Echocardiography Management for Patients Requiring Care for Non-Cardiac Surgery

Step 1: Patient selection

The first step in the EGHEM/EGAM process is appropriate patient selection. Patients who have any of the following cardiovascular risk factors and/or comorbidities and are scheduled for a non-cardiac surgery are candidates for EGHEM/EGAM:

1. Urology/gynecology/General surgical patient
2. Non-cardiac surgical population
3. age 65 years or older, OR 19 years or older and one of the following risk factors:
4. Hypertension (HTN)
5. Diabetes
6. Obesity (body mass index [BMI] >35)
7. Renal insufficiency
8. Tobacco usage
9. Hypercholesterolemia
10. Sleep apnea/heavy snoring at night
11. Clinical diagnosis of congestive heart failure (CHF) as defined by:

• Dyspnea on exertion
• Paroxysmal nocturnal dyspnea
• Orthopnea
• Elevated jugular venous pressure
• Pulmonary rales
• Third heart sound
• Cardiomegaly or pulmonary edema on chest x-ray
• Peripheral edema
• Hepatomegaly
• Pleural effusion

1. Palpitations/irregular heart beats
2. Chest pain at rest and or exercise
3. Murmur on examination
4. Known coronary artery disease (CAD)/stents/coronary artery bypass graft (CABG)
5. Known valvular disease
6. Known stroke or transient ischemic attacks (TIA) Standard Medical Care Step 2: Pre-op assessment

Step 2 in the EGAM process involves a bedside, transthoracic echocardiography (TTE) pre-op assessment. The pre-op TTE should be performed by one of the co-investigators, and take less than 10 minutes to complete. The information acquired by TTE during the pre-op assessment should include the following five evaluations, in order of importance:

1. Cardiac output on the left side of the heart using spectral Doppler measurements;
2. Left ventricular outflow tract (LVOT) velocity time integral (VTI)
3. Heart rate
4. Filling pressures on the left side of the heart using spectral Doppler measurements;
5. The pulmonary venous flow pattern defined as co-dominant, systolic dominant or diastolic dominant
6. The mitral inflow pattern defined as normal, impaired relaxation, pseudonormal or restrictive
7. The E/e' ratio of velocities
8. Mitral valve structure and function;
9. Aortic valve structure and function; and
10. Biventricular contractility.

These evaluations are performed using the following TTE views:

1. Parasternal (PS) window: With the patient in the left lateral decubitus position, the TTE probe is placed on the 3rd left intercostal space next to the sternum; the light on the probe should be directed toward the patient's right shoulder. The 2-dimensional image of the long axis (LAX) should be acquired first. In this view, the following are evaluated:

• Color Doppler on aortic valve (AV) and mitral valve (MV)
• E-point septal separation (EPSS) To evaluate the PS short axis (SAX), the probe should be rotated clockwise 60 degrees. The 2-dimensional view should be obtained at the mid-papillary level.

1. Apical window: With the patient in the same left, lateral, decubitus position, the probe is placed between the 5th and 6th intercostal space on the left side, close to the nipple line. The light on the probe should be directed toward the floor or the bed for the 4-chamber view. The following assessments should be performed in the 4-chamber view:

• Two-dimensional image;
• Pulsed-wave (PW) Doppler in the right upper pulmonary vein;
• PW Doppler at the tip of the MV;
• PW Doppler on the MV annulus for tissue Doppler;
• Color Doppler on the tricuspid valve (TV) and MV if necessary based on the PS LAX window.

For the apical LAX, the probe should be rotated counterclockwise so that the light is directed toward the patient's right shoulder. In the LAX view, velocity time integrals (VTIs) using PW in the left ventricular outflow track (LVOT) and continuous wave (CW) at the level of the AV should be acquired.

1. Subcostal window: With the patient supine, the TTE probe is placed under the right costal ridge and directed toward the heart. The light should be directed toward the sonographer (toward the patient's left) to assess the 4-chamber view.

For the subcostal inferior vena cava (IVC) view, the probe should be slightly rotated counterclockwise until the IVC can be assessed.

Standard Medical Care Step 3: Management strategies Step 3 in the EGHEM/EGAM process is to define patient management strategies based on the pre-op TTE assessment. The main goals of patient management are to maintain normal cardiac output and filling pressure. Primary and secondary findings and the associated EGAM strategies to achieve these goals are outlined in Table 1 and Table 2, respectively.

Table 1: Primary findings and associated management strategy to maintain normal cardiac output and filling pressure.

Echo-Generated Findings EGHEM/EGAM Strategy Cardiac output status Filling pressure status Normal High Preload reduction Low Normal Afterload reduction Low High Afterload and preload reduction High High Preload reduction High Normal or low Increase preload

Table 2: Secondary findings and associated management strategy to optimize patient management.

Echo-Generated Finding EGHEM/EGAM Strategy Filling Pressure Other High Aortic stenosis Preload reduction Normal Aortic stenosis Safe for afterload reduction

• Mitral regurgitation Afterload reduction
• Low contractility Inotropic support
• Suspected or confirmed CAD Maintain heart rate in the 50 - 60 bpm range right ventricle (RV) volume overload Preload reduction RV pressure overload Pulmonary afterload reduction Standard Medical Care Step 4: Ongoing intra-operative assessment Based on the appropriate EGAM strategy defined in Step 3, either TEE or TTE should be used during the surgical procedure for the ongoing patient assessment every 15 to 20 minutes. The PI or Secondary Investigator will determine whether a TEE or TTE should be conducted intra-operatively. The results of these tests will be used for research purposes. During surgery: fluid administration, afterload adjustments, and supported contractility can be implemented to optimize patient management. It is difficult to assess cardiac output with the current standard medical care without invasive monitoring. There is minimal risk if the physician gets distracted by the echocardiogram or the algorithm of the study however it is unlikely this tool would be a distraction to the physician as it is monitoring the patient.