David M Gaba
health care
Anaesthesiology as a model for patient safety in
Updated information and services can be found at:
These include:
14 online articles that cite this article can be accessed at:
This article cites 24 articles, 5 of which can be accessed free at:
Rapid responses
You can respond to this article at:
3 rapid responses have been posted to this article, which you can access for free
Email alerting
the top left of the article
Receive free email alerts when new articles cite this article - sign up in the box at
Topic collections
(589 articles)
Quality improvement (including CQI and TQM)
(172 articles)
Other Anaesthesia
Articles on similar topics can be found in the following collections
To order reprints follow the "Request Permissions" link in the navigation box
go to:
To subscribe to
on 16 January 2008
Downloaded from

Kanki B, Helmreich R, eds. Cockpit resource management. San Diego: Aca-
demic Press, 1993:3-45.
Amalberti R. La conduite de systèmes à risques. Paris: Presses Universitaires
de France, 1996.
Helmreich RL, Merritt AC. Culture at work: national, organisational and
professional influences. Aldershot: Ashgate, 1998.
Helmreich RL, Merritt AC, Wilhelm JA. The evolution of crew resource
management in commercial aviation. Int J Aviation Psychol 1999;9:19-32.
Federal Aviation Administration. Aviation safety action programs. Washing-
ton, DC: FAA,1999. (Advisory circular 120-66A.)
Helmreich RL, Klinect JR, Wilhelm JA. Models of threat, error, and CRM
in flight operations. In: Proceedings of the tenth international symposium on
aviation psychology. Columbus: Ohio State University, 1999:677-82.
Klinect JR, Wilhelm JA, Helmreich RL. Threat and error management: data
from line operations safety audits. In: Proceedings of the tenth international
symposium on aviation psychology. Columbus: Ohio State University,
Helmreich RL. Culture and error. In: Safety in aviation: the management
commitment: proceedings of a conference. London: Royal Aeronautical
Society (in press).
Helmreich, RL, Wilhelm JA. Outcomes of crew resource management
training. Int J Aviation Psychol 1991:1:287-300.
10 Reason J. Managing the risks of organisational accidents. Aldershot:
11 Helmreich RL, Schaefer H-G. Team performance in the operating room. In:
Bogner MS, ed. Human error in medicine. Hillside, NJ: Erlbaum, 1994:
12 Helmreich RL, Davies JM. Human factors in the operating room: Interpersonal
determinants of safety, efficiency and morale. In: Aitkenhead AA, ed. Baillière’s
clinical anaesthesiology: safety and risk management in anaesthesia.
London: Ballière Tindall, 1996:277-96.
13 Sexton JB, Thomas EJ, Helmreich RL. Error, stress, and teamwork
in medicine and aviation: cross sectional surveys. BMJ 2000;320:
Anaesthesiology as a model for patient safety in health care
David M Gaba
Although anaesthesiologists make up only about 5% of
physicians in the United States, anaesthesiology is
acknowledged as the leading medical specialty in
addressing issues of patient safety.1 Why is this so?
Firstly, as anaesthesia care became more complex
and technological and expanded to include intensive
care it attracted a higher calibre of staff. Clinicians
working in anaesthesiology tend to be risk averse and
interested in patient safety because anaesthesia can be
dangerous but has no therapeutic benefit of its own.
Anaesthesiology also attracted individuals with back-
grounds in engineering to work either as clinicians or
biomedical engineers involved in operating room
activities. They and others found models for safety in
anaesthesia in other hazardous technological pursuits,
including aviation.2 3
Secondly, in the 1970s and ’80s the cost of
malpractice insurance for anaesthesiologists in the
United States soared and was at risk of becoming un-
available. The malpractice crisis galvanised the profes-
sion at all levels, including grass roots clinicians, to
address seriously issues of patient safety. Thirdly, and
perhaps most crucially, strong leaders emerged who
were willing to admit that patient safety was imperfect
and that, like any other medical problem, patient safety
could be studied and interventions planned to achieve
better outcomes.
