Mod1: Monitoring for Cardiac Surgery - EKG Flashcards
Monitoring for Cardiac Surgery
Why should invasive monitoring be consistently utilized in pts with significant CV dz?
Hemodynamic changes can occur rapidly
Corrective measures need to be instituted promptly.
Monitoring for Cardiac Surgery
True or False: ANESTHETIC MANAGEMENT should be tailored to allow for the measurement of physiologic parameters in order to maintain hemodynamic stability to reduce perioperative complications
True
Monitoring for Cardiac Surgery - ANESTHETIC MANAGEMENT
What are ASA minimal monitoring standards?
Oxygenation
Ventilation
Circulation
**Temperature
These standards could be exceeded
(You could use more than what’s required)
However the basic monitoring must always be continiously maintained
(with the exception of Temperature)
Monitoring for Cardiac Surgery - ANESTHETIC MANAGEMENT
Temperature does not necessarily need to be monitored continiously; except in which case?
When the anesthesia provider anticipates clinically significant changes in body temperature
Otherwise, it could just be measured regularly
Monitoring for Cardiac Surgery - ANESTHETIC MANAGEMENT
True or False: The most invasive form of monitoring is the preferred choice for the anesthesia plan of care
False
The least invasive forms of monitoring that will provide and idea of the total picture of the pt is considered safe for the anesthetic plan
Monitoring for Cardiac Surgery
Which factors make monitoring for Cardiac Surgery CHALLENGING?
Risk of placing monitors
(Pneumothorax, ischemic arm, bleeding etc.)
Acting on erroneous/incorrect results
Over treatment
Distraction d/t too many monitored variables
Cost
Monitoring for Cardiac Surgery
ULTIMATE GOALS:
Improve patient outcome
Minimize Risk
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
What are the two meanings of “positive” and “negative” with regard to THREE-LEAD SYSTEM?
- Deflection of the EKG tracing
- Direction of depolarization
Electrocardiography- THREE-LEAD SYSTEM (Bipolar lead)
Upward deflection on isoelectric line means:
Positive deflection of the EKG tracing
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
Downward deflection on EKG isoelectric line means:
Negative Deflection of the EKG tracing
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
What does a Positive Direction (or deflection) of the electrical activity means?
Depolarization is going towards that electrode
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
What does a negative Direction (or deflection) of the electrical activity means?
Depolarization is moving away from that electrode
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How does electricity moves in Lead I between RA and LA?
Lead I (-) RA => (+) LA
We know this because the atria depolarizes first, followed by the ventricles
The LA can be either (+) in lead I or (-) in lead III depending on which lead is used to measure
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How does electricity moves in Lead II between RA and LL?
Lead II (-) RA => (+) LL
The LL is always (+) because depolarization is always going towards it
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How does electricity moves in Lead III between LA and LL?
Lead III (-) LA => (+) LL
The LL is always (+) because depolarization is always going towards it
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How is the heart observed in Lead I?
The heart in observed from the LA, looking at the RA
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How is the heart observed in Lead II?
The heart in observed from the LL, looking at the RA
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How is the heart observed in Lead III?
The heart in observed from the LL, looking at the LA
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
What’s the Standard of Care Monitor (AANA/ASA Monitoring Guidelines) with regards to Electrocardiography?
Every pt receiving anesthesia must have Electrocardiography continiuously monitored from the begining of care till the time they are prepared to leave the anesthetizing location
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
Why is the use of THREE-LEAD SYSTEM (Bipolar lead) limited in myocardial ischemia
It provides a narrow picture of myocardial electrical activity
It uses a single positive electrode and a single negative electrode between which electrical potential is measured
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How many limb electrodes?
3 limb electrodes
RA (White)
LA (Black)
LL (Red)
Use of a single positive electrode and a single negative electrode between which electrical potential is measured.
