Cardiopulmonary bypass (CPB) is a technique that temporarily takes over the function of the heart and lungs during surgery, maintaining the circulation of blood and the oxygen content of the body. The CPB pump itself is often referred to as a Heart-Lung Machine or the Pumper. Cardiopulmonary bypass pumps are operated by allied health professionals known as Perfusionists in association with surgeons who connect the pump to the patient's body. CPB is a form of extracorporeal circulation.

Cardiopulmonary bypass is commonly used in heart surgery because of the difficulty of operating on the beating heart. Operations requiring the opening of the chambers of the heart require the use of CPB to support the circulation during that period.

CPB can be used for the induction of total body hypothermia, a state in which the body can be maintained for an hour or more without perfusion (blood flow). If blood flow is stopped at normal body temperature, permanent brain damage normally occurs in three to four minutes — death may follow shortly afterward.

ECMO is a simplified form of CPB sometimes used as life-support for newborns with serious birth defects, or to oxygenate and maintain recipients for organ transplantation until new organs can be found.

Surgical procedures in which cardiopulmonary bypass is used

• Coronary artery bypass surgery
• Cardiac valve repair and/or replacement (aortic valve, mitral valve, tricuspid valve, pulmonic valve)
• Repair of large septal defects (atrial septal defect, ventricular septal defect, atrioventricular septal defect)
• Repair and/or palliation of congenital heart defects (Tetralogy of Fallot, transposition of the great vessels)
• Transplantation (heart transplantation, lung transplantation, heart-lung transplantation)
• Repair of some large aneurysms (aortic aneurysms, cerebral aneurysms)
• Pulmonary thromboendarterectomy
• Pulmonary thrombectomy

History

Dr. Clarence Dennis led the team that conducted the first known operation involving open cardiotomy with temporarary mechanical takeover of both heart and lung functions on April 5, 1951 at the University of Minnesota Hospital. The patient did not survive due to an unexpected complex congenital heart defect. This followed four years of laboratory experimentation with dogs.^[1]

John Gibbon is credited with developing the first truly practical heart-lung bypass machine; he performed the first successful surgery with it on May 6, 1953 in Philadelphia, an atrial septal defect repair. But although he is accredited with the invention, many suspect that he was not awarded the Nobel Prize for it because of his failure to mention the other members of the team working with him. Other surgeons such as Bernard J. Miller, a young doctor at the time, created many of the pieces that make the machine function.

Components of cardiopulmonary bypass

Cardiopulmonary bypass consists of two main functional units, the pump and the oxygenator which remove oxygen deprived blood from a patients body and replace it with oxygen-rich blood through a series of hoses.

Tubing

The components of the CPB circuit are interconnected by a series of tubes made of silicone rubber, or PVC. The tubing in the CPB circuit is similar to transparent garden hose.

Pumps

Roller pump

The pump console usually comprises several rotating motor-driven pumps that peristaltically "massage" tubing . This action gently propels the blood through the tubing. This is commonly referred to as a roller pump, or peristaltic pump.

Centrifugal pump

Many CPB circuits now employ a centrifugal pump for the maintenance and control of blood flow during CPB. By altering the speed of revolution (RPM) of the pump head, blood flow is produced by centrifugal force. This type of pumping action is considered to be superior to the action of the roller pump by many because it is thought to produce less blood damage (Hemolysis, etc.).

Oxygenator

The oxygenator is designed to transfer oxygen to infused blood and remove carbon dioxide from the venous blood. Cardiac surgery was made possible by CPB using bubble oxygenators, but membrane oxygenators have supplanted bubble oxygenators since the 1980s.

The oxygenator was first conceptualised in the 17th century by Robert Hooke and developed into practical extracorporeal oxygenators by French and German experimental physiologists in the 19th century. Bubble oxygenators have no intervening barrier between blood and oxygen, these are called 'direct contact' oxygenators. Membrane oxygenators introduce a gas-permeable membrane between blood and oxygen that decreases the blood trauma of direct-contact oxygenators. Much work since the 1960s focused on overcoming the gas exchange handicap of the membrane barrier, leading to the development of high-performance microporous hollow-fibre oxygenators that eventually replaced direct-contact oxygenators in cardiac theatres.^[2]

Another type of oxygenator gaining favour recently is the heparin-coated blood oxygenator which is believed to produce less systemic inflammation and decrease the propensity for blood to clot in the CPB circuit.

