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>> THE THIRD-STAGE OPERATION IS A VARIANT OF THE FONTAN
OPERATION.
>> AND THAT GENERALLY TAKES PLACE SOMEWHERE AFTER TWO
YEARS, BUT THE CHILD'S PHYSIOLOGY REALLY TELLS US
THE BEST TIME TO DO THAT.
>> THERE ARE TWO TYPES OF FONTAN OPERATIONS.
ONE IS CALLED THE LATERAL TUNNEL FONTAN,
IN WHICH A BAFFLE IS PLACED INSIDE THE HEART TO REDIRECT
THE BLOOD FLOW FROM THE LOWER PART OF THE BODY
TO THE LUNGS.
THE OTHER IS CALLED THE EXTRA CARDIAC FONTAN,
WHERE WE ACTUALLY USE A TUBE THAT BRINGS THE BLOOD
OUTSIDE THE HEART, UP TO THE PULMONARY ARTERIES.
>> BUT THE FONTAN OPERATION IS BASED ON CONNECTING
THE VEINS FROM THE BODY DIRECTLY TO THE ARTERIES TO THE LUNGS.
>> NORMALLY, THE INFERIOR VENA CAVA,
WHICH DRAINS THE BOTTOM OF THE BODY,
ATTACHES TO THE HEART AT THE INFERIOR OR BOTTOM PORTION.
AND WHAT WE DO IS TO LITERALLY DIVIDE THIS FROM
THE HEART.
WE SEW UP THE PORTION OF THE HEART WHERE THE INFERIOR
VENA CAVA ENTERED, AND THEN WE SEW A TUBE END-TO-END
TO THE REMNANTS OF THE INFERIOR VENA CAVA.
WE TAKE THIS TUBE AND LOOP IT AROUND THE SIDE
OF THE HEART AND SEW IT INTO A HOLE WE MAKE
INTO THE PULMONARY ARTERY.
SO WE ESSENTIALLY BYPASS THE ENTIRE HEART.
>> IT'S A MORE EFFICIENT CONNECTION BECAUSE THE TUBE
IS A VERY SPECIFIC SIZE, AND THE BLOOD GOING THROUGH
THERE IS NOT TURBULENT.
TURBULENCE LOSES POWER, AND POWER LOSS IS A PROBLEM
IF YOU DON'T HAVE ANYTHING PUSHING BLOOD THROUGH
THE LUNGS.
IT CANNOT WORK UNLESS THERE'S LOW RESISTANCE
IN THE LUNGS.
AND THE KEY IS YOU HAVE TO HAVE A GOOD PUMPING CHAMBER
ON THE OTHER SIDE WHICH ESSENTIALLY SORT OF SUCKS
BLOOD THROUGH THE LUNGS.
>> NOW, THE ONE MODIFICATION IS THAT WE PUT A SMALL HOLE
IN THE SIDE OF THE HEART AND IN THE SIDE OF THIS GRAFT
AND SEW IT TOGETHER WITH WHAT'S CALLED
A FENESTRATION.
>> AND THE REASON WE DO THAT IS THAT IT'S BEEN SHOWN THAT
HAVING THAT LITTLE HOLE, WHILE IT DOES ALLOW SOME
BLUE BLOOD TO MIX WITH THE RED BLOOD,
IT ALSO DECREASES THE RISK OF DEVELOPING FLUID AROUND
THE LUNGS AFTER SURGERY, SOMETHING CALLED
A PLURAL EFFUSION.
EFFUSIONS USED TO BE THE BIGGEST PROBLEM AFTER
THE FONTAN OPERATION.
CHILDREN WOULD HAVE THE SURGERY AND DO QUITE WELL,
BUT THEY WOULD DEVELOP A LOT OF FLUID THAT COLLECTED
AROUND THE LUNG, AND THEY'D OFTEN HAVE TO HAVE A TUBE IN
THE CHEST FOR WEEKS OR EVEN MONTHS TO DRAIN THAT FLUID.
NOWADAYS, WITH THE USE OF THIS FENESTRATION,
THAT IS A VERY UNCOMMON EVENT,
WHEREAS IT USED TO BE ROUTINE.