Bennett Anesthesia Ventilator

WLMD ID: amen
The Model BA-4 Anesthesia Ventilator, made by Bennett Respiration Products, Inc., is an example of first generation ventilators made specifically for use with an anesthesia machine to administer inhalation anesthesia. Introduced around 1963, it was fourth in a succession of anesthesia ventilators that started with the Bennett Assister around 1958. The company described the Model BA-4 as a pressure generator in which inspiration was either pressure- or volume-regulated depending on which preset limit was reached first. Expiration was either time- or patient-regulated.

At the heart of the BA-4 ventilator was the Bennett Valve. This valve was an important component in most of the company’s early ventilators. It was sensitive to negative pressure generated by the inspiratory effort of the patient. This allowed the Bennett ventilators to assist patient breathing or control ventilation if the patient’s respiratory effort diminished or ceased.

The valve, and much of the company’s equipment, was designed by its founder, engineer V. Ray Bennett. He had originally designed the valve during WWII as part of a system to deliver oxygen to pilots flying at high altitude. Between 1946 and 1949, devices produced by Mr. Bennett and his company (then called V. Ray Bennett and Associates) were used to aid in the treatment of polio patients at Los Angeles County Hospital’s Communicable Disease Unit. During polio epidemics in 1948-1949, positive pressure ventilation administered with Mr. Bennett’s equipment saved the lives of a significant number of patients for whom the negative pressure ventilators (i.e. iron lungs) alone were insufficient.

Catalog Record: Bennett Anesthesia Ventilator

Access Key: amen

Accession No.: 1991-12-17-4 A

Title: [Anesthesia ventilator] / Bennett.

Author: Bennett, V. Ray (Vivian Ray).

Corporate Author: Bennett Respiration Products, Inc.

Title variation: Alt Title
Title: Bennett model BA-4 anesthesia ventilator.

Title variation: Alt Title
Title: Assistor/controllor model BA-4 anesthesia ventilator.

Publisher: Santa Monica, California : Bennett Respiration Products, Inc., [between 1963
and 1975?].

Physical Descript: 1 ventilator : metals, rubber, plastic ; 92.5 x 50 x 45 cm.

Subject: Ventilators, Mechanical.
Subject: Anesthesia, Inhalation – instrumentation.

Note Type: General
Notes: The early year in the date range for the possible year of manufacture of this
Model BA-4 ventilator is based on the earliest date on a document containing
the model (a 1963 company booklet). The end year is an estimate based on the
the evidence of heavy use of the machine and on the frequency of references
to the model and the years in documents on Google Books and Google Scholar.
The date range could change if documentation, or expert opinion, indicates
that it should be corrected.

Note Type: General
Notes: The title is based on markings that appear to have been rubbed off of the
front of the machine over time. In images of the same model the following is
marked on the front, “BENNETT | ANESTHESIA VENTILATOR”. The last four letters
(ATOR) are still visible on this machine.

Note Type: Citation
Notes: The Bennett Assister [advertisement]. Anesth Analg. 1958;37(2):41 of ads.

Note Type: Citation
Notes: Bennett: Assistor/Controllor, Model BA-4 Anesthesia Ventilator. Santa Monica,
California: Bennett Respiration Products, Inc.; 1963.

Note Type: Citation
Notes: Bennett Assister: … Instruction Manual. Los Angeles, California: Bennett
Respiration Products, Inc.; 1961.

Note Type: Citation
Notes: Bennett VR. Oxygen valve. U.S. patent 2,483,722. October 4, 1949. https://www.
google.com/patents/US2483722. Accessed October 22, 2015.

Note Type: Citation
Notes: Dunne PJ. History of respiratory care. In: Kacmarek RM, Stoller JK, Heuer AJ,
eds. Egan’s Fundamentals of Respiratory Care. 10th ed. St. Louis, Missouri:
Elsevier Mosby; 2013:6, 10.

Note Type: Citation
Notes: Obituary notices: Bower—Dr. Albert G. Bower. Pasadena Independent. August 4,
1960:C-3.

Note Type: Citation
Notes: Somerson SJ, Sicilia MR. Historical perspectives on the development and use
of mechanical ventilation. AANA J. 1992;60(1):90. https://www.aana.
com/newsandjournal/Documents/historical_perspectives_0292_p083.pdf. Accessed
October 22, 2015.

Note Type: Citation
Notes: Sykes K. From Copenhagen to critical care. In: Eger EI 2nd, Saidman LJ,
Westhorpe RN, eds. The Wonderous Story of Anesthesia. New York: Springer;
2014:777-779.

Note Type: Citation
Notes: Trubuhovich RV. On the very fist, successful, long-term, large-scale use of
IPPV: Albert Bower and V Ray Bennett: Los Angeles, 1948-1949. Crit Care
Resuscit. 2007;9(1):91-100.