Cannulae

Multiple cannulae are sewn into the patient's body in a variety of locations, depending on the type of surgery. A venous cannula removes oxygen deprived blood from a patients body. An arterial cannula is sewn into a patient's body and is used to infuse oxygen-rich blood. A cardioplegia cannula is sewn into the heart to deliver a cardioplegia solution to cause the heart to stop beating.

Cardioplegia

Main article: Cardioplegia

A CPB circuit consists of a systemic circuit for oxygenating blood and reinfusing blood into a patient's body (bypassing the heart); and a separate circuit for infusing a solution into the heart itself to produce cardioplegia (i.e. to stop the heart from beating), and to provide myocardial protection (i.e. to prevent death of heart tissue).

Operation

A CPB circuit must be primed with fluid and all air expunged before connection to the patient. The circuit is primed with a crystalloid solution and sometimes blood products are also added. The patient must be fully anticoagulated with an anticoagulant such as heparin to prevent massive clotting of blood in the circuit.

Complications

CPB is not benign and there are a number of associated problems:

• Postperfusion syndrome (also known as Pumphead)
• Hemolysis
• Capillary Leak Syndrome
• Clotting of blood in the circuit - can block the circuit (particularly the oxygenator) or send a clot into the patient.
• Air embolism
• Leakage - a patient can rapidly exsanguinate (lose blood perfusion of tissues) if a line becomes disconnected.

 References

http://en.wikipedia.org/wiki/Heart-lung_machine

Cardiac surgery is surgery on the heart and/or great vessels performed by a cardiac surgeon. Frequently, it is done to treat complications of ischemic heart disease (for example, coronary artery bypass grafting), correct congenital heart disease, or treat valvular heart disease created by various causes including endocarditis. It also includes heart transplantation.

The earliest operations on the pericardium (the sac that surrounds the heart) took place in the 19th century and were performed by, among others, Francisco Romero,^[1] Dominique Jean Larrey, Henry Dalton, and Daniel Hale Williams. The first successful surgery on the heart itself, performed without any complications, was by Dr. Ludwig Rehn of Frankfurt, Germany, who repaired a stab wound to the right ventricle on September 7, 1896.

Surgery on the great vessels (aortic coarctation repair, Blalock-Taussig shunt creation, closure of patent ductus arteriosus), became common after the turn of the century and falls in the domain of cardiac surgery, but technically cannot be considered heart surgery.

 Closed heart surgery

Surgery on the great vessels was followed by the development of closed heart surgery, where the surgeon blindly worked on the beating heart. It left a great deal to be desired, but had much to offer for great risk. Palliation of severe mitral valve stenosis, which was common in the past due to rheumatic fever, could be accomplished by poking a finger into the (mitral) valve through an incision in the left atrium.^[2] If a finger didn't do, a knife was passed through the incision to cut out tissue. Following successful treatment of mitral stenosis, a special cutter for aortic valve stenosis was developed, that maneuvered through an incision in the left atrium, accomplished much the same thing as the surgeon's finger in a stenosed mitral valve.

Operations under hypothermia

It was soon discovered that the repair of intracardiac pathologies required a bloodless and motionless environment, which means that the heart should be stopped and drained of blood. The first successful intracardiac correction of a congenital heart defect using hypothermia was performed by Dr. C. Walton Lillehei and Dr. F. John Lewis at the University of Minnesota on September 2, 1952. The following year, Soviet surgeon Aleksandr Aleksandrovich Vishnevskiy conducted the first cardiac surgery under local anesthesia.