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
How many views (leads)
3 views (leads)
Lead I : RA -; LA +
Lead II: RA -; LL +
Lead III: LA -; LL +
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
True or False: THREE-LEAD SYSTEM (Bipolar lead) monitors Inferior & lateral myocardial walls for ischemia
True
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
True or False: THREE-LEAD SYSTEM (Bipolar lead) can also monitor ANTERIOR OR POSTERIOR walls
False
THREE-LEAD SYSTEM (Bipolar lead) cannot monitor ANTERIOR OR POSTERIOR walls
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
In the THREE-LEAD SYSTEM, what’s the more disirable lead and why?
Lead II is the more desirable lead, because
it is in line with the vector forces of the heart, resulting in
large p-waves and large QRS complexes, and making it
easier to dignose dysrhythmias
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
What’s the positive electrode in an Augmented Unipolar lead
Each of the limb lead
(RA, LA, LL)
•Augmented leads (aVR, aVL, aVF)
•Termed “unipolar” because the one positive pole is at each limb and the negative pole is the center of the heart
•“Augmented” because they have a low electrical potential and must be augmented 1.5 times
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
What’s the negative electrode in Augmanted Unipolar lead?
The center of the heart
(which is theoretically electrically neutral)
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
Which leads monitor inferior wall?
II, III, AVF
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
Which leads monitor the lateral wall?
I & AVL
Electrocardiography - THREE-LEAD SYSTEM (Bipolar lead)
Which lead in the THREE-LEAD SYSTEM (I, II, II, avL, avF, avR) monitors the anterior or posterior walls?
None
Electrocardiography - MODIFIED THREE-LEAD SYSTEM
What’s the other name for the MODIFIED THREE-LEAD SYSTEM, and why is it called that?
Lewis Lead (S5-Lead)
Because it was created by Thomas Lewis
Electrocardiography - MODIFIED THREE-LEAD SYSTEM
Thomas Lewis created the MODIFIED THREE-LEAD SYSTEM for what purpose?
In response to decrease in p-wave amplitude with traditional EKG placement
The thinking was that by repositioning the lead, the p-wave height will be maximized, so that
Atrial arrhythmias could be quickly identified
Electrocardiography - MODIFIED THREE-LEAD SYSTEM
How is the MODIFIED THREE-LEAD SYSTEM used in practice?
It’s a modification of standard bipolar limb lead system
Place LA electrode in the V1 position,
then select the lead I on the monitor
Rarely used in practice because more advanced technology has been discovered
Electrocardiography - V1 FIVE-LEAD SYSTEM
Researchers began challenging the effectiveness of 3-lead EKG and their ability to diagnose and distinguish which two arrhythmias?
SVT and VT
SVT and VT were correctly identified only about a third of the time
Electrocardiography - V1 FIVE-LEAD SYSTEM
Why was the 3-lead EKG not effectiveness in diagnosing or distinguish SVT vs VT?
The traditional EKG positions don’t offer enough amplitude on the p-wave to be able to distinguish SVT from VT
Electrocardiography - V1 FIVE-LEAD SYSTEM
How frequently did the Use of a 12 lead EKG resulted in correct identification of SVT vs VT?
90% of the time
Electrocardiography - V1 FIVE-LEAD SYSTEM
Which lead in the V1 FIVE-LEAD SYSTEM was found to be the single best lead in determining SVT from VT
Lead V1
Could be paired with the modified-lead placement
Came out superior in its ability to distinguish SVT from VT
The 5-lead with V1 position is most effective in viewing ventricular activity
When compared to modified lead placement, V1 more superior
Electrocardiography - V1 FIVE-LEAD SYSTEM
Which lead position is most effective in viewing ventricular activity?
A. The 5-lead with V1 position
B. The modified lead placement
A. The 5-lead with V1 position
B. The modified lead placement
- Because V1 is the best lead to view ventricular activity*
- This is the reason why the modified lead placement isn’t used*
- P-wave are also bigger and ….(inaudible!!!!)*
Electrocardiography - V1 FIVE-LEAD SYSTEM
In the V1 FIVE-LEAD SYSTEM, where is the V1 lead placed?
