September 2001
Volume 65 |
Number 9
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| A Focus on History |
James C. Erickson III,
M.D.
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What is this?
1. A filter system
2. A Waters canister
3. A to-and-fro system
4. All of the above.
The Wood Library-Museum of Anesthesiology has an extensive
collection of medical artifacts, which includes this device
dating from the 1920s. (Answer
to “What is this?” )
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WLM Collection |
Inhalation anesthesia of the early 1920s consisted of either
breathing anesthetic gases and vapors via a mask and bag, or by
open-drop of volatile liquids (diethyl ether or chloroform) on
a gauze mask. There were no intravenous agents to speed induction.
One-hundred percent nitrous oxide was administered for gas induction
and attainment of maximum anesthesia. Induction was usually accomplished
within two to three minutes and was followed by addition of 10
percent to 15 percent oxygen, or more, to avoid cyanosis. “Too
much oxygen” was shunned to avoid diluting the nitrous oxide.
If deeper anesthesia or relaxation was needed, diethyl ether,
chloroform or ethyl chloride were added. High flows of the gases
were maintained to avoid accumulation of carbon dioxide and the
consequent “pushing” respiration that hindered abdominal
surgery.1
Ralph M. Waters, M.D., applied the strategy of carbon dioxide
absorption to his practice of anesthesia while in Sioux City,
Iowa, from 1920 to 1921. 2 He familiarized himself
with an experiment described by Dennis E. Jackson, M.D., in 1915.
3 Jackson kept two dogs anesthetized in a closed
cabinet for 24 hours. It was initially filled with a given volume
of nitrous oxide, with oxygen added in amounts sufficient to meet
the metabolic needs of the animals. There was also a pump devised
to recirculate the exhaled gases through an alkali in order to
absorb carbon dioxide. The dogs emerged unharmed from this experiment.
Dr. Waters adapted this technique by introducing a canister filled
with “granular sodium and calcium hydrate” between the
mask and a five-liter rebreathing bag. The canister was added
to the system after the induction. It was quickly inserted during
an exhalation phase of respiration; some anesthetists of the era
complained that this maneuver was too complex and were reluctant
to accept it. Once induction was accomplished, very little additional
anesthetic was added. Dr. Waters then decreased the gas flows
and maintained an oxygen inflow sufficient to satisfy the patient’s
metabolic needs. The gases flowed “to and fro” from
patient to the bag and returned to the patient, passing through
the absorbent “filter system” twice per respiratory
cycle. Dr. Waters determined that the best measurements for the
cylindrical canisters were 9.0 cm in diameter and 13 cm long,
containing 500 grams of absorbent.
It was common practice in that era for patients to receive generous
doses of morphine as preanesthetic sedation, with more opiate
often added just prior to induction. This strategy enhanced the
ease of induction and the attainment of deeper anesthesia. Rectal
tribromethanol was often added for this purpose. Intravenous barbiturates
were not yet in use until a decade later.
With the induction complete, the canister is quickly inserted
into the system during the expiratory phase of respiration.6
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In his first article about the to-and-fro system, Dr. Waters
summarized its benefits as follows:
1. Marked improvement of economy for gases and vapors. “There
is no waste of drugs into the operating room.”
2. Greater convenience in administration of inhalation anesthesia
because of the use of smaller containers of gases and drugs.
The reduced weight and bulk of apparatus enhanced his practice
by virtue of easing the transportation of his equipment into
homes and offices.
3. The odors of the anesthetics are kept away from the operating
teams, and potential explosion hazards are reduced.
4. Conservation of heat and moisture contributed to the benefits
of the canister system and the improved state of his patients.
2
He also emphasized its limitations and recommended these cautions
for the closed system:
1. An airtight connection of the mask on the patient’s face
and between all components of the system is imperative. Surgery
in mouth and nose is precluded.
2. The constant addition of oxygen to satisfy the patient’s
needs is necessary.
3. The absorbent must be replenished after prolonged use. Dr.
Waters changed the filters after five hours of use, although others
found that they lasted about 10 hours.
4. The filter can be sterilized in an autoclave. 2
Philip D. Woodbridge added his recommendation that the fine alkali
dust should be forcibly blown from the canister to avoid irritation
of the patient’s lungs. 5
When Dr. Waters began his work with this system, fresh gases
were fed into the tail of the rebreathing bag. His experience
soon suggested the advantage of placing the inflow of fresh gases
and vapors into the mask or the adjacent canister to speed the
change of concentrations of fresh gases more efficiently.
Dr. Waters’ innovations and his emphasis on carbon dioxide
physiology and absorption and the rebreathing technique paved
the way for the development of effective circle systems and for
the introduction of cyclopropane several years later. The Waters
canister was made by the Foregger Company and was still in commercial
production during the 1960s.
References:
1. Gatch WD. The use of rebreathing in the administration
of anesthetics. In: Gwathmey JT, ed. Anesthesia. New York: Appleton
and Company; 1914:100-116.
2. Waters RM. Clinical scope and utility of carbon
dioxid filtration in inhalation anesthesia. Anesth Analg. 1924;
3(1):20-26.
3. Jackson DE. A new method for the production
of general analgesia and anaesthesia with a description of the
apparatus used. J Lab & Clin Med. 1915; 1:1-12.
4. Waters RM. Advantages and technique of carbon
dioxid filtration with inhalation anesthesia. Anesth Analg. 1926;
5(3):160-162.
5. Woodbridge PD. Better gas anesthesia at less
cost: The carbon dioxid absorption method. Anesth Analg. 1933;
12(4):161-173.
6. Waters RM. Carbon dioxid absorption from anesthetic
mixtures. Anesth Analg. 1932; 11(3):97-110.
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James
C. Erickson III, M.D., is Professor Emeritus of Anesthesiology
and Pain Medicine at Northwestern University Medical School,
Chicago, Illinois. Dr. Erickson is also a volunteer at the
Wood Library-Museum of Anesthesiology at the ASA headquarters
in Park Ridge, Illinois. |
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