ANESTHESIA MACHINES AND WORKSTATIONS
Anesthesia machines have evolved from simple, pneumatic devices
to complex, computer-based, fully integrated
* Portions of this chapter
have appeared with permission in Andrews JJ, Brockwell RC: Delivery systems for
inhaled anesthetics. In Barash PG, Cullen BF, Stoelting
RK (eds): Clinical Anesthesia, 4th ed. New York, Lippincott-Raven, 2000, pp 567–594.
Figure 9-1
Datex-Ohmeda S/5 Anesthesia Delivery Unit (ADU) workstation.
anesthesia workstations ( Fig. 9-1
and Fig. 9-2
). Centralized
display integration and functional integration are the hallmarks differentiating
simple anesthesia machines from current, sophisticated anesthesia workstations.
A few years ago, a rudimentary background in pneumatics sufficed, but today, an understanding
of pneumatics, electronics, and even computer science is useful. Even though it
is becoming increasingly more difficult for the anesthesiologist to achieve a thorough
understanding of a modern anesthesia workstation, understanding the equipment remains
essential to the safe practice of anesthesiology. The anesthesiologist must be aware
of unique design differences between manufacturers so that appropriate preoperative
checks can be performed.
Figure 9-2
Dräger Narkomed 6000 anesthesia workstation.
Standards for Anesthesia Machines and Workstations
Standards for anesthesia machines and workstations provide guidelines
to manufacturers regarding their minimum performance, design characteristics, and
safety requirements. During the past 2 decades, the progression of anesthesia machine
standards has been as follows:
- • 1979: American National Standards Institute (ANSI) Z79.8-1979[4]
- • 1988: American Society for Testing and Materials (ASTM) F1161-88[5]
- • 1994: ASTM F1161-94[6]
(reapproved in
1994 and discontinued in 2000)
- • 2000: ASTM F1850-00[7]
To comply with the new 2000 ASTM F1850-00 standard, newly manufactured workstations
must have monitors that measure the following parameters: continuous breathing system
pressure, exhaled tidal volume, ventilatory carbon dioxide concentration, anesthetic
vapor concentration, inspired oxygen concentration, oxygen supply pressure, arterial
hemoglobin oxygen saturation, arterial blood pressure, and continuous electrocardiogram.
The anesthesia workstation must have a prioritized alarm system that groups the
alarms into three categories: high, medium, and low priority. These monitors and
alarms may be automatically enabled and made to function by turning on the anesthesia
workstation, or the monitors and alarms can be manually enabled and made functional
by following a checklist before use.[7]