Accomplishments in patient safety in
Anaesthesia: safer than ever
It is widely believed that anaesthesia is much safer
today (at least for healthy patients) than it was 25 or 50
years ago, although the extent of and reasons for the
improvement are still open to debate. Traditional
epidemiological studies of the incidence of adverse
events related to anaesthesia have been conducted
periodically from the 1950s onwards.4–6 Many of these
studies were limited in scope, had methodological con-
straints, and cannot be compared with each other
because of differing techniques. An important out-
come has been the emergence of non-traditional
investigative techniques that aim not to find the true
incidence of adverse events but to highlight underlying
characteristics of mishaps and to suggest improve-
ments in patient care.
Such techniques have included the “critical incident”
technique adapted by Cooper from aviation2 7; the
analysis of closed malpractice claims8; and the Australian
incident monitoring study (AIMS).9–12 These approaches
analyse only a small proportion of the events that occur
but attempt to glean the maximum amount of useful
information from the data.
Technological solutions
Once the range of patient safety problems in anaesthe-
siology had been defined, several strategies have been
used to improve safety. One is to apply technological
solutions to clinical problems. Anaesthesiologists have
become expert at realtime monitoring of patients
(both electronically and via physical examination). In
the industrialised world electrocardiography, pulse
oximetry, and capnography (analysis of carbon dioxide
in exhaled gas) have become standards and are
thought to have contributed substantially to safety. No
study to date, however, has had sufficient power to
prove an outcome benefit from the use of these
Summary points
Anaesthesiology is acknowledged as the leading
medical specialty in addressing patient safety
Anaesthesia is safer than ever owing to many
different types of solutions to safety problems
Solution strategies have included incorporating
new technologies, standards, and guidelines, and
addressing problems relating to human factors
and systems issues
The multidisciplinary Anesthesia Safety
Foundation was a key vehicle for promoting
patient safety
A crucial step was institutionalising patient safety
as a topic of professional concern
Although anaesthesiology has made important
strides in improving patient safety, there is still a
long way to go
Education and debate
Patient Safety
Center of Inquiry,
112PSCI, VA Palo
Alto Health Care
System, 3801
Miranda Avenue,
Palo Alto, CA
94304, USA
David M Gaba
[email protected]
BMJ 2000;320:785–8
BMJ VOLUME 320 18 MARCH 2000
on 16 January 2008
Downloaded from

Another technological strategy is the
use of “engineered safety devices” that physically
prevent errors from being made. There are many of
these in anaesthesiology, but a classic example is the
system of gas connectors that prevent a gas hose or
cylinder from being installed at the wrong site.14
New technologies have also been developed for
managing the patient’s airway, resulting in a plethora of
useful devices. In particular, the adoption of fibreoptic
laryngoscopy has revolutionised the management of
patients with known anatomical difficulties in endotra-
cheal intubation, and the laryngeal mask airway has
secured important niches in both routine and
emergency airway management.
Standards and guidelines
A second strategy adopted by anaesthesiologists in the
United States in the 1980s was the promulgation of
“practice parameters” (standards and guidelines)
developed to provide guidance or direction for the
diagnosis, management, and treatment of specific clini-
cal problems.15
The first set of standards for basic
monitoring was developed by the Harvard hospitals,16
and similar ones were later adopted by the American
Society of Anaesthesiologists. These standards
included such basic requirements as the continuous
presence of a qualified anaesthetist, the use of electro-
cardiographic monitoring, and assessment of ventila-
tion. The standards have since been updated to require
pulse oximetry for patients during anaesthesia of all
types and during post-anaesthesia recovery, as well as
the use of capnography during general anaesthesia.
The monitoring standards, though voluntary, are
thought to have been effective in ensuring that these
basic practices are followed and represent a de facto
standard of care. They have also been matched by
similar standards in other countries. Other standards
from the society with important implications for
patient safety have dealt with the management of the
difficult airway, sedation and analgesia by non-
anaesthesiologists, and office based anaesthesia.