 Operations on the open heart

Surgeons realized the limitations of hypothermia - complex intracardiac repairs take more time and the patient needs blood flow to the body (and particularly the brain); the patient needs the function of the heart and lungs provided by an artificial method, hence the term cardiopulmonary bypass. Dr. John Heysham Gibbon at Jefferson Medical School in Philadelphia reported in 1953 the first successful use of extracorporeal circulation by means of an oxygenator, but he abandoned the method, disappointed by subsequent failures. In 1954 Dr. Lillehei realized a successful series of operations with the controlled cross-circulation technique in which the patient's mother or father was used as a 'heart-lung machine'. Dr. John W. Kirklin at the Mayo Clinic in Rochester, Minnesota started using a Gibbon type pump-oxygenator in a series of successful operations, and was soon followed by surgeons in various parts of the world.

 Modern beating-heart surgery

Since the 1990s, surgeons have begun to perform "off-pump bypass surgery" - coronary artery bypass surgery without the aforementioned cardiopulmonary bypass. In these operations, the heart is beating during surgery, but is stabilized to provide a (almost) still work area. Some researchers believe this approach results in fewer post-operative complications (such as postperfusion syndrome) and better overall results (studies results are controversial as of 2007, surgeon's preference and hospital results still play a major role).

Minimally invasive surgery

A new form of heart surgery that has grown in popularity is robotic heart surgery. This is where a machine (today by far and away the most popular is the da Vinci surgical system by Intuitive Surgical) is used to perform surgery while being controlled by the heart surgeon. The main advantage to this is the size of the incision made in the patient. Instead of a incision being at least big enough for the doctor to put his hands inside, it does not have to be bigger than 3 small holes for the robot's much smaller hands to get through. Also, a major advantage to the robot is the recovery time of a patient, instead of 6 months of recovery time, some patients have recovered and resumed playing athletics in a matter of weeks.^{[citation needed]}

 Risks

The development of cardiac surgery and cardiopulmonary bypass techniques has reduced the mortality rates of these surgeries to relatively low levels. For instance, repairs of congenital heart defects are currently estimated to have 4-6% mortality rates.^[3][4]

A major concern with cardiac surgery is the incidence of neurological damage. Stroke occurs in 2-3% of all people undergoing cardiac surgery, and is higher in patients at risk for stroke. ^{[citation needed]} A more subtle constellation of neurocognitive deficits attributed to cardiopulmonary bypass is known as postperfusion syndrome (sometimes called 'pumphead'). The symptoms of postperfusion syndrome were initially felt to be permanent,^[5] but were shown to be transient with no permanent neurological impairment.^[6]

 See also

• Cardiac surgeon
• Cardiothoracic surgery
• Vascular surgery

 References

 Further reading

• [edited by] Lawrence H. Cohn, L. Henry Edmunds, Jr (2003). Cardiac surgery in the adult. New York: McGraw-Hill, Medical Pub. Division. ISBN 0-07-139129-0.  Full text online

There is nothing so useless as doing efficiently that which should not be done at all.

Always bear in mind that your own resolution to succeed is more important than any other one thing.

Try not to become a man of success but rather try to become a man of value.

Success is not the key to happiness. Happiness is the key to success. If you love what you are doing, you will be successful.

If I have been of service, if I have glimpsed more of the nature and essence of ultimate good, if I am inspired to reach wider horizons of thought and action, if I am at peace with myself, it has been a successful day.

To follow without halt, one aim; there is the secret of success. And success? What is it? I do not find it in the applause of the theater; it lies rather in the satisfaction of accomplishment.

All my growth and development led me to believe that if you really do the right thing, and if you play by the rules, and if you've got good enough, solid judgment and common sense, that you're going to be able to do whatever you want to do with your life.

The secret of success is constancy to purpose.

There are no gains without pains.

Yesterday I dared to struggle. Today I dare to win.

He has achieved success who has lived well, laughed often and loved much; who has gained the respect of intelligent men and the love of little children; who has filled his niche and accomplished his task; who has left the world better than he found it, whether by an improved poppy, a perfect poem, or a rescued soul; who has never lacked appreciation of earth's beauty or failed to express it; who has always looked for the best in others and given them the best he had; whose life was an inspiration; whose memory a benediction.

published 11/30/1905 in the Lincoln (Kansas) Sentinel - an adaptation of this is often attributed to Ralph Waldo Emerson, though nothing like it has been found in his writings.

