Sphygmomanometer

Measuring blood pressure has become a normal part of any medical examination. A medical examination is incomplete without noting down the blood pressure numbers, which would have been impossible without a sphygmomanometer or blood pressure monitoring instrument. This medical breakthrough has helped in diagnosing, and hence, treating many suffering from hypertension.

The history tells�
In 1863, sphygmographs were taken as an early attempt to measure blood pressure that proved to be difficult and inaccurate. The instrument had a spring pressed on one end of a lever onto the wrist, compressing an artery. The lever rose and fell with each pulse wave. This recording device traced the movements on a smoked paper.

In 1898, sphygmomanometer were in use but had a cuff that was too narrow. The 1901 sphygmomanometer model had a wide cuff, but doctors used their fingers to detect arterial blood flow as they watched for changes in pressure

In 1905, Russian surgeon Nikolai Korotkoff reported the modern technique of using a stethoscope to listen for the sounds of blood flowing through the artery. His method proved to be extremely accurate and led to the discovery of hypertension. This involves measuring systemic arterial pressure with an inflatable cuff placed around a patient's arm, using a stethoscope to listen to sounds in the brachial artery. Since then, this method has remained the most acceptable method way of measuring arterial blood pressure. In 1920, mercury sphygmomanometer was developed

ECG - Electrocardiogram

Electrocardiography is of paramount importance in the understanding the cardiac rhythm. An ECG can be a part of a routine physical examination or it may be used as a test for heart disease. It is also used to investigate symptoms related to heart problems. ECG is a quick, safe, painless and inexpensive diagnostic test that is routinely performed if any abnormal heart condition is suspected.

And now a quick glimpse on the development history of ECG�
In 1887, the physiologist Augustus Desire Waller working in St. Mary's Hospital, London, recorded the first human surface electrocardiogram using the Lippmann capillary electrometer to deflect a light beam.

In 1892, another physiologist, Willem Einthoven, shares the honour with Waller of finding this new diagnostic technique - electrocardiogram. Einthoven recorded the first human electrocardiogram in Europe on April 11th, 1892 using the Lippmann capillary electrometer. He initially indicated the four observed deflections with the alphabets A, B, C, D but later adopted the middle alphabets: P, Q, R, S and T

In 1902, he made the first direct recording of the true human electrocardiogram. This was done using a modified string galvanometer. In 1924, Willem Einthoven was awarded the Nobel Prize for Physiology and Medicine for his electrocardiography work in developing the string galvanometer. Later, there were further researches done to upgrade this diagnostic tool.

Those lines on an ECG are the life lines of your heart. Any abnormality in these lines means your heart is in danger. So, to check your heart life, ECG is the best investigative test every doctor advices for.

Defibrillator

Defibrillation is the definitive treatment for the life-threatening cardiac conditions. Defibrillation consists of delivering a therapeutic dose of electrical energy to the affected heart with a device called a defibrillator. This allows the heart to beat at a normal rhythm. Defibrillators can be external, transvenous or implanted depending on the type of the device used. But to technically create so many types of defibrillators, the inventors have worked a lot behind their discovery.

A glance on the story history beholds behind the defibrillator invention�
As early as 1899, Prevost and Batelli were able to stop ventricular fibrillation in a dog. They did this by applying an electric shock to the animal's exposed heart. Claude Beck successfully used this technique on a human patient in 1947. Beck first used the technique successfully on a 14 year old boy who was being operated on for a congenital chest defect. The boy's chest was surgically opened, and manual cardiac massage was undertaken for 45 minutes until the arrival of the defibrillator. Beck used internal paddles on either side of the heart, along with procaine amide, a heart drug, and achieved return of normal sinus rhythm.

In 1957, William B. Kouwenhoven, an American electrical engineer at Johns Hopkins University in Baltimore, developed a closed-chest defibrillator. The unit was first tested on a dog. It sent electrical shocks to the heart through electrodes placed on the dog's chest. In 1961, American cardiologist Paul Zoll applied this alternating current defibrillator to human patients. But the direct current defibrillator introduced by Lown and Neuman in 1962 provided greater reliability and safety.

Defibrillators greatly improve the ability of patients to survive when their heart starts to fibrillate. Today most of the hospital emergency rooms have been equipped with electric defibrillators. Portable devices are now becoming standard equipment for ambulances. Automatic defibrillators detect abnormal heartbeats and deliver the appropriate electrical shocks and unlike standard defibrillators, operators can use these devices with much less training than paramedics.

Cardiopulmonary Bypass Machine

Coronary artery bypass surgery is one very common surgery performed today. This surgery is a life saving surgery. But this surgery would have not been successful with out the invention of cardiopulmonary bypass machine (also called as heart-lung machine or pump oxygenator).

Let's have a look on what history has to say about this breakthrough�
John Heysham Gibbon is considered the inventor of the heart-lung or pump oxygenator. The first heart-lung machine was built by him in 1937, who also performed the first human open heart operation. The death of a young patient in 1931, first stirred Dr. John Heysham Gibbon's imagination about developing an artificial device for bypassing the heart and lungs which ill allow for more effective heart surgery. He was discouraged by all with whom he mentioned the subject, but he continued his experiments and invention independently. In 1935, he successfully used a prototype cardiopulmonary bypass machine to keep a cat alive for 26 minutes.

Later in 1946, John Gibbon joined forces with Thomas Watson. Watson, an engineer and the chairman of IBM (International Business Machines), provided the financial and technical support to Gibbon for further development of his bypass machine, and hence, came up with an improved machine that �minimized haemolysis and prevented air bubbles from entering the circulation.� The device was only tested on dogs and had a 10% mortality rate.

Further improvements kept happening with contributions of the inventors like Clarence Dennis and Viking Olov Bjork. The first heart lung bypass machine was first used on a human in 1953, and in 1960, it was considered safe to use the cardiopulmonary bypass machine along with hypothermia to perform coronary artery bypass surgery.