Human factors and the systems approach to patient
Anaesthesiologists have also been leaders in applying
techniques and lessons from human factors engineer-
ing and the systems approach to safety. Analysis of
anaesthesiologists’ tasks dates back nearly 30 years17
and has grown in sophistication.18 Investigators have
analysed the decision making processes in anaesthesi-
ology with various methods, including direct observa-
tion,19 review of videotapes of real cases,20 assessing the
descriptions of cases presented at morbidity and mor-
tality meetings, and the use of patient simulators.21
Much of the work has been conducted by academic
anaesthesiologists who adopted the techniques of the
human factors field. This “inside out” approach—in
which the practitioners are also the researchers—has
been powerful both for generating knowledge and for
generating a cadre of safety experts. These “insiders”
have also succeeded in generating interest among a
number of well known “outside” human factors
researchers—most of whom develop close links with
anaesthesiologist collaborators.
Anaesthesiologists have been leaders in looking at
safety from the standpoint of systems as well as
individuals. In 1987 the work of Charles Perrow on sys-
tems issues in accidents was applied to anaesthesiol-
ogy,3 22 and, soon after, the work of James Reason on
the latent error model systems accidents was incorpo-
rated.23 24 In 1990 the Anaesthesia Patient Safety Foun-
dation and the US Food and Drug Administration
sponsored a groundbreaking expert workshop on
human error in anaesthesiology. This brought together
experts in human performance, human error, and
organisational safety and experts on error and safety in
anaesthesiology. Currently, anaesthesiologists are also
involved in considering the theory of high reliability
organisations (see article by Reason, p 768) as a model
for performing highly hazardous activities with very
low failure rates.
Applications of patient simulation
Anaesthesiologists have been pioneers in developing
and applying patient simulators for research and train-
ing (see box and figure). Helmreich’s article (p 781)
deals with some of the simulation based, teamwork
oriented training in more detail.
Simulation for research and training
Anaesthesiologists pioneered the development of computer screen and
mannequin based interactive patient simulators and also have created most
of the training plans for their use.25–33 Use of patient simulators has become
widespread in anaesthesiology and has expanded into other areas.
Advantages of simulation for research, training, and performance
No risk to patients
Many scenarios can be presented, including uncommon but critical
situations in which a rapid response is needed
Participants can see the results of their decisions and actions; errors can
be allowed to occur and reach their conclusion (in real life a more capable
clinician would have to intervene)
Identical scenarios can be presented to different clinicians or teams
The underlying causes of the situation are known
With mannequin based simulators clinicians can use actual medical
equipment, exposing limitations in the human-machine interface
With full re-creations of actual clinical environments complete
interpersonal interactions with other clinical staff can be explored and
training on teamwork, leadership, and communication provided
Intensive and intrusive recording of the simulation session is feasible,
including audiotaping, videotaping, and even physiological monitoring of
participants (such as electrocardiography or electroencephalography); there
are no issues of patient confidentiality—the recordings can be preserved for
research, performance assessment, or accreditation
Applications and target groups
Education of students (high school and professional school in physiology,
pharmacology, or physical assessment)
Training for allied health professions
Training of clinical students in routine procedures and specialty specific
medical issues
Training of junior doctors (residents) in routine procedures and in critical
Training of healthcare staff in crisis management
Preprocurement assessment of clinical equipment
Staff training in the use of clinical equipment
Performance assessment of all grades of medical staff
Research on decision making by clinicians, on human-machine
interactions, and on factors that affect performance (such as fatigue)
Education and debate
BMJ VOLUME 320 18 MARCH 2000
on 16 January 2008
Downloaded from

Patient safety in anaesthesiology—a glass
only half full
Anaesthesiologists are justly proud of how their
profession has acknowledged and begun to tackle
tough issues in patient safety. The glass of patient safety
in anaesthesiology, however, although fuller than in
other healthcare fields, is still only half full:
x The overall reduction in negative outcomes that are
related to anaesthesia may not be as great as the
purported drop in mortality resulting from anaesthe-
sia alone for healthy patients having routine surgery.