4th ICS, RSB
Electrocardiography - FIVE-LEAD SYSTEM
Which 7 leads can be viewed and recorded simultaneously with the FIVE-LEAD SYSTEM?
6 standard limb leads (I,II,III, aVR, aVF, aVL)
1 precordial/unipolar lead (brown lead - Could)
Brown lead could be placed in any precordial position, V1 through V5
Electrocardiography - FIVE-LEAD SYSTEM
What does precordial lead placement depends on?
Depends on
“What needs to me monitored in the pt”
Electrocardiography - FIVE-LEAD SYSTEM
What’s the standard precordial lead for cardiovascular surgery? why?
V5
Best to assess ST segment depression
Electrocardiography - FIVE-LEAD SYSTEM
Where is V5 placed?
5 ICS anterior axillary line
Electrocardiography - FIVE-LEAD SYSTEM
What is a major monitoring benefits of the FIVE-LEAD SYSTEM over the Three-lead system?
With the addition of only two electrodes in the ECG system, as opposed to the 3 electrodes in the Three-lead system, up to 7 different leads can be monitores simultatneously
This allows one to monitor several areas of the heart for ischemia
Monitors Lateral, inferior & ANTERIOR myocardial walls monitored for ischemia
or to establish a diagnosis between atrial and ventricular arrythmias
Diagnosis atrial or ventricular arrhythmias
Electrocardiography - FIVE-LEAD SYSTEM
True or False: The FIVE-LEAD SYSTEM allows to monitor Posterior wall?
False
NOT POSTERIOR
Electrocardiography - FIVE-LEAD SYSTEM
Which leads have the Greatest sensitivity in the detection of ischemia?
Lead V5 (75%)
Followed by Lead V4 (61%)
Electrocardiography - FIVE-LEAD SYSTEM
Which is a benefit of Monitoring leads V4 & V5 simultaneously in the detection of ischemia
Increases sensitivity to ischemia to 80%
Electrocardiography - FIVE-LEAD SYSTEM
Which is a benefit of Monitoring V5 & Lead II simultaneously in the detection of intraoperative ischemic events?
Enhances detection of intraoperative ischemic events (90%)
Electrocardiography - FIVE-LEAD SYSTEM
Which is a benefit of Monitoring 3 leads (II, V4 & V5) simultaneously in the detection of intraoperative ischemic events?
Increases sensitivity (98%)
Electrocardiography - FIVE-LEAD SYSTEM
True or False: Modern ECG monitors incapable of simultaneous display of more than one precordial lead
True
This is significant because lead II monitoring only recognizes ischemia in 35% of the cases
Electrocardiography - FIVE-LEAD SYSTEM
True or False: This is significant because lead II monitoring only recognizes ischemia in 35% of the cases
True
Electrocardiography - FIVE-LEAD SYSTEM
Which leads look at the inferior wall ischemia (RCA distribution), and at the superior wall for atrial arrhythmias
Lead II, III, & aVF
Electrocardiography - FIVE-LEAD SYSTEM
Which leads look at the Lateral wall left ventricle (Circumflex)
Lead I & aVL
Electrocardiography - FIVE-LEAD SYSTEM
Which leads look at the Anterior wall ischemia (LAD artery distribution)?
Lead V5
Electrocardiography - 12 LEAD SYSTEM
Which leads constitute the 12 LEAD SYSTEM?
Precordial leads (V1 through V6), and
Unipolar leads that take a perpendicular look at the heart muscle directly underneath the leads
Electrocardiography - 12 LEAD SYSTEM
Which leads look at the septum?
V1 & V2
Electrocardiography - 12 LEAD SYSTEM
Which leads look at the Anterior wall?
V3 & V4
Electrocardiography - 12 LEAD SYSTEM
Which leads look at the Lateral wall?
V5 & V6
Electrocardiography - 12 LEAD SYSTEM
Since none of the leads in the 12 LEAD SYSTEM will monitor the posterior heart, how can we assess changes in the posterior heart?
Must look at reciprocal changes in V1 & V2
