Exam 7 - Vent / Suction / Prime Flashcards
1
Q
Normal return to Ventricles
A
- Right: systemic venous return coronary sinus drainage \+/- small cardiac vein - Left: Bronchial circulation - Both: Thebesian veins Cardioplegia
2
Q
Abnormal return to Ventricles
A
- Right: LSVC
Atrial/Ventricular septal defects
-Left: PDA (bypass lungs)
Systemic to PA shunt
Anomalous systemic venous drainage to heart
AI
Atrial/ventricular septal defects
3
Q
Bronchial circulation
A
- nutrients to lungs
- Normal: 1-3% CO
- can be up to 10% if COPD / lung infection / lung inflammation - Bronchial veins empty to pulmonary veins then back to LA
4
Q
Small cardiac vein
A
- usually empties to coronary sinus but may also to:
- RA / middle cardiac vein / or may not be there
5
Q
Thebesian Veins
A
- Spongy veins in endocardium of heart
- blood bleeds through these into all 4 chambers of heart
- only minor blood return to heart
6
Q
Antegrade Cardioplegia
A
- Left coronary
- drains into coronary sinus and RA - Right coronary
- drains into RA via small cardiac vein - Some flow return to all chambers via thebesian veins
7
Q
Retrograde Cardioplegia
A
- Most empty into aortic root / L ventricle via left coronary ostia
- not that good at protecting heart (not protecting R heart)
- can’t do at same time as antegrade…heart will blow
8
Q
LSVC
A
- normally drains into coronary sinus (92%)
- 0.3-0.5% of pop but 2-10% of patients w/ heart disease
- Problem if opening right heart or bi-caval cannulation
- Problem w/ retrograde cardioplegia
- delivery up the LSVC and/or dilution of solution from return
- Failure of L. Brachiocephalic vein to develop
- Failure of L common cardinal vein to disappear
9
Q
Blalock-Taussig Shunt
A
- Right subclavian to Right PA
10
Q
Waterston Shunt
A
- Posterior ascending aorta to anterior R PA
11
Q
AI
A
- not a problem if heart is beating
- X-clamp stops regurgitation from arterial cannula - can occur during cardioplegia delivery (low aortic root pressure)
- can cause LV distension in fib or arrested heart
- makes putting in balloon pump not worth it
12
Q
Vent purpose
A
- prevent ventricular distension
- improve exposure
- aid in myocardial protection
- remove air
- prevent pulmonary venous hypertension
13
Q
Where to vent
A
- Both R and L ventricles
- PA vent used if blood is coming back to RV
14
Q
Myocardial protection
A
- Keep heart empty
- Decompression: reduces resting O2 use by reducing stretch
40% of protection - Increased subendocardial perfusion: keeping LV empty is optimal for LV coronary perfusion
- Prevent myocardial rewarming: 10% / remove systemic return keeps cool
15
Q
Air removal
A
- Venting removes air that got in after closure but before x-clamp removal
16
Q
Venous cannulation and Return Concerns
A
- must collect from: SVC / IVC / Coronary sinus
- Bi-caval cannot collect from coronary sinus
- Improper cannula placement
- wrong cannula size
- improper height gradient
17
Q
Vent locations
A
- Aortic root: can add cardioplegia line if want
- Right Superior Pulmonary vein: can go into LA or LV
- Main PA: can interfere with Swan catheter (rarely used)
- Apex of LV (least common)
18
Q
Mechanical drainage
A
- roller pump
- one way valve to prevent air backflow
- OK to use high RPM w/ vacuum relief valve (prevent hickies)
- Must use low RPM in no vacuum relief valve
- best to monitor LA pressure (to prevent hickies) - just occlusive