Errors, mistakes, and system failures continue to
plague anaesthesiology as well as the other healthcare
x Death or brain damage still occurs from hypoxae-
mia after oesophageal intubation or from other easily
detectable and correctable events, even when modern
monitoring technologies are in place
x The most basic standards are not followed
uniformly—reliable anecdotes persist of anaesthetised,
paralysed, and ventilated patients being left without an
anaesthetist in the room, even in reputable hospitals
x Advanced simulation training is available only to a
tiny minority of anaesthetists, and no certification
requirement exists for continuing skills training or per-
formance assessment
x Clinicians still practise when fatigue, illness, or stress
prevent them from performing optimally
x Even modern equipment remains beset by human
error; knowledge levels and training of clinicians about
equipment remain suboptimal.
x It is therefore important to recognise that the various
safety advances that have been made in anaesthesiology
are an important model for the rest of health care, but
they remain a work in progress and will require long
term commitment to achieve their full promise.
Institutionalisation of safety
In the long term the most important contribution of
anaesthesiology to patient safety may be the institu-
tionalisation and legitimisation of patient safety as a
topic of professional concern. The formation in 1985
of the Anesthesia Patient Safety Foundation was a
landmark. Unlike other professional trade organisa-
tions, such as the American Society of Anesthesiolo-
gists, the foundation can bring together many
constituencies in health care that may well disagree
over economic or political issues but which all agree on
the goal of patient safety.
The foundation has several prominent activities. Its
quarterly newsletter is mailed to every anaesthesiolo-
gist and nurse anaesthetist in the United States. The
newsletter is currently the pre-eminent publication in
the world on anaesthesia and patient safety and is
thought to have the widest circulation of any
publication in anaesthesiology. The foundation also
runs a programme of research grants, which has
funded many important projects that would probably
never have been funded by a “traditional” agency. In
the first 13 years of the programme, for an investment
of about $1.5m (£937 500), 159 publications resulted
directly or indirectly from such funding. Among the
important topics of investigation have been patient
simulation, human factors or human performance,
outcome assessment, and the formation of carbon
monoxide in the anaesthesia breathing circuit.
Yet the most influential outcome of the grants pro-
gramme may be not the knowledge gained but the new
cadre of investigators and scholars it has fostered by
creating a source of funds and an intellectual home for
individuals devoting their careers to patient safety. A
similar story can be told for the Australian Patient
Safety Foundation, whose relative influence has far
exceeded the size of the Australian population.
Recently, the American foundation has taken a stand
on several policy issues based on the principle of estab-
lishing a burden of proof regarding practices or policies
that seem to deviate from existing norms. The
foundation believes that in all cases the default policy
should be the one that at face value seems to yield maxi-
mum patient safety (a “fail safe” approach). If clear and
convincing data are presented showing that an
alternative policy is equally safe, it can be adopted. In the
absence of such data the apparently safer policy should
prevail. The foundation has recently advocated, for
example, that a single standard of safety for surgical and
anaesthetic procedures should exist, whether these take
place in a hospital, an outpatients unit, or a physician’s
office. The default assumption is that achieving this uni-
fied standard will require functionally equivalent organi-
sational features including equipment, staff, emergency
backup, and accreditation in each of the practice
settings. The burden of proof to provide convincing data
to overturn this assumption rests with those who believe
that the physician’s office can be a safe site for anaesthe-
sia and surgery without these features.
It is no wonder that when the American Medical
Association decided to create a National Patient Safety
Foundation it did so in open imitation of the methods
and success of the Anesthesia Patient Safety Founda-
If the national foundation and other similar
organisations throughout the world can replicate the
cadre forming aspects of the anaesthetists’ foundation
(as well as its roles in education and research), patient
safety in all areas of health care will probably make
great leaps forward. None the less, this will only be
achieved with hard work—the price of patient safety is
eternal vigilance.
Simulation room of the simulation centre at VA Palo Alto Health Care System, California, with
arthroscopic knee surgery in progress. The computerised patient mannequin and associated
equipment provides clinical cues and electronic data to patient monitoring devices. The
simulator is controlled from an adjoining control room
Education and debate
BMJ VOLUME 320 18 MARCH 2000
on 16 January 2008
Downloaded from

The author is also professor of anaesthesia at Stanford
University School of Medicine, Stanford, California.
