McKesson Model N

WLMD ID: aqsq
American physician and inventor Elmer I. McKesson, M.D. (1881-1935) founded a company to manufacture anesthesia equipment of his own design. By the mid-1930s, the company had hired Mr. John L. Bloomheart to design its equipment. The patents for several of Mr. Bloomheart's inventions were assigned to Dr. McKesson's widow, Mrs. Martha F. McKesson. These included the patent for the McKesson model N machine. On the market by 1948, this was a big departure from the Nargraf machines that had been introduced in 1930. The model N featured a new carbon dioxide absorber and simplified flowmeters. The example shown here was probably made in the late 1950s. It could administer nitrous oxide, oxygen, cyclopropane and ether.

Catalog Record: McKesson Model N McKesson Model N

Access Key: aqsq

Accession No.: 2001-08-12-1 B

Title: McKesson model N.

Author: Bloomquist, John L.

Corporate Author: McKesson Appliance Company.

Title variation: Alt Title
Title: J. Bloomheart multiple purpose gas unit.

Publisher: Toledo, Ohio : McKesson Appliance Company, [between ca. 1956 and ca. 1962.]

Physical Description: 1 anesthesia machine : metals, glass, plastics ; 88 x 102 x 72 cm.

Subject: Anesthesia, Inhalation – instrumentation.
Subject: Anesthesia Machines.
Subject: Cyclopropane.
Subject: Ether, Ethyl.
Subject: Nitrous Oxide.
Subject: Oxygen.

Note Type: General
Notes: The title is taken from the object. The alternate title is taken from U. S. Patent 2,407,221.

The first year in the range of dates of possible manufacture is based on the earliest description of the McKesson “twin absorber” found by the cataloger. This design replaced the earlier “Absorberizer”, which was advertised in that same year.

Described from the perspective of the user, with the head unit turned to perpendicular to the frame. In this
orientation, all the controls and gauges face forward.

Note Type: With
Notes: As received the cataloged object lacked a nitrous oxide flowmeter; a second oxygen flowmeter had been installed in its place. The mismatched oxygen flowmeter was removed and transferred to the WLM’s collection of McKesson parts. It was replaced by the nitrous oxide flowmeter removed from Acc. # 2001-08-12-1 A.

Note Type: Physical Description
Notes: Bloomheart JL, inventor; Martha F. McKesson, assignee. Multiple purpose gas unit. US patent 2,407,221. September 10, 1946.

Note Type: Citation
Notes: McKesson Company File. Archives. Located at: Wood Library-Museum of Anesthesiology, Schaumburg, Illinois.

Note Type: Citation
Notes: Mead SV. Anesthesia in Dental Surgery, 2nd ed. St. Louis: C. V. Mosby Company, 1951:398.

Note Type: Physical Description
Notes: One anesthesia machine; The width given in the short description positions the head unit in alignment with the frame; Turned perpendicular to the frame, for ease of access to all controls and gauges, the width is approximately 71.5 centimeters (the same as the depth); The H-shaped frame has a stout pole mounted on the front, which holds the head unit; A large knob is mounted on this pole; Two more poles mounted in the center and on the back of the frame, respectively, support a cross bar that would hold the gas cylinders; Two yokes are mounted on the front of this bar and two in back; From left to right, the front yokes are labeled “Nitrous Oxide” and “Oxygen” respectively; Each of these front yokes has an associated pressure gauge mounted directly above it;

The head unit consists of a carbon dioxide absorber with an ether vaporizer mounted on the front of the absorber and a bank of three flowmeters immediately behind and above it; The top of the absorber has seven elements arranged in a circle; From left to right these are: a dial marked “CANISTER IN USE [new line] CANISTER IN USE”, a dial marked “OFF ABSORBER RANGE ON [new line] CANISTER OFF”, a glass window into the interior of the absorber; a dial marked with a red dot, a second window, a valve, and a second dial marked “CANISTER IN USE”; The dial with the red indicator controls the breathing bag; The markings for this occupy the center of circle, and read, from top to bottom: “McKESSON [new line] [left facing arrow] [right facing arrow] ABSORBER [new line] MODEL 625 [new line] REBREATHING [new line] BAG [new line] OFF ON [new line] VALVE”; The front edge of the absorber has connectors for two hoses;

The top of the ether vaporizer is marked, from left to right: “FILL, OFF, 1, 2, 3, 4, 5, 6, 7 ON [new line] TOLEDO, OHIO, U. S. A. [new line] VAPORIZER [new line] MODEL 965 SER. NO. E3129”; From left to right, the three flowmeters register nitrous oxide, cyclopropane and oxygen; A label on the back of the head unit reads: “McKESSON APPLIANCE CO. [new line] MODEL N SER. NO. 1265 [new line] TOLEDO, OHIO, U. S. A.”; Immediately below this label there are two connections for piped gas; That connector on the left is marked “Oxygen”, that on the right is marked “Nitrous”; There is space between these marked “Cyclo.”, but there is no associated connector.

Note Type: Reproduction
Notes: Photographed by Mr. Steve Donisch, January 17, 2018.

Note Type: Historical
Notes: Around 1910, Elmer I. McKesson, M.D. (1881-1935) founded the Toledo Technical Appliance Company to manufacture anesthesia equipment of his own design. In 1930, the company name was changed to the McKesson Appliance Co. The year 1930 also saw the introduction of McKesson’s Nargraf machines. By 1936, the year after the founder’s death, the company had hired Mr. John L Bloomheart to design equipment.

The patents for several of Mr. Bloomheart’s inventions were assigned to Dr. McKesson’s widow, Mrs. Martha F. McKesson. One of these was the patent for the McKesson model N machine, filed in 1944 and granted in 1946. This was departure from the Nargraf machines, which were called models J and L. No McKesson model M is known. The “New Model N” was advertised in 1948. New “biphase” flowmeters were designed for the model N. It originally featured a combined carbon dioxide absorber and ether vaporizer called the “Absorberizer”. Around 1956, the Absorberizer had been replaced by a “Twin absorber” and separate ether vaporizer; these are present on the cataloged object. These later components were also features of McKesson’s cabinet machines.

The cataloger found the model N mentioned in only one textbook, published in 1951 (Mead, p. 398.) A brochure dated 1957 describes two related models. One of these was “model LN”, a hybrid machine that combined the Nargraf model L with the absorber of the model N. The other was the “model N cabinet model”. By 1962 the company had become a division of American Cryogenics, Inc. By 1975, McKesson had become a division of Narco Medical Co.

Note Type: Exhibition
Notes: Selected for the WLM website.