1. ASSISTED VENOUS DRAINAGE

2. Gravity Drainage Patient to reservoir height gradient*
07/16/96
Gravity Drainage
Patient to reservoir height gradient
[ table height ]
Venous line resistance as contributed by the venous cannulae ( cannulation site )
Central venous pressure
Venous line length & size
Venous reservoir *

3. Why Assisted Venous Drainage?
Adults
Video-assisted surgical procedures and minimally invasive techniques with CPB
Higher support flows can be achieved with cannulae of smaller diameter
The primary aim of AVD is to optimize venous return flow with the utilization of a reduced diameter venous cannulae
Pediatrics
Reduce priming volume (VAVD)
To facilitate drainage with complex venous cannulation (air locks)

4. Assisted Venous Return Techniques:
Roller- Pump Assisted
“Better-Header”
Kinetic-Assisted
Vacuum-Assisted

5. Kinetic-Assisted Venous Drainage
Involves the integration of a centrifugal pump into the venous line to actively aspirate venous blood from the patient

6. Roller Pump Assisted Venous Drainage
Involves the integration of a roller pump into the venous line to actively aspirate venous blood from the patient

7. Vacuum-Assisted Venous Drainage
With this technique, the venous line is connected directly to a sealed hard shell venous reservoir
A regulated suction to the venous reservoir and closing all vented ports.

8. Vacuum-Assisted Venous Drainage

9. Advantages of VAVD Improved venous return Lowering the priming volume.
Markedly reduced intra-cardiac suction levels
Improved visibility and ability to use smaller incisions
Alternative venous cannulation sites
In some Re-Do cases, may eliminate need to dissect for snares around the Cava
Almost impossible to have an air-lock in the venous line
Improved drainage in special procedures. [ Heart port, modified access cases ]

10. Disadvantages and Pitfalls
Possibility of transmission of gaseous micro-emboli form the venous line to the arterial side of the circuit
Concerns on the effect of higher negative pressure on the RA and coronary sinus(due to Vacuum)
It may cause displacement of retrograde cardioplegia cannulae
It may distort the inter-atrial septum due to negative pressure in the RA
Over pressurization of the sealed venous reservoir
Increase arterial line filter shunt

11. Advantages of VAVD over other AVD Techniques
Superior handling of Venous Line Air
Easy to set-up
Cheaper

12. Equipment
CPB circuit with a sealed hard shell venous reservoir & integrated oxygenator
Pressure vacuum regulator with custom VAVD tubing set
Negative and positive pressure monitoring device
A very responsive positive pressure relief valve

18. Special Considerations*
Special Considerations
07/16/96
Care should be taken when adding fluids through the quick prime line
Care should be taken when administering pharmaceuticals through the manifold.
Watch the negative pressure when adjusting the vent and the inter-cardiac suction flow.
If venous return ceases during CPB, clamp the venous line for a second and release.
Preventative measures to prevent air being pulled in the circuit have to be taken. *

19. Special Considerations
In the event of atrial tear or unsecured caval canulae, side clamping of the venous line is essential
VAVD is no substitution for good cannulation
If excessive venous chatter occurs, consider hypovolemia, cannula size and cannula position
If circulatory arrest is required, vacuum is removed from the reservoir and only applied again when restarting bypass
Always remember to vent the venous reservoir when down on flow or when VAVD is not in use.