Competing interests: The author is the secretary of the
Anesthesia Patient Safety Foundation. He also licensed simulation
technology to CAE-Link in 1992, for which he received a licence
and royalties on the sale of patient simulators. He is also, periodi-
cally, a paid consultant to MedSim, the company that now owns
the rights to the licensed simulation technology.
Leape L. Error in medicine. JAMA 1994;272:1851-7.
Cooper J, Newbower R, Long C, McPeek B. Preventable anesthesia
mishaps: a study of human factors. Anesthesiology 1978;49:399-406.
Gaba D, Maxwell M, DeAnda A. Anesthetic mishaps: breaking the chain
of accident evolution. Anesthesiology 1987;66:670-6.
Lunn J. Epidemiology in anaesthesia. London: Edward Arnold, 1986.
Derrington M, Smith G. A review of studies of anaesthetic risk, morbidity,
and mortality. Br J Anaesth 1987;59:815-33.
Warden JC, Borton CL, Horan BF. Mortality associated with anaesthesia
in New South Wales, 1984-1990. Med J Aust 1994;161:585-93.
Cooper JB, Newbower R, Kitz R. An analysis of major errors and equip-
ment failures in anesthesia management: considerations for prevention
and detection. Anesthesiology 1984;60:34-42.
Cheney FW. The American Society of Anesthesiologists closed claims
project: what have we learned, how has it affected practice, and how will it
affect practice in the future? Anesthesiology 1999;91:552-6.
Runciman WB, Sellen A, Webb RK, Williamson JA, Currie M, Morgan C,
et al. The Australian incident monitoring study. Errors, incidents and
accidents in anaesthetic practice. Anaesth Intensive Care 1993;21:506-19.
10 Webb RK, Currie M, Morgan CA, Williamson JA, Mackay P, Russell WJ, et
al. The Australian incident monitoring study: an analysis of 2000 incident
reports. Anaesth Intensive Care 1993;21:520-8.
11 Bhasale AL, Miller GC, Reid SE, Britt HC. Analysing potential harm in
Australian general practice: an incident-monitoring study. Med J Aust
12 Beckmann U, West LF, Groombridge GJ, Baldwin I, Hart GK, Clayton
DG, et al. The Australian incident monitoring study in intensive care:
AIMS-ICU. The development and evaluation of an incident reporting
system in intensive care. Anaesth Intensive Care 1996;24:314-9.
13 Orkin FK, Cohen MM, Duncan PG. The quest for meaningful outcomes
[editorial]. Anesthesiology 1993;78:417-22.
14 Petty C. The anesthesia machine. New York: Churchill Livingstone, 1987.
15 Arens J. Practice parameters: some new, others under development or
revision. ASA Newsletter 1999;63:26-8.
16 Eichhorn JH, Cooper JB, Cullen DJ, Maier WR, Philip JH, Seeman RG.
Standards for patient monitoring during anesthesia at Harvard Medical
School. JAMA 1986;256:1017-20.
17 Drui A, Behm R, Martin W. Predesign investigation of the anesthesia
operational environment. Anesth Analg 1973;52:584-91.
18 Weinger M, Herndon B, Gaba D. The effect of electronic record keeping
and transesophageal echocardiography on task distribution, workload,
and vigilance during cardiac anesthesia. Anesthesiology 1997;87:144-55.
19 Xiao Y, Milgram P, Doyle D. Incident evolution and task demands: an
analysis and a field study of “going sour” incidents [abstract]. Proceedings
of the Human Factors Society’s 36th Annual Meeting 1992:1279-83.
20 Mackenzie CF, Craig GR, Parr MJ, Horst R. Video analysis of two emer-
gency tracheal intubations identifies flawed decision-making. Anesthesiol-
ogy 1994;81:763-71.
21 DeAnda A, Gaba D. The role of experience in the response to simulated
critical incidents. Anesth Analg 1991;72:308-15.