Success

To laugh often and much;
To win the respect of intelligent people and the affection of children;
To earn the appreciation of honest critics and endure the betrayal of false friends;
To appreciate beauty, to find the best in others;
To leave the world a bit better, whether by a healthy child, a garden patch or a redeemed social condition;
To know even one life has breathed easier because you have lived.
This is to have succeeded.

This is a very good piece of thought. Read carefully and relate it to your life. The Law of the Seed

Take a look at an apple tree. There might be five hundred apples on the tree and each apple has ten seeds. That's a lot of seeds!

We might ask, "Why would you need so many seeds to grow just a few
more apple trees?"

Nature has something to teach us here.
It's telling us:

“Not all seeds grow. In life, most seeds never grow”.

So if you really want to make something happen, you had better try more than once."

This might mean:

You'll attend twenty interviews to get one job.

You'll interview forty people to find one good employee.

You'll talk to fifty people to sell one house, one car, one vacuum cleaner, one insurance policy, or a business idea

And you might meet a hundred acquaintances just to find one special friend.

When we understand the "Law of the Seed", we don't get so disappointed.

We stop feeling like victims.

We learn how to deal with things that happen to us.

Laws of nature are not things to take personally.

We just need to understand them - and work with them.

IN A NUTSHELL
Successful people fail more often. But they plant more seeds.

When things are beyond your control, here's something that you must
NOT DO so as to avoid misery in your life:
- You must not decide how you think the world SHOULD be.
- You must not make rules for how everyone SHOULD behave.
- Then, when the world doesn't obey your rules, you get angry!
- That's what miserable people do!
On the other hand, let's say you expect that:
-Friends SHOULD return favours.
-People SHOULD appreciate you.
-Planes SHOULD arrive on time.
-Everyone SHOULD be honest.
- Your husband or best friend SHOULD remember your birthday.

These expectations may sound reasonable. But often, these things won't
happen!

So you end up frustrated and disappointed.

There's a better strategy:
Demand less, and instead, have preferences!

For things that are beyond your control, tell yourself:
"I would prefer this, but if that happens, it’s OK too!"

This is really a change in mindset. It is a shift in attitude, and it gives you more peace of mind ...

You prefer that people are polite ... but when they are rude, it doesn't ruin your day. You prefer sunshine ... but if it rains, it is ok too!

To become happier, we either need to:
a) Change the world, or
b) Change our thinking.

It is easier to change our Thinking!

IN A NUTSHELL
It is not the problem that is the issue, but rather it is your attitude attending to the problem that is the problem.
It's not what happens to you that determines your happiness.
It's how you think about what happens to you!

END

Study this small story; I hope that makes a BIG change in you.

Professor began his class by holding up a glass with some water in it. He held it up for all to see & asked the students,' How much do you think this glass weighs?'

'50gms!' .... '100gms!' ..... '125gms' .. the students answered.

'I really don't know unless I weigh it,' said the professor, 'but, my question is: What would happen if I held it up like this for a few minutes?'

'Nothing' the students said.

'Ok what would happen if I held it up like this for an hour?' the professor asked.

'Your arm would begin to ache' said one of the student 'You're right, now what would happen if I held it for a day?'

'Your arm could go numb, you might have severe muscle stress & paralysis & have to go to hospital for sure!' ventured another student & all the students laughed.

'Very good. But during all this, did the weight of the glass change?‘ asked the professor.

'No'

Then what caused the arm ache & the muscle stress?' The students were puzzled.

'Put the glass down!' said one of the students

'Exactly!' said the professor.' Life's problems are something like this. Hold it for a few minutes in your head & they seem OK. Think of them for a long time & they begin to ache. Hold it even longer & they Begin to paralyze you. You will not be able to do anything. It's important to think of the challenges (problems) in your life, but EVEN
MORE IMPORTANT to 'put them down' at the end of every day before You go to sleep. That way, you are not stressed, you wake up every day fresh & strong & can handle any issue, any challenge that comes your way!'

So, when you leave office today,
Remember to 'PUT THE GLASS DOWN TODAY! '