350 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1955 



about half of that pressure which is considered safe. In addition, all 

 passages through which the flow of blood must pass should be such 

 that high velocities at localized points should be avoided. For this 

 reason the finger cots with limited pressure action and weighted valves 

 with large seats were chosen as pumping components. 



In order to construct a machine that could be used for small children 

 as well as large adults, they decided that the capacity of the machine 

 should be variable. Thus the mechanical heart was designed so that 

 the operator can use only as many mechanical pump units as are neces- 

 sary to handle the patient's blood volume. 



Since the element of sterility is a prime necessity in any operating 

 room, it is doubly important in a machine in which the blood of a 

 living patient will be circulating. Therefore, all parts of the glass, 

 steel, and rubber mechanical heart that come into direct contact with 

 the blood are carefully smoothed and coated with a nonwettable sur- 

 face to prevent blood-cell breakdown and all are easily cleaned and 

 autoclaved just as is any other surgical instrument. 



The Dodrill-GMR mechanical heart was designed after the Dale- 

 Schuster pump (previously mentioned) and consists of two inde- 

 pendent units, one to take the place of the right heart and the other 

 to take the place of the left heart. The pumping action is obtained 

 by collapsing and expanding latex rubber finger cots with positive 

 and negative air pressure. Collapse of the finger cots results in blood 

 being drawn into the glass cylinders from the patient through inlet 

 valves, while expansion of the finger cots forces the blood out through 

 outlet valves. (See pi. 2, fig. 2, and pi. 4, fig. 2.) 



Following its successful use, which made medical history, the Dod- 

 rill-GMR mechanical heart was named one of the top 10 scientific 

 developments of 1952 by the National Association of Science Writers 

 and received the Hektoen Bronze Medal for original investigation 

 awarded by the American Medical Association in 1953. 



Since Dodrill's successful use of the mechanical heart, John H. Gib- 

 bon, Jr., at Philadelphia's Jefferson Hospital performed the first suc- 

 cessful operation on a human patient using a heart-lung machine. 

 On May 6, 1953, Gibbon operated upon an 18-year-old girl and closed 

 a large defect in the septum between the right and left auricles while 

 the entire cardiorespiratory functions of the patient were maintained 

 by the heart-lung machine for a period of 26 minutes during the in- 

 tracardiac operation (Gibbon, 1954). Using the Melrose heart-lung 

 apparatus previously mentioned, Aird and colleagues (Aird, Melrose, 

 Cleland, and T^ynn, 1944) operated on a 32-year-old patient at the 

 Hammersmith Hospital, London, England, on December 9, 1953, "to 

 assist the circulation . . . throughout a severe cardiac operation which 

 would not have been attempted without some kind of artificial help." 

 Even more recently at the University of Minnesota Medical 



