 permit complete bypass of the heart and lungs during surgical operations of the heart. Dennis built a modified Gibbon pump. Dennis needed an oxygenator that would do the following: use a minimum amount of blood, do as little damage to the blood cells as possible and to acheive a critical level of oxygenation without excess foaming. This new pump consisted of a nest of vertically revolving stainless steeel cylinders. These were mounted over a revolving funnel in which the blood, oxygenated on the walls of the cylinders, was collected. New roller pumps were used to cause less haemolysis. This apparatus was cumbersome and difficult to clean. Most dogs died during the testing of this machine either during perfusion or shortly afterwardss. Dennis discovered that the oxygenator was contaminated and many of the animals died from infections. The method of sterilization along with the design of the oxygenator was changed.
In Sweden, a physician by the name of Viking Olov Bjork had invented an oxygenator with multiple screen discs that rotated slowly in a shaft, over which a film of blood was injected. Oxygen was passed over the rotating discs and provided sufficient oxygenation for an adult human. Bjork along with help of a few chemical engineers, one of which who was his wife, prepared a blood filter and an artificial intima of silicon under the trade name UHB 300. This was applied to all parts of the perfusion machine, particularly, the rough red rubber tubes, to delay clotting and save platelets.
The first heart lung bypass machine was first used on a human in 1953. In 1960, it was considered safe to use the CBM along with hypothermia to perform CABG surgery. Heat exchangers were used to cool and rewarm the blood. Using these heat exchangers helped to eliminate the tedious process of surface cooling.
The CBM has not changed much in the past 30 years. The CBM is a large machine that takes up a lot of room in an operating room. Engineers are working on designing a smaller unit that will not take up as much room. This is just one example of how engineering and medicine have worked together to invent machines to advance medical technologies.
If you would like more information on CBM that is available on the internet you could visit the following site: Baxter Healthcare