Sunday, May 04, 2008

Pediatric VAD by Gryffindor 501


Firebolt Pump with Novel Technique to Create Pulsatile Flow
by Gryffindor - 501
Farida Akberali, Risa Aprilria, Kristina Barsten, Nicholas Brown, Cody Covington, Christine Elkins, Mark Felder, Lauren Fife

Pump design background:
  • Based off of current technology from the Hemopump Cardiac Assist System and the Impella by Abiomed
  • Both devices are used to assist/unload the heart
  • Very small; can be implanted in the heart by a catheter inserted into the femoral artery
  • The tiny pump uses axial flow to reduce myocardial workload and oxygen consumption, while increasing cardiac output, coronary- and end-organ perfusion
Our pump design:
  • All parts are made out of titanium
  • The impeller is magnetically levitated in the middle of the shell
    • reduces hemolysis
    • no "wear and tear"
  • Parts are shell, front magnetic bearing, impeller, rear magnetic bearing, motor, and battery
  • The device has a diameter of 4.5 mm, length of 55 mm, and weight of 15 g.
  • Can generate:
    • Flow rate of 0.5 - 3.2 L/min
    • Pressure of 100 - 140 mmHg
    • Angular velocity of impeller is 19,000 - 22,000 rpm
  • Requires a power of 3.5 - 4.2 Watts
  • Designed for patients over 10 kg
  • Inserted into the left ventricle and stabilized just above the aortic valve
Muscular surgery:
  • A strand of muscle will be wrapped around the aorta, just above the pump, to create a pulsatile flow
  • Left latissimus dorsi will be cut where it terminates on the side of the ribs under the shoulder and peeled back until there is a strand 0.75 - 1 inch wide; do not denervate or detach the muscle
  • Encircle the muscle around aorta and suture the free end to the strand so that it sits snuggly around the aorta without compressing it
  • Insert the electrode from a modified pacemaker for muscular stimulation
  • The chosen pacemaker is a Cardiomyostimulator Medtronic Model 4,710 Transform
  • The pacemaker should be positioned in the left abdominal wall pocket
  • One lead is connected to electrode and another to the pump
  • The pacemaker will act as an integrating signal that integrates flow measurements and frequency of stimulation needed to increase/decrease pulsatility rate
  • A voltage of 3.5 V is needed for stimulation of the muscle
  • The muscle has a resistance of 200 ohms, therefore the necessary power is 0.06125 Watts
  • This power will create a pulse of 95 bpm
Gryffindor's technique and pump are both designed as a bridge to recovery.

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