Cardiac Monitoring

Question 1

What does the wave a represent on the CVP waveform?

Answer 1

Atrial Contraction
-Occurs during end diastole

Question 2

What does the c wave represent on the CVP waveform?

Answer 2

Tricuspid valve elevation into the Right Atrium. (bulging)
-Occurs during early systole

Question 3

What does the v wave represent on the CVP waveform?

Answer 3

Back pressure wave from blood filling the right atrium.
-Systolic filling of the atrium.
-Occurs during late systole

Venous filling during Ventricular Systole

Question 4

What does the x descent represent on the CVP waveform?

Answer 4

Downward movement of the contracting right ventricle.
-Atrial relaxation
-Occurs during mid systole

Question 5

What does the y descent represent on the CVP waveform?

Answer 5

Tricuspid valve opens in early ventricular diastole
-Early ventricular filling
-Occurs in early diastole

EarlY diastolic emptYing into the RV.

Question 6

What are complications associated with CVP monitoring?

Answer 6

-Arterial puncture
-Hemothorax
-Pneumo (Most common with SC attempts)
-Pericardial effusion and tamponade
-Embolism
-Nerve injury (Brachial plexus, Stellate ganglion, Phrenic)
-Arrhythmias (Watch as guide wire is passed into RA/RV)

Question 7

How do you place a Swan Catheter?

Answer 7

-Placement is through central venous access (same as CVP line).
1) RA waveform is seen until the catheter crosses the tricuspid valve and enters RV 2) In RV, ↑ systolic pressure but little change in diastolic pressure. May see arrhythmias at this point.
3) When the catheter crosses the pulmonic valve →dicrotic notch appears on the pressure waveform along with an ↑ in diastolic pressure.
4) PCWP tracing is obtained by passing the catheter 3-5 cm further.

Question 8

Why should a PA Catheter be continuously monitored if present?

Answer 8

To ensure the catheter does not float to wedged position leading to pulmonary infarction.

Question 9

What are the absolute contraindications to PA catheter placement?

Answer 9

1) Tricuspid or pulmonic valvular stenosis → might ↓ flow through stenosis
-Don’t want to decrease flow through an already stenotic valve
2) RA/RV masses → mass may dislodge embolus
3) Tetralogy of Fallot → RV outflow tract is hypersensitive → Pulmonary artery catheterization could induce hypercyanotic episode by eliciting spasm of RV infundibulum

Question 10

What are the relative contraindications to PA catheter placement?

Answer 10

1) Severe arrhythmias
-Esp LBBB, Heart block…
-If the L bundle is already blocked, only electrical conduction working is Right bundle. A PA cath could hit the right bundle and turn you into a complete heart block.
2) Coagulopathy (catheter is coated in heparin to prevent thrombosis (foreign body)
3) Newly inserted pacer wires

Question 11

What are complications seen with PA Catheter placement?

Answer 11

-Arrhythmias are usually transient (can treat with lidocaine if necessary)
-Complete Heart Block
-Endobronchial hemorrhage
-Pulmonary infarction (Rare, can dec risk by continuously monitoring PAC to prevent inadvertent wedging)
-Catheter knotting & entrapment
-Valvular damage (Withdrawal of catheter with balloon inflated)
-Thrombocytopenia (↑ platelet consumption possibly due to heparin coated catheter)
-Thrombus formation (Pulmonary Artery Catheter is foreign body in the bloodstream)
-Balloon rupture (Inc. risk if catheter in for > few days or balloon inflated with >1.5cc of air)

Question 12

When could complete heart block occur with PA catheter placement?

Answer 12

-May occur with patients with LBBB.
-Pressure from catheter tip can cause transient RBBB as it passes through RV outflow tract

Have an external pacer available when placing PAC in patients with LBBB.

Question 13

Describe Endobronchial Hemorrhage.