Note Type: Physical Description
Notes: One anesthesia ventilator in rectangular housing; The housing is supported by
a single stand on a base of four legs with wheels; The measurements provided
in the physical description field include the stand and wheels; The
rectangular housing, with connection on its right side, measures
approximately 25.5 x 42.5 x 25 cm (height x width x depth); The bellows
housing measures approximately 24 cm in height and 25 cm in diameter; Most of
the rectangular housing is white, while the lid is gray; On the front of the
ventilator, starting on the left, is a volume gauge marked in increments of
100 “CC” (cubic centimeters); The following increments are numbered: 0, 100,
200, 300, 400, 500, 1000, 1500, and 2000; To the right of the volume gauge,
part of the Bennett Valve is visible; To the right of this is a gauge for the
system pressure; It is marked in increments of one centimeter of water, from
negative 10 to positive 60; The following increments are numbered: negative
10, 0, 10, 20, 30, 40, 50, and 60; Below the two gauges and the valve is a
row of control knobs; Beginning on the right is a black colored turn-knob
labeled “PRESSURE”; This knob has no other markings; To the right of this is
a turn-knob marked “VOLUME”, and “• DECREASE” followed by a right pointing
arrow; To the right of this is a turn-knob marked “PEAK FLOW” and “•
DECREASE” followed by a right pointing arrow; To the right of this is a
turn-knob labeled, “SENSITIVITY” and “• INCREASE” followed by a right
pointing arrow; To the right of this is a turn-knob labeled “RATE” and “•
INCREASE” followed by a righting pointing arrow; A few of the last letters
remain from what appears to be markings that have been rubbed or worn away
(over time) from the front of the device; These remaining letters are,
“ATOR”; In images of this device, such as in the company’s marketing booklet,
the following text is pictured where the lettering on this machine has worn
away, “BENNETT | ANESTHESIA VENTILATOR”; A Dymo punch tape label with the
number “3” is located on the front of the machine just above the area with
worn away lettering; On the left side of the machine is a torn sticker with
the following markings visible, “Property of MORTON HOSPI” and “No. 837”; To
the right of this sticker the number “837” is handwritten in permanent black
ink; Below both of these are the remnants of an old sticker that has been
pulled off; On the right side of the machine is the “tee-valve selector”,
which is where the patient and gas machine would be connected to the
ventilator; Fixed to the top of the device is a plate with the following text
“Donated By The MORTON HOSPITAL and MEDICAL CENTER [new line] TAUNTON, MA.
[new line] To The [new line] WOOD LIBRARY MUSEUM OF ANESTHESIOLOGY”; Below
this is a yellow maintenance sticker marked with the following: “MAINTENANCE
REQUIRED [new line] DATE 4/90 DEPT Anesthesia [new line] TECH BJM / Biomed
[new line] This unit is no longer used for anesthetic use. [new line]
Antique”; The lid opens to expose the inner mechanisms; Located on the inside
of the lid is a label with manufacturer markings; “BENNETT RESPIRATION
PRODUCTS, INC. [new line] 1639 ELEVENTH STREET SANTA MONICA, CALIFORNIA”; To
the right of these is, “DISTRIBUTED BY Puritan COMPRESSED GAS CORP.”; The
bellows is located below the rectangular housing; Its clear outer canister is
densely scratched[?] and degraded; A tube for a scavenger system that was
likely added to the machine a number of years after its manufacture is
located below the bellows; Some tubing still runs from the lower portion of
the bellows into the rectangular housing and to the tee-valve.

Note Type: Reproduction
Notes: Photographed by Mr. Steve Donish, June 5, 2015.

Note Type: Acquisition
Notes: Donated to the Wood Library-Museum of Anesthesiology by The Morton Hospital
and Medical Center in Taunton, Massachusetts.

Note Type: Historical
Notes: The first mass produced ventilator manufactured by V. Ray Bennett and
Associates was the Bennet TV-P2, which was introduced in 1948. Ten years
later, the company produced the Bennett Assistor, the first in a series of
ventilators made specifically for use with an anesthesia machine to
administer inhalation anesthesia. The Model BA-4 was the fourth in this
series, and was introduced around 1963. The company described the Model BA-4
as a pressure generator in which inspiration was either pressure- or
volume-regulated depending on which preset limit was reached first.
Expiration was either time- or patient-regulated. The limit for expiration
also depended on which variable was reached first. In this case, only the
time limit was preset.

At the heart of the BA-4 ventilator was the Bennett Valve. This valve was an
important component in most of the company’s early ventilators. It was
sensitive to negative pressure generated by the inspiratory effort of the
patient. This allowed the Bennett ventilators to assist patient breathing or
control ventilation if the patient’s respiratory effort diminished or ceased.

The valve, and much of the company’s equipment, was designed by its founder,
engineer V. Ray Bennett. He had originally designed the valve during WWII as
part of a system to deliver oxygen to pilots flying at high altitude. In 1946
Mr. Bennett began working with Albert G. Bower, M.D. (1890-1960), Chief of
Staff of the Communicable Disease Unit of Los Angeles County Hospital. This
unit cared for a large number of patients suffering from acute poliomyelitis.
Between 1946 and 1949, devices produced by Mr. Bennett and his company (then
called V. Ray Bennett and Associates) were used to aid in the treatment of
polio patients. During polio epidemics in 1948-1949, positive pressure
ventilation administered with Mr. Bennett’s equipment saved the lives of a
significant number of patients for whom the negative pressure ventilators (i.
e. iron lungs) alone were insufficient.

In 1956, V. Ray Bennett and Associates was acquired by Puritan, a maker of
medical gases and respiratory therapy equipment.

Note Type: Publication
Notes: DeForest RE. Council on physical medicine and rehabilitation: Apparatus
accepted: Bennett pressure breathing therapy unit, Model TC-2P. JAMA.
1954:154(12):1003.

Note Type: Publication
Notes: Dillon JB. The beginning of mechanical intermittent positive pressure
ventilation. Anesth Hist Assoc Newsl. 1990;8(3):1, 9. https://ahahq.
org/Bulletin/AHA_GB_1990-07.pdf. Accessed October 22, 2015.

Note Type: Citation
Notes: Mushin WW, Rendell-Baker L, Thompson PW, Mapleson WW. The Bennett model BA-4
‘anesthesia ventilator’. Automatic Ventilation of the Lungs. 2nd ed. Oxford:
Blackwell Scientific Publications; 1969:327-341.

Note Type: Exhibition
Notes: Selected for the WLM website (noted October 21, 2015).