22 Galletly D, Mushet N. Anaesthesia system errors. Anaesth Intensive Care
23 Gaba D. Human performance issues in anesthesia patient safety. Problems
in Anesthesia 1991;5:329-50.
24 Eagle C, Davies J. Accident analysis of large-scale technological disasters
applied to an anaesthetic complication. Can J Anaesth 1992;39:118-22.
25 Schwid HA. A flight simulator for general anesthesia training. Comput
Biomed Res 1987;20(1):64-75.
26 Gaba D, DeAnda A. A comprehensive anesthesia simulation environ-
ment: re-creating the operating room for research and training. Anesthesi-
ology 1988;69:387-94.
27 Good ML, Gravenstein JS. Anesthesia simulators and training devices. Int
Anesthesiol Clin 1989;27:161-8.
28 Gaba D. The human work environment and anesthesia simulators. In:
Miller R, ed. Anesthesia. 5th ed. New York: Churchill Livingstone, 1999.
29 Marsch S. Team oriented medical simulation. In: Henson L, Lee A, eds.
Simulators in anesthesiology education. New York: Plenum Press, 1998.
30 Raemer D, Maviglia S, van Horne C, Stone P. Mock codes: using realistic
simulation to teach team resuscitation management. 1998 Meeting of the
Society for Technology in Anesthesia. Tucson, AZ
31 Kurrek M, Devitt J, Ichinose F, Bhatnagar G. Simulator team training: a
concept beyond anesthesia. 1998 Meeting of the Society for Technology
in Anesthesia. Tucson, AZ.
32 Raemer D, Barron D, Blum R, Frenna T, Sica G. Teaching crisis manage-
ment in radiology using realistic simulation. 1998 Meeting of the Society
for Technology in Anesthesia. Tucson, AZ.
33 Small SD, Wuerz RC, Simon R, Shapiro N, Conn A, Setnik G. Demonstra-
tion of high-fidelity simulation team training for emergency medicine.
Acad Emerg Med 1999;6:312-23.
34 National Patient Safety Foundation. Prospectus of the NPSF: importance
of leadership. Chicago, IL: NPSF, 1997. (
npsf/leader.htm; accessed 10 March 2000.)
Using information technology to reduce rates of
medication errors in hospitals
David W Bates
Data continue to show that medication errors are
frequent and that adverse drug events, or injuries due
to drugs, occur more often than necessary.1–4 In fact, the
frequency and consequences of iatrogenic injuries
seems to dwarf the frequency of other types of injuries
that have received more public attention, such as aero-
plane and automobile crashes.2 A recent meta-analysis
reported an overall incidence of 6.7% for serious
adverse drug reactions (a term that excludes events
associated with errors) in hospitals.4 Between 28% and
56% of adverse drug events are preventable.3 5–7
Though the reasons this issue has received so little
attention are complex, the reasons that medical injuries
occur with some frequency are perhaps less so; medicine
is more or less a cottage industry, with little standardisa-
tion and relatively few safeguards in comparison to, say,
manufacturing. In fact, most of the systems in place in
medicine were never formally designed, and this holds
for the entire process of giving drugs.
Take, for example, the allergy detection process used
in our hospital several years ago, which was similar to
that used in most hospitals at the time. Physicians, medi-
cal students, and nurses all asked patients what their
Summary points
Although information technologies are widely
used in hospitals, relatively few data are available
regarding their impact on the safety of the
process of giving drugs
Exceptions are computerised physician order
entry and computerised physician decision
support, which have been found to improve drug
Other innovations, including using robots to fill
prescriptions, bar coding, automated dispensing
devices, and computerisation of the medication
administration record, though less studied, should
all eventually reduce error rates
The medication system of the future will include
these and other technologies, all electronically
Education and debate
Division of General
Medicine and
Primary Care,
Brigham and
Women’s Hospital,
75 Francis Street,
Boston, MA 02115,
David W Bates
BMJ 2000;320:788–91
BMJ VOLUME 320 18 MARCH 2000
on 16 January 2008
Downloaded from