Answer 13

-Risk factors include→ elderly, female, Pulm HTN, Mitral Stenosis, coagulopathy, distal placement of the catheter, balloon hyperinflation
-Balloon inflation in the distal PA probably accounts for most episodes of rupture high pressure generated by the balloon.
-Mortality 50-70%
-Bright red blood in ETT is hallmark sign

Question 14

What do you do with PA catheters and Hypothermic CPB?

Answer 14

-Hypothermic CPB is increased risk for catheter migration and stiffening.
-Pull catheter back when going on bypass
-Risk of causing pulmonary injury due to cold.

Question 15

What is important to know regarding PA catheter knotting & entrapment?

Answer 15

-Coiling of PAC in RV -do not advance catheter if distance does not correlate with waveform.
-Nml distance from RIJ is 50-55cm

Question 16

What is Near-Infrared Spectroscopy (NIRS)?

Answer 16

-Measures perfusion and O2 delivery (NOT the same thing as EEG or BIS).
-Used to detect problems with cannula or head position during CPB.
-Also used on CAEs: monitor cerebral SpO2 to ensure getting flow to the brain.
-Uses 2 sensors: right and left. (Midline forehead)
-NIR light is emitted from LED. Light gets reflected back to the detectors. Different tissues reflect or scatter.
-Monitor trends. 20% drop from baseline is considered significant and requires intervention.

Question 17

What are the interventions to improve Cerebral rSO2 (NIRS)?

Answer 17

-Rule out mechanical causes
-Increase O2 Supply
-Decrease O2 Demand

Question 18

What mechanical causes have to be ruled out with NIRS?

Answer 18

-Head position
-Cannula position

-Cannula could be placed wrong
-Could be missing one of the Carotids.

Question 19

What are ways to increase the supply of O2 (Improve Cerebral rSO2 with NIRS)?

Answer 19

Increase CO
Increase BP
Hgb (O2 carrying capacity)
Increase DO2 (inc FiO2)
Increase PaCO2
Increase Hct

Question 20

What are ways to decrease the O2 demand (Improve Cerebral rSO2 with NIRS)?

Answer 20

Increase anesthetic
Decrease temperature

Question 21

What is a transvenous pacer?

Answer 21

-Pacing wire is threaded down the jugular vein with an introducer like a PA line introducer
-Makes contact with the RV
-Wire attached to generator box
-Heart is paced

Question 22

What is a transcutaneous pacer?

Answer 22

Uses external pacing pads connected to device.

Question 23

What is a Transthoracic pacer?

Answer 23

-Using wires inserted during surgery (epicardial wires)
-Lead outside of the chest to a control box

Question 24

What does the First Letter indicate with pacing?

Answer 24

Chamber Paced.
-A = Atrium
-V = Ventricle
-D = Dual (A+V)

Question 25

What does the 2nd Letter indicate with pacing?

Answer 25

Chamber Sensed.
A= Atrium
V= Ventricle
D= Dual (A+V)
O= None

Question 26

What does the 3rd Letter indicate with pacing?

Answer 26

Response pacer makes to a sensed intrinsic beat.
I = Pacing Inhibited
T= Pacing Triggered
D= Dual (I+T)
O= None

Question 27

What does the 4th Letter indicate with pacing?

Answer 27

Programmability.
P = Rate & Output
M = Multiprogramable
C = Communicating
R = Rate adaptive
O = None

Question 28

What does the 5th Letter indicate with pacing?

Answer 28

Arrhythmia Control.
P = pacing
S= shock
D= Dual (P+S)
O = None

Question 29

What is asynchronous mode?

Answer 29

Decreases sensitivity of the box.
-No sensing to detect intrinsic R waves.
-Can compete with pt’s HR and cause VT/VF

Question 30

What is synchronous mode?

Answer 30

Increases sensitivity of the box.
-Detects intrinsic heart depolarization -> pacer will either be activated or inhibited.

Question 31

How do you troubleshoot Failure to Capture?

Answer 31

-Will see random spike with no QRS following it.
-Turn up the mAs.

Question 32

How do you troubleshoot Failure to Sense?

Answer 32

-Will see spikes during native heart rhythm
-Increase sensitivity (lower the fence)
-Make it MORE sensitive