:“PLAX view”

Aorto-PA Sulcus:“PLAX view”

Epicardial EchoRV 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

cardiac assessment in the operating room

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